Is there anything as important as a raised bed?
The raised garden bed, whether for commercial market gardens or for home grown goodness, is an essential design element of garden success. This is because it has so much to offer growers, including crop planning, management efficiency and plant health.
We’ll look at these reasons below, as well as explore Permabed gardening, as we consider the value of our raised garden beds.
What is a Raised Garden Bed?
A raised garden bed can be between 8 to 12 inches (or higher) above the grade of your garden plot. It should be a mix of local soil and good, nutrient-rich compost that is high in organic matter and any missing micronutrients from your soil tests.
Raised beds can be organized perpendicular to the slope of your land and can be grouped in units of three (called triads) to facilitate intercropping of food plant guilds. (I cover this triad guild concept in my book, The Permaculture Market Garden; we’ll discuss it in future articles, as well.)
These groups of three beds can be repeated across any size field. They can be any length that your property can fit, from 10 to 300 feet.
What is a Permabed?
A Permabed, however, is somewhat different from a raised garden bed.
Many raised garden beds are formed through tillage in the spring, then the whole plot is plowed at the end of the season. Permabeds, however, are formed but never destroyed. They have a fixed place in space.
Also, some raised beds are built using wooden sides or are raised by “fluffing” the soil through tillage. But Permabeds are made of soil and formed by raising the soil physically with shovels (or a disc bedder on a tractor). This forms a permanent raised garden bed that will not experience a large amount of settling.
Furthermore, Permabeds are specifically designed to follow an organized system for diversified garden production. In the Permabed System, a single Permabed is the unit of planting, watering, weeding and other tasks. But the triad three-bed unit is the basic unit of guild design.
Permabeds have a specific architecture, as illustrated in the above infographic. This includes:
- Bed top: the portion of the bed that is planted in crop, weeded and watered
- Path: where people move and tractor wheels go (if you are a larger farm)
- Shoulders: the zone between path and bed top where you can easily pass a hoe to manage weeds; you can also use the soil here to hill up a crop like potatoes or beans
Yes, Permabeds are designed to facilitate the efficient management of diversified vegetables and berries, fruits and other edible and useful plants. But on the most fundamental level, they are raised garden beds and offer the key services of crop planning, management efficiency and plant health.
One of the logistics of crop planning is knowing which crops will do well in your garden.
A big part of crop health comes down to choosing plants that are site-suitable. That is, plants that will work well in your climate, soil and moisture regime.
We can do a soil test in our garden and determine that we have, say, a clay loam. But when it comes to market gardening and farming there can be surprisingly big differences in soil, moisture and micro-climate conciditions across your vegetable field or orchard plot.
Because Permabeds have a permanent place in space, we are able to test multiple beds to collect environmental data and improve crop planning. Each bed can build its own â€ścharacterâ€ť based on this knowledge. We can use this knowledge when crop planning to improve eventual crop production.
For instance, we can note that bed 6 and bed 7 stay wet through most of the spring. So we avoid planting early crops there. On the other hand, these would be ideal sites for planting a water-loving summer crop, such as melons.
Gardening is about getting your work done quickly. If you donâ€™t, the weeds get too big, the plants get dehydrated and the beans get over-ripe.
Permabeds are deigned to improve garden management because they are uniform, raised and organized. This is because the raised beds are all the same height, width (usually between 3 to 4 feet) and length. Also, you have a predetermined number of rows used for different crops (either 1, 2, 3 or 5).
In practice, this means all beds of squash will have the same spacing for weeding on either side. So you can quickly move up the row with a garden hoe in the same manner you will weed the zucchini planted in another row.
Similarly, in a bed of carrots, there is an equal spacing of 12 inches between the three rows. This is the same spacing for all the other three row crops (beets, lettuce, etc.). So all can be weeded in a similar manner.
By reducing the number of variables you use to organize cropsâ€”number of rows, bed length and bed widthâ€”your garden’s efficiency increases. And tasks such as hoeing, purchasing the right lengths of irrigation and evaluating the yield of a crop take less time and effort.
Because Permabeds are raised, they reduce the compaction impact from foot and tractor traffic in the path.
Less compaction improves soil life habitat, because these valuable organisms need soil porosity to thrive. Because Permabeds are formed but never destroyed, and because tillage is limited to the 3-inch surface to improve seed germination, the core of the Permabed is left untilled. This is good, because tillage destroys the fragile aggregates that form the homes of soil organisms.
And because Permabeds are never destroyed and encourage perennial and annual crop integration within a garden or field, we get improved conditions for soil organisms. How? A diversify of crops above ground and a more constant cover over the winter protects the organisms from harsh winter conditions.
By reducing tillage, compaction and improving aboveground biodiversity, we achieve higher populations and more varieties of soil organisms within our soil.
The resulting underground ecosystem builds symbiotic relationships with our crops. This results in improved nutrient and water fixing, storage and cycling for higher yield of healthier crops.