August gardens are exploding with fresh veggies. You can keep that supply of home-grown, nutrient-rich produce coming. Now is the time to plant your fall/winter garden. They grow after the first frost and before the last frost. The first and last frost date vary by geographic area. Find the frost dates for any US zip code using either of these sources:
The Old Farmer’s Almanac: https://www.almanac.com/gardening/frostdates/
The National Gardening Association:  https://garden.org/apps/frost-dates/

What to Plant

Mid-July to early September is the best time to plant seeds or starts of cold-tolerant varieties of brassicas and root crops in the Pacific Northwest (PNW). Between rows of winter-hardy vegetables, plant spinach, chard, and Pac choi, which can be harvested until the first frost. Pac choi can even withstand a light frost.

Each of these crops can be started from seed in late July or early August, which is a cost-effective way to keep a garden productive. What a treat to have garden-fresh vegetables to prepare for a winter meal.

Here are some fall and winter crops recommended by OSU Extension and Master Gardener volunteers. Follow the planting instructions on the seed packages. For small garden spaces, you can plant rows closer together than recommended and thin as needed.

Fall Harvest Vegetables

  • Spinach: Tyee or Melody
  • Swiss Chard: Bright Lights
  • Pac Choi: Chin Chiang

Brassicas for Winter Harvests

  • Broccoli: Purple Sprouting
  • Cabbage: January King
  • Cauliflower: Purple of Sicily
  • Collards: Old Timey Blue
  • Kale: Tuscan (many good varieties to choose from!)

Root Crops for Overwintering

  • Carrots: Yaya (seeds only)
  • Beets: Lutz, Detroit Dark Red (seeds only)
  • Rutabaga: Purple Top
  • Turnip: Purple Top White Globe

Less Insect Damage

The pressure from some troublesome insect pests decreases in late summer and fall in the PNW. Leaf miners complete their last cycle in late summer. Aphid populations tend to be highest in early spring, then decrease over the summer as food availability changes, and predator populations increase. Cabbage white butterflies will continue to lay eggs through September. Using row covers and hoop houses can reduce damage. Regular monitoring for pests is still recommended, especially in late summer and early fall.

Selecting and Preparing a Winter Bed

Choose a location that receives at least 8 hours of sunlight during the winter months when the sun is lower in the sky. Mound your soil or plant in a raised bed to prevent roots from sitting in water, which can cause a lack of oxygen. Ideally, choose a location that is somewhat protected from winter winds. Take advantage of a southern exposure or an area near a structure that absorbs heat during the day.

If you’ve just harvested another crop from the bed designated for fall or winter crops, add 1 inch of garden compost.

Protecting Plants from Cold and Pests

There are several easy and inexpensive ways to protect plants from pests and cold weather. The level of protection the plants will need depends on the severity of the winter weather. Some crops, like root vegetables and brassicas, may not require cold protection in the PNW. The root crops are protected underground. Starches in beets and other root crops convert to sugar in cold temperatures, so they are sweeter when overwintered. Many varieties of kale, collards, and cabbage are cold hardy, as is radicchio.

Floating Row Cover:

A row cover is a very versatile, inexpensive and useful tool. It is made of lightweight, non-woven fabric. When placed directly on the soil, it raises temperature and moisture levels. It also acts as a barrier against pests that like to dig up seeds and plants, as well as insect pests that feed on our newly planted crops. Secure the edges by rolling them with wooden stakes and weighing them down with rocks or bricks. Regularly inspect and vent the hoop house to ensure that pests have not been trapped and that plant growth is not restricted.  Row covers of different weights are easily available through garden supply companies.

Cold Frames:

Cold frames can be used to start spring crops, harden off seedlings, and cover winter beds to keep plants warm and protect them from ice and snow. A cold frame is a clear, lidded box with a mechanism for propping the lid open. Many types are available for purchase, and YouTube provides instructions on how to make them from used materials. Cold frames must be ventilated during warm or sunny weather to prevent overheating the plants.

Hoop Houses:

Hoop houses are structures similar to greenhouses that protect plants from cold and pests. They can be built inside a raised bed or directly on the soil. In PNW gardens, using a heavyweight row cover fabric generally provides enough protection from light frosts and winds. In very cold climates, heavy-duty plastic is necessary to prevent plants from freezing.

Different weight materials can be used for the hoops. Metal hoops are useful for tall structures but require specialized tools and some strength to bend.

For quick and effective hoop houses over shorter beds, irrigation tubing, PEX pipe, and PVC pipe can be cut into desired lengths using a knife or PVC pipe cutter. The end of the pipe is inserted over rebar, or bamboo stakes, or into metal tubes placed in the soil to hold the hoops in place. Cover the hoops with row cover, leaving plenty on each side to tuck in. Use binder clips or garden clips to secure the row cover onto the hoops.  Be sure to secure the edges with weights to prevent intruders!

Hoop houses are great for protecting plants in early spring when insect activity is high.

Cloches and Water Teepees

To protect individual plants from cold and pests, cut off the bottom of a plastic milk, juice or water jug. Leave the lid on to retain moisture and remove it when the temperature rises to vent the moisture. Cut a hole in the jug’s handle and insert a stake through the hole to secure the cloche. Water teepees are plastic sheets with hollow tubes filled with water. When placed around a plant, the water absorbs the sun’s heat during the day and releases it at night, helping to keep plants warm early or late in the year.

OSU Extension Service Resources:

PNW Pest Management Handbook: https://pnwhandbooks.org/insect

Extension publications online at https://catalog.extension.oregonstate.edu

  • Fall and Winter Vegetable Gardening in the Pacific Northwest PNW 548
  • Constructing Cold Frames and Hotbeds FS 246-E
  • How to Build Your Own Raised-Bed Cloche EC 1627

Click here for a printable pdf of this article. Text and photos by Carole Hardy, July 2025