It's not too late to plant vegetables to take advantage of the less intense half of California's year-round gardening climate. Gardening is less intense in the fall and winter because vegetables grow more slowly, so you can often “store” them in the garden until you are ready to use them. In cooler weather, less watering is needed, even if rainfall is below average. Weeds, pests, and diseases are usually less of a problem. Herbs such as cilantro are easier to grow when the weather is a little cooler. Finally, some crops such as kale or broccoli actually taste better after a light frost.
In Los Altos, “the key months for planting the cool-season garden are August and September. The goal is to have everything in by mid to late September,” said Candace Simpson, who talked about cool-season gardening in a program sponsored by the UC Master Gardeners (MGs) of Santa Clara County last month. The MGs offer research-based classes and home-gardening advice. “The plants need to get going while the soil is warm,” Simpson said, “so they can be really well established before the world gets cool.”
Their website offers a useful Vegetable Planting Chart that summarizes what to plant when. Simpson explained that the chart is for the whole county, including hotter San Jose, and that optimal planting times are at least a couple weeks earlier for Los Altos. Not much growth occurs in December and January, but once the weather starts warming up again in the spring, your crops will put on new growth. Furthermore, if you miss the planting window this fall, you can start many cool-season crops in February and March.
Depending on the weather, your microclimates, and your expectations, however, you can stretch those deadlines a bit. Last year, I was out of town for part of September, and I didn't get around to planting a newly installed garden bed until the first week of October. I had broccoli, collard, and beet transplants from garden friends, and I planted lettuce, peas, and carrots from seed a week later. By the first week of November, everything was doing well. October is probably too late to plant more demanding vegetables such as brussels sprouts and cabbages, though.
If your garden is small, planting cool-season crops means you have to take out your summer garden first. By the time cooler nighttime temperatures set in around mid October, I've learned my tomatoes don't taste as good or produce as much, but it's still hard to pull them all up.
For a successful garden, the first priority is good soil. “Add nitrogen you must,” Simpson said. Most of the soils in this area require only nitrogen, and alfalfa pellets (in 50 lb. bags from pet stores) are a cheap way to add it. For a 100 square foot garden bed, mix about 10 pounds of alfalfa pellets into the top 10 inches, she advised. “Organic fertilizers have to be worked on by soil microbes” before the plants can use them, she said. Sammy Horie, who manages the vegetable seedlings section at Summerwinds Nursery in Palo Alto, said “vegetables grow up to twice as fast” in healthier soil that's rich in microbes.
The best vegetables to grow are the ones you will eat! Most garden centers, particularly the Los Altos Nursery and Summerwinds Palo Alto, carry a good selection of cool-season vegetables well into fall.
Peas are my favorite cool-season crop. I eat most snap peas right in the garden. I prefer starting them in 6-packs, then planting out 2-3 weeks later. They still need to be protected from birds for a while, though.
Leafy greens such as kale, lettuce, spinach, mustard, and arugula can be grown as individual plants, or (especially in the spring) broadcast thickly to be cut as baby greens. Baby greens can be ready in as little as 30 days from seed, and you can “cut and come again” several times. To reach mature size, individual plants must be spaced appropriately. They take longer to produce full-size leaves, but once they do, they can be harvested over a longer span of time. Lettuces have shallow roots and are easy to grow in containers.
Root vegetables such as beets, carrots, turnips, and some radishes can stay in the ground until you are ready to use them. “Thinning is essential” for root crops, said UCMG Ann Burrell at another talk. Carrots and radishes are best planted directly from seed, and once the plants emerge, it's important to ensure proper spacing so the roots can reach their mature size. Beets and turnips can be grown from seed or transplants, but they also need to be spaced appropriately.
Herbs such as dill, cilantro, and fennel can be grown in the fall. Cilantro can be difficult to grow in the warm season because of its tendency to go to seed too quickly.
To grow onions, you can plant seed as early as mid October, or onion transplants in November or December, for a June or July harvest. If planted earlier, warmer temperatures may make them go to seed instead of producing bulbs. MG Susan Zaslaw, in a recent garden talk about onions and garlic, advised choosing the sunniest part of your winter garden for onions, and planting them 3-4 inches apart. “Unlike other cool-season vegetables,” she said, onions need 8 hours of direct sun per day. Avoid buying onion “sets,” which typically go to seed without setting bulbs. The best varieties for our climate are intermediate-day varieties, or else “short-day varieties that resist cold.” Some of Zaslaw's favorites are Red Crimson, Solano, and Candy.
Garlic is one of the easiest crops. Zaslaw advised planting from mid October until late November. “Water the soil thoroughly a few days before planting,” she said, then don't water again until you see green sprouts emerging from the soil. Get certified disease-free garlic from nurseries or mail-order, and plant 1 in. deep and 4 in. apart, she said. Shallots are planted just like garlic, but 8 in. apart.
If you know you won't be planting a cool-season garden, you can sow some cover crops such as fava beans, rye, vetch, and clovers. They will add nutrients to your soil when you chop them up to enrich your soil in the spring. Also mulch your beds well to protect the soil.
Ann Burrell demonstrated how to separate seedlings by removing them from the container, holding the rootball gently with the seedlings upright, and then dropping the whole thing a foot or so. When the whole root ball is dropped, the seedlings naturally separate, and you don't have to tear them apart. (Photo: Tanya Kucak)
Susan Zaslaw encouraged gardeners to plant onions and garlic. Not only do you have a larger selection of varieties, but garlic from your garden is juicy and much fresher. (Photo: Tanya Kucak)
Local nurseries such as Summerwinds in Palo Alto have a large selection of healthy seedlings for cool-season planting. Sammy Horie stressed the importance of healthy soil rich in microbial life. Longer-maturing broccoli varieties can be tastier, he said. (Photo: Tanya Kucak)
On kale and broccoli, keep an eye out for green cabbage worms, which are often camouflaged in the leaf veins. (Can you find all 5 worms in this photo?) If you see black droppings and holes in your leaves, chances are it's a caterpillar. (Photo: Tanya Kucak)
If you plant right away and the weather cooperates, your cool-season garden will be in good shape by the time cooler temperatures slow down plant growth. Last year, I planted this garden bed in early to mid October with collard, broccoli, and beet transplants, then planted seed for snap peas, snow peas, lettuce, and carrots. By the beginning of November, this is what it looked like. (Photo: Tanya Kucak)
Be sure to give your vegetables enough space. Look on the seed packets to find out how far apart to plant each variety so that it can mature properly. These Winter Density lettuces were planted closer than recommended so that I could harvest every other one as a young lettuce, and leave the rest to form heads. (Photo: Tanya Kucak)
A few weeks after planting, this cover crop of fava beans and rye was doing well with minimal care last December. The fava beans add nitrogen to the soil if they are chopped up and incorporated into the soil when about 10 percent of the plants have started to flower. (If you wait until the plants produce beans, some nitrogen will go into the beans.) Rye, like other grasses, has deep roots that bring minerals up toward the surface. When it is chopped up and incorporated into the soil, it contributes those minerals to the soil. (Photo: Tanya Kucak)
Carrots need loose soil at least a foot deep to produce long, well-formed roots. At the Self Sufficient Life farm in East Palo Alto, instead of amending a whole bed of clay soil, the gardeners filled milk crates with Lyngso's Vegetable Blend to grow long, straight carrots. (Photo: Tanya Kucak)
The Los Altos Nursery has an ample selection of cool-season vegetables and organic soil amendments. Note that the nursery closes for the winter months. (Photo: Tanya Kucak)
© 2015 Tanya Kucak