September

Reduce irrigation times as day length shortens and plant growth slows. Photo: Courtesy UC Regents

Maintenance and prevention

Reduce irrigation times as day length shortens and plant growth slows.
Add garden waste, grass clippings, pruning material, and leaves to your compost so long as they are not diseased. Turn compost and keep it as moist as a wrung-out sponge.
Refresh the spring application of mulch to bring it to two to four inches.

Planting and propagating

Divide overgrown perennials as they finish blooming. Before replanting them, weed and amend garden beds.
Renovate lawn by seeding bare spots, dethatching, and fertilizing. Consider replacing or reducing lawn area. Learn more about lawn care.
Plant ornamental grasses, shrubs, perennials, evergreens, and groundcovers.

Cutting and pruning

Cut strawflowers, statice, yarrow, and other flowers that preserve well. Hang them to dry for use in arrangements.
Prune evergreen, summer-flowering shrubs.

Pests and weeds

Reduce spider mites, scale, and other insect pests by taking houseplants outside and spraying them down with the hose in a part shade area. Keep the foliage dust free to discourage indoor pests.
Use caulk to seal entries that ants may use to enter your home.
Manage aphids and scale on outdoor and indoor plants to discourage ants.

Feed and fertilize

Fertilize houseplants if needed.
Feed azaleas, camellias, and rhododendrons with an organic fertilizer with no nitrogen.
Feed citrus for the last time of the year, if needed.

Edibles

Plant cover crops to improve soil structure and fertility.
Plant artichokes, arugula, cauliflower, celery, chard, collard greens, kale, lettuce, bunching onions, and peas.
Learn more about crops to plant in September and other activities in the edible garden.

Fire-smart Landscaping