Prepare Garden Soil
Get vegetable and flower beds ready for fall planting. Mix a generous 4-6 inch layer of compost into the top 12-18 inches of soil. Add soil sulfur, which improves drainage and somewhat lowers pH temporarily. Add nitrogen and phosphorous sources. (Most desert soils have sufficient potassium, or add an all-purpose fertilizer.) Water evenly and let weeds sprout before planting. Pull weeds, rake smooth, and you'll soon be sowing seeds.
Lightly prune roses to ready them for their second bloom period of the year. Fertilize with a fertilizer formulated for roses or use a compost tea. Some people report good luck spreading coffee grounds around the base of their roses to provide a slow release of nitrogen. Water deeply to a depth of about two feet for mature roses. Refresh the mulch around the shrub if needed.
Do Some Research
Fall planting season isn't far off. Determine what types of plants you want to add to your garden or landscape. Read books and talk to nursery personnel about plant requirements and decide also what your yard has to offer. It is especially important to match a plant's light requirements with the amount of sun that it will actually receive in its intended location.
Fertilize Landscape Plants
Fertilize landscape plants this month with nitrogen. This gives them a "boost" after the long hot summer and before winter dormancy sets in. Don't overfertilize! Water thoroughly before and after applying any fertilizer to help prevent burn.
August/September is the time to apply the last feeding for citrus until next year. If you didn't fertilize citrus in August, apply it now. Make sure fertilizer is applied slightly past the tree's canopy, or dripline. This is where the feeder roots that take up water and nutrients are located. Fertilizing near the trunk of a mature citrus does no good.