Plant garlic this weekend, if you haven't already. It won't take long, and it's well worth it.

Garlic is a magical plant in the organic garden, functioning as a repellent as it grows. When ready for harvest, it can be blended with other materials and water for use as an insecticide. Aside from repelling many sucking and chewing insects, garlic has been used successfully as an antibacterial and antifungal agent in many organic gardens.

And it tastes great in aioli, too.

Buy bulk garlic from a supermarket that carries it (not all do). Don't use boxed garlic -- the cloves aren't large enough. Get about a half-dozen heads so you can select only the fat cloves, storing the others for cooking.

When you get home to your warm kitchen, separate the cloves, trying not to damage them. You should be able to choose at least six or eight cloves out of each head. If you want to plant smaller cloves, go ahead, but keep in mind that small cloves will grow into small heads of garlic.

Head out to the vegetable patch and punch holes in a row or a bed, whichever suits you. The holes should be just over two inches deep, so that two inches of soil will cover the clove. Cloves should be spaced every four inches or so.

If you plant cloves around the area where you plan to put in cabbage, broccoli, cauliflower or Brussels sprouts (brassicas), the garlic is supposed to discourage the cabbage looper. A word of warning: Plant tall- growing broccoli or Brussels sprouts no closer than 18 inches to the emerging garlic in the spring, or they'll overshadow the garlic.

Cover the planted cloves with mulch now, if you wish, or later when you mulch the garden for the winter. Shoots will emerge early in the spring, and by June or early July you'll have garlic ready to harvest, and that's about when you'll need it as an insecticide.

This member of the allium family has been known to repel, kill and prevent many pests and diseases. Grown as a repellent, garlic scares off not only loopers but also aphids, which suck the sap out of many young vegetable plants, including peppers, cucumbers and melons; borers, which love to attack all kinds of squash; and Japanese beetles, which eat anything green, it seems.

As an insecticide and fungicide, garlic cloves are mixed with water, pure soap, hot peppers -- any number of combinations. There are almost as many recipes for garlic sprays as there are organic gardeners. A good source of information is Organic Plant Protection (Rodale Press, 668 pp., $18.95.), which lists several combinations. Try your own version, according to the particular insect you're trying to eliminate.

DAHLIA CARE: Whether you grew them from tubers, seeds or bought plants, dig your dahlias after they've been hit by frost to ensure a good supply next spring, when you'll plant them again. If dug every year, dahlias will last seemingly forever, and will save you plenty of money.

Cut off all the greenery down to the soil, and carefully dig out the tubers, trying not to damage them. Shake off all the excess soil and leave them out to dry with cut-stem part turned down, for half a day. Don't leave them overnight. They can be stored in a plastic bag filled with peat moss or sawdust. If the tubers are large, allow one to each gallon bag. Tie the bag loosely, or punch a few small holes in it to prevent too much moisture from building up inside the bag.

Dahlias should be stored in a place that won't freeze, but will stay cool and damp. Since they don't take up very much room, it shouldn't be too hard to find a corner of the house that meets those specifications.