Saintpaulia, or African violet, is one of our widely grown house plants. Its popularity is based upon the beauty and wide variation of both flowers and foliage.
The great adaptability to household conditions, and the comparatively little care required to have some show of blossoms over a long blooming season.
Requirements For Good Plant Development
The home environment, however, is often far from ideal and generally a far cry from the conditions found in Tanganyika, the native home of the species.
Good plant development requires proper light, temperature, water supply, and fertility balance. Species have their optimum requirements, and these vary widely.
Experimental work reported in Bulletin No. 501 from Louisiana University indicates that the following conditions favor the African violet.
- An intensity of 1,000 – 1,100 foot candles of natural light or 600-foot candles of fluorescent light for 12-18 hours daily.
- An intensity of 1,300-foot candles causes the leaves to become small and crinkly and turn a light green color.
- Floriferousness is also curtailed. Insufficient light results in dark green leaves on long petioles.
- A range of 70° to 75° degrees Fahrenheit during the day and 60° to 65° degrees Fahrenheit during the night.
- Overhead sprinkling with water at room temperature with the watering interval being one to four days depending upon relative atmospheric humidity.
- A complete fertilizer is applied in liquid form with moderation every four to eight weeks.
Unfortunately, the average homeowner interested in African violets cannot supply the conditions described above.
In particular, they are hard to maintain during the summer season. Light intensity, unless carefully controlled, will be too high and the days too long.
Temperatures are likely to be above the optimum point but watering and fertilizing can be done as needed.
Most Complicating Factor
Perhaps the most complicating factor, however, is the fact that the average family goes away for a vacation.
During this time, the plants are often sadly neglected even though a generous neighbor may take over their care. For example, African violets have been grown at our house for several years.
Reasonable success has been achieved, and our east and north windows have been masses of various colored blooms during the major portion of the year.
Almost invariably, however, our return from a vacation finds the plants in poor shape, not because of neglect by the neighbor but because of the environmental conditions to which they have been exposed.
Efforts To Eliminate Such Factors
Various efforts have been made in past years to eliminate some of the unfavorable factors.
Plants have been placed on tables some distance from the windows to lessen the light intensity.
The watering interval has been lengthened by placing the pots in pans and thus watering them from the bottom.
One year an outside shelter was used. A light frame was covered with clear biofilm, which was allowed to hang loosely well down over the sides.
The pots were plunged into a water-holding mulch, and the frame was placed in the shade of some old spruce trees.
Results were encouraging, except that the foliage was spotted near the edges of the frame because cold raindrops had been driven under the cover by the wind.
One year we decided to make the sides of the enclosure tight. In essence, a giant terrarium was constructed.
The reasoning behind this was that the need for frequent watering would be reduced since little or no actual water loss would occur due to the absence of ventilation.
A framework about four by 6’ feet and 18” inches high was constructed of 1 x 4’s and 1 x 2’s.
A removable top with corner braces was made. The sides and top were covered with a heavy clear plastic material used for greenhouse coverings.
Making Watertight Pan
A space underneath a group of spruce trees large enough for the frame was smoothed and covered with waterproof tar paper on which the seam had been sealed with hot tar.
The edges of this paper were brought up inside the frame to make a watertight pan.
This pan was filled with a three or four-inch mulch of sphagnum moss and partially decomposed corn silage.
The mulch was copiously watered, and the free water was drained off a couple of days later.
Summer Conditioning of Plants
The plants were conditioned for the summer by being repotted whenever necessary, fertilized, and well-watered. They were all in clay pots, usually of a three-inch size.
On June 17, the pots were plunged nearly full depth into the damp mulch with ample room between the pots. The cover was then put into place.
Results seemed to justify expectations fully. After 12 weeks of exposure to the conditions described, the plants were vigorous and full of bloom, and the leaves were unspotted.
Philodendron and begonia plants in the enclosure also looked very happy. Unfortunately, during this period, no water was supplied nor fertility added.
The 100% percent relative humidity, indicated by condensation on the inside of the plastic covering, was sufficient to eliminate evaporation from the plants nearly.
Any water loss was replaced by absorption from the mulch material. Such moisture may also carry with it a certain amount of fertility.
Light conditions were conducive to good plant growth since the plants received almost no direct sunshine except for a brief period in the late afternoon.
44659 by C. C. Wiggans