Q: I'm very new to gardening. My father-in-law made me some boxes without bottoms (about 3' x 4' x 8"). We put landscaping cloth in the bottom and sat them on a concrete slab in our yard. We filled them with good soil and planted tomatoes, bush beans, peppers and flowers, one plant per box. Nothing grew! While they are mostly alive, they never got bigger and they look sick. I got one sick bean and one sick tomato from my plants. We did notice a lot of crows and there are squirrels — we couldn't tell if they were the problem. I'm afraid to try again next year. Any ideas of what I did wrong?
It looks like you might have a handful of strikes against you in your first gardening experience. To begin with, 8 inches is a little too shallow for most plants. And, although you lined the boxes with hardware cloth for good drainage, putting the boxes on a concrete slab will keep water from draining properly. Crows like seeds, and squirrels will dig most anything out of the ground, so they may factor into the failed garden experience as well. Since you didn't say whether or not the boxes are in full sunshine, nor did you say how often things were watered and fertilized, I'll have to count those things as possible problems, too.
Raised beds are excellent ways to raise vegetables and grow flowers. But most plant roots need a depth of 12 to 18 inches of soil to give the roots enough room to develop and support the plants. (Some exceptions might be small annuals.) Perhaps your father-in-law can be persuaded to add another 8 inches to the boxes to give your plants 16 inches of soil depth. I'd suggest either moving the boxes to a better draining area, or putting them up on 2" x 4" blocks to allow water to drain beneath them (you'll need to reinforce the bottom if you do; hardware cloth and its fasteners probably won't be able to hold the weight of the soil and water). If the boxes are in full sunshine, the concrete will reflect heat onto the plants and into the soil. With such a shallow depth of 8 inches, the roots probably cook every afternoon.
Finally, if crows are a problem, you may want to lay birdnetting over the newly planted boxes to protect the seeds. Once the plants are 4 to 6 inches high, you can remove the netting because the plants will be big enough to take care of themselves. When your veggie plants are up and growing, be sure to provide water as often as necessary when the soil begins to dry out.
I hope these results won't keep you from trying again next year. Following the above suggestions should result in a thriving, productive garden. Better luck next season!