Seaweed keeps garden pests at bay

Paradoxically, it was a storm on Cape Cod a few years ago -- ``a real howler,'' to quote residents -- that set Canadian businessman Alan D'Orsay on the road to large-scale seaweed composting and what he refers to as ``pest-free gardening without the need to spray.'' Alan and Patricia D'Orsay, who were vacationing on the cape at the time, live close to the heart of Toronto, in a house with just enough land at the back for a compact vegetable garden and six highly productive apple trees that Mr. D'Orsay no longer has to spray. He has harvested blemish-free fruit for the past three seasons, in part, he says, because of that storm.

The waves had thrown a thick carpet of seaweed over Cape Cod beaches. So when it came time to leave, the D'Orsays took along as much seaweed as they could cram in the trunk of their car.

``I had been told,'' Mr. D'Orsay says, ``of a Maine farmer who didn't spray his trees, yet was confident enough to offer a dollar for every worm found in one of his apples.'' According to the farmer, the seaweed mulch spread under his trees each year gave them the needed pest resistance.

Although Mr. D'Orsay hoped the seaweed would have a suppressing effect on insect pests, the results were beyond anything he expected. There wasn't a marked apple on the trees that year, he recalls. Annual applications of seaweed, composted with fish waste, have kept the garden pest-free in the two seasons since then and produced some of the ``best tasting'' vegetables he has grown in his many years of gardening.

Mr. D'Orsay, whose family hails from New Brunswick, was well aware of the mountains of seaweed available along its coastline. The province also has a fishing industry that produces enough fish waste to be a nuisance, but not enough to supply a full-scale fishmeal plant. The two products were a logical combination, as fish waste is rich in the one plant nutrient, nitrogen, that seaweed lacks.

With a little experimenting, Mr. D'Orsay was able to get an appropriate mix -- seaweed, fish waste, and rock powders. Composting in its initial stages is necessary to reduce bulk, concentrate nutrients, and eliminate all odor. The result is a moist granular product, now coming onto the commercial market from Port Elgin, New Brunswick, that improves soil structure, provides a rich blend of nutrients, and also appears to lower pest problems.

Though research in Norway and Scotland has detected greater pest resistance in plants where the soil has been enriched with seaweed as well as improved cold tolerance, Mr. D'Orsay says he doesn't offer the product as a cure-all for pests.

``I can only say that my garden [where the soil has been improved over the years by tilling in several inches of leaves each fall] is virtually pest-free.''

At one stage he wondered if his region of town had suddenly become unusually pest-free, until a woman moved into a house two doors away and began to garden. In the poor soil of that garden, ``her plants were devastated by insects while mine were untouched,'' Mr. D'Orsay says. ``I didn't rejoice in her problems, but I believe it did prove that there was something to seaweed-enriched soil and pest resistance.''

Other trials, principally around Toronto, all indicate greater pest resistance when the granular product is mixed in with the topsoil. Pisces Organic Plant Food, as the product is known, has not been tested for its pest-reducing potential at any agricultural school or experimental station. But the seaweed, fish waste, and rock powders it contains are proven soil-building materials, which Mr. D'Orsay believes bring soil life and plant nutrients into such an ``ideal state of balance that plants grow vigorously and maybe even produce their own insect repellents.''

While there are liquid seaweed concentrates on the market, Mr. D'Orsay knows of no other product quite like his. ``At horticultural trade shows I see a dozen different people selling milled peat but no one selling milled seaweed.''

Before he began to market Pisces, Mr. D'Orsay had it analyzed at Guelph University's School of Agriculture. ``You have a good product there,'' he was told, ``but it's nothing we could not duplicate by mixing 5-10-10 fertilizer and micronutrients with peat moss.''

Mr. D'Orsay's response: ``That may well be, but would it keep the worms out of the apples?''

To learn about availability in your area, write to Sea Harvest Company, 47 Winston Grove, Toronto, Ontario, Canada M8Y 2L1.