It's a cinch to know your onions

If the records are correct, onions fed the slaves that built the pyramids; and Alexander became ''the Great'' because, among other things, his armies were adequately supplied with this nutritious member of the lily family. More recently, General Grant's men were said to have complained with some force when onions weren't included in the day's rations.

Not everyone likes onions, of course, but from all accounts, a vast majority of folks do.

In our home, when the chowder or stew recipe calls for two onions we are likely to reach for three - or maybe even four. That's why we give more than 100 square feet of our garden bed to onion production, which, we figure, generally provides us with at least a nine-month supply.

Onions are the first crop to go into the garden in the spring - even earlier than the peas. It's important that they get an early start, because onions grow leaves during the cooler months and bulb out only after the sun peaks in the sky and the weather becomes hot. The bulbs, in fact, grow large on the food produced by the leaves. It follows, then, that the more abundant the leaves, the bigger the bulb will be.

The largest onions are grown from seeds sown the same year. I grow the bulk of my onions, however, from sets (little onions bulbs grown the previous season) , although periodically I send away for started plants.

Sets are much easier to plant. Years ago a well-known Vermont gardener, Dick Raymond, said of onion sets: ''You can't kill them with anything less than a hammer on a hard surface.'' And he is right. I simply broadcast the sets over soil and, using a plank, walk them into the soil. They come up every time. On other occasions, I follow the Ruth Stout method and cover the scattered sets with about two inches of mulch (usually shredded leaves) and they do just as well.

In broadcasting sets you will notice that the onions lie on their sides, but this doesn't seem to bother them. The roots simply pop out of one end and turn down into the soil while the leaves emerge from the other end and turn up. Pretty soon the onion rights itself.

If you have the time, it obviously pays to plant each individual bulb carefully, if only because this allows you to space them perfectly. Push the blunt end into the soil. I push it deep enough so that just the tip of the bulb shows aboveground. I plant each set 5 to 6 inches apart in every direction.

If you like spring onions in your salads, halve that distance and pull up every alternate onion when they are about as thick as your little finger. Leave the rest until the tops fall over and they are ready for harvest.

In selecting onion sets, choose those that are about nickel-size or fractionally smaller. Larger sets tend to go quickly to seed, while very tiny ones simply lack the vigor to get going.

If you buy started plants - about two months old when they come to you - trim between 1 and 2 inches off the top and bottom and place them in a pail of lukewarm water for about 24 hours to allow them to freshen up after their long journey from the nursery. It also helps to add a weak solution of plant food to the water. My preference is for seaweed solution.

The easiest way to plant onions is to open up a furrow in the soil and then prop up the seedlings against one side of the furrow. Then come back and push the soil firmly around the roots. Water well.

I like to spread about an inch-thick layer of compost or aged manure over the surface of the bed. Using a rake, scratch the compost or manure into the top two inches of soil (digging it in deeply might suit carrots but not the shallow-rooted onions). A sprinkling of wood ashes and bone meal is helpful as well because it provides additional potash and phosphate. If you lack an adequate supply of compost, etc., add a balanced garden fertilizer.

Weeds are said to be the worst enemies of onions.

I have very little trouble with onions for two reasons. First, by scratching only the top two inches of soil in the bed, I do not bring any deep-lying, dormant weed seeds to the surface where they can germinate. And second, I always apply a one- to two-inch mulch to the bed, which effectively smothers any would-be weeds.

My soil is a light, sandy loam, which enables me to do this. If it were a heavy clay, the mulch might keep the soil too cool. By the time the onions are ready to bulb up, the mulch has decomposed enough so that is does not prevent the light from getting to the bulbs - something they need if they are to develop well.

Shortly before harvest time, the onion tops will begin to fall over. When two-thirds of the bed have fallen naturally, bend the rest of the tops over yourself, which appears to give a last-minute spurt to bulb production.

At harvest, pull the bulbs up and leave them for a day or two in the sun to dry out. Then take them out of the direct sunlight and into a well-ventilated area and leave them to dry out for several weeks. When the roots are so dry that they can be rubbed off with your fingers, they are ready to store - in string bags with the tops removed or with the tops braided and then hung from a suitable rafter.

Last summer we simply gathered the onions in bunches, tied a string around the unbraided tops, and hung them up. It worked well enough so that we are not likely to go the time-consuming braiding route again.

Onions prefer to be stored in a cool, dry area at temperatures just above the freezing mark. This winter we left many bunches hanging out in the garage, where they froze solid. To my surprise they have so far weathered this indifferent treatment very well. Still, I do not recommend this sort of treatment.