Gardening does not have to end with summer if you live in the Pacific Northwest. With a little planning, common sense and knowledge of what to plant and when to plant, you can have fresh vegetables harvested from your own garden any time of the year.
Choosing a Location
Use your "green" common sense when choosing a location for a fall or winter growing spot. A southern-facing side of your house, a shed, wall or barn is a good location for sun exposure and protection from northerly winds. A south facing slope would be ideal as well. According to Ed Hume, an expert gardener with one of the longest running gardening television shows in history called Gardening in America, a wall or windbreak can add from 10 to 15 degrees of warmth to your fall or winter garden.
Preparing the Soil
Good soil preparation results in healthier plants. Make sure the soil has good drainage, especially in areas such as the Pacific Northwest, where heavy rain can occur in the fall and winter months. Raised beds help with drainage and can also help raise the temperature of the soil by 8 to 12 degrees according to Ed Hume. Raised beds should be at least 12 inches deep and can be supported by lumber, stone, brick or concrete. Old tires can be used to make single plant raised beds. The black tires absorb heat from the sun, which helps warm the soil inside.
The particle size of the soil also affects the drainage. Sand particles are the largest and allow good drainage, while clay particles are the smallest and often hinder drainage. If your soil has poor drainage or it drains too fast, you can help improve it by adding organic matter such as:
- Leaf mold
Manure or an organic fertilizer will also help add nutrients to the soil that are essential for good plant growth.
When to Plant
A variety of factors must be considered when planting vegetables for a fall or winter harvest. The length of time it takes for each vegetable to mature is one factor. The approximate date of the first killing frost in your area is another factor. Check with your local garden authorities for estimates on dates of the first killing frosts and information on the hardiness of different vegetable crops.
Ed Hume Seeds.com suggests the following planting guide for vegetables in Oregon, based on a late October freeze:
Mid-July (Late Maturing Crops - 90 days)
- Brussells sprouts
- Fava beans
- Globe onions
Mid-August (Mid-Season Crops - 60 days)
- Early cabbages
- Early carrots
- Perennial flowers
- Perennial herbs
- Swiss chard
- Winter cauliflower
Mid-September (Early Maturing Crops - 30 days)
- Bunching onions
- Cover crops
- Lawn seed
- Leaf lettuces
Alternative Cold Weather Gardening Methods
You can protect your plants and actually extend your growing season past the killing frost date by building different types of structures that trap heat and prevent wind, frost and excessive rain from damaging your crops.
A cold frame is a wooden box or structure with no bottom. You can easily build them using old window frames and a little bit of lumber, bricks or other building material. If the glass is broken, you can use clear plastic or fiberglass. Build the base using the same dimensions as the window frames, however, make sure the back of the frame is higher than the front, so that when the frame is sitting on the ground, it slopes downward from back to front. A good size would be 18 inches high in the back and 12 inches high in the front (or a slope of at least six inches). The cold frame should be placed in a sunny area, where natural light will provide the warmth for the plants inside.
A hotbed is another growing structure similar to a cold frame except that the extra warmth is provided by the soil. The soil is usually heated in two different ways.
- Manure Hotbed: For a manure hotbed, dig down about 9 to 10 inches into the ground and then add about eight inches of straw and horse manure. Cover the manure with about six inches of good soil.
- Electric Hotbed: An electric hotbed is made very similar to a manure hotbed. Dig an eight to nine inch deep area. Lay the thermostat controlled heating cable, which you can buy at a garden center, in the bed, carefully looping the cable back and forth with even spacing. Make sure not to cross or touch the cable to itself. Cover the cable with two inches of sand and then lay a piece of hardware cloth over the sand. Finally, add about four to six inches of good soil.
A cloche is a lightweight, portable and reusable cover that traps solar heat and moisture. Originally made from glass jars placed over individual plants, cloches can be made into tunnels to cover entire rows. Cloches can be as simple as:
- Two glass panels hinged at the top for A frame type covers
- Plastic or glass bottles over individual plants
- Tunnel-shaped wire frames covered in fiberglass or clear plastic
Enjoying the Fruits (or Vegetables) of Your Labor
The mild winter climate of the Pacific Northwest makes it possible to grow and harvest fresh vegetables in the fall and winter months. Cold weather gardening is different from warm weather growing, as plants tend to grow slower in cooler weather, and extra efforts must be made to protect the plants from harsh weather. However, when you can walk into your backyard and gather fresh ingredients for a dinner salad in the middle of January, you'll know it was worth the extra effort.