Gardening Articles: Care :: Soil, Water, & Fertilizer
Soil for Seed Starting (page 3 of 3)
by Jack Ruttle
Where to Buy
You can buy mixes in three very different places. Superstores with gardening sections will have a wide choice of brand names and will offer smaller packages. At local nurseries and garden centers, the choice in brand names will narrow, but there will be a full line of soils, some of them in larger sizes.
At a retail nursery that produces at least some of its own plants from seed or cuttings, you have the narrowest but perhaps best choice of all: the mixes that professional growers use themselves. Very often the owner will sell a bale or large bag. These materials cost from $8 (for a 40-pound bag) to $14 (for a 70-pound bale) wholesale. So even if you pay twice that, you are getting a tremendous bargain if you can find a grower willing to sell some, and increasingly many growers will do that.
If you keep the bag tightly closed and protected from the rain, the material will keep well for more than one season. The plastic covering on commercial-sized bags and bales is usually treated with ultraviolet light inhibitors, giving the material about a one-year life when stored in the open. But all materials should be kept closed tight to keep out disease organisms and maintain the moisture level of the material in the bag, which should be just very slightly moist.
Making Your Own Seed-Germination Mix
The quality of professional seed-starting and growing mixes is so high that there is little reason for anyone to bother with the dusty job of mixing their own. Still, if you somehow can't find a good one to buy, the recipe for a peat-lite mix is very simple: Make the blend between half and three-quarters milled sphagnum peat moss and the rest horticultural-grade vermiculite. For maximum air circulation and water drainage, substitute perlite for half the vermiculite.
If the peat is coarse or lumpy, break up clods and take out large pieces with your hands, or use a 1/4-inch screen. Mix in some dolomitic limestone, at the rate of five pounds per cubic yard of mix. It's important to incorporate the lime thoroughly through the mix. At least one day before you plan to plant, sprinkle the mix with water to allow it time to permeate the peat. Rather than trying to mix in fertilizer, it's better to wait until seedlings are up and then begin feeding with a nutrient solution right away.
Jack Ruttle is a former senior editor at the National Gardening Association.
Photography by John Goodman