Shortcut: When the trees arrive, place them directly into the compost heap.

Seriously, neither tree will thrive in the Phoenix area, and they don't set fruit much.

If you are really determined, go talk to the Tropical tree nursery guy on Baseline and buy from him. His stuff at least has a bit of a chance.

For avocados, make sure you get one of the following varieties grafted onto Lula rootstock:

Brogdon, Day, Lula, Choquette, Marcus, Winter Mexican. Avocados grafted onto the mexican rootstocks they use in California will have little chance of surviving here.

For the atemoya, 48-26 and gefner will both set fruit but will need frost protection and shade cloth the first summer.

If you have not done this yet attend the next ARFG meeting and talk to Doug.

My tip is to not plant avacados, especially if you are doing this with the expectation that they will fruit. I am currently nursing one along outside on the north side of my house, under 50% shade cloth. It is not doing well. Avacados don't seem to do well in our rocky soil, high temps, lack of humidity, and saline water.

Figs and citrus can sure do well here though.

Dave

Avocado will grow here with a combination of good soil, mulch, shade first few years, and not overwatering. I dug down 40 inches to get out the Az soil. Growing from seed is the best way to succeed. I know of a few people here that have multiple 30 foot trees that fruit.

Here ya' go. This will lead you to more info than you ever needed.
http://www.ucavo.ucr.edu/
Be aware that harvest season will vary from area to area. Generally, Mexican varieties are earlier than the others and more hearty against frost.
also be sure to get both A and B flowers for best pollination.
You may also want to consider ordering locally or from CA instead of FL, since they are growing varieties and grafting on root stocks that are better adapted to our soil and climate in the west. FL's humid climate does better with different choices.

Here's my 3 choices
Name - flavor - oil content - season - size - flower type - parentage - temperature hardness.

Mexicola Good Purple 20% Sept. to Nov. 4- 8 oz Type A Mexican Very Hardy to 20ºF

Stewart VeryGood Purple 18% Oct. to Dec. 6-12 oz Type A Mexican Very Hardy to 24ºF

Jim VeryGood Green 18% Nov. to Feb. 8-12 oz Type B Mostly Mexican Very Hardy to 24ºF

PS a good way to deal with TRUE caliche, is to use pool acid and let it soak in then peal back that layer. Learned that trick from my geology professor.