Gardening just may be America's most popular sport—bigger than golf, jogging or bowling. At least that's the claim of gardening expert Jerry Baker, 58. Baker, who calls himself America's master gardener, predicts that this summer 69 million Americans will be battling bugs and weeds outside or plucking dead leaves off house-plants inside. If they followed Baker's advice, they could save themselves some expensive trips to the local garden supply shop. A very down-to-earth gardener, Baker is a believer in folksy remedies that can be fetched out of the cupboard and refrigerator. He recommends spraying ammonia and beer on grass to fertilize it, for example, and whacking trees with newspapers to stimulate growth.

Although his methods do not win the approval of some conservative gardeners, Baker insists his solutions are not as weird as they sound. He knows his turf. He is a national spokesman for K mart. He has written 45 gardening books, including Make Friends with Your Lawn and The Impatient Gardener, and starred in two gardening videos, has his own national radio show called on the Garden Line and publishes a gardening newsletter. He has also worked on one of the most successful prison education programs in the U.S., the Hardrock Horticultural Center at the State Prison of Southern Michigan. It permits prisoners to earn a college degree in horticulture.

A Korean War vet and an ex-member of the Detroit police vice-and-narco squad, Baker has gardened from childhood. He made it his career in 1960, and today, in addition to his work in media, he religiously tends his half-acre plot in Troy, Mich. Recently he passed along some choice horticultural tips to Detroit bureau chief Julie Greenwalt.

How do you start a garden?

First of all, find the sunniest spot you have. But if you have real bad soil, don't bother to dig down. Just put down railroad ties or two-by-twelves on their edges. Nail them together like a kiddie sandbox and fill it full of everything and anything you can get your hands on: grass clippings, leaves, sawdust, stuff from the table. You can build it as high as you want. I know of places where older people who cannot bend over have literally put their garden on legs.

How do you prepare the soil?

For a 100-square-foot garden, add four pounds of diatomaceous earth—that's what's used in swimming pool filters—and one bushel of wood ashes. This earth is made from powdered seashells. It's razor sharp and gets into all the sluggies and buggies. The wood ashes coat the insect's breathing and eating systems as he moves through the soil. Then you till it all up and start to plant.

When is the best time to work in the garden?

For best results, vegetable and flower gardens should be worked on the first thing in the morning and after 7 P.M. when it is comfortable for the plants and you. When you get out there in the heat and start hoeing, you kick up the soil, and the heat and dryness suck the moisture out of the holes you make.

When should you water your lawn and garden?

Always water the lawn between 5 and 9 A.M., the vegetable and flower gardens after 7 P.M., never when the sun is at its peak. Try not to let the water touch the vegetables or flowers. That's because water—if it's from a city or suburban reservoir—leaves behind a film of chemicals on the plants when it dries. I use what I call a soaker-floater which lets water gurgle all over the place. Take a couple of the kids' old sweat socks and put one inside the other. Then tie them around the end of the hose. Just lay this contraption on top of soil, and it literally soaks your garden. One watering about every three days is all you will need.

How often should you mow?

Mow your lawn on Monday and Thursday only, after 7 at night. If you mow it Thursday, that leaves Friday, Saturday and Sunday to enjoy your yard. That's the schedule they follow on golf courses. Also make sure you have a sharp blade on your mower. Dull blades ruin more lawns than disease and bugs. And most important, always wear golf shoes. The cleats on the shoes penetrate the surface and leave those little bitty holes. This is especially important if drought is a worry. When you water, the water penetrates the holes instead of rolling off into the gutter.

How do you control weeds?

If you do it right, you should never have to spray weed killer on the whole yard more than once a season. Just pay attention when you're mowing the lawn and spot-kill the weeds. I add the right amount of weed killer for, say, 32 ounces of water. Then I add a tablespoon of liquid dish soap, which helps penetrate the soil. Now, when I'm mowing, I hang that sprayer from my thumb, and when I see a weed, I zap it. The reason not to use weed killer on an entire turf area is because the chemical in weed killers sets back turf production 16 to 20 days.

What are some natural bug repellants?

If you plant marigolds in your vegetable garden, they discourage mosquitoes. Onion and garlic juice are two other great repellants. To keep ants away, add a quarter of a teaspoon of spirits of peppermint or wintergreen to a quart of nice warm water with a tablespoon of soap. Spray it around where ants would come in. If you're going to have a backyard picnic and want it to be mosquito free, spray with flea-and-tick shampoo under benches, trees, shrubs and evergreens before the guests come.

How helpful is fertilizer?

Whatever is growing should be fed at least every two weeks—and that includes the lawn, the garden, the trees and shrubs. Feed in the morning, because plants, unlike people, only ingest and digest during daylight hours. To fertilize, take a hose-end sprayer. Pour in one cup of liquid lawn food and follow with a can of beer, a cup of flea-and-tick shampoo and the balance in household ammonia. Then add a golf ball to the brew. It rolls around and keeps the stuff stirred.

Are you kidding about the beer, flea shampoo and ammonia?

Absolutely not. Ammonia, which is nitrogen in liquid form, gets plants' engines running. The flea-and-tick shampoo removes surface tension so when it rains, the water goes down into the ground instead of rolling off. It also contains a very mild form of insecticide, which is made out of chrysanthemums. As for beer, it contains an enzyme activator that triggers organic activity in the soil like nothing you ever saw.

Are there any shortcuts for a traditional compost pile?

Actually some communities outlaw compost piles because they attract vermin. You can make instant compost. Take table scraps, coffee grounds, orange and potato peels and put them into the blender with some water. Then add a pinch of Epsom salts and of baking powder and a teaspoon of ammonia. Pour this compost cocktail in your garden and you don't have to wait for compost.

Any special treatment for trees?

Yes. Roll up a newspaper and crack the trees from their ankles to their armpits. Really smack them. It stimulates sap flow and begins production. You'll have more foliage, flowers and fruit than you know what to do with. But I suggest you do it late at night. Otherwise the neighbors will think you are nuts.

What if you live in an apartment and don't have space for a garden?

People who live in apartments can grow anything I can grow. For a patio garden all you need is a bag of professional soil mix and a container—it can be a wastepaper basket or a garbage can. Peas and beans do extremely well, but I wouldn't try watermelons on the 25th floor. The one thing to remember is to water frequently. The pot sitting on a balcony gets hot and dries up the soil in a hurry. Also, put some mulch on the top.

Do you ever feel pressure to have a perfect lawn and garden?

No, I don't feel I have to be perfect, and sometimes I screw up. But gardens do take a little physical effort. There's a poem by Kipling that describes it best: "Oh, Adam was a gardener, and God who made him sees/ That half a proper gardener's work is done upon his knees." That, I think, just about sums it up.