Season-Extending Techniques

Few gardeners are content with the length of their growing season. In the far North, there's barely enough time to ripen tomatoes or melons. In the South, drought and intense heat limit gardening activity to the spring and fall months.

The good news is that by using a few simple season-extending techniques and plant-protection devices, you can shield your plants from extremes of weather, and stretch your gardening season by two, three or even six months.

Lettuce growing in greenhouseWith a cold frame or greenhouse, you can get started earlier in spring and garden longer into the fall.

Reduce wind exposure

If the plants in your garden must battle strong winds, they'll need to use most of their energy to survive, rather than developing strong root systems and putting on healthy growth. To protect your garden from wind, you can build a wood fence; plant a windbreak of trees and shrubs; or put up windbreak netting. Your goal is to reduce the wind speed, not create a dead calm.

If there's a prevailing wind direction, a fence on that side of the garden may be all that's needed. If putting up a permanent fence or hedge requires more time or financial commitment than you are ready to make, try a temporary plastic mesh fence or cover your plants with polypropylene garden fabric or special covers or cold frames. Seedlings grown under the shelter of garden fabric will often put on twice as much growth as control plants.

Warm up the soil

If you protect your garden over the winter with a thick layer of mulch, be sure to pull the mulch off the planting beds in early spring to expose the soil to the sun. Raised beds are another way to warm the soil more quickly. Covering cold spring soil with black plastic can also boost soil temperature by several degrees. The plastic can be left on all season or removed prior to planting.

Combining black plastic mulch on the soil with plant covers or garden fabric will get melons and other heat-lovers off to a fast start. In the fall, covering plants with garden fabric will retain heat and keep soil several degrees warmer. This can give heat-loving crops, such as peppers, okra and tomatoes, a couple extra weeks to ripen.

Provide protection from sun and heat

Hot weather can be just as challenging as cold weather. Young plants can be stressed and stunted by excessive heat; salad greens turn bitter and go to seed, and getting seeds to germinate can be very difficult. Shade netting keeps plants and soil cool and helps retain moisture. It can be laid right over wire hoops or a movable wooden frame. A piece of wood lathe attached to a frame can serve the same purpose.

Block spring and fall frosts

Garden fabricGarden fabric (row covers) can be placed right on top of the crops you want to protect. Another option is to use flexible hoops to support the fabric.

For most gardeners, frost is a limiting factor in both spring and fall. One night of 32 degrees F. will usually put an end to all but the hardiest of garden crops. Sheets, blankets and cardboard boxes are good emergency solutions, but garden fabric (or row covers) is far easier to handle and much more effective. These fabrics are available in a variety of thicknesses, and some, such as GardenQuilt, will protect to temperatures as low as 25 degrees F.

Cold frames and portable greenhouse structures can offer even greater cold protection, often allowing you to extend your harvest season of cold-weather crops right through the winter.

Three Techniques for Stretching the Harvest

Start by considering your local climate. How much do you want to stretch the season, and how much time you are willing to invest? If you live in a cold climate and want to extend your harvest season year-round, you will probably need to invest in a greenhouse and be prepared to provide daily attention. On the other hand, if you just want a few extra weeks of ripe tomatoes in the fall, and salads a couple of weeks earlier in the spring, the solution is easy and inexpensive.

    1. The 30-day stretch: If you can provide a sheltered growing environment that protects your plants from hot sun, cold wind, frost and insects, your seedlings will get off to a much faster start. When transplanting, try to keep seedlings covered with garden fabric for the first couple of weeks. Garden fabrics made of spun polyester or polypropylene are sun-, air-, and water-permeable, which means excess heat can escape and rainwater can pass through. Checking your plants weekly, for water and weeds, is all the attention that's required.
Special cover protects young plants from frostThis special cover has a zippered top that can be opened on warm days.

Individual plants can also be covered with plastic milk jugs, coffee cans with both ends cut out, or tomato cages encircled with clear plastic. Just be sure that the cover is vented, and that you stay on the lookout for signs of overheating.

    1. The 60-day stretch: Using garden fabrics in both spring and fall can add two months to your harvest season. Use them in the spring as described above, but plan to use a heavier fabric in the fall, such as GardenQuilt, to retain soil heat and prevent frost from damaging the foliage.

Choosing the right plant varieties can make a significant difference too, because some varieties are more suited to early- or late-season production. There are some varieties of broccoli, for instance, that thrive in cold spring soils, but go to seed quickly once warm weather arrives. There are other varieties that will tolerate heat, and still others that thrive in the low-light conditions and cold temperatures of late fall.

    1. A stretch of three to four months: In many parts of the country, protection tents and greenhouses can extend your harvest almost year-round. Managing a protected growing environment in the face of widely fluctuating weather extremes is actually easier than you might imagine. The rewards — salad greens in February and tomatoes right through Thanksgiving — far outweigh the investment.

The key to success is to concentrate your energies. Focus on a few crops or a particular section of your garden. Salad greens and root crops are easiest. You'll find that a 3 ft. x 4 ft. bed of greens can provide many months' worth of salads. Choosing the right varieties and following a continuous planting schedule is essential.

Growing under cover opens up an exciting new world with big rewards. Imagine having a salad bar with fresh, organic produce right outside your door, eight or ten months a year!

Frost covers for plantspop-up plant covers allow you to grow earlier in spring and later in fall.

Last updated: 11/17/2023