The Late Cool-Weather Food Garden
If you haven't planted your fall and winter food garden, it's time to get busy! The last day Sonoma County has 10 hours of daylight is November 18 and, as that date approaches and weather cools, plant growth slows down. Plus, frost will be here before we know it. Our goal is to select crops and varieties that will mature before these dates. Plus, we need to know what cool-weather crops might overwinter for a extended harvest during winter or in early spring when growth begins again. This effort is worth it. Not only are cool-weather vegetables delicious, they are the most nutrient-dense crops that you can grow. Master Gardener Janet Barocco provides the information you need to plant your cool-weather garden in the nick of time.
In the Garden
Transitioning to the Fall and Winter Food Garden
There is some very important information that translates into having a successful fall, winter and/or early spring harvest. All of this information is used now as we transition our summer garden to fall.
1. Hardy vs. Half-Hardy Cool Weather Vegetables. Refer to page two of the Year-Round Food Gardening in Sonoma County publication to see what veggies can be planted in September and October. Not all of these veggies withstand the same degree of cold weather. Half-hardy crops (such as lettuce and cauliflower) can withstand a limited or light frost whereas hardy crops typically can tolerate a heavy frost (24-28 degrees F). If you want to harvest over the winter and/or early next spring, include hardy crops such as broccoli, Brussels sprouts, cabbage, collards, corn salad, garlic, kale, leeks, bunching onions, radishes, Daikon radishes and spinach. Also, note that most root crops can be "stored" in the ground as long as the ground doesn't freeze (for example, turnips and beets--unless you are growing them for their greens).
2. Average First Frost Date. If you've lived in your current location for some time, you probably can estimate the first frost date based on past experience. But, if you're not sure, NOAA has you covered. They produce averages based on the past 30 years of collated data (updated every 10 years) for every weather station. We've made it a little easier to find this info by extracting the data for Sonoma County weather stations (see First and Last Frost Dates for dates based on different risk percentages in your area). Bring half-hardy veggies to maturity before this date and hardy veggies to at least near maturity by this date. As they say in banking, past performance is not an indicator of future earnings, but this is the best information we have for planning purposes.
3.Ten Hour of Sunlight. At Sonoma County's latitude, we have less than 10 hours of sunlight from November 18 to January 23. During this time, crops imperceptibly grow or stop growing. If your area's first average frost date falls after November 18, use November 18 when determining when to bring a crop to maturity. Some hardy crops, if brought to a reasonable size by November 18, can be harvested throughout the winter and/or will begin growing again after January 23 for an early spring harvest.
4. Days to Maturity. Every crop (and every variety) has a "days to maturity"--the days from when the seed or transplant is put in the ground to the date the first edible leaf or fruit matures. Usually you can find this information on the seed packet. If not on the packet, you will find it easily on the Internet. The date you plant and how you harvest (e.g., harvesting baby lettuce leaves) will affect your variety selection.
Now that you are armed with essential information and using the "days to maturity" for the varieties you've selected, count back from your area's last average frost date (or November 18, if earlier). Now add two weeks--remember that maturing will slow as the days get shorter and cooler. The date you calculate using this process is the last day to get your crops in the ground if you intend to harvest them before frost arrives (and, for a decently long harvest of half-hardy crops, you'll want them to mature a bit sooner). If you find that you're too late to plant a particular variety, just select another variety with a shorter days to maturity. You have a little wiggle room (but not much) if you intend to bring hardy crops to near maturity (for an early spring harvest) by that date. Your cool weather crops will enjoy starting in the warm soil and maturing in the cooler weather. And, if you are the industrious type, you can use season extenders (cloches, frost cloth, plastic tunnels, etc.) to protect the half-hardy crops when frost is extended or heavy. Enjoy your fall and winter harvest!
We don't normally quote Geraldo Rivera, but food gardeners will appreciate this: "Mother Nature may be forgiving this year, or next year, but eventually she's going to come around and whack you. You've got to be prepared." Cold weather is coming. Buy supplies now (frost cloth, garden stakes, ground staples, cloches and/or materials to prepare protective tunnels). And pay attention to the weather reports when the weather cools. Read more about winter weather.
Food Garden Specialists
Food Garden Specialists (FGS) are volunteers in the UC Master Gardener Program of Sonoma County. They have a passion for and extra training in sustainable food gardening. In addition to offering food gardening workshops, they provide free advice and consultation services to community gardens throughout Sonoma County. Read more.
Food Garden Tips
October Food Garden Tasks and Tips
For what to grow this month, click here.
- If a fall/winter garden was not planted, plant a cover crop, such as fava beans or red clover, to add nitrogen and organic matter, to improve the soil tilth and water penetration, and to help mitigate disease issues related to crop rotation. For maximum nitrogen benefit, cut down the crop next year just as flower buds begin to form, leaving the roots in the soil. The tops can be simply chopped and dropped or put in your compost pile.
- Mulch perennial crops and any bare soil. Option: rake leaves into a pile, run the mower over them and use this as organic mulch; 3-4 inches are recommended to retain soil moisture even in the cooler fall when drought conditions persist. Mulch also reduces splash and, therefore, reduces the number of disease spores that might move from the soil to your fall and winter crops.
- If tomatoes are still in the garden, cut off their water to help ripen what is left. Pruning the growing tips of indeterminate tomatoes will encourage the plants to direct all of the sugars and energy to ripening the existing fruit before the first frost (on AVERAGE, mid-Nov to early-Dec in Sonoma County).
- As veggies fade, cut the plants off just below soil level to preserve the soil micro-biology on the roots. Toss any plants showing signs of pests or disease. The rest can go into the compost. If you are immediately replanting the bed, just add a 2” layer of compost and if you encounter the existing sub-surface root, just put each new plant-start to the side of it.
- Strawberries can be planted October through spring. We recommend day-neutral (“everbearering”) varieties for Sonoma vs. short-day types, but, if planting short-day varieties, they should be planted now through February. Trim off all runners as they develop because they weaken the mother plant and reduce fruit size. See University of California guidance.
- Lightly fertilize cool-season vegetables in a fall/winter garden if compost or a slow-release fertilizer was not added earlier. Do not add nitrogen to root crops. Citrus: apply 1/2 lb of 5-2-1 mixed with 1 tablespoon of Epson salts and water well.
- Fruit Trees: apply 7-5-7 per bag instructions around drip line of trees and work in, being careful not to disturb roots.
- Despite the fertilizing schedule outlined above, reduce the amounts if the rainfall outlook suggests below normal precipitation as more vigorous plants require more water.
- Turn off your automatic watering system when rainy weather arrives. But, if a dry spell follows the first rain storm, don’t forget to turn it back on. A drip system is the most efficient way to deliver water to your veggie garden. If you didn’t install one this spring/summer, now is a good time to rectify this.
- Clean, sharpen and oil garden tools and store them in a dry space. Steel wool will remove rust build up (wear gloves); some gardeners use wax paper throughout the year to wipe cleaned and dried blades after use to prevent/reduce rust. Drain garden hoses and hang them in the garage during the rainy season.
- If there is disease in your orchard or food garden, wipe or dip your pruners with alcohol (ethanol or isopropyl) or spray with a disinfectant spray after every cut so that you do not spread the infection.
- Fight critters with critters – build a bat or owl house. Bats eat moths like the ones that lay eggs on vegetables, eggs that turn into hungry caterpillars. Voles are a tasty treat for owls.
- Inspect crops regularly throughout their growing season for early problem diagnosis and resolution. Refer to University of California’s Integrated Pest Management (IPM) site.
- Know what pest you are fighting so that you can select effective pest management strategies. Check out University of California’s natural enemies gallery.
- Good cultural practices (i.e., the correct location, light, water, pruning, fertilizer, planting date) contribute to healthy plants. Sanitation is an important aspect of disease prevention: clear garden debris and, then, clean and disinfect tools with isopropyl or ethanol alcohol.