Kitchen Gardeners International: Carve Out a Cozy Niche For Cold-Sensitive Plants
By Barbara Damrosch
After an April marked by high drama (airports paralyzed by storms, peaches frozen on the trees), spring planting requires an extra shot of courage. Even if you've hardened off cold-sensitive transplants such as tomatoes and cucumbers by setting flats outside on sunny days, it's an act of faith to finally put them in the ground. Has the weather "settled," as it must for tender crops? Will it ever?
Siting a garden with wind and frost in mind will help conquer spring's uncertainties. The soil at the foot of a south-facing, heat-absorbing wall is prime real estate, and any piece of ground protected from wind by a fence or hedge is better than one out in the open. Wind does more than just batter plants, it dries them too. Sunny enclosures act like sun traps during the day, then reduce radiational cooling at night, when the earth gives back the warmth it absorbs during the day. Most yards have a variety of microclimates from which you can choose, but you can also create them. One of the many tips found in T. Bedford Franklin's wonderful little 1955 book "Climates in Miniature" is a temporary windbreak made by sticking two-foot spruce boughs into the ground along the north side of a planting row -- thereby gaining two or three degrees of heat.
Over the years gardeners have used many tricks to cosset spring plantings. Hilling soil into a ridge running east to west, then planting a row on the south-facing side of the ridge, will boost the temperature a few degrees. So will darkening the soil, since a dark surface absorbs heat. In the old days people spread soot or charcoal (worth a try, but avoid chemical-laden briquettes). A black plastic sheet, slit with an X at each planting hole, is a modern solution. If your soil is "black gold," thanks to enrichments with compost and manure, you're a bit ahead of the game. Protective devices such as cold frames work for small areas and low-growing plants. Floating row covers can be spread over larger beds. Insulators that surround each plant with an upright, water-filled plastic cylinder have been sold in catalogues for years.
Until such companies come out with a gardener's crystal ball, the thermometer will always give the final go-ahead. For tomato transplants, night temperatures should be at least in the 50s. For direct-sown cukes or squash, the soil should be about 70 if possible.
And at that point you will simply decide that spring is here and get on with it.
Article originally published in the Washington Post. Reused with the permission of the author.
Photo credit: Lord Bute
Posted by KGI on May 9, 2007 5:02 AM to Kitchen Gardeners International
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