One of the rewards of gardening in a relatively mild climate is the opportunity to raise a long and productive fall garden. The salad spinner, still since June, now thinks it's a whirling dervish.

This is due to my sowing seeds of cool season, leafy greens in August and September.

It's probably too late to sow fresh seed now, though garlic cloves can still go in, and you could risk sowing fava beans and spinach for a spring crop.

The greens that are up in November take two basic forms - those that are at or near maturity and can be harvested at your convenience, and the smaller ones that will sit through the winter and grow quickly in February and March as the days lengthen and the sun strengthens.

Both need protecting now that freezes are upon us. More on that in a bit.

Raising the autumn crop is not as foolproof as it might seem. Lettuce seed scattered in August is loath to sprout in hot soil, though some varieties seem more willing than others. It is worth sticking with it, however, because fall is a better season for heading lettuces than spring, in my experience.

Now, the romaines, butterheads and bibbs mature as the temperatures are cooling and they are happy to await harvest without bolting. I have learned to have enough reserve seed ready to fill the gaps of failed germination. I might re-sow two more times in September if the first seedlings are no-shows before giving up. In a row that has partially sprouted, the re-sowing is a simple procedure. Using a pocket knife, I score surgically a new furrow between sprouted plants. I am careful to space the fresh seed to minimize thinning.

I now have lettuce in various stages of growth, from full-blown heads of the butterhead Adriana and a mini-romaine named Dragoon, to one quarter-size Marvel of Four Seasons, large seedlings of an eye-catching lime green with red speckles. Thinning brings a harvest.

These lettuces will take a light frost but nothing much colder, so they must be covered now that the nights are freezing. The cabbage family crops are hardier beasts (with the exception of bok choy, which surrenders flaccidly to a couple of degrees or so of frost), but they, too, have been growing under insulating covers. This is not because of the cold but the arrival of pests soon after sowing. The flea beetles were so eager to devour the mustard greens that the first batch was a write-off - the seedlings were peppered with holes. In went new seed, but this time under row covers. A nearby and exposed line of turnips was also attracting another serious pest of brassicas, the harlequin bug.

Row covers are made of spun polypropylene and let in water and reduced levels of light. They are not cheap - a 50-foot length costs between $30 and $50 - but with care they can last several years.

Once the protected plants start growing, you have to elevate the cloth. This is done by fashioning hoops every four feet or so to create a low growing tunnel. Mine are about 18 inches high.

One way to provide the supports is with galvanized wire you cut into lengths, which might vary from four to six feet, depending on the width of your row. In one long bed, I have fashioned something a little fancier by buying lengths of half-inch and quarter-inch PVC plumbing pipe. I used a hacksaw to cut the half-inch pipe into 18-inch lengths, which were hammered into the soil in opposing pairs. The narrower pipe was cut to 48 inches. The ends of the section were pushed into the larger pipes to form a perfect arch between them.

The row covers fall into two basic types - lightweight versions that screen out insects but provide no real insulation, and thicker ones that do both. The heavier type is meant for use only in cool months, but that's all I had on hand against the pests in late summer, so on it went. Lo, the re-sown greens seemed to like it. I squeezed in a line of radishes between them, and all are now robust and begging to be eaten.

I bought the row cover several years ago from Johnny's Selected Seeds, whose catalogue carries four grades of insulating cover, varying in weight, price and frost protection. The lightest adds two to four degrees of frost protection, the heaviest more than eight degrees, said Jen Goff, product technician for tools and supplies.

The thicker the cover, the more light it blocks, which is an issue as we approach the darkest weeks of the year. "One common practice is to uncover crops on nice days," she says. This will also help with air circulation against fungal diseases.

I have been using clothespins to secure the fleece to the hoops, but a more common approach is to anchor the cloth along the sides of the tunnels. You can use pieces of wood, but they must be secure against stiff winds. Goff uses sandbags and knows of growers who rely on heavy chains.

You will have gathered that installing row cover tunnels is a laborious affair, but they can make the difference between a successful fall garden or not, and will get hardy greens such as kale, collards and spinach through the winter. This year, I'm growing a kale named Winterbor, having grown weary of Red Russian and Toscano, and the collard variety Flash.

Weeds continue to grow in these tunnels, but there is nothing more satisfying on an autumn afternoon than peeling back the covers and rendering the growing beds fluffy and weed free.

One crop not getting the blanket is the parsnip. Sown in April, the parsnips have been ready for some time, but I've been waiting for some frosts before digging them. This week's freeze will make them sweeter.

Gardening tip:

Fallen leaves are a valuable resource for improving soil. Shred raked leaves with a lawn mower and return them to garden beds. Or stack leaves in a circle of chicken wire, where they will be ready in spring for incorporating into soil.