How To Prevent Damping Off
My grandfather used to say that gardening is like cooking. You never walk away from the stove.
What he meant, of course, is that gardening requires a lot of attention. Sticking seeds in the ground and just letting them go is akin to throwing some onions in oil over a hot burner and walking off. When it comes to controlling damping off, the fungal attack that destroys seedlings before they have a chance to flourish, attention to detail can be the organic gardener’s best tool, especially when it comes to watering.
Damping off is a common problem for those starting seeds indoors. But it can also be harmful to seeds planted directly in the garden. Shortly after emerging, seedlings develop a discolored, often black color at the soil line. This rot eventually claims the plant. There’s also a pre-emergence form of damping off that rots the seed before it’s had a chance to germinate. A number of fungi present in soils will cause young seedlings to die. And all of them like wet conditions. Not all fungi are evil … some are beneficial.
This is where attention comes in. If your seeds are growing in flats or starting pots, don’t keep them overly moist. Allow the soil to become dry before watering. Make sure drainage is good. Soil can dry on the surface but be saturated at the bottom of a pot. Again, monitor conditions closely. There’s a fine line between soil reaching a crumbly dryness and drying out rock solid at which point the seedlings tender roots will also dry and shrivel. Not good.
Of course, you have only one-sided control of the seeds in your garden. Giving them a good soaking once they go in the ground is required. Keeping them moist when the seedling are tender and vulnerable is also paramount. But pay attention to your soil’s drainage and don’t over water. Of course, you can’t control the weather. Cold temperatures following planting are harmful. The longer your seed is in the ground ahead of germination, the more susceptible it is to damping off. And persistent rainy periods after germination, something common in many parts of the country during spring, also encourage damping off.
Good organic practice, as it is in all things, is your best weapon against the fungus that cause damping off. Making sure your seed starting mix is well-drained and has plenty of organic material will help prevent the extreme and persistent moisture conditions that encourage the fungi. Keeping the soil surface dry with a layer of perlite, vermiculite or sand helps. Regular introduction of compost to your garden soil also introduces beneficial microbes of the sort that feed on harmful fungus in the soil. When growing indoors or in green houses, practice cleanliness. Don’t use containers or soil in which damping off has occurred.
If you suspect damping off is beginning to occur, you can try spraying with Neem Oil to help plants at the surface. Seaweed extracts can help surrounding seedlings stay healthy and resist the fungus. But once damping off is established, there are no guarantees. The only other solution — and it’s not organic — is to treat your soil in advance with agricultural fungicides. And we all know that fungicides can be dangerous, a detriment to the health of both you and the environment. Yes, you can by seeds that are treated with fungicides. But that doesn’t treat the causes of the problem in the first place. And wouldn’t you rather defeat these problems organically, use organic seed, and have peace of mind?
And follow grandpa’s advice — pay attention; to soil and moisture conditions, to the weather and to your seedlings. It’s your first line of defense in all things to do with your garden.
Tip: AquaShield is a liquid compost solution that has been shown to help suppress damping off diseases in both soil and hydroponic gardens.
Photo Credit: Department of Crop Sciences, University of Illinois