I've got few tomato plants in the glassy room with lots of light. The temepartures dropped significantly over the last weeks from 25°C to -5. The room T where I kept the tomatoes could fall below 15°C, but I am pretty sure if was above 10. Tomatoes had a little purple dots on the leaves. That dots got substantially larger over the last 2 weeks, although the room T is above 15° all the time. Also the leaves have purple veins and the stems are also purple. So I added a fertilizer containing phosphorus.

Does the purple leaves, veins and stems ever return to normal green color? How bad do you think is the condition of my plant? enter image description here enter image description hereenter image description here enter image description here enter image description here

This one was taken 10 days ago:

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  • just the bottom ones. the ones that are purple. but to be honest, everything about this tomato is a side shoot. the growing tip was cut off 4 weeks ago
    – sanjihan
    May 3, 2017 at 12:16
  • 1
    yes, that is the conventional method for growing tomatoes. I am trying to make something more bushy. Not saying that is the way to go. see this guy: youtube.com/watch?v=YCVhrP4et30&t=487s
    – sanjihan
    May 3, 2017 at 12:18
  • I am not sure, but there might be results in one of the later videos. too bad this channel isn't organised. but I kinda trust the guy, because he doesn't try to sell anything. Either way, all of those 3 stems are side shoots of the main stem and had flower clusters on, but I cut them in favor of maturing the plant first.
    – sanjihan
    May 3, 2017 at 19:28

1 Answer 1


No more fertilizing. This looks just fine. The leaves with purple dots just nip them off at the main stem. The plant would do the same to itself only slower. Damaged or too old leaves are not going to be able to do enough photosynthesis to help the plant itself. The purple veins are NORMAL and healthy. Have you grown tomatoes on this window sill and had any tomatoes to harvest? I'd put these plants in 5 gal to 10 gallon pots to go outside. 10 minutes the first couple of days...20 the next couple of days...called acclimation. Need to know where you live and your zone. If you've got iffy nights just keep plants out doors during the day and bring them in at night. To make tomatoes you've got to have lots of light.

Careful with fertilization...use only fertilizer where the nitrogen is the lowest number of the 3 biggies; N P K. 10 -12-12 for instance. You shouldn't fertilize again until you've transplanted into larger containers with fresh potting soil and are taking them outside to acclimate to the out of doors. When acclimated you should be able to plant them directly into the garden soil, don't worry about any additions to the soil...a little fertilizer after they acclimate to their new home. If that is what you want to do.

Too much nitrogen, no tomatoes, just lots of healthy leaves. Too much fertilizer will kill your plants. They look great right now.

  • Thanks for, as usual, great tips. Nope, this is my first time growing tomatoes indoors. The ones in the pictures are in around 4 gallon pots. I will put them outside to acclimate, but these plants won't be transplanted in the soil. It seems to be good idea to put them outside but is it also necessary to have any tomatoes on the plant (besides easier pollination)? Those plants are my attempt to harvest tomatoes in the winter..
    – sanjihan
    May 4, 2017 at 7:18
  • If you got a great grow light, 600 watts HPS or the 600 watt MH and grew your tomatoes in an enclosed/controlled room. Even 250 watt T5HO fixture would work. The deal to grow tomatoes during the winter are the shorter daylight hours. They need 16 hours of good light, not weak light which is what we get during the winter with the sun at such a low angle. Pollination you can do manually, a good shake now and then. Make sure you have a good fan that remains blowing 24/7 to reduce fungus problems. A timer to start the light (s) at say 6am and turn off at 9pm. Then undisturbed darkness.
    – stormy
    May 4, 2017 at 16:44
  • Those spots could have been a phosphorous deficiency that you've taken care of with the fertilizer. Or, looks to me like it could have been sunburn or too cold while that leaf was touching the glass? Also, I think you need to take that soil down a good inch from the rim of your pot. You will have a heck of a time watering. And all those baby weeds tell me you used garden soil? I'd allow them to grow and the next time you transplant use potting soil. Give them the best chance to make tomatoes. Allow the soil to dry before watering again. Just lift to feel the weight. When light water...
    – stormy
    May 4, 2017 at 16:54
  • If you want tomatoes in the winter forget worrying about acclimatizing out of doors. Where is it that you live again? Southern hemisphere somewhere?
    – stormy
    May 4, 2017 at 16:59
  • I think I made something unclear. I have a full of summer yet to come, but I would like to keep these plants also in the winter. That is why they are set in pots. I am from south-central europe. T from -15 to 35 Celcius.
    – sanjihan
    May 5, 2017 at 7:26

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