Seedlings yellowing

5 years ago

I transplanted my tomatoes about a week ago. I had multiple seedlings in cells and separated them each into their own 3.5" square pots (5" tall). About half of them are currently not looking very good; the cotyledons yellowed first, and then the true leaves also started to yellow. Here's a photo:

I tried dilute fertilizer on a few of them maybe 4 days ago (Miracle-Gro 15-30-15, at 1/2 tsp per gallon), but it doesn't seem to have helped yet. I thoroughly watered the pots after transplanting, but haven't watered since (other than giving a few of them fertilizer). However, the pots are still damp. Maybe they're too big? (But I know plenty of people pot up from cells into pots about this size.)

Does anyone know what's going on, and what (if anything) I can do? If it's too late for these I might have time to start new seeds, but I don't know what I should do differently to keep it from happening again.

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michael19
Original Author

5 years ago

I just wanted to update: I got those seedlings out of that soil and into Miracle-Gro potting soil (without moisture control). It was much finer, similar to the seed starting mix I used when starting seeds. Within a week (possibly sooner) the seedlings were looking much better. They are now green without any hint of yellow. I guess I won't be using the other potting soil again! Thanks for the help!

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Comments (6)

Labradors
5 years ago
I wonder if it's the medium you are using. It looks (and sounds) very wet. Perhaps it's holding too much moisture. I see a fertilizer blob there, so you probably didn't need to give more fertilizer right after potting up. You could always try transplanting some of the seedlings into a different potting mix to see if it makes a difference.

Linda
michael19 thanked Labradors
JoJo (Nevada 9A)
5 years ago
My guess would be too much moisture in the potting mix, and/or not enough nitrogen. What kind of potting mix is that?

Are you growing them under lights and using a fan? This usually helps with drying the medium faster.

I recommend feeding seedlings with fish or fish/kelp emulsion. It's very gentle but gives them just enough nitrogen to keep them green and growing.
michael19 thanked JoJo (Nevada 9A)
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michael19
Original Author
5 years ago
I'm using this Vigoro potting mix. The bag lists the NPK as 0.07-0.04-0.03, which I figured was too weak to matter--maybe wrongly? I also see now that it says it "helps retain moisture." Drat. That is probably why it is staying wet so long, and it sounds like you both think too much water is the problem. I think I will have to try to find some potting soil that doesn't have moisture control.

I grow under lights but don't usually use a fan. I started using one for a few hours a day earlier this week and the soil is still damp.

I'm nervous about transplanting them again so soon after the first time (those poor roots!)...but maybe it's better than leaving them in this soil? What do you think?
Labradors
5 years ago
I would get them out of there. They can take it. That moisture-retentive mix is horrid!

Linda
Labradors
5 years ago
Many thanks for letting us know. That moisture-retentive potting mix certainly can make life difficult and I'm really glad that you were able to get your seedlings out of it :).

Linda