Temperature unlocks the key to gardening activities in September, the start of an important planting season through October.
This 30- to 45-day period when regular daytime temperatures drop below 100 F is ideal for new plants to develop roots when the soil is warm before cooler air temperatures in late fall and winter slow plant growth.
Start by preparing your garden for fall planting by amending with compost and slow-release fertilizer. Replenish depleted and sparse mulch material.
Transplant deciduous and citrus container-grown plants while soil temperatures are still warm enough for rapid root growth. Plant spring-flowering perennials this month.
Fertilize citrus trees this month and water deeply before and after fertilizing. Once temperatures drop below 100 F, start adjusting how you water citrus and other fruit trees. Water deeply but not as often as in the summer months.
Avoid pruning fruit trees this month but begin fertilizing roses. Once temperatures dip below 100 F, prune roses lightly to remove dead or diseased canes.
Here’s one low-desert planting guide to bring visions of winter and spring gardens bursting with vegetables to fruition.
- Early in the month (before Sept. 15), plant seeds of summer squash and beans.
- All month plant seeds of bok choy, broccoli, Brussel sprouts, cabbage, carrots, cauliflower, celery, chard, collard greens, cucumbers, endive, kale, kohlrabi, leaf lettuce, mustard, green onions, parsnips, radishes, rutabagas, spinach and turnips.
- After Sept. 15 plant transplants of broccoli, Brussel sprouts, cabbage, cauliflower, celery and lettuce.
- After Sept. 15, plant potatoes, strawberries and beet and pea seeds.
Sources: “Flower Planting Guide for the Low Desert,” by University of Arizona College of Agriculture and Life Sciences; Growinginthedesert.com; “Lush and Efficient: Desert-Friendly Landscaping in the Coachella Valley,” by Coachella Valley Water District; “Month by Month Planting Guide for the Coachella Valley,” by Palm Springs High School Sustainable Garden Club.