Raised-bed gardens help vegetables
One of the best ways to grow vegetables in cool climates is to plant them on raised beds. When the soil is elevated it dries more quickly, warms faster and provides deeper soil for the root crops to develop. You can plant earlier in the season and harvest later into the fall.
Raised-bed gardening can increase soil temperatures by eight to thirteen degrees over ground level soil temperatures. The soil is more exposed and the sun and wind tend to dry and warm the soil quickly.
In cool climates, the spring rains keep vegetable-garden soil wet and cold. So by raising the soil, excess moisture tends to drain away more quickly and the soil remains warmer, thus allowing for earlier planting.
Vegetable-garden beds can be raised by mounding the soil with a shovel or rake, using a hiller-furrow attachment on a rototiller or enclosing the soil in wooden frames.
Another great advantage in raising the soil is that the depth makes it much easier to grow deep-rooted crops such as carrots, beets and radishes. In addition; the warmer soil often makes it possible to grow some vegetable crops that you couldn't grow before because of the colder soil and shorter growing season. For example, I have been able to grow some short-season varieties of melons in raised beds, which I could never do in a conventional ground-level vegetable garden.
The width of the raised beds is up to the home gardener. The national average is about 21 inches. However, I find it convenient to make my beds about four feet wide, which makes it easy to reach in, two feet from each side, to weed, water, thin and harvest crops. My son uses 24 inch beds for tomatoes, which is an ideal width for a single row of plants.
If you have limited space, one of the best methods is to use wooden frames to hold the vegetable-garden soil. This way space is not wasted on aisles between each crop. (For truly maintenance free aisles, try weed-block fabric and bark in the areas between your beds.) Instead, the vegetables can be grown in wide rows, spacing the crop the same distance in all directions. For example, a crop of carrots would be planted two inches apart in a bed rather than in part rows, with isles between.
It is usually recommended that the wooden frames be made of 2 X 10s or 2 X 12s. If you use treated wood, be certain that the preservative is safe to use around edible vegetable crops. I find that I can usually get about five years out of a bed made from untreated 2 X 12s before boring insects and dry rot take their toll.
The soil in the raised beds should be high quality. Regular garden soil enriched with compost, processed "steer manure" and peat moss is ideal for growing vegetables. Or, if you need soil to fill the wooden frames, you can purchase quality topsoil such as three- or five-way topsoil or landscape type topsoil. I think it is a good idea to see the soil before you buy.
Whichever way you form the raised beds, it is important to rake the soil level so there are no low spots where moisture can gather.
Vegetables can also be grown in other containers. In containers, the soil will still warm up and dry out quicker. Plus, dark containers absorb heat during the day then radiate it at night, keeping the crops warmer overnight.
For a longer growing season, warmer soil and the possibility of growing a wider range of vegetables, it may be worth trying a few raised beds.