We have some tomatoes which look... off, slightly yellowing leaves.

Is there anything we can do differently here? Or anything really obvious?

These plants have more or less lived under grow lights for a while. They were transplanted recently, too.

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  • All plants we humans try to grow will need fertilizer. Chemistry they can use for photosynthesis to make their own food for energy, repairs, growth and storage. Save the Epsom salts for experts. Your plants need a little...balanced...fertilizer; NPK; nitrogen phosphorus and potassium. Start with that. Did you transplant these starts from indoors directly to the out door garden? To real sunshine? Big no no unless acclimated. Get Osmocote 14-14-14 extended release fertilizer beads. Safest bet for newbies! Tell us more about your conditions and we will be able to recommend others.
    – stormy
    Apr 25, 2018 at 9:13
  • If these tomatoes aren't in the garden soil yet, we need to talk before you transplant. If they are in pots, they should be in potting soil as well as given a balanced fertilizer.
    – stormy
    Apr 25, 2018 at 9:15
  • @stormy they were transplanted into pots that are now in our sunroom, so not outdoors without acclimiation.
    – enderland
    Apr 25, 2018 at 12:40
  • Good...just to make sure, however, plants going from the out of doors to the indoors environment also need acclimatization. Just need fertilizer...keep the Nitrogen in the formula LOWER than the P and the K or equal numbers. I just got some Dr. Earth 5-5-5 All Purpose while standing in the grocery store line...follow the directions. Did you use potting soil? I hope? This plant needs fertilizer, it isn't able to make its own food via photosynthesis. That will make a huge difference within days.
    – stormy
    Apr 25, 2018 at 20:35
  • 1
    @stormy well I will trim the blossoms at this point since they aren't super big and not going outside for almost a month ;) But yeah, should be fun.
    – enderland
    Apr 26, 2018 at 0:10

2 Answers 2


It could just be the new soil and growing conditions, but it looks like magnesium deficiency, since the leaf is yellowing with darker veins, as I've read happens with magnesium deficiency. You might give the plant some Epsom salt (magnesium sulfate).


You've likely exhausted the micronutrients in the potting soil you're using. Potted plants are entirely reliant on external fertiliser use since they don't have access to the soil. The early interveinal chlorosis that you're seeing could be magnesium, manganese etc. And you don't know what deficiency is going to appear next. So, better to give a general purpose fertilizer such as Miracle-gro that contains micronutrients and not just NPK.


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