Damping Off Help Needed

[MuddyBuckets]

I have multiple varieties of tomatoes started from seed in mid December to mid January that were growing very well under lights and most have now started to wither and die. Stems were strong and leaves robust. Now, stems are contracting and leaves withering. They have been up-potted in clean media but seem to be damping off on the stems. Root systems appear normal and robust.

Perhaps over/under watering, over fertilization or ?.

Help is appreciated in isolating the problem.

[zendog]

Usually overwatering will make it worse, so I would suspect that plus possibly poor drainage in your soil mix. You should add a fan if you don't have one already. Definitely let the top of the soil dry between waterings. You could also try watering with 1TBS of hydrogen peroxide per quart of water the next time you water, or even put some in a spray bottle to spray just at the surface. This this should reduce some of the bacteria and fungal spores, plus aerate the soil to help below the surface as well. It has helped stop my losses the one time I had damping off from trying a new seed starting mix.

I don't have direct experience with it, but many people have suggested adding worm castings to your mix (or worm compost tea) to add some beneficial microbes or other substances that can help prevent damping off as well.

[BigVanVader]

How often are you watering? Are you bottom watering or top watering? Do you use a fan to help reduce fungus?

[KarenO]

Can you post some photos. Also what varieties and where was your seed from?
KarenO

[Cole_Robbie]

Pythium bacteria cause damping off. They build up when soil is too wet, over fertilized, and not aerated enough. You could try mixing more perlite into your media. Cold weather seems to make it worse, especially when using any organic fertilizer or media with organic components. If you are under flouros, you might try upgrading your light to something bigger and hotter. Heat from a light is a good thing if the weather is cold.

[b54red]

Were you suffering from damping off before potting them up?

Bill

[SQWIBB]

@MuddyBuckets, I see from your "fans on seedlings" thread that you are using a fan, is this correct?


Are you using a dome or cover, if so, remove it.
Are you top watering, if so, start bottom watering.
let the soil at the top dry out between watering, especially when plants are growing.
Stop fertilizing until you resolve the problem.

I keep the soil moist to the top when sowing seeds but try to be more careful once seeds have germinated.

[MuddyBuckets]

Cole Robbie
Guilty, guilty and guilty...over pampering the seedlings. Letting them dry out with a fan on them to see if some recover.
BigVanVader
Top watering using double cup method so the media drains.
SQWIBB
Covers came off once the seeds sprouted.
b54red
Some were damping off before potting up.
KarenO
Seeds were from my grow out last season.

Thanks for all the advice, starting some new seeds today and will not over pamper them this time!

[Labradors2]

Just another thought. One winter I had mice nesting in my bag of Pro-mix which I keep in the basement for potting up my seedlings. I only found out because there was a piece of pink insulation inside the bag. I used it anyway, thinking that mouse droppings would be a healthy addition, but I was wrong because I lost a lot of seedlings .

Anyway, just throwing it out there.

Hope you can figure out what happened so as not to repeat .

Linda

[Fusion_power]

Damping off is caused by either contaminated growing media or too much water. The most common problem is over watering. Seedlings need bright lights and dry soil to grow healthy. I use promix MPX seed start mix for sterile media. Once seed germinate, the seedlings get water ONLY when they start to wilt. This is very important to maintain healthy roots. Let the leaves start to droop before giving water to seedlings. As you may guess, the single biggest cause of dead seedlings is overwatering. The second biggest is not using sterile growing media.


The third biggest cause of dead seedlings is over fertilizing. I use 1/4 teaspoon of miracle grow or equivalent per tray of 48 seedlings. This is more than enough to get the seedlings to 10 inches tall. Caveat that Promix MPX has some fertilizer already in the mix. If you start with media that is not fertilized, go up to 1 level teaspoon of fertilizer per 48 plants applied twice, once just after the seed germinate and again when the seedlings reach 4 inches tall.

[BigVanVader]

Yes, I only water once a week typically. That is almost assuredly ur issue.

[brownrexx]

Damping off fungus thrives in cool, damp conditions. I start my seeds in sterile media and in a warm room in my house. I water almost every day from the top and I have never had damping off issues.

In my opinion sterile media and pots as well as a warm environment is the secret. If the spores are not present, water will not make them appear.

I do not use a fan either.

[KarenO]

The reason I asked re photos and seed source is that perhaps there is something going on besides damping off. Another disease for example.
You are certain of the diagnosis? Damping off is a catch all term that describes several different pathogens that can affect seedlings, usually very young ones. Yours were planted in December?
KarenO

[zipcode]

Cold is a big helper, besides the wet conditions. Also, from my own observations, not seen it anywhere confirmed, potting up is another major trigger, especially if you are burying them deeper then original level.

[MuddyBuckets]

KarenO

Here a couple of pics, larger tom is a ColdSet Dwarf (sprouted mid December and potted up in early February) and smaller is Fire Marzano Roma sprouted early January.