You have your seeds. You start them indoors in little pots under a grow light at the right time. Seeds are germinating. Everything’s going great.
Then for some unknown and awful reason precious seedlings start to keel over at soil level and die like a tiny logger has gone to work on your future garden. Aaaahhhh!
It’s damping-off. And it’s not pretty.
What is it?
When seedlings die at or around the soil line from a fungal disease it is called damping-off. It may be caused by one of several different types of fungi in the soil. Sometime the seeds will fail to germinate because of it, at other times the seeds will grow but fall over, wither, drop leaves, or discolor and die suddenly.
There is not much you can do once this has struck except start over with clean soil and sterilized containers, but there are steps you can take to help prevent this from happening. Here are some tips to keep it from clear-cutting your seedling forest:
- Use sterilized planting medium.
- Use clean, sterilized containers with good drainage.
- Obtain seeds from reputable suppliers to increase the likelihood they are disease-free.
- Soak seeds in water with crushed garlic prior to planting (I’ve never done this, but if I had a bad bout with damping-off I would be liable to try it).
- Don’t start seedlings in a moldy, mildewy environment.
- When you sow, instead of making a hole and burying the seeds, place them on the surface of the planting medium and cover lightly with one of these instead of soil: Fine sphagnum moss, chick grit, or sterile coarse sand
- Sterilize garden tools which have been used outside before using them around the indoor seedlings
More mind-numbing (but useful) damping-off tips:
- Water with spanking clean water–save the rain barrel water for plants outdoors or sterilize it first.
- Water from the bottom and don’t overwater.
- Limit use of tray covers.
- Limit nitrogenous fertilizers–they can promote fungal growth.
- Don’t crowd seedlings.
- Provide air circulation–a small fan in the room–near but not directly blowing on the seedlings
- Thin seedlings to promote good air circulation (snip them off with scissors– pulling them out by the roots may damage nearby seedlings).
- Maintain optimal light conditions
- Mist seedlings daily with chamomile or clove tea or an infusion of stinging nettles.
- Dust soil surface with powdered charcoal or cinnamon.
There are some who feel the sterilization of soil and containers is another case of taking clean too far, like antibacterial soap for handwashing, etc. I tend to feel they have a very valid point–helpful microorganisms in balance are the strength of soil. However, when all my baby seedlings are at stake, I err on the side of caution and try to keep things reasonably “clean” (we’re talking dirt here).
And if you feel you’d like a book on the subject, here is a well-reviewed guide: Starting Seeds: How to Grow Healthy, Productive Vegetables, Herbs, and Flowers from Seed.
Image source: Seeds of Change.com