Scratch seeds now for strong blooms later

Halloween is past, but its still a good time for scarification. "Scarification" has nothing at all to do with "scaring." Scarification means "to scratch" and in the world of gardening scarification means "to scratch a seed." You scarify seeds whose seed coats are so hard that they are impervious to water and gases.

Under natural conditions, such seeds eventually imbibe water and gases, but only after the seeds have lain in the soil for a few years or passed through animals. Many gardeners are too impatient to wait a few years for germination.

Seeds of some perennial plants need to be scarified now so that they will be able to germinate next spring. In some cases, scarification is needed because two to three months of cool, moist conditions are needed to break down germination inhibitors naturally present in many seeds. That breakdown cannot occur unless the inside of the seed is cool and moist. Less than 10 percent of redbud tree seeds, for instance, sprouted when they were either scarified OR kept cool and moist, but a whopping 88 percent germinated when the seeds were scarified AND THEN kept cool and moist. Inhibitors and a hard seed coat, alone or together, serve the useful purpose of holding back seed germination until growing conditions are favorable.

The mechanics of scarifying are straightforward enough if you have just a few large seeds. Take the word scarification literally, and scratch each seed with a file. Or, you could whack the seed with a hammer (not too hard), or nip at it with a wire cutter.

To scarify small or many seeds, follow the lead of nature: Put them into a bag with some moist soil, and keep the mix warm for a couple of months. Then, if necessary, move the bag somewhere cool for another couple of months. Another way to scarify is to just plant seeds outdoors early enough in summer. Or pour some boiling water over the seeds, then let them stand in the water for a day.

Scarification is needed mostly by perennials in the pea family, and that would include such trees and shrubs as honeylocust, black locust, wisteria, broom, mimosa, and redbud, as well as the herbaceous perennial lupine. Scarification also speeds germination of some non-legumes, such as rose, cotoneaster, linden, and witchhazel.

Some annuals also benefit from scarification. Nip the tips off morning glory seeds before sowing them and young shoots should poke up through the soil within two days.