October is a busy month in the California garden. With warm days, cool nights, and anticipation of the rainy season, it is a month of transition out of warm season and into cool season, and preparation for winter. October has mostly pleasant weather for working out of doors, although some days may still be quite warm, and we may see a major storm with wind and downpours before the month is out.
PLANTING: October begins the main planting season for most ornamental trees, shrubs, perennials, vines and ground covers. Autumn is the best season to plant some of our favorite California native species like manzanita, California Lilac (Ceanothus), and Silver Bush Lupin (Lupinus albifrons) Have your irrigation system ready before you plant so you won’t miss watering them during typical dry days. Those new transplants will need regular water for at least the first few weeks. Don’t put your plant in a hole; leave an inch or two of the crown, or center of the plant, above the soil level. The planting hole should be a little wider than the nursery container.
Top off with two or three inches of mulch after planting. You do not need to add fertilizer or amendment to the planting hole, but if you insist on fertilizing, use a timed-release granular product. Towards the end of the month, begin to plant spring-blooming bulbs such as daffodils and tulips, or you can wait until November. For bulbs, plant three times as deep as the size of the bulb, and don’t overwater them. Plant native local wildflower seeds as the rains begin. Besides poppies, try clarkia, tidy tips, gilia, phacelia and lupine. There are seed sources online for California native wildflower mixes. If live in the mountains or foothills, consider using only locally collected seed of wildflowers you see in the wild, to preserve watershed genetic purity.
In the vegetable garden, plant chard, spinach, turnips, beets, snow peas, carrots, cilantro, lettuce, and Asian greens from seed. Continue planting seedlings of greens, broccoli, cauliflower, cabbage, and bulb onions.
MAINTAINING: Complete your annual yard clean up, especially if you have planting beds or entire yards based on naturalistic styles. Don’t be afraid to cut those spring-blooming shrubs back to a third their size. Don’t trim deciduous trees yet; we’ll wait until winter for that. The exception may be the popular Desert Museum Palo Verde, which does not appreciate frost at all and may do best trimmed in summer or early fall. Don’t prune citrus, avocado or other frost-sensitive plants until spring.
Deadhead roses one final time for a fall bloom. Divide perennials and replant. You can replant iris or wait another month. If you can, grind up the plant trimmings and use them as mulch for the garden, or add ground up plant debris to the compost bin. Don’t use any plant material that had disease or pest issues; dispose of them in green waste bins in urban areas and the trash can elsewhere. But any healthy twigs, leaves and old flowers make an excellent mulch in the garden. Use it wherever you can instead of having it hauled to the landfill. “Leave the leaves” is a catchy slogan being promoted nationwide through the Xerces Society, Master Gardeners and others, and it is good advice. Please let your plants help you lower their maintenance demands and keep them healthy and vigorous year after year.
If we have a few dry weeks, deep water your trees as they enter dormancy. Don’t forget to adjust automatic systems (or ask your gardener to do it) to reflect cooler temperatures. In the mountains and foothills, wrap your pipes and remove and store faucet timers before the first frost.
You can apply pre-emergent herbicide this month to help prevent annual bluegrass, mustard, mallow (cheeseweed), clover and purslane. Don’t apply it where you plan to grow wildflowers or bulbs. Just like with grass species and edibles, we have two main seasons of weeds: warm and cool. If you already have some of these cool season weeds, you will want to remove them mechanically (pulling, hoeing) or use a post-emergent herbicide and a pre-emergent follow up.
This is a good month to check your tree stakes in anticipation of winter winds. IF the tree can stand up on its own and the root ball seems secure, remove the stakes completely, and let it bend in a breeze; this will help the trunk gain strength. Stakes should never be right up against the trunk. Those stakes are for transporting from the nursery, not long-term. If you need to stake a tree, we have information on our website on how to do it properly.
Go easy on the nitrogen-heavy fertilizer as we go into fall, to avoid frost burn of new foliage. This is the season, however, to fertilize your cool-season lawn if you still have one, and lightly feed winter-blooming annuals, perennials, and container plants. Don’t fertilize succulents or cactus.
CONSERVING: Chemical free weed control and plant nutrition is possible. Schedule some time every week or a few times a week to pull or hoe out small weeds as they emerge. Top dress your planting beds and even your lawn compost. Your compost pile must reach 160 degrees Fahrenheit to make sure it is weed and seed free. Compost that is not “sterile” can be used in most planting beds, just be aware you may get some germination of whatever seeds went into the compost (including volunteer tomatoes, melon and weedy grasses). Add another layer of organic mulch to keep your soil healthy. Mulch, whether organic or inorganic (rock and decomposed granite) also decreases damage to the soil from rain and reduces both wind and water-caused soil erosion. Although we may need to manage many pest insects in the cool of fall, especially in our edible gardens, identify an unknown insect before you kill it or use insecticides.
You may be surprised to find you have a wonderful ally in a beneficial insect. Consider planting a hedgerow in or near your garden or orchard to encourage and increase predator insects and pollinators. In the edible garden, if a plant is overtaken by a pest or a disease beyond easy control, it is probably best to remove the plant with the pest. Ornamental, non-annuals can usually tolerate some damage and give you the time to solve the challenge. For many disease issues, cultural practices, such as increasing air circulation, weed control and encouraging beneficial insects, should be considered part of the solution.
Pumpkin season is also here. Last year I had a lot of fun buying pumpkins for an event I was hosting from backyard farmers in the county, driving around to purchase from honor-system farmstands. I recommend it: take some time to enjoy our county, small farmers, and a consciously leisurely pace for a half day during this busy month! Happy October!
Peyton Ellas is a UCCE Master Gardener of Tulare-Kings Counties.
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