Gamebird,

Damping off is a real bummer.

Any and all plants can be susceptible to damping off.

Damping off is caused by several different fungi and it is likely that some vegetables are more susceptible to some fungi than others which is why some of your plants are affected and others seemingly are not.

Damping off can be caused by the fungi Botrytis spp., Phytophthora spp., Pythium spp., Rhizoctonia solani and sclerotinia spp. as well as a few less commonly seen fungi. These fungi are found universally in soils and can damage virtually any plant you are propogating.

Once your plants have been infected by one or more of the fungi that cause damping off, there is little you can do to save them. Different fungi affect the plants in different ways. Pythium types, for example, start way down at the tips of the roots and work their way up the plant. Once you see the above-soil symptoms of damping off (the characteristic 'wire stem' that is weak, spindly and collapsing), the entire root system is affected.

If you scatter sow a lot of seeds in one flat, damping off first may be observed as a circular area of weakening, dying plants in one location in the flat. Often, once it starts, the circular area gradually enlarges as more plants are affected.

You can have pre-emergent damping off where the seeds are infected and die before they sprout, but more often you have the post-emergent type where they sprout, grow and then die.

Sometimes you can see white or brown fungal growth on the soil surface. Sometimes you can see little hair-like growths.

There is no cure for damping off although I have seen an occasional plant survive it.

Prevention is the best cure.

Here's how to prevent it:

Before you plant in flats, pots, cups or whatever you use, clean them and sterilize them if they've ever held soil before. You can clean them with 70% rubbing alcohol or with a water/bleach combo (1 part bleach to 4 or 5 parts waer).

Use only sterile soil-less seed-starting mix, which usually consists of peat and vermiculite or something similar. (Some organic gardeners prefer to use compost and believe the biological activity in the compost prevents damping off.)

Place your sterile seed flats filled with sterile soil-less mix only on sterile areas (shelves, tables, greenhouse benches, etc.) or, if you're using an area that cannot be sterilized, place several layers of newspaper between the flat and the surface.

If damping off is a huge problem, you can purchase treated seed (sometimes) that's been pre-treated with a fungicide. Treated seed is not available for all vegetable varieties because some seeds/seedlings cannot tolerate the fungicides.

If you have been working outside in the yard, wash your hands and tools before you touch your seedling flats so you do not transfer the fungi to your sterile flats.

If any flats become affected by damping off, remove them from the area where the other flats/plants are kept to avoid spreading the disease.

Damping off is most common in flats that are kept excessively wet. Damping off is more common if flats suffer from a lack of air movement.

When you sow seeds inside, try to keep them as healthy as possible by:

Ensuring they have proper heat and light so they can sprout and grow quickly before the fungi have a chance to infect them.

Ensuring they are not excessively wet. Water the soil before you plant. Then, plant your seeds, mist lightly and do not water again until the flat is dry--just stick a finger down into the soil to check for drying

Ensuring they have good air flow. I keep a ceiling fan on all day long in the room where the plant shelf sits. I also turn on an oscillating fan for a few hours a day.

If your seeds are in peat pellets, pots or paper/plastic containers, make sure you do not leave any standing water in the flats after watering. Drain off any water that drains from the containers into the bottoms of the flats.

People fight damping off before it starts it many ways. In addition to the measures mentioned above, you can sprinkle any one of the following in a very thin layer on the soil surface to combat damping off:

corn meal
cinnamon
sand

You can water your plants from day one with chamomile tea, clove tea, liquid seaweed, molasses tea, garlic tea, Garrett Juice or fish emulsion. Some people add a little 3% hydrogen peroxide to the water each time they water their seedlings (you'd want the peroxide to be about 5% of your watering solution).

You probably could reuse the potting soil if you spread it on a cookie sheet type tray and sterilze it in the oven, but be advised it will stink up the house.

The plants that already have damping off are unlikely to survive since it is a fungal infection that is already present in the plants.

Even when you haven't seen any signs of damping off, it often seems to "appear" when small seedlings are pricked out of the flats and potted up. Likely, the disease was there all along and it was coincidental that it seemed to appear just after the plants were handled. However, it also is possible that the act of potting up spread the damping off that already existed in the soil.

I don't do anything extraordinary to prevent damping off--just avoid overwatering and try to ensure good air movement. You just never know when damping off will strike. Some years I have a little of it, some years I have a lot and some years I have none. (So far this year, none, knock on wood.....and I am sure I just jinxed the seedlings by saying that.)

In wet and rainy years, I try to harden off plants on the porch or patio on sterile tables and I try to avoid setting flats directly on the ground since a rain shower could spread damping off fungi from the soil outside to the flats sitting on the soil.

I'm sorry you've had such a bad experience with damping off. It can be very discouraging. Normally, once your plants are 3-5 weeks old, they are old enough and strong enough to fight the fungi that causes damping off.

Dawn

I know that some varieties, even, are more susceptible to damping off. My favorite Baker Family Heirloom tomato, is the first to damp off, if I'm going to have problems.

George

Okay. Thanks for the info. After removing and counting up the losses, it's only 25 plants out of 126, though I figure I'll lose a couple more that look iffy. I've started another flat of seeds to fill in. That will do it for most of the tomato seeds Dawn sent me. I've still got 9 varieties unused. I'm aiming to have 100 viable plants. 101, as I have now, is just too small a margin for the expected and usual losses.

I've also had one grey stripe sunflower lay down and die with a brown stem. I have another that has ceased to stand tall and firm, so it might be a goner too. Nothing else seems to be having a problem. I'll be careful on the watering.