Jane brought up a good point about the clear containers causing problems. Roots don't like light, but they like to stretch out. Most potting soils are dark and will absorb heat, and most roots don't like too much heat -- enough, but not too much.

Three liter containers may provide just enough soil, but it had better be GOOD soil with a good bit of compost, because what is in there is all the nutrients there are. If you have to water it a lot to keep the soil moist, a lot of the nutrients will be washing out with the extra water. A pint or so of Worm Tea from an organic gardening source is fine, about one tablespoon of it mixed into one gallon of water, fed to the plants once a week. If you have your own homemade compost, put a couple of handfuls into a bucket and fill with water, stir well and feed weekly. Or the same thing with composted (not fresh) manure.

I wouldn't use chemical fertilizers here, as they would be running over the fruit, which they wouldn't ordinarily be doing if the plants were right-side-up.

By the way, if you see wilting in the afternoon but the containers are damp, they don't need more water; they've just had a little more sun than they need. If it keeps happening, try moving them to another spot that has a bit more shade. I've seen this with zucchini more than anything else.

I would really like to know how this idea works out, if you think of posting the results this summer/fall. What worked, what didn't.

Sue