Chapter 21: Nearly Ten Ways to Extend Your Growing Season

In This Chapter

Starting your veggies earlier in the season

Extending your harvest into the cold-weather season

After you start vegetable gardening, you may get hooked on having fresh vegetables from your garden year-round. Unless you live in a mild climate, such as zones 9 and 10 (see the appendix for more on zones), the best way to get the most vegetables from your garden is to use season-extending devices. These devices protect your vegetables from deadly frosts in fall and enable you to get an earlier start in spring. Of course, selecting the right vegetables to grow also is vital to your success.

In general, greens, root crops, and cool-season cole crops are the best vegetables to grow in cold weather. (See the specific chapters on these vegetables for growing information.) However, you can extend the length of time that you harvest warm-season crops — such as melons, tomatoes, and peppers — by using the season-extending methods in this chapter. Whatever plants you grow, these techniques enable you to harvest fresh vegetables for most of the year.

Choose Clever Planting Locations

Where you plant your vegetables has as much to do with avoiding frosts and cold weather as when you plant. Every yard has pockets or areas that warm up earlier in spring and stay warmer later into the fall. For example, the nook near my kitchen window on the south side of my house is such a location. That area is the first place that snow melts, and plants in this location grow well past the time when frost has killed vegetables in my main garden. Find these nooks in your yard, plant cold-hardy vegetables like spinach and broccoli, and enjoy harvesting earlier and later than anyone else on the block.

Some good nook areas to check out in any yard are the south-side walls of buildings, especially if you can find a spot that's protected from wind. Courtyards are notoriously good microclimates. (See Chapter 3 for more on microclimates.) Other good spots include areas around evergreen shrubs (as long as enough sun pokes through them to grow the plants) and near paved surfaces such as driveways or walkways — especially if the pavement is dark colored.

Time Your Planting Wisely

Timing is important when you grow vegetables. Here are some guidelines to follow:

If you want early vegetables, start your seeds indoors in late winter or early spring (as I explain in Chapter 13). Then you can transplant the young seedlings into a season extender, such as a cold frame, cloche, or hot cap (all of which I describe later in this chapter).

If you want your vegetables to last longer into winter, start them at the end of the summer, but be sure to start them early enough that by the dark months (December and January), they'll be full-sized and edible. During these months, don't expect much growth, even in warm areas, because the light is less intense and the day is much shorter. You'll be extending the harvest season, not the growing season. (Unless, of course, you're in a warm location and trying to overwinter these vegetables for a spring harvest; see Chapter 19 for details.)

Protect Plants with Hot Caps

Hot caps are a great way to protect individual prized plants from the cold. A hot cap is usually a clear plastic, pyramid-shaped cone with an opening in its top to let hot air out. You can buy these cones at garden centers, or you can create your own by cutting the bottoms out of clear plastic milk jugs. If you do create your own, be sure to cut a vent at the top of the milk jugs to let hot air out on sunny days. Or use them only at night. You can cover the hole with a blanket at night if you expect chilly temperatures.

Add Elegance to Your Garden with Glass Cloches

If you really want something elegant in your garden, you can spend up to $50 on tinted glass hot caps, affectionately called cloches, as shown in Figure 21-1. They're sturdy and beautiful, and yes, they protect tender plants from the cold — even a little better than plastic hot caps do. However, cloches don't have vents, so during sunny days you need to remove them or prop them up to let cool air in.

Buy or Build Cold Frames

Cold frames essentially are mini-greenhouses. They're usually wooden boxes covered with windowpanes or clear plastic (see Figure 21-2). Some professional gardeners as far north as zone 5, where winter temperatures can dip down to -20 degrees Fahrenheit, can harvest vegetables every month of the year by planting cold-weather-tolerant crops in cold frames.

You can purchase a premade cold frame for $100 to $200, or you can create your own simple cold frame by following these steps:

1. Build a 3-foot-x-6-foot box from untreated lumber. Cut the box so that the back is 18 inches high, sloping to a front height of 14 inches.

This sloping angle enables more sun to reach the plants, and it sheds rain and snow as well.

2. Hinge an old window sash over the top of the cold frame or make a frame by using tightly stretched clear plastic, which creates a sealed growing environment.

You can insulate the cold frame by adding rigid foam insulation around the insides of the cold frame and by weather stripping along the top edge.

3. Position the cold frame so that it faces south.

It's best to put a cold frame next to a structure, such as a house, toprotect it from cold winds.

Even though the purpose of a cold frame is to trap heat, on sunny days, even in winter, a cold frame can get so hot that it burns the plants. Check your cold frame once a day on sunny days, opening or venting the top slightly to allow hot air to escape.

Drape Row Covers over Veggies

A row cover can be a clear plastic cover draped over half-circle wire hoops to create a tunnel effect (see Figure 21-3), or it can be the new lightweight cheesecloth-like fabric that's so light it floats on top of your vegetables. Both plastic and floating row covers protect plants from light freezes; however, if you expect really chilly temperatures (around 20 degrees), use another protection device, such as a cloche.

Clear plastic heats up your crops faster and warmer than floating row cover material, but it needs venting to keep the plants from overheating. Floating row covers let in air, light, and water and don't overheat as easily as clear plastic row covers. You also can use both materials to protect your plants from insects.

Place Wall O' Waters around Plants

Wall O' Waters (see Figure 21-4) are double-walled, clear-plastic cylinders that hold narrow columns of water around your favorite vegetables. By placing Wall O' Waters around heat-loving plants, such as tomatoes, you can get a jump on spring. The water in the cylinders absorbs the warmth of the sun during the day and slowly releases the stored heat at night to protect your plants in cold temperatures. Even if the water freezes, it releases enough heat to protect your plants. Wall O' Waters have been reported to protect tomatoes in temperatures as low as 16 degrees.

To prevent overheating during the day, leave the tops open. For added protection at night, collapse the tops of these devices into a pyramid shape. Of course, after a plant has grown for a few weeks, it will outgrow the plastic cylinder, so you'll have to remove the Wall O' Water. But what a jump on the growing season you'll have by then!

Try Portable Greenhouses and Hoop Houses

If you really want to extend the growing season, stop fooling around with hot caps and blankets and buy a portable greenhouse or hoop house. You can find many different free-standing portable greenhouses on the market that are great for getting an early jump on the growing season and extending it into the fall. Walk-through hoop houses also have become popular because of their low cost and ease of use. They have a metal shell with clear plastic pulled over it and doors on either side. They keep the air warmer than a cold frame, but they're not as warm as a conventional greenhouse. Greenhouses and hoop houses can range in price from $200 to $2,000, depending on the materials and size. In the appendix, I list a number of manufacturers and suppliers that can help you choose the right greenhouse or hoop house for your location.