Leaf mulch warms a row of parsnip plants in winter. Dark-coloured mulches such as leaves, wood chips, or black plastic will warm the soil more than light-coloured materials.
Mulch, such as straw or dried grass clippings, can warm the soil during cold seasons and help retain soil moisture during hotter months. When mulching around plants, take care to leave air space around the stems.
Burlap coffee sacks, (available free from coffee roasters) make good mulch material or pathway liners. In addition to warming the soil, they also help to suppress weeds.
Water-filled containers, such as 2-liter plastic milk jugs, can help warm seedlings. During the day the sun heats the water in the jugs. This continues to provide warmth and wind protection for the plant after the sun goes down.
Cold frames will stand up to wind, rain and snow to provide warmth and protection for plants throughout the winter. Old windows are excellent choices for cold frame tops. Scrap wood, hay bales, large stones, or bricks make good materials for the frame.
Hoop-style covered supports that span across a garden bed can protect seedlings or established plants. Thick-gauged wire, fiberglass garden rods or bent pvc pipe can form the supports. Plastic tarps (3 mil or higher), bed sheets, or Reemay (a polyester fabric that allows in light) are common coverings.
Wind protection can make a huge difference, especially in early spring. Planting near existing walls or fences offers protection against cold wind. You can also build temporary wind breaks with plastic or other materials.
Traditional cloches are bell-shaped glass covers placed over individual plants to protect them. Translucent plastic 4-liter milk jugs with the bottoms cut out will serve the purpose. By removing the cap, air can circulate in the cloche, while still providing warmth. A tall stick through the opening helps to anchor the cloche.
Raised garden beds, whether built in neat cedar boxes or by simply mounding up soil, will capture the warmth of the sun and give plants an advantage. The cool air sinks down to the surrounding pathways. Adding stones or gravel to the surrounds is another way to capture heat.
Plants situated against a sunny south-facing wall or fence often bear fruit larger and longer than in less protected areas. With extra warmth and wind protection, these locations are especially good for heat-loving plants like tomatoes and peppers.