Tomato problem

What is wrong with these tomato leafs? Should I pinch them off? Also I have some seedlings that have purple leafs, why is that?

I don't really attend much to individual plants, so I have no suggestions about pinching those leaves. But in my mix of tomatoes, purple foliage is likely to correspond to purple fruit, so that's lucky!

I'm not sure about your leaf blotches - looks like a fungal infection to me, but it could be sun scorch perhaps?
Purple growing leaves are a sign of stress or deficiency - I quite often get that if the tomato plants are a bit cold, they usually grow through it as they get older. It could be Phosphorus deficiency perhaps though; a drink of compost tea will likely fix that. Possibly they are a bit water logged, I've had that happen where the compost is not well drained - it is dry on the top so you water, but the poor things actually have soggy bottoms so I make the situation worse. You can check the dampness through the soil by putting a wooden skewer into the pot and check by pulling it out before you water.

I second what Nancy says as a possibility. However, when my tomatoes were stressed and purple, the whole leaf was purple. So it is possible the blotches are some sort of disease.

i have some russian purple tomatoes coming up and they are visibly more purple than the other plants in the foliage.

as for the spots, it might be useful to know if you have diseases in your area that produce that. where i live, any tomato grown in the open will get those black spots from fungal disease, and so all tomatoes have to be grown under a roof of some sort. We have folks from all over the world here so if you say you're in, say, Delaware, someone can probably give you an idea of what you can expect in your region.

It could be bacterial or fungal diseases. Are the spots first appeared from lower leaves? Wet weather can cause soil borne pathogens to splash onto the leaves. If so mulching will help. You could also put an overhead tent to keep the leaves dry from rain or dew.

We recently had 90 degree temps for close to a week and now we dropped down to frost warnings almost nightly (yay northern Minnesota). So the sun, wind and heat exposure for all my seedlings has been very inconsistent to say the least. I have sprinkled some happy frog 6-4-5 in the bottom of my 1020 trays (a teaspoon) and bottom watered as I always do. Hopefully that turns the purple seedlings around. The two sweet 100 cherry tomato plants I also fertilized with a tiny dusting and got them outside, hoping they come around as well. Not a long growing season up here, so to start over could possibly be complee failure, I'd have to go to the garden center and buy some veggie starts. Thank you for all the replies, they are very helpful

I agree with the others that this is a fungal issue especially since there are black spots.

It seems to be a fungal disease, and what might help is a spray of horsetail (Equisetum arvense) tea (the salicilic acid in horsetail will likely induce systemic acquired resistance (SAR)).

My suspicion is that the purple leaves and black spots are two different phenomena; the purple tinge is either from cold or soil deficiency which will likely go away as soon as you set the plants outside but the black spots are a disease--I get blights every year, I think usually early blight, which that does not look like, sometimes septoria which looks like early blight, and sometimes late blight which does involve black spots on leaves but starts on the underside of the leaves--the picture looks like it's on the top side. The last couple years I've grown a variety called Chocolate Stripes that makes big round tomatoes with deep red color striped with dark green, very tasty and productive--it got lots of late blight both years but it didn't seem to harm the plant nor did it spread to other tomatoes--perhaps because I choose disease-resistant varieties and many really do resist late blight while the early blight resistance is weak. Best I've found are Defiant and Stellar, both unfortunately hybrids featuring expensive seed--and this year I got nine seedlings out of the ten seeds of Defiant and then some wretched mouse--I guess--took to biting the junction of the seed leaves, killing the plants--took out many Defiants (and cutworms got a couple too, the only ones they hit!) and ALL of my Carmen peppers, also expensive seed. The little b$$% has expensive tastes I guess.

Hi Josh! You're definitely not alone — tomato leaves can be very expressive when something's off. Let’s break it down:

🟢 1. Leaf Curl / Distortion
If the leaves are twisting, curling, or looking misshapen, common causes include:

Environmental stress: heat, wind, or inconsistent watering

Over-fertilization: especially high-nitrogen feeds

Herbicide drift: even a small amount from nearby can affect tomatoes
In most cases, if it’s just a few affected leaves, you can pinch them off, especially if they’re older, lower leaves. This can help airflow too.

🟣 2. Purple Leaves on Seedlings
Purple coloring on tomato seedlings is usually a sign of phosphorus deficiency. This often happens when:

Soil is too cold (phosphorus becomes less available)

You're using a soilless mix without added nutrients

The seedlings are underfed

✅ Try moving the seedlings to a warmer spot and giving a balanced liquid feed (like a diluted tomato fertilizer or a complete organic mix). Once they go into the ground and warm up, the color usually normalizes.

If you have pics, I’d be happy to take a closer look — it’s much easier to diagnose visually.

Hope that helps, and good luck with your tomatoes! 🍅

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(NightshadeFamily.com – We grow and troubleshoot nightshades all day!)

Josh Dagle wrote:What is wrong with these tomato leafs? Should I pinch them off? Also I have some seedlings that have purple leafs, why is that?

Tomato and potato both belong to the solanum family. Potato blight, a fungal disease, can affect tomatoes as well. Usually occurs in hot humid conditions. I have had it several years, but often the tomatoes are OK.

My 2 cents; it looks like your tomato is infected by Septoria lycopersici fungus.  
It starts as small black dots and then it spreads.  I am not 100% sure, it just looks like it to me.
As for purple color under tomato leaves, I never worry about it. All my seedling always  have it, and then all leaves turn green once hardened off to grow outdoors.
I was trying to insert pictures, but not sure if it will work.

My purple leaked tomato seedlings appear to be stunted, they have not sprouted another leaf or grown at all in the last almost 3 weeks. I transplanted some out into the garden with happy frog all Purpose fertilizer and a sprinkle of eggshells from our chickens and watered them in. So far 8 have died overnight. Thankfully I did 3 successions of tomatoes and have some really little ones coming up in trays. Im way behind though with our short northern minnesota growing season. The three that had the spots I bought from our local greenhouse so I at least have something going. I will post pics of the purple ones tomorrow, im at work for the night right now.

Your long days will probably make up for the shorter season. To speed up fruiting, after the tomato seedling produces first flower, pinch it off, and remove the sucker immediately below. This way you will have a plant with a single leader. It will put out one flower cluster every three leaves. Keep on removing suckers and you will have an early harvest as the plant will put all energy into growing fruits.