If in fact your soil has that high of a pH then not much will grow in it other than natives. Contact the AZ cooperative extension service. They will be able to help you. Good luck.

I live in Phoenix and had alkalinity problems too. Here's what you do. Go to Home Depot and buy liquid pool acid. Mix it about 1 tsp to 5 gallons of water. Then use a watering can or something to water your bed. Worked like a charm for me! I have read elsewhere that you shouldn't do that because it creates salts in the soil. Chemically that makes sense, but all I know is that now my veggies and flowers look fantastic! Note that this is not a substitute for amending the soil--still gotta do that if you're looking at native Arizona soil.

A rather late follow up to the my first response, but here it goes.

1 - Although 'braddenton's method would work in the very short short run, maybe half a season, it does cause additional salt buildup for the long run. Our water supply, whether city or well, has more than enough salts dissolved in them to cause problems.

2 - Mother Nature took millions of years to make this soil, what make any of us think we can change it in a few years.

3 - Most plants will grow well in soil with a pH of 6.0 - 8.0, including vegetables.

4. - I suggest you contact you county Coop Extension Service and have them do a complete soil analysis of your soil. In NM it cost $20.00.

well you approached the problem right by checking the ph first. as stated above, 6.0 - 8.0 will support almost anything. 8-10inches dries fast in az, maybe try raising the beds another 8 inches? sounds like you need to rotate your crops. your soil is probably totally depleted from the first year- especially in 8-10 inches of soil. ive never been able to grow anything in the same spot 2 years in a row except lettuce. corn, tomatoes- forget it. actually most of my tomatoes got blossom end rot from calcium deficiancy before the first season was even done so this will be a seasonal fight. if ph is close to neutral, then i would try to bust some of that caliche and add as much organic matter as possible and you should be ok. i make my own compost in a rubbermaid container from walmart w/ a lid. fill with anything that is natural and can rot. i.e. banana peels, apple peels, any fruit period, crushed egg shells, spent coffee grounds are great, leaves, last seasons dead crop, try to avoid sticks unless they're mulched. no meat, no wrappers, no metal, no animal poo, etc, you will need to stir once a month and keep moist. container will get warm during decomposition, be sure to decomp first. this saved my garden last year. look for worms- thats a sign things are getting better. for now you can buy it at H.D. mycorrhizal fungi is my new kick, check it out.

http://gardening.about.com/od/gardenprimer/a/Amending_Soil.htm

http://www.bghydro.com/BGH/itemdesc.asp?ic=NEGRM16 best deal ive seen so far for mycorrhizae

Adding a 4 inch layer of organic matter each year will help make your soil friable and will help reduce the pH a little. Also, adding soil sulfur will further reduce the pH. You can use the product known as Dispursul or Ammonium sulfate.

In my garden beds I use a mixture of 4 inches native soil, 4 inches sand (pumice is better) and 4 inches of composted mulch and blend it until its uniform. I often add ammonium sulfate when tilling the beds.

You will need to add 4 inches of composted mulch each year as our alkaline soils burn up the organic matter quickly.

I hope this helps.