Phoenix, Arizona is not known for good growing soil. When tilling up the ground you will find dense clay soil, rocks, and sand. Underneath the rocky clay soil you may also find caliche.
Caliche is soil commonly found in the Southwest. It is cemented together with calcium carbonate. This material is so hard it is used in construction and in the manufacturing of cement. Plants require well-draining soil. The soil in Phoenix has a composition which makes soil aeration more difficult.
Phoenix Garden Soil: Common Problems
As you can imagine, the composition of soil in Phoenix can be a challenge for gardening. Some problems that arise include
- Inadequate soil drainage
- Plant growth stunted
- Difficult excavation
- Lack of nutrients specifically Nitrogen, Phosphorus, and Iron.
Importance of Soil Drainage
Understandably this compact composition prevents soil from aerating. Well-draining aerated soil allows air to circulate. Well drained soil provides oxygen to the plant. How can you fix this problem? Organic matter added to your soil improves soil drainage. Perlite can also be mixed in with soil.
What You Need to Know About pH
The soil in Phoenix is less than ideal for growing a garden. With a pH range of 7 to 8.5 Phoenix soil is considered very alkaline and in the pH range of 7-8. The average or “normal” pH level in the low desert is 7.5. What does this mean for your garden?
Soil pH levels refers to how acidic or how alkaline soil is. A pH level below 7 is acidic and pH above 7 is alkaline. The most favorable pH range for plants is between of 6 and 7.

Soil with high alkalinity, like soil in Phoenix, means you will need to amend the soil used in your garden.
Excavating Landscape
Due to the soil conditioning tilling a garden or planting a tree can be more difficult in Phoenix. Sometimes you will need a pick ax to break up the ground. Don’t forget to check with Arizona 811 before you dig. You don’t want to accidentally hit an underground utility line.
Raised gardening can help mitigate problems associated with excavating soil.
Nutrients Lacking in Phoenix Soil
Similar to people, plants need nutrients to survive. Phoenix soil makes it difficult for plants to obtain water. It is also lacking in three main nutrients needed for gardening: nitrogen, phosphorus, and iron. Typically you will stunted plant growth and yellowing of the leaves if your plants are not getting the nutrients they need.
Nitrogen is important for your plant’s protein production. Too little nitrogen means your plant’s growth will be stunted.
Plants need phosphorus to transfer energy such as needed in cell division. Phosphorus encourages root growth.
Chlorophyll is what makes the leaves turn green and it is an important part of the photosynthesis process. Without iron your plant will not be able to synthesize chlorophyll.
Other nutrients needed for plants to flourish are magnesium, manganese, potassium, calcium, and carbon dioxide.
How to Amend Phoenix Garden Soil
Amending your Phoenix soil is how you can fix the lack of nutrients.
Nitrogen stunts growth. You will want to amend the soil with stuff that increases your soil’s nitrogen. Compost, manure, and bone meal adds phosphorus to the soil. Manure, compost, bone meal, and iron chelate adds iron to the soil. Fish emulsion increases nitrogen, phosphorus, and potassium.
Amending your Phoenix gardening soil is vital for healthy plant growth. Some of the best things to add to your soil includes:
- Compost
- Manure
- Coffee grounds
- Bone Meal
- Iron Chelate
- Fish Emulsion
Your garden soil is your plant’s home. Create a nutrient-rich environment and your plants will reward you with some lovely flowers, produce and fruit.