Pile it on. Trash in the trench. DENIZENS OF THE HEAP

IF you've a mind to dig, there's an alternative to aboveground composting that some feel is the easiest of methods. It's sometimes called ``trash-in-the-trench'' composting, and those who practice it contend it works very well.

A veteran gardener introduced the idea to me several years ago. He dug a trench as wide as his spade and 18 inches deep across one garden end.

And like the painter who can never finish the bridge, he was always working at his ditch, adding waste at one end and removing compost from the other in a never-ending cycle. With a little renovation every now and then, he had used the same trench for something like 10 years.

It works this way: Each day, or every few days if that is more convenient, the gardener adds garden and kitchen waste to the trench, starting at one end, topping each application with soil taken from the ditch, so it is slightly mounded above the surrounding garden level.

To be sure that inquisitive dogs or curious skunks don't dig it up, the most recent applications are covered with a thick wooden board and weighted down with a stone. Within a day or so, whatever attraction the waste might have for these visitors disappears.

When the ditch is halfway filled, start removing finished compost from the front end for use in the garden or storage away from soaking rains.

A word of caution: Never site a compost trench in a low area where heavy rains might flood it or where there is standing water in the spring.