Some tomato starts not growing well and have swollen veins on leaves

Question: Some of my tomatoes are struggling to grow and I don’t know why. Most of my plants are fine but a few are stunted with some yellow leaves and swollen veins on the backside of the leaves. All my plants were planted the same time, in the same soil, in the same location, with the same lighting. Most of my seeds are saved from past years and I had two new varieties purchased from a reputable source. One new variety is struggling, the other is not. I have included pictures of the struggling plants, the normal plants for contrast, and a close up of the swollen veins. The white on the veins is not fuzzy like mold, but more like tiny droplets coming from the swollen veins. What might be happening and is there anything that I can do about it?

responder: Jacki D., Master Gardener Diagnostician Volunteer (Washington, Multnomah and Clackamas Counties) Oregon State University Extension Service Volunteer Metro Master Gardeners (http://metromastergardeners.org/) Replied April 24, 2023, 8:09 PM EDT
response: I may need to refer your question to another person. First, though, tell me about how you are keeping these warm and protected from recent hail and (in some areas) snow last week. Varieties of plants will have different cold tolerance, and even different reactions based on growth stage when cold hits.

responder: The Question Asker Replied April 24, 2023, 9:52 PM EDT
response: Today was actually the first day I had them outside, starting to harden them off. So they missed all the bad weather. I start my plants in the basement with grow lights. It’s not as warm as the rest of the house, but it does get warmth from the finished part of the basement and I’ve been using that area for years to start my plants. And some of the varieties that are having issues I have not had problems with in the past with the same setup. Thanks for looking into this for me!SarahOn Mon, Apr 24, 2023 at 5:09 PM Ask Extension <<personal data hidden>> wrote:

responder: Rhonda Frick-Wright  Replied April 25, 2023, 11:14 AM EDT
response: Hi Sarah- As Jackie said, different plant varieties have different reactions to light, heat and cold. Since the plants being affected seem to be on the same tray, I would try to figure out what was different on that or those trays. Were they a bit farther from the light or heat source? It doesn't take much distance to make a big difference in size for tomatoes.  Did you use the same bag of potting soil for all the plants? I have noticed differences in plant growth even from soil from the same company. Some bags just seem to have more bark pieces which do rob nitrogen from the soil which often causes yellowing of the leaves.   The new growth of all the plants looks good, so I would continue hardening them off, remove the yellow leaves and go ahead and plant them. If there is a variety that just did worse than others, it just might now be a good match for your starting set up.  As to the swollen veins, I found an article that might help with future growing plans. If the plants were cooler than ideal, some varieties may not be able to balance the water they were given with the ability to expel it through the leaves, and this shows up in swollen veins. That variety may just need more heat than your setup allows.  https://sites.udel.edu/weeklycropupdate/?p=17945 Hope this helps with the mysteries... and keep up the good work. Your healthy plants look fabulous!