Do you know what the high and low temperatures are? It's early in a lot of places. There's time for them to get with the program.

The past week or so we've had highs in the mid 70s and lows in the mid 40s. The next week looks like high temps all over the map, from the low 70s to the upper 80s, but the lows will hover in the mid 50s. But would temperature affect the color much? I thought yellowing was primarily a nutrition thing.

I do have about two out of the dozen or seedlings I have that look like they're greening up.

Here's a bird's-eye view of my matas which I think tells the tale a little better.

What did you plant them in? Looks like ground up small sticks or bark, if so not good. Big huge complicated reason behind it so I'll leave it at that.

It's a commercial potting mix -- Kelloggs, I believe. It's what I grew my tomatoes in last year (in containers) and they did pretty well. Objects in the mirror may appear chunkier than they are, so to speak. It's not really as chunky as the surface may lead one to believe. Think I should yank 'em out of there and put them in a more standard Miracle Grow kind of mix?

Here's the deal and I'll try to keep it simple, when high carbon items are added micro organisms have a feeding frenzy on the carbon which causes a population explosion but they also consume nitrogen as a food source. Because the carbon amount to nitrogen is so high with certain things like wood, sticks and bark there isn't enough nitrogen to feed the huge population of micro organisms and the plant. When you add nitrogen the bugs will feed on it and may not be enough for the plants unless you increase the amount. They will finally die and release the nitrogen which the plants can use or it can be consumed buy even larger generations of bugs. It's simply the cycle of composition but at some point a high percentage of the bugs will die once most of the carbon is consumed and will release a lot of nitrogen.

You can continue to feed the micro organisms and the plant with extra nitrogen using the greening of the leaves as a guide until transplanting out doors, or re-pot them into something already completely composted. Your choice.

The picture does help.

"But would temperature affect the color much? I thought yellowing was primarily a nutrition thing."

It is usually "nutritional", but lots of things can effect the take up of nutrients. Especially pH, but think temperature as well. Are they outside?

So in a nutshell, Kevin, because the soil mix contains so much bark, the plants aren’t getting the nitrogen they need. So I’d probably be better off replanting them in a different mix, correct?

And Nan, yes, they are outside 24/7 now.

Sounds as if they need some more nitrogen. They are probably sulking a bit because they are outside and it's cooler, but they should get over it with some new potting mix, and as long as the weather improves.

Yep, replant or up the nitrogen fertilizer a little bit. I looked the potting soil up and personally I'd just get the plants green and leave them until replanting outdoors.

Kellogg's products have a lot of forest products not completely decomposed but the ingredient list show they add chicken manure to supply nitrogen so they know. Just increase the frequency you add your fertilizer mix until green.

Thanks for the suggestion, Kevin. These are actually leftover tomato plants I was saving for friends and neighbors, but I can’t order them looking like this. 😯

Ya think the alfalfa tea is a good enough nitrogen source? Or can you recommend something better? And how often would you fertilize in the hope of greening these babies up?

Thanks Labradors. Well, it’ll certainly start warming up now. Supposed to be 90 degrees today. In April! That’s unusual even here in sunny California.

My neighbor comment should be I can’t OFFER them like this, not “order.”

Ray, what your using is just to little nitrogen, Fish emulsion has the lowest C:N ratio and very little nitrogen for organic amendments so bump up the feeding, you just need more nitrogen, your feeding billions of micro organisms plus your plant I'd suggest no more Epsom salt (magnesium sulfate). The plant needs very little and to much of anything will cause toxicity. I pot plants using 1 to 2 cups of Jobe's organic fertilizer which is just composed chicken manure in a 5 gallon bucket of potting soil to get the nitrogen for the plants. Most brands of potting soil use ground up high carbon woody products which aren't completely composted and carbon to nitrogen ratio is just too high.

The ideal C:N ratio in the soil is 25:1. Straw like rye, wheat, oat have a C:N ratio 75 to 100:1 The woody forest stuff in you potting soil has a C:N ratio of between 135:1 all the way up to 1200:1. and is why they put chicken manure in it .

Kevin, I think your theory about the wrong potting mix is right on the money. I examined my seedlings this morning and noticed that only two out of the whole bunch look decent. Then I realized that these were the last two I potted up. I had run out of pots and potting mix, so I had to scrounge around for both. Instead of that bark Kellogs stuff, I used some old potting mix from a pot I had just sitting around. Those two plants look green and healthy. Everything else, not so much.

So I spent my morning repotting all my seedlings in some Miracle Grow potting mix my wife had lying around for a house plant. I'm sure those seedlings did not appreciate being transplanted yet again, but I don't think they would have survived a whole lot longer as they were.

So, should I keep them in the shade for a few days before putting them back out in the sunshine? Should I wait a while before fertilizing them again, or might they appreciate a little alfalfa tea this evening?

That's what I do Ray. They're in a state of shock so water good and wait a day or two to put in the light. I usually re pot and sit them on a lower shelf for a day out of direct light. I also wait for a cloudy day or in late afternoon toward twilight to transplant them outdoors. As far as fertilizing I always mix it in with the potting soil so it's there but I really can't say if it's the right way. I do a lot of things not exactly considered normal and sometimes laughable. I've tried so much recommended by others as the best way, or the easiest way or the wife tales people swear too that I gave up and now source professional publications for commercial farmers and science for the answers.

Now I know 1 banana peel Jerry said to put in with a tomato plant is wrong. Science taught me it takes almost 4 peels spread over the season is what is needed to supply the potassium for an average tomato plant. Sorry Jerry Baker but YOU ARE WRONG! I know how much of any macro or micro nutrient to feed a tomato plant to the milligram and what stage it feed it. It's become an obsessive addiction and all because of Jerry. But anyway Ray, good luck and I hope your plants thrive.

Thanks Kevin. Your input has been so helpful, and I really appreciate it, along with the other input folks have offered here. I'll report back in a week or two with a progress report. Fingers crossed.

That's great you were able to turn them around. My tomatoes are getting yellow too and I just repotted them today with added compost. Hope that does the trick plus I gave it some tomato food.

Good luck, Windstruck. I'm surprised we love growing tomatoes so much when they can downright hard to grow sometimes.

Raymondo, it's good to know that you discovered the problem and were able to fix it :). Often the potting mix is water-retentive and, consequently too wet for the seedlings :(. I try to stay away from it!

Linda