Garden Know-how: Extend Your Growing Season

Image Gallery Plastic-covered tunnels make perfect mini-greenhouses for early spring planting. ROBIN WIMBISCUS

As late winter days lengthen, resourceful gardeners scurry to collect cloches, erect plastic-covered tunnels and put together a workable cold frame. Using season-stretching devices such as these can add four to six weeks to the front end of your growing season (and many of them will be handy again in the fall).

You can make an amazing array of season-stretching garden gear from found or recycled materials, and you won’t have to rely on electric grow lights to get delectable spring greens in time for Easter or have the first ripe tomatoes on your block. Creating season-extending equipment is fun because you’re working with free solar energy. The trick is to come up with simple structures that can withstand strong winds, shed rain and snow, and absorb and store solar warmth for the plants you’re protecting.

Physical shelter from blustery weather will help any plant, but cool-natured plants such as lettuce, spinach and cabbage-family crops don’t need as much heat as tender tomatoes or peppers — especially at night. Simple plastic cloches or plastic-covered cold frames raise nighttime temperatures 4 to 5 degrees, but you can double that number by throwing on an insulating blanket in the evening. Or triple the protection by adding black water bottles (see “Solar-charged Hot Water Bottles”), which release stored daytime warmth after the sun goes down.

Try Creative Cloches

Low, transparent individual plant protectors, called cloches, are the season-stretchers of choice for plants spaced more than 8 inches apart, such as tomatoes and peppers. Most gardeners keep a stash of cloches made from translucent plastic milk jugs or clear plastic bottles. I pick up roomy plastic juice jugs with handles at my local recycling center.

Before cutting off the bottom of any jug, I make a vee-shaped slit in the top of the handle. Later, I can shove a long, slender stick through the slit and down into the soil to help hold the cloche steady in the wind.

Even when anchored by mulch, strong winds may blow away many cloches — except for heavy ones such as the Wall O’ Waters (see photo), which weigh about 25 pounds when filled. A circle of water-filled plastic drink bottles duct-taped together (see illustration) is heavy enough to stay put and hold down the edges of a sheet of plastic tucked around the cloche for extra frost protection. Countless other items make great emergency cloches for freaky cold spells, including plastic cake covers, upturned flowerpots, cardboard boxes, buckets, baskets, and old lampshades or light fixtures.