Question: My house tends to be fairly cold in the winter. The room where my African violets are is usually between 60 to 65 degrees. Would it help them if I were to place them on warming (like the ones you use for starting seeds) or would that be bad for them?
Answer: Warming mats are a great idea when the house is cool. The air temperature is not as important to the plant's growth as the root temperature, and a warming mat provides just enough extra to keep the plant growing and thriving. Happy Growing! Joyce Stork
Temperature - General Culture
Question: Is there any technique to speed up the growth of African Violets?
Answer: Cell division in most plants is faster when the temperatures are warmer, however in violets the cells begin to break down (ultimately the foliage becomes glassy-looking and collapses) as the temperatures rise above 80 degrees F. On the other hand, cell division nearly stops below 65 degrees. So, while African violets will grow faster in warmer temperatures, there is a real limit to how much you can do there. Obviously you must provide the proper soil moisture, nutrients, humidity, and potting mix, but those things maintain growth without necessarily speeding it. What else can you do? There is good evidence that regular repotting and grooming by removing leaves and/or buds will stimulate more efficient growth. One researcher explained to me that any injury to the plant (such as removing a leaf) causes the plant to release a puff of ethylene gas into the air as a signal to the rest of the plant (and other plants in the immediate area) that there is a predator... the plants respond to this ethylene by increasing photosynthesis by as much as 15-20%, presumably to survive. This increased photosynthesis results in plants that have thicker, broader, healthier leaves and more flowers. Happy Growing! Joyce Stork