October is a colorful month filled with ripe but dwindling summer produce. Tomatoes are at their reddest, hoarded and appreciated; peppers are hot crimson and sweetly gold. Cucumbers are finally big, but the vines are slowing down. Squash and melon plants have sprawled and are looking spent and ready to come out.
But the first peas are big enough to pick, figs both black and white are ripe for the picking, and days are cool enough that lettuce and radishes are beginning to thrive again.
Pull out your bare-root fruit tree catalogs or call local nurseries for lists of the trees they will be offering this winter. Take advantage of October’s mild days to prepare holes for the apple, peach, plum and pear trees you want to purchase bare-root in January, when the soil may be too waterlogged. You will thank yourself in January if you do this work now. Then your rainy-season planting will be easy and successful.
October is also a good month to order compost and have it delivered. Heavy trucks will compact softened, rain-soaked soils and leave you with deep ruts to remember them by.
Are we getting at least an inch of rain a week this month? If not, continue watering shrubs and plants. Feed citrus and other shrubs such as azalea and camellia. They are all prone to chlorosis (yellowing) from iron deficiency. A trip to your favorite nursery or garden center for chelated iron may be in order.
Yellowing in other leafy plants is often a sign of nitrogen deficiency. Diluted fish emulsion, applied with a watering can, will typically “green up” leafy plants and give them a new flush of growth. But as winter approaches, the Master Gardener Month-to-Month Guide recommends feeding the vegetable garden one more time with an ammonium form of nitrogen to reduce leaching when the rains come. Your garden center can show you the options.
Are you lucky enough to have a big garden or good-sized beds? Are you replenishing this soil with cover crops yet? If you now have bare beds that produced melons, corn or other crops all summer, consider planting a cover crop to grow through winter.
Cover crops, also called green manures, protect your soil from erosion caused by winter rains. They pull up minerals deep in the soil, making them accessible to future crops. And they serve as a living mulch, smothering weeds, creating habitat for worms and other soil-forming organisms and providing pleasing visual texture through cold, gray months.
For your green manure, consider fava beans, golden mustard with its sunny yellow blooms, or oats or barley planted with clover. University of California Cooperative Extension has helpful information on cover cropping for the home gardener (http://ucce.ucdavis.edu/files/filelibrary/5842/25997.pdf). Plant cover crops now so they can grow through winter. In spring, till them into the soil. Three weeks later, the green biomass will have decomposed and the beds will be ready to plant.
Clean up your vegetable and flower garden this month and eliminate hiding places for pests and diseases. Rake up and discard fallen fruits and vegetables and spent annuals like zinnias and sunflowers. Start a new compost pile. Making these efforts now will mean fewer hiding places for snails and slugs and new soil for your garden when you need it next spring.
Now is a good time to dig up and divide crowded perennials like Shasta daisies, agapanthus, nepeta, daylilies or echinacea. Give extra plants to friends for their gardens, or expand your own beds.
If your dahlias look unhappy, let them die back and then gently dig them up and store them where they will not freeze. Keep them dry; do not wash them off or they could rot or become diseased before replanting in spring.
Chrysanthemums are still in their full autumn glory. Whether you cut them by the armfuls for indoor bouquets or enjoy them outside, examine them closely for aphids. If you spot these pests, wash them off with a good blast of water from your hose or spray bottle. Repeat diligently until you no longer spy them.
Continue planting your vegetable garden. Sow seeds of fava beans, carrots, spinach, lettuce and arugula, and plant seedlings of cabbages, Brussels sprouts, broccoli and cauliflower. All of these brassicas appreciate a floating row cover to thwart moths, aphids, birds and critters.
UC Master Gardeners of Napa County will host the workshop “Winterize Your Garden Tools” on Saturday, Oct. 8, from 9:30 to 11:30 a.m., at University of California Cooperative Extension (address below). Properly winterizing the garden helps your plants survive winter and produce in spring. Learn the importance of proper garden winterization via discussion and demonstrations. Also learn the proper care and upkeep of garden tools and get some ideas for new and/or improved ones. Feel free to bring one hand tool to refurbish. On-line registration (credit card only) mail-in/walk-in registration (cash or check only).
Free Tree Walk
On, Monday, Oct. 10, join UC Master Gardeners of Napa County for a guided tree walk through downtown Napa’s Fuller Park. The tour will start promptly at 10 a.m. and last approximately 1-1/2 hours. You will learn about more than 40 different trees. There is no charge, but registration is highly recommended as space is limited. Meet at Fuller Park, at the corner of Jefferson and Oak Streets. Online registration or call 707-253-4221.
Native Plant Sale
UC Master Gardeners of Napa County will have an information table at the California Native Plant Society (CNPS) Napa Chapter’s plant sale on Saturday, Oct. 15, and Sunday, Oct. 16, from 10 a.m. to 4 p.m., at the Martha Walker Native Garden in Skyline Park in Napa. Volunteers from both organizations will help you choose the right native plants for any spot in your garden. The preview party for CNPS members and guests is Friday, Oct. 14, from 6 p.m. to 8 p.m., at Skyline Park.