Prepare Fall Gardens
Spread 4 to 6 inches of compost or well-aged manure on top of vegetable and flower beds. Add fertilizer containing nitrogen and phosphorus according to package instructions. If drainage is a problem, soil sulfur or gypsum also can be added. Dig it all in to a depth of 12 to 18 inches. Water and let any weed seeds germinate before planting.
Chill spring-blooming tulip, grape hyacinth, and daffodil bulbs in the vegetable crisper for six to eight weeks before planting. (Note that tulips are often treated as an annual in the low desert.) Other spring bloomers don't need chilling. Buy bulbs now for planting in October, as supplies of unusual bulbs disappear quickly. Try sparaxis, ixia, watsonia, freesia, lycoris, crinum, and Dutch iris.
Fertilize Landscape Plants
A light application of all-purpose fertilizer can help stressed non-native trees and shrubs come out of summer and fuel some growth before winter. Native plants generally don't require any fertilizer. Apply it at the drip line and slightly beyond. This is where feeder roots are taking up water and nutrients. Scratch granular fertilizers into the soil and water well immediately after application.
Prune and Feed Roses
When temperatures remain below 100 for several days, it's safe to lightly prune roses to ready them for their second bloom period. Trim away dead or crossing canes. Cut back no more than one-quarter of the plant. (The heavier pruning takes place in January.) Feed with a slow-release, granular fertilizer. Water thoroughly to a depth of about two feet for mature roses.
If you didn't fertilizer in August, apply the last citrus feeding for the year. The annual requirements are split into 3 equal feedings during the year. How much to apply depends on the tree's size and maturity. As a guideline, small young trees that have been planted two to three years, take one-half pound of actual nitrogen annually. The amount increases about 1/4 pound every two years until maturity. A large mature tree that has been in the ground six or more years needs about 1.5 pounds of nitrogen annually. Mature grapefruit trees require half this amount.