New to SQF

Living right next to and under the crest of the Superstition Mt. , we grow rocks, saguaro, Mesquite, Palo Verde, Cats Claw, Jojoba, Creosote, Ironwood, Ocotillo, Cholla , (nasty thorns), and several other cactus that are indigenous to the area. I am attempting to plant a small above ground garden in a 2 halves of a horse watering tank that are about 12" or more deep. I have them side by side in an area that currently receives morning shade until about 9 - 10 am then sun until 4 -5 pm. This is in an area on the north side of the house. I have tried to garden before, but the ground squirrels, rabbits, grackles and other birds were in hot competition. I gave up and am trying again. I am interested in the type of mulch and composte used to turn our rocky, clay soil into garden soil with worms. Also is it to late to plant anything. I am going to try some squash and melon and am curious about pumpkin. As you can see I have a lot of questions and books but not the answers or advice I need. Any advice or help will be appreciated.
Superstition

Welcome Superstition!
I am assuming you are here in Az. We have been able to get compost and even mulch at Gro-well.

http://gro-well.com/

I also suggest reading the all new square foot gardening book. Lots of great info on how to make the mix for your new gardening beds.

Your garden location sounds great. Mine is on the west side of my home and gets hammered in the summer here.

Be sure to check out lots of posts here. Some people put chicken wire under their beds to keep out burrowing pests. Some have made tops to go over their beds to keep them out too. I use tulle bags over my tomatoes to keep the birds off and it has worked very nicely!

Squash, melons, basil, pumpkin, sweet potatoes, and maybe chard are the only things I would suggest planting right now. Then in Late August/early September is when you begin planting for fall.

Good luck!

Get the book! All New Square Foot Gardening. Newest edition 2013. You will refer to it often, I still do, even 3 years later, lots of great stuff in there.

To keep out bottom critters use 1/2" or 1/4 "hardware cloth, it's actually wire not cloth. Chicken wire openings can be an entire inch in diameter, letting in little critters.

Critter covers for the top of the beds is described in the book too. I've used them for nearly 3 years. It does work.

Welcome to the forum!

Welcome Superstition, Yes, you must get the book. I got mine gently-used on eBay, or was it Amazon? Any way, you will find out you don't have to "do" anything to your native soil. This is all above ground with a specific mix to fill in the boxes. You will get lots of good info from this SFG forum. Good people. I assume you get afternoon heat? Folks here can give you advice on protecting your crops from baking!