This is the week for green. St. Patrick's Day today and, come Thursday, the first day of spring, the vernal equinox when night equals day, winter recedes and the greening of the year begins.

Green, as in the vegetables of spring: thin spears of new asparagus, early peas fattening on the vine, and the dark and crinkled leaves of spinach rosettes.

Spring is the time to plant, not reap, and it will be the end of April at the earliest before local produce is available.But thanks to New Zealand, it season's the reverse of ours, and to the early harvests of California, Florida and Mexico, we can have spring vegetables now. In fact, it is a good time to lay in an asparagus steamer. (The China Closet, 6807 Wisconsin Ave. NW, Bethesda, has a limited supply of stainless-steel ones for $25, plus aluminum steamers at $15.39. The Kitchen Bazaar at 4455 Connecticut Ave. NW, has aluminum ones for $16.99.)

With steamer in hand, you are ready for a Primavera Party. This is what you could do. Fill the house with spring flowers and put Cole Porter's "Night and Day" on the phonograph, or maybe Stavinsky's "Sacre du Printemps." As your guests wander about humming, they could munch on sugar-snap peas, placed raw and unshelled in a large bowl, served with a dip made from sour cream and fresh dill, although they are sweet enough to eat alone, shell and all. (They and the dill are available at Hudson Bros. greengrocers, 3206 Grace St., in the Georgetown Market.)

For a first course, give each guest a small helping of pasta with pesto sauce. (Hudson's also is getting a fresh basil; tarragon, too.) Or you could make a risotta primavera, rice with spring vegetables, or even a potage St. Germain, a pea soup that can only be made with fresh peas. For a main course, it is the season for shad, broiled filets with parsley butter surrounded by asparagus spears. For dessert, drown strawberries in Devon cream and sprinkle with fresh mint. (The P Street Store, 2120 P St. NW, has been carrying real Devon cream imported from England at $2.75 for an 8 oz. bottle.)

Instead of letting your guests lie around sated with crocus and cream, buy a lot of kites, paint the frames with glow-in-the-dark paint and, wind and weather willing, lead everyone on a late-night kite-flying adventure. That would be a good and silly thing to do, the kind of sport you might expect from someone suffering spring fever.

If the wind is not willing, you could use glow-in-the-dark Frisbees and see how many of your neighbors report the first flying saucers of the season.