If you have sown your seeds correctly and placed them in a warm area, they should germinate and emerge from the soil within a few days.
Take your germinated seeds off of the heating mat and get them into some bright light. Your heat mat can be now used to start the next batch of seeds.
Not all of us have access to a greenhouse or a sun room to grow our newly emerged seedlings. A bright, sunny window with a southern exposure works almost as well. The other alternative is to place the seedlings under florescent lights. Two 40 watt fluorescent tubes will provide all the light your baby plants need. Special “grow lights” or “full spectrum” are really not necessary just use an ordinary shop light. The trick is to make sure the seedlings are about 2 inches from the lights, certainly not more than 3 inches.
The young plants need only about 15 to 16 hours of light a day. They must have a dark period in order to grow properly.
Direct the air from a small fan onto your growing seedlings. The movement caused by this small amount of air helps strengthen the young plants and helps prevent fungus from infecting them.
If you notice that your plants are getting “lanky”, top heavy, or lean toward the light, then you know they are not getting enough light, so make the necessary corrections to improve the lighting conditions. Often they will get so top heavy that they will fall over. If this happens, transplant them into another container at a deeper depth. Many times you can salvage your seedlings in this manner.
Fluorescent tubes do give off some heat. This heat combined with the fan may tend to dry out the potting mix a little so be sure to check on your seedlings a couple of times a day…they are babies after all!
As your seedlings start to grow, keep an eye out for a problem called “damping off”. It is disheartening to get to the point where the seeds are up and growing fine only to find one morning that the plants have fallen over and are starting to die.
Damping off is caused by a fungus that usually infects the seedlings’ stems right at the soil line. You will notice that the stem of the seedling is shriveled. The plant cannot recover at this point. The most common cause is using potting containers that were not properly cleaned or using seeding mix that was not sterilized. Lack of air movement and soggy soil can also make the problem worse.
Fertilize your seedling every other watering or so with a diluted half-strength solution of soluble plant fertilizer. Use distilled or RO water for your seedlings. Chlorine from city water can damage them. If you don’t have access to distilled water, leave a potful of tap water out overnight to let the chlorine “gas off”. Placing the growing container in water and letting it soak up from the bottom will help keep your seedlings from being knocked over by a stream of water from the watering can.
Eventually your seedlings will need to be transplanted. We’ll discuss that and other things in the next post.