Spring is pushing into summer. School doors are closing. Nervous? Need something to occupy your kids for three months? How about something that offers a learning activity so hidden even Tom Sawyer wouldn't know he'd been had -- and one that doesn't involve any driving or schedule-shuffling.

The answer lies fallow in your own backyard -- a real children's garden, dug, planted, weeded, debugged and harvested by your own offspring. It's possible, healthful, time-consuming and fun.

Begin small. You don't have to plow up the backyard for this project. An intensive garden, rich and deep, yields twice as much as a conventional tilled garden. A sunny spot only four feet square is enough to produce more than half a dozen varieties of vegetables, flowers and herbs.

An intensive garden needs to be double- dug. Remove the top eight inches of soil in a trench along the width of the garden. Then use a spade and loosen the soil below another eight inches. Add manure and/or compost and mix them together with the soil. Rake in the topsoil you removed. Your garden plot should now be several inches higher than the ground around it. Help the kids find some boards to sink in the ground as a border and pound in some stakes to keep them in place. You won't have to dig the garden again next year because you won't be walking on it, just around it.

Don't expect the digging to be a quick process. This is a summer-long activity. Let the kids take their time. Look for interesting rocks (we found a fossil), examine bug larvae, and compare the size of captured earthworms (and then go fishing). A neighbor donated a large used sandbox for our garden and the kids wallowed in it. They buried themselves, threw a lot of dirt around and got ecstatically filthy. We entertained the neighborhood children for several days and doubled the local detergent consumption.

When it's time to plant, let the kids decide what they want; it's their garden. You can have your own elsewhere in the yard.

Your child may want to stick to the standard eating varieties may want to grow some of the clowns of the garden world. The gourd family, for example, offers gigantic vines and strange fruits that can be variegated warty wonders or develop into dippers, bowls, bird's nests or a luffa sponge. Let your child scratch his or her name into the young fruits. The scar tissue will be indelible proof of who grew which.

They can grow broomcorn and make their own brooms in the fall, or plant popcorn that will puff up summer memories through the winter. Monster sunflowers grow the way a child believes everything grows: overnight. Their seeds are wonderful for both birds and kids. Sunflower seeds planted in a semicircle and interspersed with scarlet runner beans produce nature's own teepee. All you have to do is tie the sunflower heads loosely together at the top, and there's the neighborhood clubhouse.

There are a few tricks you can use during planting to help insure success. When planting small seeds (lettuce, carrots, many flower varieties), mix them with a little sand in an old spice jar with a shaker top. Make a wide row and let your child "salt" it with seeds. This helps to spread them all along the row instead of dumping everything in the first three inches.

When you plant thirsty greenery such as tomatoes, eggplants (assuming your child is that rarity that actually eats these vegetables), peppers, squash or pumpkins, punch holes in a coffee or fruit juice can and bury it next to the young plant with the top above ground level. When it comes time to water the garden, the child can fill the coffee can and insure that these heavy drinkers get enough before the child's patience with a hose runs dry.

Before you plant get out the magic markers and 3 x 5 file cards. Have the kids draw what they are planting; slip the drawings into a plastic recipe saver and staple them to popsicle sticks or whatever you have on hand. Given the number of days until maturity on the seed packet the kids can estimate the harvest date of each vegetable. Include this date on the markers. This helps with hidden crops such as carrots, which look done to most children at least a month before they're ready.

As the tomatoes grow, they will benefit from "caging". This means some means of supporting the vines. Get the kids some garden books with examples of caging techniques and let them build what they want. Materials can be scrounged.

When the seedlings are up, it is time to mulch the garden. This keeps weeds down and moisture up. Make an excursion to a farm to buy some straw (not hay, it's full of weed seeds). Or use lawn clippings or newspapers (leave out the color sections, because the ink contains toxic heavy metals). These are all biodegradeable and can be turned under in the fall.

Even with the sentry marigolds and herbs your kids will still have to keep a wary eye out for maurauding insects, a task these little buglovers seem to enjoy. There are recipes in organic gardening books for homemade, nonpoisonous sprays. Give the kids the recipe and let them cook up a batch to spray their garden.

The lethal cutworm can devastate the garden before it even gets started. This nasty creature hides in the soil during the day and comes out at night to decapitate lovely young peppers, tomatoes, cabbage, beans and corn. You can avoid such tragedy with the trusty coffee can. This is no super-bug, he can't chew through metal. So remove the lid from both ends of the coffee can and push it into the soil around the young plants about two or three inches.

To trap the incredibly ugly and disgusting slug, just place a flat wooden board in the garden near the tomatoes. After dark you can lead a flashlight foray to unmask and remove the blighters. You don't want to touch them, so take along a jar with a lid to scoop them up. Or you can leave beer bottles with a little brew still in them around the garden and empty out the drunken slugs in the morning. Your kids might enjoy decorating these slug traps with appropriate markings.

When the harvest begins, be ready for some very proud kids and act accordingly. Share with good friends, but let the kids make the presentation. You can pickle green tomatoes for Grandma's Christmas present, or dry some rosemary or basil for a favorite aunt. Hang your autographed gourds on the door for Thanksgiving. And by all means, let the gardeners help cook their bounty.

Order some seed catalogues. When snow blankets the ground next January, your kids can leaf through the catalogues, decide what they will grow next year and remember the summer of their very first garden.