seedlings looking bad

[drh146]

So I started some tomatoes under a light a few weeks ago. Everything was fine until I forgot to turn the light off one night so they got over their 16 hours and probably got more like 30 hours that time. This was almost a week ago. Since then they have curled, yellowed, and seemingly stopped growing...

Below is a picture of one. I pretty sure water is ok. Temperature is low to mid 70s. I'm thinking about getting a timer so they don't have to rely on my questionable memory, but can anyone tell by looking what could be wrong and how I can rectify ?

[wolfwalker]

Wonder if the soil is overly wet. I have had the lights on a few days and the plants never turned yellow. Keep the light close to the plants about a inch above. Good luck

[applestar]

I agree -- more like water logged soil. Put more drainage holes in the container -- utility knife slits will work too ...slit the side of the bottom rim in 6-8 places.

-- and don't water again until
• surface of soil is lighter in color and barely damp (nothing sticks to finger when pressed)
• In a clear container like this -- the sides inside should look dry.
• Also heft and feel the container and water when it feels lighter.

[imafan26]

Do not let pots sit in water either. There should be no water in the tray.

[drh146]

I thought it looked like damage from too much water, but I guess I was in denial...

I'll slow the watering and get a little fan. The heater"s fan isn't getting to them enough.

Thanks for the help!

[Bobberman]

How much fertilizer have you used. Too much stops the plants form absorbing water! Too much is as bad or even worse than none!

[drh146]

Just what's in miraclegro potting soil. I mix 1 part miracle grow potting soil, 1 part black kow, 1 part peat moss..

[applestar]

Ouch that sounds a little too rich and water retentive for seed starting.

This year, I'm taking a break from making my own mix since I caught a substantial discount + free shipping on Espoma organic potting mix last fall and stocked up.

I normally dilute the potting mix 2:1 with inert material for starting seeds -- last year was perlite, pumice gravel and coir. I'm trying to use up bags of sand from last year so I'm just diluting the potting mix with sand right now (Coir box is buried ATM )

This will likely change once I get organized and start sowing the peppers and tomatoes.

When I uppot, I add to the potting mix for a richer/more fertile mix and for increased drainage.

[drh146]

Ok... Well then what about just mixing black kow and peat moss?

And these are uppoted from my germination bin. They were 2 or 3in when I did so?

[applestar]

For seed starting, I would rather go with the miraclegro + sand or perlite if you already have the potting mix. Blackkow is basically N rich compost and doesn't have all nutes, micros needed for plants to grow.

From your description of the current mix, the yellowing seed leaves could very well be due to excessive nutrients. The seed leaves feed the seedling, but if there us excess of available soil nutrients, the seed leaves are superfluous and drop off (but in doing so, the seedling loses the seedleaves' chlorophyl/solar energy collectors.

I don't uppot to richer mix until 2nd pair of true leaves start to grow. In any case, you don't want to over fertilize the tomato and pepper seedlings because they grow too fast -- too tall to fit under the lights, too wide/compete for space and shade each other, and also too spindly and weak.

I mix 1 part miracle grow potting soil, 1 part black kow, 1 part peat moss..

IMHO I think this is good combination for older seedlings IF you also add 1 part sand/perlite. (Though, personally, I would use coir instead of peat moss. You could also leave out the peat moss/coir altogether.)

[Susan W]

Not to stir a bad pot, but I just checked the partial bag of BlackKow I have. NPK are listed as .5-.5-.5. I have gone to it to mix in, perhaps 1/4 to 1/3 in my containers and freshening ground areas. It does have sand and other dirt, ground wood etc. If anything, there may be too much peat (water holder) in these tomato start cups.

Next comment is I don't know what to suggest to seed start in a container, and not a bitty cell/coir pellet.

[applestar]

Oh dear -- sorry I assumed it was a brand of composted cow manure. It's not the one that has a bad rep/review is it? There a brand -- sold at one or many of the big box stores -- that has been mentioned time and time again as being junky and I sufficiently composted (robs N).

For composted amendment, I usually buy BumperCrop (Maine), Mushroom Compost (Lancaster Co., PA), or Humus (can't remember now but it was a local source) if I buy them in bags at all -- mostly I prefer to use my own compost pile compost or vermicompost.

I really shouldn't make any comment re:MG potting mix -- I tried their so called "organic" potting soil and regretted it a few years ago, but that's the extent of my MG potting soil experience unless we go back 20 yrs or so. I like the Espoma organic I'm using now, also Dr. Earth organic, Gardener's Gold organic by same folks as BumperCrop, and I liked Pro-Mix Pro Ultra organic that I tried several years ago but that was the most expensive one ever. They have changed their recipe and name/packaging since then, I think, because I couldn't find the same one on their website last year.

[IndyGerdener]

I used MG last year in the beginning because I didn't have the parts to make my normal mix yet. I had a few tomato seedlings do this same thing. I don't know if the "Extended release" balls released all at once, or what, but once I changed over to my mix of (2 "pro mix", 1 mushroom compose, .5 sand, .5 perlite) I have not had the problem again.

[drh146]

So we originally said it was too much water. Now its too much fertilizer making them not absorb water. Arent those contradicting diagnoseses?

[Bobberman]

Too much fertilizer will cause damage to the tiny roots and they cannot absorb water no matter how wet. Too much water pushes the air out of the soil and drowns the plant! When plants go into the garden the roots spread more and have less stress because the soil depth is better and too dry or too wet changes at different depts. so the plant can adapt! I am actually trying to think like a plant!

[imafan26]

If you have too much nitrogen in a seed starting mix, sometimes the plants won't even germinate.

If you do use MG potting soil, do not use the moisture control. The hydrogels hold too much water at the wrong time. The regular MG potting soil works fine as a seed starting mix but a little more perlite will help it drain better. I do not use the peat pellets or peat pots. I find they also hold too much water.

[IndyGerdener]

I am going to wager that it is a fertilizer problem and not a watering problem. although I have been wrong in the past...

[applestar]

I had another thought about the MG potting mix. Is the mix dry in the bag when you first open it? If they are pre-moistened, maybe the moisture and fertilizer salts wick up and concentrate in uneven areas of the bag?

Maybe it's a good idea to thoroughly mix the bag before opening or the contents after opening.

[IndyGerdener]

I had another thought about the MG potting mix. Is the mix dry in the bag when you first open it? If they are pre-moistened, maybe the moisture and fertilizer salts wick up and concentrate in uneven areas of the bag?

Maybe it's a good idea to thoroughly mix the bag before opening or the contents after opening.

That is a good thought. I would add some sand to it as well (If you are mixing it anyway)!!

[drh146]

So the fertilizer makes them not absorb water, and appear as they have too much?

They aren't drying out.

[applestar]

I'm not really sure about how the mechanism for not absorbing water works, but -- if I understand the process and the problem correctly -- IF the plant can't absorb water, then the amount provided would remain in the soil, and IF there is too much moisture in the soil because it is not being taken up by the plant, then the soil can become anaerobic and lead to increased fungal problems as well as root rot, then the plant can't take up water and the leaves would yellow.

Hmmm thinking about it -- are we talking about osmosis? Too much salts in the soil would mean osmotic pressure would cause water to leave the plant roots or at least cause negative pressure so the plant can't absorb water?