The hummingbirds that spent the summer in my garden left last week, so I know winter is coming. It's time to get busy planting winter crops and making plans for their protection, which is rewarding work indeed. Spinach and parsley planted now will produce a little crop in late autumn and a much larger one in spring, and every year I am blown away by the quality of onions grown from overwintered plants.
But I have learned this truth about growing winter vegetables the hard way: Grow only as much as you can protect from the elements, because that's the essence of the task. Where I live, winter temperatures occasionally drop below 0°F (-18°C), with several significant snows and winds that howl for days at a time. Spinach resting in a cold frame with a tempered glass lid (made from an old shower door) scarcely know what's happening, and the same goes for onions snug inside a sturdy tunnel covered with heavy-duty row cover (garden fleece) and an old quilt.
My protective frames and covers don't need to be in place until November, and they can be opened or lifted in March. During that time, the plants grow very little due to cold temperatures and limited light from short, dim days. But as soon as days start to lengthen in late winter, overwintered vegetables make rapid growth and are ready to start picking when spring plantings are just going into the ground – the neatest thing about growing winter vegetables.
What to Grow in Winter
The top winter vegetable to grow is probably spinach, which has no trouble surviving cold temperatures with a secure glass, plastic or cloth cover. I like to work with well-established plants that are well rooted, but even young spinach plants will survive winter under cover with no problem. Arugula (rocket) and parsley make good neighbours for winter spinach, so I often growth them together in the same enclosure.
When handled just like spinach and grown through winter with protection, special varieties of overwintering onions make wonderful spring crops in the US. American gardeners must start varieties such as Top Keeper and Desert Sunrise from seed, but in Europe gardeners can grow autumn onions like Senshyu Yellow from sets. I am now hooked on this lovely type of onion, which is mild and juicy yet stores beautifully, but the best part is that they mature so early, in June. I get the best results from plants growth from direct-sown seeds that are never transplanted, one of many unexplainable mysteries associated with the growing of good onions. Garlic is a much more straightforward crop that I will plant in late October, and it needs no cover beyond a good mulch of chopped leaves.
Finally there are the little greens -- mache (lamb's lettuce) and claytonia (miner's lettuce) – which stay tiny the first half of winter and then explode with new growth in early spring. A fleece-covered tunnel keeps these little wildlings happy through winter's worst cold, and they will produce several small but welcome harvests while cold weather lingers. The plants will be in full bloom when the hummingbirds return, perhaps offering up spring sips of nectar – another reason for growing winter vegetables.