Does anyone have any ideas why tomato seedlings turn yellow?

Other plants we have or landscape elements like ponds.

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stevelau1911
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Does anyone have any ideas why tomato seedlings turn yellow?

Post by stevelau1911 »

All my vegetable seedlings are thriving and dark green with the exception of my tomatoes, and I have no idea why.

I give them plain water with a small amount of liquid kelp mixed in. They also have very purple stems. Is there any way to green them up safely? They are growing in straight peat moss.

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Tarzanus
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Re: Does anyone have any ideas why tomato seedlings turn yel

Post by Tarzanus »

Purple usually means K or in some cases Mn deficiency. Yellow with dark green veins can mean it's lacking Mg, yellow on top leaves first - iron deficiency, yellow on the bottom of the plant first - nitrogen deficiency.

Since I know you most likely feed it abundantly, it can easily be overfeeding issue. Adding too much MgSO4 to treat Mg deficiency will lock up iron availability. I would flush the soil or at this stage, wash the soil off the test seedling and place it into fresh peat moss or even better garden compost/peat moss mixture. I would keep fertilizers away and only use water for at least a week or so.

Salt buildup can destroy the soil completely for plants that can't tolerate it. Overfed plants often get that kind of salt buildup and start showing signs of deficiencies, you react by feeding them even more and they eventually die. we all do the same mistake. :mrgreen:
stevelau1911
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Re: Does anyone have any ideas why tomato seedlings turn yel

Post by stevelau1911 »

The only thing I've been doing is giving it a bit of kelp in the water so I guess it just didn't have enough fertilizer since peat moss doesn't have nutrients. I decided to start a light regimen of miracle gro 10-15-10, and the fertilized ones turned green again while the unfertilized ones got worse.

Here's the same one from the other picture after a couple days of fertilization.
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The unfertilized ones are getting worse and worse so I plan to start fertilizing those too since the results appear pretty clear now.
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johnw
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Re: Does anyone have any ideas why tomato seedlings turn yel

Post by johnw »

How salty is that kelp you're using?
johnw coastal Nova Scotia
stevelau1911
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Re: Does anyone have any ideas why tomato seedlings turn yel

Post by stevelau1911 »

I just used liquid kelp, but obviously it didn't have enough NPK for tomatoes which appeared to be my only type of seedling that needed more fertilization. The leaves are even darker now because the miracle gro seems to get into the leaves almost immediately. All it took was about a tablespoon of miracle gro per gallon to fix this deficiency.

When they turn darker green, they also appear to be growing bigger now that they can get more photosynthesis. This seems to be the same exact pattern on the garlic as well. The fertilization turns them slightly darker giving them more ability for photosynthesis which causes the fertilized garlic to now look clearly larger than the unfertilized ones after 2-3 weeks. On garlic fertilization seems to help, but ultimately scape removal may be the most important step or else lots of bulb size gets lost.
stevelau1911
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Re: Does anyone have any ideas why tomato seedlings turn yel

Post by stevelau1911 »

Miracle Gro is definitely living up to its name in regards to tomato plants. After feeding the non fertilized ones with it too, they have started greening up as well.

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This has made a huge change in just 48 hours.
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Miracle gro is pretty expensive for it's quantity so I reserve it only for seedlings or potted plants.
johnw
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Re: Does anyone have any ideas why tomato seedlings turn yel

Post by johnw »

Steve - Here you can go to a commercial supplier to get the Professional version of the same fertilizer - made by Peters or Plant Prod - and get a 15kg bag for about half the price of the Mircale Gro.

Once upon a time there was a fertilizer brand called RX that everyone said was vastly superior to the Peters equivalent. When RX went belly-up no one would switch to Peters and yet Peters had been supplying RX with the fertilizer all along.

john
johnw coastal Nova Scotia
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