Paper mulching is for the birds

ROBERT Cowan, a communications consultant from Alpharetta, Ga., came straight to the point. ''Your gardening advice,'' he said in the opening sentence of a letter to me, ''is for the birds.''

Mr. Cowan meant exactly what he said, and to prove the point, an accompanying package contained a bird's nest made up largely of shredded newspaper.

I have periodically written on the value of paper (preferably the black-ink pages of a newspaper) as a garden mulch, particularly if it is shredded.

Mr. Cowan took the advice - and the birds loved him for it. In Georgia, mulching time (when it starts getting good and hot) and nesting time frequently coincide, so the birds were able to take full advantage of his concern for his garden. Where he recognized a temperature-stabilizing, moisture-conserving mulch in the paper, the birds saw an effective nest-building material in quantities they had never known before.

Fortunately, the birds' raids on the mulch did little to reduce its effectiveness, and Mr. Cowan, an avid gardener, reported beneficial results, as did many other gardeners who responded to a survey by the Brooklyn Botanic Garden last year.

Any organic material (something that has once lived and therefore will ultimately decay) will make a good mulch. Compost, old manure, hay, leaves (preferably shredded), partly rotted sawdust, and paper or cardboard all make useful mulches, whether alone or in combination.

Of them all, old newspapers are the most readily available material for most gardeners. It makes good sense to use them, whether or not it is nesting season in your area. Newsprint is 75 percent wood pulp and 25 percent purified fiber or cellulose. All the nutrients, including trace elements, that went into the original tree are in that pulp and will eventually become available to your plants, be they flowers or vegetables, as the paper decays.

Black newspaper ink, by the way, is made from carbon black and mineral ink, which are in no way harmful to plants and microbial life and may even include some beneficial micronutrients. Colored inks, too, are now relatively benign. It is still considered advisable, however, to exclude the glossy colored advertising inserts. As for the rest, the occasional colored printing in the newspaper is no longer considered dangerous to the soil.

Newspaper is particularly attractive to earthworms. I used to think this was merely because of the soft physical properties of the mulch. Those working with earthworms at Cornell University, however, say it is much more than that.

Decay bacteria grow readily in the moist paper (even though it is initially rot-resistant), forming a nutritious food for the earthworms. In eating the bacteria, the earthworms necessarily ingest the paper and, in the process of digestion, convert it into a fine gray powder that decomposes readily.

Last week I raked what remained of a thick paper mulch from a garden bed. The newly exposed soil, protected from the elements all winter long, was filled with the tracks and holes of earthworms. It had the texture of small pebbles, which soil textbooks describe as ideal. Nearby soil that had received no similar protection was not in such good physical condition.

Once the newly planted parsnips are up, a new paper mulch will go back on this particular garden to keep the soil in top condition.

Besides conserving moisture, moderating soil temperatures, and slowly adding humus to the soil through decomposition, the mulch also restricts weed growth and largely eliminates the one gardening chore that I term drudgery.

I pass moistened newspaper through a power shredder to turn it into an effective mulch. But you can use whole sheets (several pages thick) if they are weighted down with soil or stones or otherwise fastened so they do not blow away. A word of caution, though: Whole newspaper sheets sometimes shed rain. Punching a few holes in the paper, so that the rainwater can drain into the soil , will overcome the problem.

There is also a hand shredder on the market that does to newspaper what the office shredder does to documents deemed too sensitive to be merely thrown away. All you need do is stir the resulting paper strips and wet them so they mat together to form a stable mulch when placed on the soil.

Meanwhile, those Georgia birds have a lesson to teach us paper mulchers. Their nest, while made mostly of shredded paper, was lined on the inside with grass. Looking directly into the nest from the top, you could barely tell that it was made up largely of paper. Similarly, a paper mulch can be dressed up if it's in that part of the garden where good looks count. Just cover with a thin layer of shredded leaves, peat moss, or soil.