New to Seedstarting?
Answers to frequently asked questions about starting seeds indoors
A seedstarting kit, such as the Seedstarting Grow Kit, makes it easy to grow vigorous, healthy seedlings.
I've talked to so many gardeners who are experienced at growing plants outdoors but hesitate to start seeds indoors. To me, starting seeds is one of the most rewarding parts of gardening. It gets my hands in the soil (or at least the seedstarting mix) during the dark, cold days of late winter and early spring. And it's so amazing and rewarding to plant a seemingly lifeless seed and watch it sprout and grow. Here are answers to some of the hundreds of questions I've been asked about seedstarting. When you see how easy it is, I hope you'll give it a try!
What Went Wrong?
Even the most experienced seedstarters occasionally have problems. Here are some symptoms, and possible causes.
Poor germination. Although most common vegetables and annual flowers germinate readily, some types of plants have notoriously poor germination rates. Often, this is indicated on the seed packet (with the suggestion to sow extra seed). First of all, be sure you've given plants enough time to germinate. At sowing time, mark the pots with the type of plant, date of sowing, and days to germination (found on the seed packet). Some seeds take two weeks or more to sprout. Poor germination can be caused by overly wet or cold soil, which causes seeds to rot. (The latter can be remedied with a Heat Mat.) If the soil was too dry, the seeds may not have been able to absorb enough moisture to sprout. And if the soil dried out even once after they began growing, the fragile new roots may have died before the shoot even emerged above the soil. Poor germination can also be caused by out-dated seed, and seed that hasn't been properly stored.
Damping off. If, after a few days, some of your seedlings keel over, as though a tiny lumberjack felled them at the soil line, then you're probably seeing the effects of damping off. This is caused by soil-borne fungi attacking the stem. There's no cure, and the seeds won't resprout. Start over with clean containers and sterile seedstarting mix. Allow the soil surface to dry out slightly between waterings, and place a fan in the room for good air circulation. To disinfect used containers, sterilize them in a 10% bleach solution (1 part bleach to 9 parts water.) To learn more, read the article Damping Off
Mold and algae growth. If you see fuzzy white growth or slimy green patches on the surface of the planting mix, or on the outside of biodegradable pots, it's probably mold or algae. Although generally harmless to the seedling, they both indicate that the seedstarting mix is too wet. Allow it to dry out slightly between waterings and use a small fan in the room to increase air circulation.
Pale, stretched-out seedlings with weak stems. "Leggy" seedlings are often the result of inadequate light, both in intensity and duration. Place plants under grow lights, arranging them so the lights are a few inches above the tops of the plants, and keep the lights on for about 14 to 16 hours per day. Leggy plants can also result from too-warm room temperatures and overcrowding. Inadequate fertilizing can lead to pale, weak-stemmed plants.
Discolored leaves. If seedling foliage is pale green, yellowish green, or has a purple cast to it, the plants may need a nutrient boost. Begin fertilizing seedlings when they're an inch or two tall, or when they have their second set of true leaves. Use a water-soluble fertilizer that's diluted to half-strength, applying weekly for the first few weeks. After that, you can go up to full strength applied weekly. (Be sure to follow the label directions for dilution rates.)