10 Season Extension Strategies

Protected growing means using structures and materials that buffer crops from the weather, and it is a standard part of growing at nearly every scale. Market farms and home growers rely on high tunnels, low tunnels, row covers and mulches because they make it possible to harvest sooner in spring and longer into fall, spread out the harvest of many crops, improve quality and flavor, reduce pest and disease problems, and raise yields. Used well, they support production in all four seasons, not just the shoulder months.

Here row cover and irrigation keep insects out and cool the soil for a freshly sown crop that germinates best at lower temperatures, while late-summer days are still hot.

Row covers are made in several weights for different jobs: evening out temperature swings, shielding plants from wind damage and drying, cutting harsh sun, and keeping pests off.

Browse our Row Cover & Accessories

Perhaps the biggest benefit is a more even workload across the year, with less summer burnout and more work done in comfortable weather. For commercial growers, a longer season also means more income, and many find the return on these fairly modest investments worthwhile.

Growing under protection makes a farm or garden more complex, and it can change how you plan. The last-frost date matters less and day length matters more. One big planting may give way to many smaller or successive plantings in different settings, and you may find yourself growing crops that never did well for you in the open field.

Below are 10 ideas for getting started with season extension. Treat them as a starting point: as you try protected growing on your own farm or in your garden, you will likely find more ways to improve your crops, add income and enjoy the work.

Shade cloth is also sold in several densities for different crops and times of year. In this photo it lowers the air temperature and shields young lettuce from strong midday sun.

Most season-extension materials have several uses for buffering conditions and stretching production over more of the year.

Browse our Season-Extension Tools & Supplies

1. Sow cold-tolerant crops in a high tunnel in January or February and protect them with row cover over hoops.
2. Sow leeks in a cold frame during January or February, then move them to a low tunnel once the ground is workable.
3. Start cool-season crops under a low tunnel two to three weeks before you would sow them in the open.
4. Set out cucumbers and tomatoes in a high tunnel about a month ahead of field planting.
5. Plant eggplant under low tunnels with light row cover to keep flea beetles off.
6. Put shade cloth over hoops in summer and grow heat-tolerant lettuces.
7. Lay shade cloth over the soil for about a week before sowing fall crops to help seeds germinate during hot weather.
8. Keep heavy row cover ready for an unexpected late spring or early fall frost.
9. Plant spinach and carrots in the hoophouse, planting enough to keep harvesting all winter.
10. Plant spinach under low tunnels for the winter; it starts growing again in late winter or early spring and gives the first harvest of the year.

Growers of any size can extend the season. In home gardens, low tunnels and cold frames are an affordable alternative to a high tunnel for winter harvests.

Winter Growing & Overwintering Resources

• Winter Growing Guide: harvesting through winter and overwintering crops for spring  (article series)
• Overwintering flowers guide  (article series)
• Forcing flower bulbs guide  (article series)

Summer Growing Season Extension Resources

• Beat the Heat  (article series)
• Shade Cloth  (comparison chart, PDF)
• Planting programs: succession recommendations crop by crop (article series)
• Succession planting principles and practices • article with charts

• Greenhouse and tunnel supplies • products
• Protect Your Crops: high and low tunnel basics• article
• Row Covers • comparison chart, PDF