 About the Gesneriads:
The Gesneriads are a large group of largely tropical plants that are commonly grown as houseplants. Some of the most well known Gesneriads are the "African Violet" - Saintpaulia and the "Gloxinia" - Sinningia Speciosa. Most of the Gesneriads do well in an East window, or set back from a South window as they are native to the rain forest and only receive filtered light in their natural habitat. Most of them like a brief dry spell between watering and they should never be allowed to sit in water for a long period as they will drown.
African Violet Culture:
The "African Violet", Saintpaulia ionantha wendelii, has always fascinated me. In my experimentsgrowing plants under lights it is a winner. It is tolerant of a broad range of conditions andenvironments and thrives on low light levels 400 ft candles is sufficient but improved results are achieved with 800 ft. candles. In general my experience has shown that having the plants close to the tubes but not touching is a good starting point. The mix I use for under lights is 1/3 pearlite course, 1/3 vermiculite, and 1/3 peat moss. More recently I have started adding quite a bit of #1 stream wash gravel which is being added for weight as the pots with the light mix above do not stay well seated in flats. Also AV's like to be under potted and the stone helps large plants in small pots to remain upright. Weight used to be a big factor as we did mail order shipping. AV's can also be grown in a east window.
The potting mix has no nutritive value so the plants are depending on you to supply this. Feeding is done by what is known as a "constant feed program" or "nutriculture" this is similar to hydroponics but the plants are growing on soil. The feed I use is 1/4 level teaspoon, Peters 20-20-20, per gallon of water. I adjust this rate according to the plants response which is variable depending on season temperature, heating and other factors. With AV's it is easy to see how much nutrition they are getting. AV's should be bone dry before watering I find this period to be between 1 week and 2 weeks in my environment. In this period of time you will be able to see the effect of the last feeding because the center of the plant will reveal this. If the meristem, center of the plant, is darker than the surrounding leaves the nutrient level is high. If the central crown is lighter in color than the surrounding leaves the nutrient level is low.
A word of caution is necessary about "Constant Feed Programs". Each time you water you put the feed solution in at the top of the pot with enough excess to come out the bottom this helps to move old fertilizer salts out of the pot. Over a period of time because a lot of water is being evaporated there is a danger that fertilizer salts can build in the pot. To guard against this once ever couple of months I take my violets that are not blooming and give them a warm water shower for about 5 min. This will clean out the pot. I find that if a violet is nearing the end of its bloom cycle if you debud by removing all bloom stalks from the plant and give it this treatment they set new buds very quickly.
I grow the Gesneriads under lights for most of the year. I run my lights 14 hrs. per day. I have experimented with a broad range of bulb types and the plain inexpensive cool white seems to work just as good if not better than plant growth lights. African Violets and the rest of the Gesneriads are easy to propagate. Just stick the cuttings in a mixture of half pearlite and half vermiculite. I cover the propagation box with glass for the first 30 days after which I feed the cuttings with fertilyzer at the rate of one quarter level teaspoon to one gallon of water.
Where do you get plants from? It's easy just go on the internet and search for GESNERIADS you will be overwhelmed!
Note: One of the foremost GESNERIAD growers in the world, is Paul Sarino the operator of Lyndon Lyon Greenhouses in Dolgeville NY. Paul's father in law Lyndon was responsible for developing hundreds of hybrids in the Gesneriacea.
For more info. see:
http://www.gesneriads.ca/aboutges.htm
Various Gesneriads:
Achimenes, Smithiantha: http://www.gesneriads.ca/genach.htm Aeschynanthus:
Chirita:
Chirita Schlerophylla
Columnea:http://www.gesneriads.ca/gencolum.htm
Columnea Julia - Blooming 2006.12.12
Columnea Hirta - A species plant
Columnea "Mary Ann" - A micheal Kartuz hybrid with upright growth - free blooming
Episcia: http://www.gesneriads.ca/genepis.htm
Kohleria: http://www.gesneriads.ca/genkohle.htm
Nematanthus: http://www.gesneriads.ca/genemcod.htm
Nematanthus Wetsteinei - aka "Gold Fish Plant"
Sinningia: http://www.gesneriads.ca/gensinn.htm
Sinningia Speciosa Hybrid - aka "Gloxinia"
Sinningia Cardinalis - Formerly called Rechsteinaria Cardinalis
Streptocarpus: http://www.gesneriads.ca/genstrep.htm
Steptocarpus Maassens White
This strep is a real performer as it is male sterile. I had one which bloomed constantly for one year. I lost my stock about 20 years ago and could not find a replacement until recently when Mike Kartuz supplied me with a new plant.
Tissue Culture and the Gesneriads
During the late 1960's I began experimenting growing plants under lights. I had worked on the installation of 200 - 2000w Lucolox Lamps for Seagrote Florists a rose growing company in Berlin NY. The idea was that by extending the day length that roses could be made to bloom even in the short days of winter. Seagrote is one of the largest rose growers in the world with 4.3 acres under glass and this method allowed them to nearly double their yearly production.
This experience motivated me to start experimenting with various plants under lights. I found that most plants did not do well under lights as they required more light than my florescent lights could provide. In my search for new plants that would do well under lights I went to a small greenhouse operation in Colonie, NY. where the grower had thousands of African Violets in his cellar flourishing on nothing other than florescent lights. This was my introduction to the Gesneriads, African Violets and their relatives.
I had a friend who had graduated from Cornell who had been one of the first students to experiment with a new technology called tissue culture. This method allowed large numbers of plants to be propagated from very small pieces of plant material. I had discovered that the Gesneriads were very cooperative in propagation and perhaps this new method would work with them.
We experimented for several years with various kinds of lights, growing media, and species. The results were successful beyond our greatest expectation and in 1972 we opened the first commercial tissue culture operation in the US, "The Electric Farm".
We had simplified the Cornell procedure and created a low tech alternative. Since the gesneriads are so easy to propagate much of the expense and hardware used in the Cornell method was unnecessary. In fact we were denied a grant because our process was so simple.
Sterility is the key to successful tissue culture. We wiped all counters with Clorox, and sterilized all tools and containers in a pressure cooker. The plant material was dissected and sterilized in what we called a glove box. It was actually an aquarium placed on its side with an air tight cover with two rubber gloves attached to the cover by their cuffs. Small pieces of a leaf were first washed in a solution of 1 part Clorox and 4 parts boiled water. They were then rinsed is a solution of boiled water with a small amount of Benlate, a fungicide, added. This was all done inside the sterile environment of the glove box. The pieces were then placed in sterile canning jars that had a small amount of vermiculite placed in them for a growing media. The vermiculite was moistened with a solution of boiled water combined with 1/4 teas. per gallon of Peter's 20-20-20. The jars were then sealed and removed from the glove box and place under florescent light. For the Gesneriads we found 16hrs of light per day beneficial during the tissue culture process. We would place 4 or 5 pieces in each jar and in 4-6 months each piece would produce 5-20 plantlets. We would then open the jars, divide the plantlets and pot them in 2 1/4" pots.
This method allowed us to produce thousands of plants from one in less than six months!
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