Seedling shedding true leaves for no apparent reason

[applestar]

OK, I’m encountering a problem with my tomato seedlings that I don’t recognize and can’t figure out.

They are starting to SHED true leaves. Oldest first. They just fall off ...sometimes when I’m spraying them to give them their morning mist — not that strong of a blast. And they detach cleanly at the stem, and they look totally fine, green, no marks.

Maybe they are telling me to hurry up pot them up DEEP in bigger containers, but honestly, they are not THAT root bound....


...not critical yet, but a few have shed leaves to the point that they ONLY have the latest yet not fully unfurled true leaves. This would obviously set them back in growth I would think. Have they run out of nutrients? Would a weak balanced fertilizer Help? I don’t feel like I’m doing anything particularly different than other years, albeit I did have last year’s gap.

[pepperhead212]

Are any of them getting flower buds starting on them? This would be another sign of stressing, and maybe being rootbound, though it's peppers I see this with, more than anything. Are you using any different soil mixes, or anything different that you can think of? How old are they, how large, and what size are the pots? And what have you fertilized them with? For a weak fertilizer, I use some of my hydroponics nutrients - uses very little, like a half tsp of the liquid, to each gallon, when watering.

[TomatoNut95]

Oh wow, I've never encountered such an issue!

Are you allowing the soil to dry out between mistings? Try not to get the foliage wet when misting them?

Sorry I can't help much!

[UTtomatoman]

Just curious, what size cell are they planted in?
When were they planted?
What planting medium and fertilization if any?

[applestar]

Damping off in older seedlings?

[applestar]

BAD NEWS — of all this year’s tomato seedling trays, the one tray with all of the established variegated leaf varieties — Faelan’s First Snow and Shimofuri F9, as well as Sweet Splash trial — have been struck by the dreaded “damping off of the older seedlings”.

This is the kind that causes steady wilting and dropping of lower leaves starting with the seed leaves. I’ve had to give up on 3 seedlings already when the disease spread all the way to the growing point. A handful are in jeopardy with only a couple of sets of top most leaves left.

I believe the disease was introduced when I unthinkingly used bamboo skewers that were probably left from last year’s seedling grow out (when I first discovered and learned about this disease). I didn’t realize they had not been properly sterilized (and I also underestimated that it would not still be lurking on them.)

…it’s not as easy to tell that Sweet Splash seedlings are being affected, but they seem stunted and their (rugose potato leaf?) true leaves are maintaining curled edges without stretching out …unlike true leaves that wilt in stages one leaflet at a time from the tip.

…One other variety in the tray — Beaverlodge Slicer — don’t seem to be affected? OR VERY LITTLE. It will be interesting to find out if they are resistant.

I am continuing to treat the tray —

(1) started with spraying the surface of the mix with straight drug store hydrogen peroxide, then thoroughly watered with 50% diluted. Also sprayed the stems with neem-soap solution — that didn’t seem to help

(2) thoroughly cleaned the bottom drip tray and sprayed the underside of the cells with hydrogen peroxide

(3) mixed up a small batch Ehime AI-2 (or near approximation) — yogurt, yogurt whey, brown rice milk, yeast, natto powder, cane sugar — and after overnight culture, applied 3 drops per cell, then watered and drenched with decoction of dried willow bark, willow branch tips, sliced fresh ginger.

(4) Inoculated the leftover willow bark decoction with the probiotic culture and have been continuing to apply to seedlings that have deteriorated.

[imafan26]

It's those hidden troubles that come back to bite you. I just weeded in the garden and encountered more root mealy bugs in the soil. The good thing they were growing on weeds. I also forgot and stepped in my bed that I took out the parsley that had nematodes so I had to wash the tools, bucket and my shoes. I sprayed the bucket with alcohol and I am going to wash the shoes with soap and water. They are crocs so they can handle it. I will have to wait for a while for everything to dry out again. I will spray the bucket and hand tools with a quarternary ammonium ( odoban) disinfectant one more time.

[applestar]

Yep. It’s easy to get complacent, relax the clean up regimen, then BAM!

Invisible/microscopic garden soil borne or clothing/tools/hands transferred diseases and parasites are the WORST!

I’ve had similar issues from Clubfoot on brassicas and russet mites on tomatoes. You have to go through the motions even though you can’t tell that you have anything on you or the tools/boots, etc., knowing this is the mitigation to prevent spreading the little horrors to other parts of the garden.

(Hmm that sounds familiar to another situation…. )

[applestar]

Although many texts say damping off is “fatal” and everything should be discarded forthwith, as hobby gardeners, we sometimes push the envelope and try to save those precious seedlings (whether this choice is good or bad ).

From what I’ve learned so far, “damping off” is a generic descriptive term, and the culprit can be one or more if several —

https://content.ces.ncsu.edu/damping-of ... -seedlings
Damping-off is primarily caused by fungi present in the growing medium. The fungi include species of Rhizoctonia, Pythium, Fusarium, Phytophthora, Sclerotinia, Sclerotium, Botrytis, and others.

My nemesis is likely Pythium. (There are no sign of cottony moldy spots. The older affected tomato seedlings end up with shriveled corky basal stem.) This one is also spread by fungus gnats (ugh).

Last year, I didn’t notice/realize what was happening and good number of seedlings died off one by one. Some seemed more susceptible. Others essentially outgrew the damage and recovered once they were planted deep, past the shriveled basal stem, so they could grow new roots in the soil.

These are much younger seedlings than last year’s and don’t have as much upper growths to sustain/resist the damage, but maybe my countermeasure strategy of introducing probiotics to outcompete the disease organisms will have a beneficial effect and turn the tide.

[imafan26]

I am encountering that too in my conventional cucumber pot. I have two cucumbers that are fine but two others withered away. I dug out the soil and replaced it with new, and transplanted more seedlings, but they died too. This time I transplanted a seedling with a good well established root system and see what happens. Actually, I think part of the problem is that I have been trying not to replace all the soil in the containers because it is too hard to get. Under normal conditions, I would dump out the soil in the yard and start fresh in the pots. Not using fresh soil every time, pathogens can build up in the soil and come back to bite me.

[applestar]

Try to introduce probiotics to counter the inimical microbes.

Simplest method is to start with nutrient dense liquid like brown rice washing water, whole grain pasta cooking water, greens parboiling water (don’t add salt), then add some fruit scraps like banana peel, fruit core peel, etc (I only use organically grown fruits)
…or diluted juice and/or milk…or just some brown sugar and a pinch of sea salt… then add yogurt whey, bread baking yeast, mashed natto or natto powder, etc.

If you have vermicompost, that could be source of good microbes too.

Allow to ferment and culture in warm place for at least 24 hours to 72 hours, then dilute 1/10 and use to moisten the soil.

You can add used coffee grounds, tea leaves, etc. to add fresh “food” for your good microbes.

Be sure to dilute if you are trying to save plants that are growing in the container.

If you are trying to refresh the potting mix after losing plants — Advantage with yogurt, bread yeast, natto, etc. is they are anaerobic beneficials.

Treat the potting mix with stronger inoculant — maybe 1/2 dilution … and add more “food” — Mix well, wrap the container in plastic bag or cover top and secure, then let the microbes duke it out with the bad ones.

[imafan26]

I'll try that. I have a five gallon pail of coffee grounds, I always have yogurt going over the hill, yeast,and I have enough worm compost now to harvest some of them out. I don't have a compost pile, but I will ask my friend or at the garden if they have any ready compost. I have been using hot water treatments on the soil. It kills the good bacteria which I have to reseed with vermicompost, and I can only do that with small quantities of soil. I tried laying out the soil and letting it dry out in the sun, but it rained. I have soil in bags. I can put the bags out in the sun and let them solarize for a while.