Ammonium Toxicity~~11/1997 AVM

Ammonium Toxicity in African Violets
November/December 1997 African Violet Magazine, pgs 26-27
By Kent and Joyce Stork, Fremont, NE

     For some time we have received questions from individuals who have grown African violets successfully for years who now find that their plants will no longer grow as large as they once did. The plants described exhibited a number of symptoms related to foliage, but those symptoms were not consistent with the usual problems associated with violets. We consulted several sources who suggested the possibility of ammonium toxicity... a condition linked to the use of urea or ammonium based fertilizers.
     At this time, we can find no studies of ammonium toxicity specifically targeting African violets. The condition has been studied in florists’ gloxinias, and we thank Dr. Paul Nelson of North Carolina State University for sharing the results of his studies. He believes that ammonium toxicity does affect African violets. The symptoms he described closely resemble the problems violet growers brought to us.
     In florists' gloxinias, the ammonium toxicity causes lower leaves to curl downward stiffly (not limply). The lower leaves will exhibit irregular and highly unpredictable patterns of chlorosis (lighter green patches). The leaf margins of the most mature leaves will be burned, and as the toxicity becomes more pronounced the leaf burning shows up on younger and younger leaves until it affects the crown itself. The plant may die completely. The root structure will be reduced in size and will have an orange- brown tone that is distinctly different from normal root color.
     Dr. Nelson stated that other plants which have been studied show similar patterns, although some plant types react by leaf curl that goes upward rather than down. The lighter patches of color on the leaves are consistently unpredictable on all plants studied.
     Ammonium toxicity can have a phantom-like quality. The grower may not note any changes in growing methods or conditions when plants develop symptoms. Similarly, symptoms can disappear temporarily before returning. This can lead a grower to believe that a fungus, an unseen insect, or a virus has invaded. It can also cause a grower to believe that something caused an improvement, when in fact it had no effect at all.
     The extent of the reaction can vary in different hybrid strains of one plant type. Since many African violet growers have several hybrids in their collection, it would be
expected that the pattern of symptoms would vary from plant to plant.
     Several growers who attended the 1997 AVSA convention in Florida reported very similar symptoms. They were completely puzzled until they discovered that their standard fertilizer had changed. The company producing it was bought out by a larger corporation who changed the source of the nitrogen to a much cheaper ammonia form. This change was not advertised or promoted but it had serious consequences for growers.

WHAT CAUSES AMMONIUM TOXICITY?
     Ammonium toxicity is generally linked to the use of urea-based or ammonium fertilizers along with the absence or ineffectiveness of soil bacteria. The active soil bacteria can break ammonia down into a usable nitrate form as long as the soil temperature stays above 70 degrees Fahrenheit and as long as the soil pH is 6.0 or above. When the soil temperatures cool to below 70 degrees or the pH drops into a more acid range, the soil bacteria becomes progressively less active and less able to process ammonia. This results in a build-up of ammonia to toxic levels.
     Growers in areas that experience wide seasonal temperature swings might note the problem during the winter season, but not as much in the summer. Farmers in areas with very acid water conditions (often areas that receive lots of rain yearly) report very serious problems with ammonium toxicity in field crops. Violet growers can almost certainly predict similar problems where water supplies are acid. Similarly, if the soil or potting mix is very acid (peat moss can vary in pH in somewhat unpredictable ways), the ammonium toxicity can become a problem even if the water is neutral.

HOW TO CONTROL AND ELIMINATE AMMONIUM TOXICITY
     If you grow violets in an area with well-regulated room temperatures and do not have an acid water supply, you will probably not have to deal with this problem. There is no reason to panic if you see no symptoms.
     If you must deal with seasonally cool temperatures, be aware of how it may affect your violets. Do not use the lowest shelves in your growing area during the cool months since the coolest air is always closest to the floor.
     You may wish to use less fertilizer since the soil bacteria will be less efficient at processing the ammonia. If possible, warm the room so that soil temperature does not sink below 65 degrees Fahrenheit. Avoid using cold water to water plants or refill reservoirs. (Hot water is also not acceptable.. .do not use water warmer or cooler than ten degrees from the air temperature.)
     If you must deal with persistent acid pH in your soil or water, you would be wise to consider using one of the nitrate-based fertilizer products. Read the ingredients on the label. You will need a brand that lists at least one of its sources of nitrogen using the word 'nitrate'. These will not add the excess ammonia to your soil, and are not so dependent upon soil bacteria.
     If you suspect a problem, try leaching the soil. Pour an amount of water at least equal to the size of the pot into the top of the soil and allow it to run through the plant. It is best to do this when the plant is somewhat moist so that all salts will be dissolved and flushable. Do not allow plants to stand in the runaway water. If you note an orange tone to the water that is running out, you may assume that there is some sort of fertilizer build-up in the soil. Leaching should reduce the toxic build-up and may cause symptoms to go away. It is wise to leach until the runoff water is no longer colored.
     Once recognized, ammonium toxicity should be easy to control and avoid. Best of all, the treatment is inexpensive and safe. There's no reason to panic! 

Vegetative Propagation ~~ 5/1964 GSN

 

Vegetative Propagation
By Frances Batcheller
May - June 1964, Gesneriad Saintpaulia News, pages 16-17

The Gesneriad family has a remarkable capacity for vegetative reproduction. Only two other plant families — Crassulaceae and Begonieae — have similar abilities. This characteristic is a large factor in their popularity, with the home grower who likes to share favorite plants, with the commercial grower who needs rapid multiplication and with the hybridizer who wants to perpetuate sterile hybrids. Gesneriads can be propagated from single leaves, auxilliary shoots, offsets, stolons, or tip cuttings as well as by the normal methods used by the plant for propagation with scaly rhizomes, propagules or tubers. With all these methods to work from, successful propagation can be achieved by any one willing to devote time and effort to the project.

The single leaf method is extensively used with Saintpaulia and Sinningia. The leaf may be rooted in several ways. It will generally root in water. Wax paper or metal foil should be placed over the top of the container and held down with an elastic. Holes are punched to allow the stem to reach the water. The water level must be kept high enough to reach the end of the stem during the rooting process. The main advantage of this method is visibility and being able to check on progress.

It also uses materials readily available to anyone. The main disadvantage is that the roots which develop are apt to be weak and clump together when the leaf is transferred to a pot.

Another method is to use a shallow container filled with a porous rooting medium such as moss, vermiculite or perlite. The stems are inserted in this medium which is kept damp. This method can be used for short-stemmed or stemless leaves. The roots which form are generally much stronger than by the water method and are far easier to transplant. The rooting medium should be kept loose and well aerated.

A third method is to put about two inches of damp vermiculite in the bottom of a plastic bag and insert the stems in this medium. A coat hanger will hold several bags fastened with clip clothespins. This method saves space and requires little attention. If the vermiculite is too damp, there may be some rotting of the leaves. It should be checked carefully for the first week. Leave the top of the bag open if it seems too damp.

A terrarium or large plastic box can also be used to start leaves or cuttings. An aquarium covered with a sheet of plastic can be very useful for this purpose. Some air circulation must be provided. If a large quantity of water condenses on the top and sides of such a container, the rooting medium is too damp and the cover should be left off for a time to enable it to dry out somewhat.

To increase the yield from Sinningia leaves, the stem may be split and usually a tuber will form on each half. Also the leaf may be cut in sections, taking wedge-shaped pieces from the area surrounding the main or large lateral veins. Sometimes these leaf cuttings will form only fibrous roots. After potting up new growth may appear or the mother leaf may gradually die back. In this case, a small tuber is usually found in the soil. After a resting period, this will start in with new growth.

Any large leaf, such as Sinningia, Rechsteieria or Streptocarpus is difficult to root, and results are frequently better if the leaf is reduced in size by a half or more. Generally this is done in a V cut, parallel to the lateral veins. Any cutting should be done on a flat surface with a razor blade, as this bruises the tissue far less than a knife or scissors. With these methods involving cutting, it is a good idea to practice on easily available varieties, rather than trying it for the first time on a particularly choice variety.

Another method that can be used for large flat leaves is the one frequently used for Begonias. This involves making cuts across the large veins on the underside of the leaf. The leaf is then pinned down, right side up, on damp rooting medium. New plantlets will appear around the cut area.

Offsets, or suckers, frequently form around the base of rosette-type Gesneriads, such as Saintpaulia, Petrocosmea and Boea. These may be cut off and rooted in the same manner as individual leaves. Streptocarpus plants have a tendency to progress in a straight line, rather than in a circle, and a plant can be divided by cutting between the plantlets and potting each one up separately. Extra shoots that form on Sinningias or X Gloxineras can also be cut off and rooted, as these plants are generally preferred in a single crown, as is Saintpaulia.

Stolons, long shoots produced from the leaf axils of Episcias, may be cut off and rooted, or rooted while still attached to the mother plant, as the analogous strawberry runner.

Tip cuttings, the terminal end of a stem with several pairs of leaves, are the traditional way to multiply most house plants. They will root easily in either water or rooting medium. Old woody growth is more difficult than younger growth, but very new growth is generally unsatisfactory. Any of the trailing or bushy Gesneriads do well by this method, especially Columneas and Aeschynanthus. Tip cuttings or Kohlerias frequently make better plants than those started from rhizomes.

Scaly rhizomes are a natural method of vegetative propagation for some Gesneriads. These storage roots generally form toward the end of the growing season. They resemble small pine cones, although some rhizomes, such as Kohleria, may grow to considerable length and wind around inside the pot. The rhizomes are harvested when the top of the plant dies back after flowering. This is easier if the soil is allowed to dry out so the rhizomes break quite easily, but pieces or even single scales can generate new plants. In Achimenes especially, one plant grown from a rhizome will produce fifteen to twenty new rhizomes by the end of the summer. The rhizomes should be planted horizontally and covered by not more than an inch of soil.

Scaly rhizomes may also appear in the leaf axils, usually at the end of the growing season or in protest of poor cultural conditions. These are termed propagules and can be separated off and planted. Titanotrichum has a curious whiplike growth covered with small scales which can be rubbed off and planted like seed.

Sinningias, X Gloxineras and Rechsteinerias grow from tubers. These generally do not multiply, only increase in diameter with age, therefore single leaves or shoots are used to multiply these plants. The tubers should be planted just below the surface of the soil and the pot should be shallow but large enough in diameter to allow plenty of growth room.

The ends of cuttings can be dusted with a rooting powder, but this is not particularly necessary as Gesneriads root so easily. However, a fungicide is frequently beneficial in preventing rot. If rotting does occur on a cutting, sometimes it can be saved by cutting out the bad section and dusting the cut with sulphur. Rotting generally indicates too damp conditions and poor air circulation.

Labeling cuttings or leaves is always a problem. Adhesive or marking tape can be used on leaves, but it does not always stay on in a damp atmosphere. The stem can be put through a hole in a slip of paper marked with heavy pencil. With luck this will remain legible until the leaf can be potted up. If plastic bags contain only one item, the slip can be put on the outside. If the material is rooted in a flat, each piece can have a small plastic label, which can be transferred to the pot at the proper time.

The important points to consider in propagation are to keep the material in an atmosphere of adequate humidity to keep the leaves from drying out and to keep the rooting end of the cutting in a damp medium which permits air circulation. Adequate light is necessary to keep the chlorophyll in working order to feed new growth. Strong sunlight and overheating will be damaging, however. The temperature should be kept between 7O~75 degrees if possible. Bottom heat will usually speed rooting, if it can be provided. Trial and error will demonstrate the best results in your particular conditions. Some are more successful with one method than another.

The Joy of Growing African Violets ~~ 1/1999 AVM

 

The Joy of Growing African Violets
By Anne Tinari
January/February 1999 African Violet Magazine, pages 44-45

We must never forget the general public and young people who are being indoctrinated and introduced to the joy of growing African violets.

Thus, I gave the following lecture at the Philadelphia Flower Show this spring using live demonstration to our overwhelming captive audience.

The propagation of African violets is fascinating, simple and easy; even a small child can achieve success. To see a new little plantlet form at the base of a cut leaf is a rewarding task.

Afew easy steps can assure satisfactory results.

Remove a good firm leaf with a clean break from your African violet plant. Never choose the center leaves as they are the heart of the plant, or the lower outer leaves that lack vigor. Instead, a sturdy, firm mature leaf is most suitable.

Cut the petiole, or stem, about 1" to 1 1/2", dip the cut end lightly in a rooting hormone to encourage quick, even growth. Place the cutting in a rooting medium that has been sterilized. We prefer a mixture of half builder's sand and half fine vermiculite, though other mixtures can be used such as perlite, peat moss or sphagnum moss.

Insert the cutting in the prepared rooting medium about 1/2", enough to hold the leaf firmly. Press rooting medium securely around the leaf cutting. Leaves can also be rooted in water, but they produce very fragile, fine roots in comparison to the above methods.

When the tiny leaves are about an inch high at the base of the Mother leaf (in about 2 to 6 weeks) they are ready to be lifted gently into their individual 2" to 2 1/4" pots using prepared African violet soil. Vigorous young plants are formed by the third or fourth month. Don't be too hasty to remove the Mother leaf as it supplies chlorophyll that nourishes the new, tender growth of the young plantlets.

If plants have developed several crowns and are 3" to 5" high they can be gently separated, leaving as much fibrous root as possible on each plantlet and put each separation back into a 2" to 2 1/4" pot.

Do not expect miracles, but concentrate on a good vigorous single crown plant. Even in the greenhouse, with ideal conditions for growth, it takes approximately nine months to a year to produce a flowering plant from a leaf cutting.

Environment affects African violets to a great degree and there are a few basic cultural guidelines one should follow in growing African violets and producing healthy flowering plants. Lighting is very important. Sufficient light is needed but avoid direct burning sunlight. In the winter months south and east windows are most suitable and for the hot summer months north and west.

An alternative way for growing is artificial light, which is very beneficial. Fluorescent lights are best so the light is dispersed and lights should be on 12 to 14 hours a day with eight hours of complete darkness.

Potting and soil are important factors. African violets are very shallow rooted, thus squatty pots are best and growth is in better proportion. This is a semi-tropical plant, thus we find the plastic pots are most suitable as they are warmer and do not collect salts that damage stems. They are inexpensive and easily cleaned.

Soil should be light and airy, allowing fibrous roots to penetrate. It should be pasteurized to destroy most of the harmful bacteria. We find a soil pH of about 6.4, which is slightly acid, to be most suitable.

While watering is also very important, there is a tendency to over water. Plants should always be slightly moist to the touch and receive only the amount of water, preferably warm, they can use at one time.

The size of the pot and the texture of the soil will determine how often plants will need watering. Avoid getting water on the foliage, especially if grown in natural light, as water on the foliage along with bright sunlight can cause spotting of the leaves, especially if there is a ten degree temperature variation.

Feeding also can be a great advantage in keeping plants in good growing condition. As the plant is watered many of the nutrients are leached out of the soil, so by using a diluted plant food this can be replenished. Food such as Peters or the popular well-balanced Optimara violet food can be used at every watering if used in a diluted form - 1/4 tsp to a gallon of warm water. This can help plants to maintain an even growth. Never feed plants when they are excessively dry.

Proper humidity of about 40% promotes floriferous, larger blossoms. Plants prefer a fresh buoyant atmosphere and a moderate even temperature of 70 to 75 degrees for best performance. Provide good ventilation and keep plants from direct drafts and cold window sills when low temperatures are prevalent.

You may wish to initiate a preventative spraying program with a suitable insecticide to keep plants free of pests. We find a spray used once a month can help keep your collection in a healthy growing condition.

With the thousands of beautiful cultivars ranging from colors of pure white, all shades of pink, purple, lavender and burgundy plus the two-tone flowering types, one can choose those they most prefer. Foliage, too, has become most interesting over the past 50 years in which hybridizing has been done by Americans.

Leaves can be plain, serrated, wavy or variegated and even the trailer types are fascinating. Miniatures are very interesting and of course the microminis are preferred by many who do not have space to grow the larger types.

No matter if you grow one, a hundred or a greenhouse full, African violets are known as America's #1 house plant for beauty and performance.

Happy violeting,
ANNE TINARI

Roots ~~ 1966 GSN

(Mrs. John's note: The intent is to represent the author's intent entirely and the original wording remains intact, as published in the magazine.  It is hoped that all will read the article to enjoy and learn, regardless of personal convictions.)

Wondrously Contrived
Lucile C. Rainsberger
May/June 1966 Gesneriad SaintPaulia News, pgs 46 - 48

It has been said that if you will give your attention to producing optimum growing conditions for the root of a plant, the top will take care of itself. This is true for the most part. Certainly we must stake leaves at times in order that they may grow in a symmetrical fashion. They must also be guarded against fungus and insect attacks. The plant must receive enough light to set buds, but not so much that the foliage is damaged. General health of plant, gloss and sheen of leaf, size of blossom to the limit of its potentiality comes through the root system. You may have seen African Violets with wide leaf spread, seemingly in excellent growing condition, which with an accidental pull, lifted off roots that had rotted away. It is sometimes surprising how a very poor root system will sustain a large top. But this cannot go on. Notice these plants. They do give indications of trouble to the discerning eye. One of the first of these is the diminishing of flower bud formation and the fact that when they do bloom, the blossoms are smaller than they should be for the variety. The root system is unseen and therefore easily forgotten, but if we would have first quality plants, whether they be African Violets or trees in the yard, or anything in between, look to the health of the root system.

Functions

The root performs certain important functions, that of anchoring the plant so that the top is supported and that of absorbing water and plant nutrients from the soil. In addition roots usually store a certain amount of food, at least for a short time. Some, such as sugar beets and carrots, have as their special purpose this storage of food. Roots also conduct water and mineral salts absorbed from the soil and foods that may be stored in the roots to the stem and leaves and any other organs of the plant. In turn, food manufactured by the leaves is conducted to the roots, even to the tiniest and furthest root tips so that they may have the materials upon which they depend in order to carry on life processes. The shoot system or leafy part of the plant is completely dependent upon the root and in turn the root system is completely dependent upon the shoot system. If there is anything in growing conditions that affects one, the other is affected, either favorably or adversely. In a normal, healthy plant one balances the other. It is particularly important that the total leaf surface which is exposed to the light which supplies energy for the production of carbohydrates balances the total root system in contact with the soil from which is absorbed water and mineral nutrients. A number of things can affect this balance:
1. Keeping a soil waterlogged so that oxygen is excluded will result in root injury and death.
2. Allowing a potted plant to dry out so that the plant wilts not only results in root injury and death, but prevents absorption of water and soil nutrients which must be in solution for plant use.
3. Roots may be destroyed by careless transplanting methods.
4. Either root or shoot growth may be seriously injured by insect pests or fungus disorders, thus creating an imbalance.

Root Structure and Balance

Because it has been stated that there must be a balance between the root and shoot systems does not necessarily mean that the quantity of roots will equal the quantity of shoots. This usually is not so. Investigation into the root systems of a number of plants has revealed the great quantity of roots in relation to top growth. This is normal for the well grown plant and in this case the two can be said to be in balance. For example, in the case of a sugar beet, the top is not extensive yet the root of a mature plant at the end of its growing season has been found to be five to six feet in length and have a lateral spread of as much as six feet in diameter.
A root is made in a most marvelous way. Its study reveals that only a master mind could contrive it in all its complexity and perfection. If we study a tiny root mounted on a glass slide, the most obvious fact apparent at first glance is that it is entirely divided into a great number of small squares and oblongs, but as these appear to have depth as well as length and width, they are really minute boxes or compartments. We call them cells. Over the extreme tip of the root there is a cap also made of cells. This root cap serves a very important purpose. It protects the growing point of the root as it is pushed through the soil. Without its protection the delicate tip would be injured as it is pushed against the sand and pebbles and other obstacles in its course. Cells for the replacement of the root cap are quickly worn away and are supllied by the root tip. So also are cells for the elongation of the root itself. This adds length to the root but the section of rapid elongation is just back of this growing tip where the cells are rapidly dividing. Here most of the cells are not dividing but are elongating thus pushing the root along into a new area of soil. Back of this region of elongation is the root-hair zone. Here the elongation of cells does not occur or delicate root hairs wrapped around soil particles would be torn loose. The root-hair is a lateral outgrowth of an epidermal cell and projects sideways from the root to a maximum length of about one-half inch. It originates as a slender tube but may be greatly distorted as it searches for moisture by growing between and around soil particles. The walls are very thin so that water and mineral elements in solution, known as solutes, move readily to the interior core. Their extreme delicacy makes it almost impossible to remove a plant from the soil without destroying most of them unless the plant is carefully removed with a good ball of earth. Although the root does have the ability to develop new root tips, the plant will suffer less transplanting shock if the roots are not badly disturbed.
As the root tip grows forward, new root-hairs are produced. Older root-hairs which have absorbed all available moisture collapse and die at about the same rate that new ones are produced. Usually their period of activity is limited to a few days.
And so it goes, a seemingly never-ending process. The growing point of the root does not become appreciably larger in spite of the fact that cell division is constantly taking place. These replace worn-out cap cells or add to the length of the root. A root increases in length only near the tip, but not exactly at the tip. Division of cells becomes rarer and stops altogether finally as the cells become older and larger. Here other changes take place, changes exceedingly complex and of the utmost importance. They are transformed into various types of cells each with a special purpose to perform.
Have you ever noticed that a root does not grow upwards? No matter how careless you may have been in arranging the roots of a newly potted plant, they will soon thereafter be found growing downward. This is partially explained by the influence of gravity, but not entirely. The root can not bend down in all portions of its length but in only one which is just behind the growing tip of the root, the portion we call the section of elongation. In the growing tip there is produced a minute but powerful substance called auxin. It is this which regulates the direction in which the root grows. Remember it is the elongation of cells that pushes the root through the soil. If it is growing directly downward auxin will be deposited equally on all sides of the elongating cell. If not, the auxin will be deposited on one side. Growth will be retarded and the cell will bend downward. The bending is caused by inequality in the elongation of the two sides of the root. After the cells have finished their elongation and become mature, bending can no longer take place. If there is need for bending of the root again, it will have to take place farther along in the section of the root back of the growing tip where young cells are rapidly elongating.

Water and Nourishment

Water moves upward through the root and into the stems and leaves of the plant, not through living cells but through long narrow passages, or tubes, which were once cells, one on top of another. Now, no longer alive, they have only their walls intact. These tubes form part of what is known as the conductive sys.tern of the plant. Water, at times, moves very rapidly from the soil by way of the root system. How rapidly it moves depends largely upon the rate at which water vapor is given off by the leaves. If plants were transparent and the water within colored, we would be astounded at the rapidity of movement we could observe. The large quantities of water moved through the plant body and evaporated from the leaves must be continually replaced if the plant is to live.
Just as water is carried from the root to the shoot system of the plant, food produced in the leaves is carried downward by means of special ducts in the stems and roots to all portions of the root system, even to the most removed growing tip. It is in this way they are nourished so that they are able to carry on their own special work. These ducts are usually found alongside the water carrying tubes.
This then is a root, a complex structure admirably suited to the work it has to do. It has been wondrously contrived. Water passage channels, strengthened by woody fiber, are arranged precisely according to the function they are to perform. In the root they are situated near the center forming a solid tough core like a rope so that it cannot be easily broken. Indeed, the life of the plant depends upon this. In the stem through which the water continues to be carried, the water channels are grouped in bundles near the surface. Every builder knows that to get the most strength in a pillar from a number of rods, he must place them as far from the center as possible. The Master Builder already knew this when the world began and so arranged the stiffening elements in the walls of conductive channels so that they would remain erect. Man who has studied Nature has found many ideas and truths which he has appropriated to work for him. Ideas which we consider modern in the architecture of today have been discovered by man in his study of the work of the all-wise and all-perfect Master Builder who conceived them in the beginning of time.

Temp Humidity Ratio ~~ 3/1958 AVM

TEMPERATURE - HUMIDITY RATIO

Col Bert Rosenbaum, U. S. Army
March 1958 African Violet Magazine, pgs. 46-47

During my eight years experience in growing African violets, I have worried over the many eccentricities of the African violet, such as why the whites, light blues, pinks, and holly leaf type generally need less light than the darker varieties — why do some violets use more water than others — why do the plants have a blooming cycle — why will some plants stand colder weather — why do some varieties stand higher temperatures — why do the leaves of some plants root faster, etc? Although these characteristics are sometimes irritating, they are exactly what make the Saintpaulia a wonderful experimental plant and promises us the possibility of a very superior plant for the future.
Since I feel that each of these conditions should be given at least a chapter in any book, I will endeavor to cover briefly and inadequately only one set of these conditions and how they are related. These conditions are temperature and humidity.

While many of you may have noted this relation of temperature versus humidity, maybe the opportunity to grow these plants in different parts of the world has given me an experimental advantage you have not had. I made my observations in Newfoundland; Dayton, Ohio; Mobile, Alabama, and Morocco, North Africa, my present Station. I shall describe the climatic conditions in each location. I am sure you will note that I have been given a rare opportunity to experiment.

Taking each location in order, I will describe my observations made while growing the plant at each of them.
Newfoundland: The climate had a mean temperature of approximately 240 F — the lowest temperature noted was minus 5' in winter months and highest temperature noted was a rare 840 F during the summer months. Nevertheless, the temperature inside was easy to control. The days were extremely long in the summer and short during the winter. However, growing conditions inside were excellent for the violets and they bloomed the year round with more abundance of blooms in the summer than in the winter. The humidity was high during the months of March, April, May and June, but the temperature stayed low enough to void any effects of the high humidity.

Dayton, Ohio: Dayton is just about our average weather for the United States with hot weather and high humidity during June, July, August and part of September. Here I had to devise means to combat the combination of heat and humidity. I found that a continuous flow of air over the plants kept them in good condition and generally in bloom the entire summer. Until I devised this means for a flow of air over the plants, I had only a few blooms on only a few varieties during the summer.

Mobile, Alabama: Mobile gives the violet grower a challenge unless he or she lives where there is a breeze or can force ventilation across the plants or Air Condition the room in which the violets grow. I touud that the mmonths of June, July, August and September were very hard on the plants because the average humidity was over 85 % day and night during tnese months and the temperature averaged about 90' F. Even at night the temperature rarely fell below 80' F, During these months it was very hard to start leaves and my entire culture of the African violet seemed out of balance. By lowering the temperature to an 85' F during the day and around 70' F at night, I noted a decided improvement. (Note the 15' F temperature change.)

Casablanca, North Africa: Of all places I have grown the plant, I think this is the most ideal. There is never a frost and the maximum temperature only gets into the nineties about eight or ten times a year. The average humidity at night is between 70% and 80% and during the day runs between 25% and 35%. The temperature outside varies about 25 to 30' F between day and night. Inside the temperature varies from 75' to 90' F from night to day or a spread of 15' F. Inside my violets have grown and bloomed proiusely all summer, while outside, (I have a place fixed with fluorescent lights in an open garage) the violets have grown fairly well with only a few blooms on a few plants. However, the growth was slower and the leaves very crisp.

My conclusions are:

1. That we worry about relative humidity when we should worry about moisture content of the air versus temperature.

a. Relative humidity is a ratio of saturated air at a certain temperature to what it actually does hold at the same temperature.

b. Vapor pressure is a true measure of the quantity of water in the air regardless of temperature, and represents the moisture that affect the plants. The ability of a violet to tolerate moisture is in a direct ratio to the temperature.

2. The following are my recommendations for combating humidity versus temperature:

When temperature varies from:

600 — 75 F

700 — 85 F

750 — 90 F

Humidity could vary from:

45 — 85% (Best results around 65%)

40 — 60% (Best results around 55%)

30 — 40% (Best results around 40%)

3. At any temperature above 90'F, air should be circulated through the plants and the humidity kept around 30% if possible; however, I believe a good growth and bloom can be expected with humidity up to 50% for a short period of time. If the humidity goes to 80 or 90%, as it does in Mobile, Alabama, and you cannot get a circulation of air through your plants, you can expect serious losses.
4. A fifteen degree variation of temperature between day and night, according to my experience, is best — provided the humidity can be controlled, and provided the humidity stays within a desirable range. I believe the 15 F temperature variation between day and night is more important than keeping the growing temperature at 65 F at night and 75 F during the day time. I say this because I have never had better success with my plants than I have here where the temperature inside during the day averages 88 F and at night it averages 74 F. Any greater variation will shock most of the varieties; although I noticed that Ohio Bountiful, White Madonna, Sweet Memory, Double One, Periwinkle, and my own variety, Purple Rajah, did very well even though the temperature varied outside about 25 F during the summer. Of course we all know that the African violet does have a tolerance to a variety of conditions and can adjust to a great degree in regards to numerous situations. As example, some people leave their plants sitting in water. (I personally believe this hurts the condition of the foliage even though the plant does bloom), also by carefully increasing a fertilization plan, the plants can utilize a greater amount of fertilizer, etc.
5. I do not recommend circulating a fine mist of water across plants where the temperature is above 90 F and the humidity is above 70%. This is likely to cause fungus growth and cause excessive rotting of the leaves. I would not follow a plan of regularly washing the leaves under these conditions. Instead, gently dust the leaves.

I really have no interesting information to relate regarding the growing of the African violet in Morocco. The "Vita" Nursery in Casablanca has been growing them for about three years, but they are very far behind the United States in its cultivation. I visited them and offered all the assistance I could as they are having extreme difficulty with nematodes and mites, and found them very appreciative. All of their plants are grown from seeds, and I saw no doubles. I naturally remedied that situation.
Let me extend my offer of cuttings from my seventy-five varieties to any member in Africa, provided they pay the postage charges. This is all from Morocco.             end



Food For Growth ~~ 5/1964 GSN

 

Food for ThoughtAboutFood for Growth

Bernard D. GreesonMay/June 1964, Gesneriad Saintpaulia News, pgs. 24-26

Are you confused, when you look at the label on a package of commercial fertilizer or plant food for Saintpaulias or other house plants? Usually, you will see the names of certain plant nutrients such as nitrogen, phosphorus, and potash. Or there will be something about trace elements. And as a rule nutrients will be listed by percentage, or numbers will be present like "15-30-15," "20-20- 20," or "12-31-14." Or it may be that there are terms such as "chelate concentrate" or "inert ingredients" or perhaps even more complicated terms.

You may say to yourself: "What does it all mean?" Or you may shrug your shoulders and say: "I don't really care what it means — what I want to know is: — will it really make my plants grow better and bloom profusely."

The answer to the latter question can probably be given in the affirmative for almost any plant food. For if given the proper growing conditions — the right amount of humidity, correct temperature, adequate moisture, sufficient light, a well-balanced soil mix, along with regular feedings — most plants adequately protected from disease and insects, will respond favorably and bloom.

Too often, most of us tend to garden indoors and out-of-doors, "by guess and by golly." We often fail to read labels carefully. We know too little about the food needs of the plants we are trying to grow. We wonder what happened to the plant that fails and we rarely really know why a plant did so well that it won a blue ribbon for us. Yet, the answers are usually very simple. But for a myriad of reasons the question: "What does it all mean?" very often does not get answered.

Some growers, it seems, always seem to have "good luck" and carry off ribbons galore, everytime the local society has a show. We look with some envy, perhaps, on these "lucky" growers and decide that they must possess some mysterious power, commonly known as a "green thumb."

But successful growing is not a mystery. The proverbial "green thumb" is not a mysterious gift given to some and not to others. Successful growing comes from bothering to find out "what it all means." Successful growing is a science. It involves being scientific in our approach to growing problems. All we really need to remember is that there is a reason for everything. Usually the reason is a very simple one.

Not long ago a letter came to my desk bearing this interesting statement on the envelope: "YOU NEVER OUTGROW — THE NEED TO KNOW." With this as our text, I hasten to write some things you may already know and perhaps some about which you do not know.

It used to be, when I was a kid, that when we wanted to fertilize the garden and the lawn, we bought a load of farm manure and spread it over the garden or lawn in the fall or early spring. Today, as we become more and more urbanized, it is almost impossible in many areas to buy a load of natural fertilizer. Actually, we are probably better off because animal manures are often poorly balanced.
So, today, garden centers, hardware stores florists, dime stores, and many other places of business sell many different brands of fertilizers and plant foods packaged in many different quantities. Today, you can buy a specially compounded plant food for almost any plant you want to grow. But with so many on the market, it is confusing and sometimes difficult to know which one to buy. But it helps, if you can understand the label.

To dispel some of this confusion, let us begin by making a few important definitions.

In the first place, what is a fertilizer? It is a plant food and if it is a complete food, it contains a certain percentage of plant nutrients, nitrogen, phosphorus, and potash.

These are the major elements required by all plants for
growth, maturation and flowering or bearing of fruit. They are absolutely essential to all plant life. Let there be a deficiency of any one of these life-giving elements, and the plant begins to show signs of starvation.

Secondary elements of nutrition include calcium, sulphur, and magnesium. These are usually supplied by the same fertilizers which supply the major nutrients and they are also supplied when lime is added to the soil.

Minor elements, commonly referred to as "trace elements," and highly essential to the plant, include such elements as iron, copper, zinc, manganese, boron, molybdenum, and magnesium. I believe it would be correct to say that these minor elements very often account for above average performance in a plant. Let us say that it is like adding frosting to a cake. The cake is good without it but better with it. Yet, a plant will show need for these elements by dropping its blossoms, by yellowing leaves, bud drop, and other such symptoms. But it should be added that these signs also may be an indication of disease, other hungers, too little or not enough light, etc. Like the medical doctor, a grower must often diagnose plant troubles from symptoms which result from a number of causes.

Minor elements or "trace elements" are supplied in rather generous amounts by leaf mold. They are present in varying amounts in many commercial fertilizers and in special commercial compounds such as "Tem," "Tru-Green Organic Chelates," and other such products.

The term "Chelates" (pronounced key-lates) refer to nontoxic (nonpoisonous), odorless plant food elements in dry powdered form. They are treated to keep them from dissipating from the soil with successive waterings. They are treated so that they are available as mineral salts which can pass through the roots easily and into the plant's circulatory system. Trace elements may be present in soils but they may be "locked in" or in such form that the plant can not use them. Chelatation processes protect these elements from, soil lock-up, that is, combining with other elements in the soil to form insoluble compounds which become unavailable to plants. The J. J. Mauget Company, 4151 E. Olympic Blvd., Los Angeles, California, has a very informative leaflet entitled, "Plant Hunger Chart," which I am sure you would find helpful. It tells about chelates and has a very informative chart about the characteristic symptoms of trace mineral, secondary, and major nutrient hunger signs in plants.

Nitrogen is essential to plant life because it gives the rich green color to the plant and promotes growth. It is essential to the growth of leaf, stem, fruit and seed. It is rapidly exhausted from the soil by growth processes and by leaching out (washing out).

This means that especially where plants are grown in pots, the supply of nitrogen must be replenished often. But here is probably a good place to add a word of caution. Too much of an element may be harmful to a plant. So it is best to space fertilization at regular intervals and to be careful not to overfeed. The best way to be sure is to READ the LABEL and follow the manufacturer's directions in the use of the plant food. The pitfall many growers fall into is in thinking, that since a little is good, more will be better. This is rarely the case. You cannot play games with commercial fertilizers or any plant food for that matter. Follow the directions!

There are two kinds of nitrogen, organic and inorganic. Organic nitrogen is in a form which cannot be used immediately by the plant. It must be changed by bacteria in the soil to a chemical or inorganic form before it can be absorbed into the plant system. But organic nitrogen is not so easily leached out of the soil either. And that is why soil containing organic matter such as fishmeal, blood meal, hoofmeal, bonemeal or various manures may support plant life for a longer time without additional fertilization. The bacterial action is quite slow but it may be speeded up with certain products now on the market which inoculate the soil with minions of bacteria. These bacteria condition and activate the soil, thus speeding up the release of soil nutrients.

Organic nitrogen, then, will feed much longer, but takes longer to become available. Some fertilizers contain both organic and inorganic nitrogen. Inorganic nitrogen is chemical nitrogen which has been released when dissolved in water, it is taken into the plant immediately.
Some labels on fertilizer packages tell you how much organic and inorganic nitrogen is available, but many do not. This does not mean, however, that the latter do not contain organic and inorganic nitrogen. It would be helpful, though, if all manufacturers would be more specific in their labeling. This is a problem to the consumer in buying other products such as in a food market. There is a great need for more accurate and more specific information on labels, and we might add more uniformity.

Phosphorus another vital major nutrient stimulates flowering. It is vital to root crops and crops bearing fruit. It is also vital to vigorous root development and growth. Without phosphorus there could be no life, for it is intimately associated with all life processes and every living cell, It too can be provided by some organic materials such as bonemeal Bat Guano and other manures, cottonseed meal, soy bean meal, etc. it is also provided by such inorganic materials as rock phosphate which is at least 30% P2O5. (phosphoric acid).

Potash is essential to plant life in the building of resistance to disease and in producing hardiness in petioles or stems. It also helps to give the plant vigor and keeps the plant's vascular system or circulatory system open. It Is present In varying amounts in manures, hardwood ashes, etc. It is present in large amounts in Glauconite or Greensand as well as in Hybro-Tite.

A balanced fertilizer is one which has been compounded in certain proportions to meet the requirements of certain plants. It has a formula which indicates what is in it and how much. This formula is called a ratio, that is there is a certain relationship between the elements included in the plant food. For instance there may be twice as much phosphorus in the formulation as there is nitrogen and potash. Such a ratio might be 15-30-15. This means that there are 15 measures or units of nitrogen 30 units of phosphorus and 15 units of potash. These ratios are always stated in this order nitrogen phosphorus, and potash. Thus, the first number always indicates the amount of nitrogen, the second or middle number, phosphorus, and the last number, potash.

There are many ratios. A 1:1:1 ratio means equal parts of the three elements. For example: 10-10-10 or 20-20-20 The only difference in these two is in the degree of concentration. While the two have equal parts of the three nutrients, the 10-10-10 is half as strong or concentrated as the 20-20-20. A 2:1 ratio means as we said before that there is twice as much phosphorus in the plant food as of nitrogen and potash but a 15-30-15 fertilizer is more concentrated than a 5-10-5.

African violet plant foods have many different formulas. The most standard seems to be 15-30-15. But to give you an idea of the many different ones, here are a few taken from very popular violet foods: 23-21-17 7-6-19, 12-31-14, 4-10-10, 10-52-17, etc.

A recent formulation is a 10-30-20 fertilizer geared for variegated foliage in violets. Here nitrogen is withheld to promote more variegation in the foliage.

We have already mentioned a free leaflet that tells about some of the signs or symptoms of nutrient hunger. Many violet books give these signs in quite some detail. The only trouble with these signs, if we may be permitted the luxury of repeating, is that they are not always conclusive since they may indicate other trouble too. In general, however, we suspect nitrogen deficiency when leaves turn yellow and growth is dwarfed or slow. We can blame poor bloom or no bloom on a deficiency of phosphorus. And lack of potash is sometimes indicated by weak stems curling of leaves, firing starting at the tip of the leaves and proceeding downward, shriveled blossoms, etc.

Since symptoms are not entirely reliable, there is only one sure way to know. That is to test the soil. There are chemical tests which can be applied to samples of soil that will tell the story. One way is to take a sample to your county agricultural agent and ask him to test your soil. As a result of the tests he can tell you what your soil may be lacking and he can also tell you whether your soil is too acid (sour) or too sweet (alkaline).

Another way is to invest in a soil test kit. Sudbury Soil Test Kits are advertised in almost every garden magazine. They are available in numerous sizes all the way from a very small inexpensive kit to a super deluxe horticultural kit. They are not complicated to use and do not require a knowledge of chemistry. I would recommend the kit (Model-D) which is quite adequate for growers of Saintpaulias, Gesneriads, and other houseplants.

In a future issue of GSN, we will discuss soil acidity and alkalinity or pH and what it means. In this same article we will discuss in greater detail how to test soil for soil nutrients and pH.

Like animals, all plants require food to grow and bloom. To have a "green thumb," we need to know what food is required and grow by the scientific method, not by guess.
(Modern day note: check out AVSA's FAQ page for diagnosis information.)