The raised bed is the nucleus of an intensive vegetable garden.
This fully constructed bed is now ready for planting.
Photo Credit: Joe Seals
Building raised beds goes faster with a little help.
Photo Credit: David L. Morgan
Sometimes filling beds takes group effort.
Photo Credit: David L. Morgan
It concentrates soil preparation in small areas, warms up more quickly in spring, stays warmer longer through summer and into fall, limits foot traffic to established walkways between planting beds (reducing soil compaction) and helps conserve water.
Although it does require more frequent watering due to higher plant density, a raised bed is more efficient overall. It results in higher yields for the amount of water applied, compared with larger areas watered in traditional row-walkway-row culture.
Raised beds make it easy to create a deep, fertile soil that’s high in organic matter. It allows you to completely amend your native soil – the ideal situation – or to bring in as much as 100 percent of any soil mix you’d like to fill the beds. You even can go “specialized,” making a mix that’s ideal for each of the plant types to be grown for each separate bed.
From a mechanical point of view, a raised bed facilitates better runoff (water that moves across the surface of the soil) and drainage, is easy to cover for spring and fall frost protection, can be shaded during the hottest part of summer and is ideal for enabling people with limited mobility to garden.
These beds are generally 4 feet wide and can be as long as desired. The height can be almost any dimension, although 12 inches seems to be universal and allows for good root development. (It’s the minimum height when working with hard native soil.) For watering ease, the beds should be reasonably level, both across and length-wise.
To accommodate gardeners with special needs, bed height can be raised to minimize bending or to allow gardening work from a wheelchair. (Note: Plan a walkway space between the beds that’s wide enough to accommodate specialized equipment for mobility.)
Raised beds can even be made without sides. Simply piling soil creates a “raised” bed. Walkways are dug down with the soil thrown up on the bed. This type of bed is normally 4 feet wide at the base and 3 feet wide at the top. The entire thing is covered with organic mulch to prevent soil erosion and to reduce any compaction from rain and sprinkler irrigation.
When building a frame, most gardeners tend to use rough-sawn cedar or redwood 2x12, but you don’t have to use landscape timber – concrete blocks or “plastic wood” work just as well. You can even use brick, which makes quite a classy look.
Now, in which direction should you lay out your beds?
For frost protection, an east-west orientation has a slight advantage of collecting heat, which is a good thing. For summer crops, a north-south orientation holds the slight advantage of sunlight on both sides of the plant row each day. Because there’s really no clear advantage overall, orient your beds in whatever direction works best for your landscape design.
Raised beds not only allow for more effective and efficient vegetable gardening, they can be an appealing landscape feature on the property.