I want to start some vegetable seeds soon. I did this last year for the first time, but some of my seedlings just keeled over and died. What did I do wrong?
You didn’t do anything wrong. Your seedlings succumbed to a condition called “damping off”, which is caused by a fungus that thrives in cool, wet conditions.
Fortunately there are a number of things that you can do to keep your seedlings safe.
Location: Don’t give the fungus the cool temperatures it prefers. The only time I have lost seedlings to “damping off” was the year I decided to put the grow lights (my husband calls it my grow-op) in the basement, which is much cooler than the rest of the house. Now the lights and seedlings are happily tucked in a corner of our spare bedroom, and family and friends who visit during April or May have to share quarters with the seedlings.
Good Housekeeping: Not that kind of housekeeping! Your seedlings won’t care that you haven’t vacuumed or dusted, but they will care if you haven’t used clean containers. If you reuse containers from year to year wash and sterilize them before planting your seeds. Brush all the soil you can from the containers, and scrub them to remove any stubborn bits. Sterilize them by soaking them for at least 10 minutes in a solution of 1 part bleach to 9 parts water. Give them a final rinse and they’re good to go.
Planting Tips: Use a good quality soilless potting mix, and don’t reuse it. Once you have planted and covered your seeds, try a top dressing of sand, vermiculite or chicken grit to keep the soil around the emerging seedling drier. I sprinkle a bit of cinnamon on top. I know, this sounds like an old wives’ tale, but cinnamon does have antifungal and antimicrobial properties. Besides, it smells nice.
Maintenance: Good air circulation around your seedlings is important, so don’t crowd them together. You might try a fan to stir the air. Just remember you’re aiming for a soft breeze, not a gale.
Watering from below is a royal pain, but it’s worth it. Place the containers of seedlings in a second container that is water tight (I use an old dishpan) and add room temperature water until it’s halfway up the seedling containers. Leave it until the growing medium is moist, usually 5 – 10 minutes, then lift out the containers of seedlings and let them drain. You might try watering with diluted camomile tea as it also is noted for its antifungal properties.
Good luck and good gardening!