Tomatoe cages aren't tall enough, you need to get some lumber and cut yourself some tall stakes.
Hard ground, get someone to run a plow through it, you can rent most anything you need.
Don't plan on watering a garden, nature can handle it, but a jug of Miracle grow and water mixture is good on occasion, be sure to water before and after to keep from burning it up.
I'm not a fan of poison, my family has farmed for years, great grandfather refused to poison his tobacco, silver dust is all you need.
A real fence builder doesn't need concrete, I can show you how to do one so tight to can play a tune on it.