Winter greens bring variety and zest to our cold weather meals. They've been cultivated for thousands of years from Japan to Western Europe and, as the list below shows, the majority are from the Brassica genus.
Most of the European greens are fully hardy in our mild coastal climate. Some, notably chard and spinach, are tender but will over-winter with protection. All, except the lettuces, are used in soups, stews, as side dishes and in casseroles, or like cabbage, are pickled before use.
The taste – not to mention the nutritional value – of raw food in winter cannot be overstated. A group of European greens that evolved primarily in Italy and France can be eaten either raw or cooked. Examples are: arugula, spinach, chard, kale, radicchio, Italian dandelion, and endive. These, along with the winter lettuces and mache, are staples in our winter salads.
On the coast we can also enjoy far more variety in our cuisine than do others who live in colder climates because we can cultivate the fast growing Asian greens. They do, however, usually need some protection below Zone 8a. Though none will grow from seed during winter, most can be planted in late August and will stand under cover until spring. Asian greens (and arugula) are notorious for bolting at the first sign of warm weather, so it is wise to begin timing your last Asian-inspired salads and meals when the sprouting broccoli begins to grow, and you plant the fava beans.
Ideal Site & Soil
Winter greens fall into three categories: the first group, Brassicas, are big, slow growing summer planted biennials. They need lots of room, lime, and a good helping of rock phosphate at planting. They begin slowly, get established just before frost then stand until spring or are harvested over winter. Kale and collards are the exception: these are ready in about 60 days. Brassicas benefit from lots of sun to keep away mildew and make them less attractive to late season or early spring aphids. Chard, a member of the beet genus, has the same needs as the Brassicas.
The Mediterranean vegetables comprise the second group. These, too, benefit from at least 6 hours of sun. Lots of compost, composted manure and a cup of balanced organic fertilizer (4-4-4) per square metre (or 10 ft. row) will give them enough nutrients. Some, like spinach, will begin to produce 45 days, as a late season salad crop. Others – like collards and kale – produce in 60 days to 80 days, then stand ready as a winter crop. Radicchio will offer two crops: harvest by cutting the head off at ground level; it will re-grow a couple of small heads in early spring from the old stalk.
In the third group are the race horses: the fast growing mustards and the Asian greens. These need a feeding of compost and a handful of balanced organic fertilizer (4-4-4) per square metre (10 ft row) at planting. All the Asian greens need regular moisture so good tilth is essential.
Cultivation / Plant Care
Chard can be harvested for a long time. If planted in summer you avoid leaf miner, and it will give you salad greens in 50 to 60 days, just when the lettuces begin to bolt. Add more rock phosphate and composted manure in late summer, and enjoy the crop all winter until it bolts the following March or April. Even then, cutting off the flower stalk can extend the harvest of leaves for up to another month.
For the rest of the Mediterranean group, a close-to neutral soil works well, so use lots of compost and some manure at planting. Mustard begins to produce in 45 days, corn salad in 50, and the rest in 60 to 90 days. Be sure to plant extra. Harvesting one leaf from each plant rather than several leaves at a time from one plant will yield up to four times as much food by weight. Because they grow from the centre and the central leaves are hardier, plants need as many outer leaves as possible to take up moisture and sunlight to produce new growth. If you find you have more than you need, there are lots of neighbours who would be thrilled with a gift of local fresh produce in the middle of winter.
The Asian group needs moisture-retentive soil. To ensure the correct amount of harvest, try a couple of weeks of succession planting just as the August sun begins to lose its heat. Plant short rows or 2 ft squares in soil enriched with plenty of nitrogen-based compost. Plant the seeds very thickly, thin the first group at 30 days, then thin the second group as they get crowded. By now it is the end of October, and you can let the more mature plants finish growing, thinning them to the largest plants to harvest until winter cold freezes them, or you protect them so they will stand until early spring.
Good drainage is absolutely essential in the winter garden. If you do not have raised beds, be sure to plant on small hills or raise up your rows so the water can drain off.
Mulch is also essential. Spread it in a doughnut shape around every plant, or mounded along the side of each row. It keeps the stalks from freezing, the collar holds moisture, and protects outer leaves. Mulch also feeds the soil even in winter, albeit very slowly. But many of your plants are actually feeding very slowly, thus mulch remains a benefit all year around.
Problems & Pests
In general, crops planted in late summer usually avoid the main garden pests. Onion maggot can sometimes attack scallions if you have it in your gardens. Wireworm is active until October. See the article on winter roots for dealing with these pests.
1. Slugs
These are the bane of the coastal garden, and a main pest of greens. Even under cover they can be a problem on young seedlings – and everything in early spring. Only in winter are we slug-free. Copper tape on the tops of raised beds provide a good barrier. Eco-friendly traps are also effective.
2. Wind Damage and Desiccation
Leafy winter greens can suffer greatly from the wind. They lose vigour, get damaged, and become tough and tasteless because plants have trouble absorbing moisture in cold weather. If your crops are not covered, use a simple temporary screen made from flexible deer fence or doubled-over garden netting placed on the windward side of your plot; it will make a big difference in protecting against wind as well as frost damage. If you are using plastic cloches, be sure your soil doesn't dry out. Mulch will mitigate this.
3. Frost and Freezing Weather
Reemay or clear plastic cloches both hold enough heat to keep freezing temperatures at bay in our mild climate. If using Reemay, throw some plastic over top if very cold temperatures are predicted. This will protect all but the most tender plants. Keep your cloche slightly above the top of the crop. The extra air space allows solar gain and keeps the air moving. If your plants freeze, leave them alone! When the weather warms again you may find you've lost some leaf tops or a few plants on the outer edges of the bed, but these crops were bred to withstand freezing temperatures, some to Zone 4. Even bok choy will recover nicely in Zone 7a if you trim any outer stems that went mushy from a hard frost. Winter greens are a tough tribe – they will thaw out and continue to thrive.
Botanical Origins:
Allium genus = 1 (scallions)
Beta genus = 1 (chard)
Brassica genus = 17 (8 Asian, 9 European greens)
Chicorium genus = 3 (dandelion, chicory, endive)
Eruca genus = 1 (arugula/rocket )
Sanguisorba genus = 1 (salad burnet)
Spinacia genus = 1 (spinach)
Valerianella genus = 1 (corn salad/mache)
Jo-Ann Canning
Master Gardener, Vancouver Chapter