Time to get ready for cool-season gardens

As my tomato plants start to wilt and the peppers have all been picked and roasted, my thoughts turn to a green, tasty winter garden. Who doesn’t like fresh little lettuces, crisp snow peas or broccoli straight from the plant? But that takes planning, including a strategy first to replenish the nitrogen and other nutrients that fed those summer vegetables.
Does your garden bed need another load of compost? Should it get the benefit of a cover crop to add nitrogen back into the soil? And is it time to get cabbage seedlings into the ground? The answer to all three is a resounding “Yes.”
Whether you are cleaning out your summer garden beds or starting a cool-season garden from scratch, your soil will reward you if you improve it with compost. Compost is what you’re left with when organic matter aerobically breaks down into natural fertilizer, including nitrogen, other elements and micro-organisms. Think of the soil in your garden as a living organism that needs to be fed. Compost feeds the soil that will, in turn, feed your crops. It also loosens heavy soils to improve water retention and drainage.
You can start by chopping up the leftover stalks and leaves from the summer garden, and either dig them back into the soil or begin your own compost source by layering garden waste, kitchen scraps, leaves and grass clippings. Or purchase cubic yards of compost from a reputable source (look for an OMRI label on bags of compost.) Very well rotted, no-longer-smelly manure (never fresh manure) can also be added. Either way, your garden soil will thank you after a tiring summer growing those cucumbers and squash. Plan to add 10 to 20 cubic feet of compost for each 100 square feet of garden space before planting win-
ter vegetables.
Another tactic for adding nitrogen back to the soil is to take the time to plant, grow and cut a cover crop, also known as green manure, before planting your winter vegetables. Buckwheat takes about a month to sprout and grow to flowering, at which time you can cut it down (or turn it under) and still have time to plant a winter garden or let it go to seed to make buckwheat flour.
Fava bean plants not only add nitrogen back to the soil, they also produce tasty beans, attract early garden pollinators and can be harvested and cut in time to plant more winter crops. And you can show their red nitrogen-fixing root nodules to friends and impress them with your scientific knowledge. Organic seed companies also offer cover-crop seed mixes that include grasses, clovers, vetches, and beans for nitrogen fixing, weed control, added organic matter and improved soil texture.
You are also thinking, “What about my snow peas?” Even if you add compost, plant a fall cover crop or both, you can still have a winter garden. Be water-wise and plant only what you know you will eat. As the temperatures cool off, start looking for broccoli, cabbage, cauliflower, chard, lettuces and mustard seedlings to transplant in your refreshed soil, and seeds of peas, spinach, turnips, onions and carrots. Look for the “Cool Season Vegetables” list on the website of the Master Gardeners of Santa Clara County for
more ideas.
Your well-prepared soil and regular watering should help the plants establish robust roots until the rains come. Do not add any fertilizers until the plants have large enough root systems to take advantage. Apply 2 to 4 inches of organic mulch such as shredded leaves, straw or grass clippings around established plants to hold in moisture and control weeds, but keep mulch a few inches away from plant stalks.
Jenny R. Redfern is a Santa Clara County Master Gardener. Call their hotline (408) 282-3105 from 9:30 a.m. to 12:30 p.m. Monday through Friday.