I've seen several references to ''hotbeds'' lately, but have no idea what they are, except that they're something in which to grow plants. Can you enlighten me? A hotbed is a structure built below ground level in which heat is provided for growing plants by using electric cable, electric light bulbs, or the old-fashioned method of a layer of fresh manure in the bottom.
Some folks who have steam or hot-water heat in their homes extend pipes to a hotbed.
The cover can be old storm sash, frames covered with polyethylene, or rigid plastic. Sides can be framed with wood, cement blocks, or bricks.
Folks who get the greenhouse ''bug'' usually start with hotbeds.
We are very fond of watercress and would like to grow some on our window sill during the winter. The only spot we have to grow it gets only about an hour of sun a day. Is this enough? Watercress will even grow without sun if the window gets bright light. You can sow seeds in pots of loose soil and cover lightly, but you don't even need soil. You can grow it on cotton bats kept soaked with water.
We grow ours in pie plates, sowing the seeds on perlite that is kept wet at all times; then we eat the whole plant.
By keeping several pans going, seeding at different intervals, you can keep plants growing in several stages all the time.
We're tired of mowing grass (it's so time-consuming) and would like some suggestions on what we could substitute for our large lawn area.
A landscaper suggested rock gardens, perennial beds, and a naturalized area with a low-growing ground cover. What do you think of this idea? With more than 40 years of mowing our own home lawns and more than 30 years in commercial landscape enterprises, we say ''stick with the lawn mowing.''
There are various good ground covers for special purposes, such as small shaded areas, slopes, and tucked-up front yards in cities which can use ground covers that don't require mowing. Grass, however, is a ground cover than can be walked on, sat on, and you can even play games on it.
Any planting, such as a rock garden or perennial bed, needs constant grooming (weeding, snipping, pruning) to keep it attractive. That is more time-consuming and more tedious than mowing a lawn. (Some of our best articles have been mentally written astride the riding mower.)
Other ground covers also need grooming for a year or two before they become established. If it is a large area, it will probably take longer.
Think of your lawn as a nice green welcome mat, giving off oxygen to breathe and moisture to humidify the air. On a hot day, this has a cooling effect worth 20 to 30 degrees F. when compared with bare ground, blacktop, or concrete.
Think how many weeds you're getting rid of in one fell swoop. Most weeds disappear because they can't stand being mowed.
If you have a question about your garden, inside or out, send it to the Gardening page, The Christian Science Monitor, One Norway Street, Boston, Mass. 02115.