On this Friday the 13th it seems appropriate to discuss a gruesome disease that can affect your precious tiny seedlings after you have so carefully nurtured them. Once they have it, it is fatal, so prevention is really the only “cure.” And as I have mentioned in a few prior posts, some seeds are more prone to it than others so it helps to know this in advance.
First of all, damping off is caused by any number of different fungi. You’ve heard of lots of them and they are the usual culprits behind disease in the garden: alternaria, botrytis, fusarium–and there are lots more!
How do these fungi (or funguses if you prefer) get onto your seeds? Any number of ways. They can be blown there by the wind. They can be carried there in your water. They can be on the seeds themselves. They can be in your potting mix. If you’re re-using trays, pots or tools, they can be on those implements. In other words, the fungal spores are pretty much everywhere and very hard to avoid.
They do like certain conditions–cool and damp–better than others. And of course certain folks will recommend using a fan for circulation around your seedlings. I’ve tried that. I can’t say I think it makes much difference in terms of damping off, but it does help strengthen the seedlings before you harden them off, so if a fan works for you, by all means, try setting one up near your seed starting place.
Some folks will water with different mixes–I’ve read about watering with water infused with garlic or with chamomile tea. Again, if it makes you feel better, go right ahead. For me, trying to keep the potting medium evenly moist and not overly wet, and trying to water from the bottom when possible, particularly when the seeds are young, seems to work as well as anything.
There is a product sold particularly for this purpose called No Damp Off. It claims to be an organic sphagnum moss from Wisconsin. I actually do own a bag and for very susceptible seeds, I will lightly top dress with this product. I think the bag I have has lasted me over 20 years (since I try to use non-renewable resources very sparingly!) I can recommend it, with the limitation that I wouldn’t plant directly into it myself.
If you start reading articles for the greenhouse and nursery trade, you’ll see all sorts of technical publications that talk about soil drenches for seedlings. I’ve attached one from the University of Massachusetts here. But stop just a moment and think about this. Why are you growing seeds? Surely it isn’t to drench them with commercial fungicides before they even hit your garden, is it? (Maybe it is. If so, you can skip the rest of my post).
That’s not why I grow them. I grow them to get something better than or different from what’s out there in the trade. I grow seeds because I want to choose the varieties that I want to eat. And I grow them because I want to control the process from beginning to end–what goes on those seeds. And ideally that does not include chemicals or fungicides at any part of the growing process.
So if I lose my seeds to damping off, I may have to go buy some plants at the garden center–plants that in all likelihood will have been treated, unless I can find some that say “organically grown.”
But with any luck, I won’t lose my tender little seeds. And I’ll have the pleasure of knowing I have grown my own plants organically.