Raise a crop of crisp carrots in a box

Carrots are one of the more productive crops for the amount of space they take up. That would make them prime candidates for the backyard garden, if people didn't have so much difficulty growing them. Poor soils are the principal reason for this difficulty. They are often too stony or too heavy for roots to develop easily. That's why Raymond Poincelot, author of ``No-Dig, No-Weed Gardening'' (Rodale Press, $17.95), began growing carrots in a box several years ago. He's grown fat, juicy carrots without fail ever since. I took one look at his system last year, decided it made a lot of sense, and returned home to box my next sowing of carrots. The results were good enough for me to expand the process this year.

The system involves a bottomless box 12 to 18 inches high to hold the soft fluffy soil carrots thrive in. These boxes can be made of wood that will last for several seasons, but Mr. Poincelot has also developed an economy carrot box made from inexpensive border wire and lined with newspaper or corrugated cardboard that will last for one or two seasons. Here's his system:

1.Push the fencing into the soil to make whatever size bed you want. Line it with eight or more sheets of newspaper or, better still, cardboard.

2.Fill the bed with equal parts of sifted garden soil, builder's sand, and peatmoss. If you have it, leaf mold or shredded leaves can substititute for the peatmoss.

3.Spread half an inch of composted cow manure (or your own compost if you have it) over the surface of the soil and dig it into the top six inches.

4.Take some wet newspaper, tear it into shreds, and add it to warm water, stirring vigorously to turn it into paper pulp. It pulps up much more easily if you leave the newspaper soaking overnight.

5.Pour this slurry over the surface of the soil. The water quickly soaks in, forming a papier-m^ach'e surface over the soil that won't allow any weeds to germinate. It also keeps the soil pleasingly moist even on the hottest days.

6.With your finger, poke holes through the paper about half an inch deep at two-inch intervals.

7.Using a wet tooth pick to pick up the tiny carrot seeds, sow two seeds in each hole, covering them with a little perlite. (Perlite is available from garden centers.)

Now your carrot box is set to grow. You might want to scatter a little peatmoss on top if you don't like the look of the paper mulch.

If the soil is thoroughly moist at planting time (which it should be), the paper mulch will keep it that way until germination. But it is advisable to spray the planting holes with water every few days - every day if it is particularly hot, to be sure the germinating seeds never dry out.

Carrot seeds germinate when the soil temperature is between 45 and 85 degrees F. At the cooler temperatures, seedlings can take up to three weeks to sprout, while at 80 degrees F. they will come through in less than a week.

When the carrot seedlings are about three inches tall, thin them to one plant per planting hole. It might be best to snip off the unwanted seedlings with a pair of scissors to avoid disturbing the remaining seedling. When the carrot roots are about the thickness of a pencil, start pulling every second carrot, leaving the remaining carrots to grow to full size. By the way, carrots sweeten up beautifully after they have been subjected to a few fall frosts.

Another option is to alternate every planting hole with onion sets. Then, when all the onions have been removed as scallions, the remaining carrots will have all the space they need to fill out.

This might seem like a lot of hard work for the gardener but the rewards in crisp, flavor-filled carrots are great. Most surprising will be the number of servings that come from even a small box.