Step 1 of 2: Determine your zone hardiness. Remember this includes both heat as well as cold tolerance. If your not sure what your zone is, I've provided a link to the USDA Zone Hardiness map. This will open a new window.
Once there, enter your zip code to determine your zone. Each plant description will list the compatible zones for that plant, such as Z4a-7a = most compatible for USDA Zones 4a through 7a. The further the plants are grown outside of these parameters, the more likely the plant can be lost from excessive heat or cold exposure.
Step 2 of 2; Determine soil type and moisture requirements. Desert plants can be divided into two groups with regards to soil type and moisture requirements. I recommend grouping plants separately in the garden based on these requirements, especially with an emphasis on keeping taller decidious plants away from cactus and succulents to keep the leaves and flowers from becomming entangled in the spines and plants in general.
Type 1: Low water demanding, rainfall dependant species: This includes cactus, succulents, and other plants that occur in open desert environments and grow in soils composed of mostly sand and rock with little compost and the soil pH is on alkaline side.
Soil mix for Type 1 plants, if you receive:
Less than 15 inches of rainfall annually = 6 parts pea gravel, 3 parts sand, 1 part top soil, 1 part high quality potting soil.
15-30 inches of rain annually = 10 parts pea gravel, 5 parts sand, 1 part top soil, 1 part high quality potting soil.
Above 30 inches of rain annually = 15 parts pea gravel, 5 parts sand, 1 part top soil, to 1 part high quality potting soil.
Type 2: Higher water demanding, permanent to intermittent water source dependant + rainfall species. This group includes plants occuring with desert areas but grow in wet areas near water courses, seepages, or areas where moisture collects and runs through. Also, the soil is has a higher consentration of compost to sand and gravel and the pH is more neutral to slightly acidic.
Soil mix for Type 2 plants:
Equal parts of each. 1 part pea gravel, sand, high quality potting soil & top soil.
If you receive less than 30 inches of rain per year, place plants on level ground or low lying areas where rainwater or moisture can collect.
If you receive more than 30 inches of rain per year, then place the plants in raised beds to avoid any standing water.