People have wondered why we spent all the time, money, and energy building raised beds. There are several reasons.
One reasons is because the soil is easier to use and maintain. With a raised bed, we never step on the soil, which prevents it getting packed down. Only gravity and the weather pack it down, and this makes tilling in the spring much easier.
But even more important is that the soil can be kept healthy a lot easier. The beds confine the soil, so fertilizer and worms stick around. We add some soil to the top of each bed every year (it gets used up). The soil we add is that really nice bagged stuff you buy from garden stores and lumber yards. And, once it’s bought, it stays right where we put it until plants use it up.
Another reason is structure. The beds provide a confined space to work, and the spaces between them allow us to actually be able to reach all the plants all summer long.
But, the structure also allows us to put up trellises, fences, and tunnels, each of which is valuable.
Using posts in the built-in post holders we can put up a trellis. This allows the plants in that area of the garden to climb up them. This is quite valuable for any kind of climbing plant, like pole beans and cucumbers. They are very easy to pick, and the trellis helps their growth as well.
Face it: gardens attract pests, like rabbits and deer. A fence around a garden can keep them out, but that can be pricey to build. Using the post holes on the sides of the beds, we can build modular fencing constructions to keep out the most prominent pests in our area.
A modular fence is easy to move around. One size fits between any of the post holes along the long edge of the garden, and another size for the ends rounds things out nicely. When the gardens are finished for the year, they can either be left where they are, or stacked nicely against a garage or shed wall.
But the biggest reason is that it allows us to build plastic tunnels over the beds. These tunnels lessen the impact of rather abrupt changes in weather. In Minnesota where we live, temperatures can fall to freezing in late May and early September. Typical gardening season is around 100 – 120 days.
But a tunnel can keep the temperature inside it 8-10 degrees higher than the outside air. Generally, we find that plants are completely safe even if the outside air temperature drops to 25 degrees. This extends the growing season by as much as a month in the Spring, and again in the fall.
But tunnels also double as fences. Our worst pests are rabbits and deer, neither of which will try to get through the plastic.
Yes, raised beds are not cheap. And, they take a lot of work. But it seems to me that the benefits far outweigh the costs.