Hank GH

Kris, before hauling all that soil out, I'd ask a soil lab what it would cost to check it. Describe the rusted beds and poor crop growth. A test for nutrients and pH, which measures how acid the soil is, could help with the growing problem.

If your concern is metals from the beds, ask about that as a separate question. A routine test for plant nutrients is not the same as a test for metal contamination. Oregon State Extension explains that the test method changes what the results can tell you. The lab can help choose the right test before you send soil.

One useful detail from its sampling guide: don't use galvanized tools to collect a sample for zinc testing. Follow the lab's collection instructions.

Testing guide: https://extension.oregonstate.edu/catalog/pub/ec-1616-reducing-lead-hazard-gardens-play-areas
Sample collection: https://extension.oregonstate.edu/catalog/ec-628-guide-collecting-soil-samples-farms-gardens

Splitting the lettuce and tomatoes also lets you feed each crop to suit its needs. University of Minnesota Extension recommends separate containers for them because their nutrient needs differ.

For the tomato side, I'd check the seed packet's full-grown height and width against the space under the raised light. The number of pod holes can be more than the number of full-grown plants that fit, so I'd leave some empty if the plants need the room.

Which tomato variety are you planning to try in the iDOO?

The Extension guide covers crop choice, plant size and feeds: https://extension.umn.edu/how/small-scale-hydroponics

I think adding some evergreens would help a lot, maybe something that can grow pretty large... juniper for example, its slow, or just get an older tree. below it you can get vines. and I would absolutely put up hanging lights in there. Some chairs and an outdoor table, maybe some bug-zapping solar tiki torches as well.