Recovery from leggy seedlings
Hello, this year I thought I would start my other Cucumber and Tomato plants from seeds indoors. They sprouted quickly and grew quickly, however, because I didn't have grow lights, they have become about 7 inches tall with very little foliage.... basically leggy. I also started them in rockwool and have been feeding them water from my hydroponic Tower Garden and other than the nutrient rich water, they have not been fertilized as of yet. I now have a grow light, but I'm wondering if I am better off just buying established plants this year or if it is possible to recover leggy plants?
Outside United States
Oh this happens to all of us; it can be frustrating. But alas, there is little that can be done to correct legginess. Having said that though, if they are stable enough to go through the hardening off process (and not so leggy that they just fall over or are too stretched/tender to handle), then it can be worth giving them good light and careful limited fertilizing. About 10 days before you transplant them outdoors (and cuc and tomatoes cannot take any hint of frost so you need to wait until safely in the frost-free period in your area), gradually get them used to the outdoors by putting them in a shady spot for a few hours each day... a bit longer each day and gradually into full sun. This "hardens off" the tissues.
This will work with the tomatoes, for sure since you can transplant them much deeper, burying a good portion of the stem. They will root from the stem and the plants will be as good as regular-grown stock. The cucumbers don't react well to that kind of planting though, so you may be better off simply starting seed now. Cucumber plants only need about 3 weeks between seeding and transplanting (unlike tomatoes that need between 8 and 10 weeks)... so there's still time to do your own cuc plants and you might be able to recuperate your tomatoes.