GARDENING : How Would You Like Your Seeds Treated? Buyers Have Sow Many Options

Even though nature has provided seeds with all they need to burst forth and mature into healthy plants, humans have seen fit to alter them in all manner of ways, if only to market them that much better.

This can baffle even seasoned gardeners, even if they have already considered specific varieties. There are seeds that have been treated, pelleted, organically grown and spaced on “tapes” for easier planting.

As gardeners become more concerned about environmental effects of chemicals, these distinctions are more than just academic. Treated seeds are subjected to a dose of fungicide or preservative, often seen in large seeds or slow germinators: peas, beans, corn, spinach, beets.

The chemical prevents seeds from drying out, rotting or generally deteriorating in storage and after sowing. Varieties that are aimed primarily at the agricultural market (which buys 95% of the seed sold in this country) are treated with a pesticide to prevent infestations in storage.

With some types of chemicals, the evidence of treatment is obvious: The seeds come out in lurid shades of neon pink, green and blue. But more often, the seeds display no outward change in color or appearance, so the only way to know the seeds have been treated with a fungicide, preservative or pesticide is if seed companies reveal that fact. Most of the time, they don’t.

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The pros and cons of treated seeds must be weighed by gardeners. It has not been found that treated seeds produce chemically laced plants--a question posed quite naturally by the beginner. And seeds that have had a chemical dose are less likely to rot in the ground, which is an issue in cold, damp climates.

Using chemical preservatives on seeds to prolong their shelf life seems less justified. Seeds sold to the home-garden market should be the freshest, especially since they are most often sold in minuscule amounts and planted quickly. Nearly all seeds sold to the home gardener have been grown within the previous 12 months; some are put on the shelf six months after harvest.

With proper storage, there is no reason to worry about infestation or deterioration of quality.

Telling if seeds have been treated is not easy, although some mail-order companies stock untreated seeds to sell to people who feel strongly about this. Gardeners who are not sure if seeds have been treated, especially with seeds bought from retail sources such as garden centers and hardware stores, can call and ask the company that packaged them.

Organically grown seeds--harvested from plants that have been raised free of inorganic chemicals--are sought by purists. There may be scant difference between these seeds and the seeds of traditionally grown plants, but the increasing demand demonstrates the philosophical commitment of gardeners who desire untreated products. More and more, it seems, organically grown seeds will be easier to find.

Pelleted seeds have been coated with a substance--usually bentonite clay--to make them more visible. This makes them easier to sow, simpler to space correctly for plants to thrive--and a boon for gardeners whose hands are arthritic and cannot hold the very small beginnings of their garden.

But pelleted seeds tend to be pricier, and the “shells” that are formed with the clay are slow to allow water in: Moisture is vital for germination.

Last year, as an experiment, I sowed pelleted carrots and was delighted. Carrot seeds are difficult to detect against dark soil and, in the past, I have always broadcast them too close together. The pale-colored pelleted seeds showed up well, making the spacing much easier. The resulting harvest was very satisfying.

Some vegetables are available as seed tape--a roll about the size of a tape measure, made of lightweight translucent paper pocked with seeds every few inches.

The paper decays in the ground, allowing the seeds to germinate freely. The tape can take the worry out of spacing seeds, especially tiny ones, such as carrots, beets, spinach and lettuce. Among disadvantages: The soil must be very even and smooth to receive the tape. Also, the tape tends to be a little unwieldy; many gardeners may find it easier to sow by hand.

Of course, not every gardener will speak fondly of all these seed choices. It’s hard enough to figure out what to plant without having to worry about the embryonic forms.