|Intensive Vegetable Gardening for Profit and Self-Sufficiency (Peace Corps, 1978, 158 p.)|
|Chapter five: soil preparation for intensive gardening|
A raised bed is a planting area which has been forked and worked so that the planting surface is 4 to 10 inches higher than the original ground level. Raised beds are usually made 3-5 feet wide and any length that the gardener wishes.
The width of a raised bed has a great number of advantages over wider beds. Garden jobs, such as weeding, planting, fertilizing, harvesting and insect control, can be performed from each side of the bed without having to walk on the bed. This is important because vegetables are short-lived plants, so their root growth and health is very important. To walk near vegetable plants compacts the soil around them, making root growth more difficult and even injuring the roots which have grown. Root hairs are the actual "mouth" of the plant as they take in nutriments, water and air for the plants. Plants lose their root hairs when they have to push through tightly packed soil.
When planning an intensive farm and garden, all planting space must be used to maximum advantage. Pathways and roads should be carefully located so as to be convenient while at the same time taking up as little arable and productive land as possible. Permanent raised beds allow maximum use of a planting area. With permanent raised beds, all fertilizers and soil conditioners are placed directly in the root areas, never in paths. Beds are usually raised 4-10 inches higher than the walkways, so the areas where plants are grown are clearly distinct from other work areas.
Preparing the raised bed is the most important step in intensive vegetable cultivation. The prepared bed should have a loose soil, with good texture and nutriments. This allows steady penetration of the roots for growth and thus uninterupted growth of the plants.
In the intensive method of vegetable cultivation, crops are grown so closely together that when the plants are almost mature, their leaves are barely touching. In other words, when an intensively planted bed of cabbage is almost mature, there is almost no visible ground in the raised bed. You would see a solidly covered bed of cabbage plants.
This method of planting not only allows more plants to be grown, but permits the closely-spaced plants to develop what is called a "mini-climate". That means that the plants are grown so closely together that they shade the soil surface, like a living mulch. This keeps the most important area in the soil, the top soil, cooler and more moist. The shade also keeps down weeds when the plants are large enough. It keeps the soil surface from forming a hard crust and conserves moisture and water for the plants. With the increased number of plants in a bed, it is however very important to prepare, fertilize and maintain the beds properly.
To make room for the roots of this large number of plants, intensive vegetable cultivation requires deep soil preparation. With deep preparation of the soil, roots will grow down instead of spreading out and robbing the nutriments from neighboring plants. The deep growth of the root systems also reduces the need for watering since the deeper soil holds water longer. Deep penetration of the roots also reduces the need for heavy fertilization during the growing season as the deep roots bring up nutrients from the subsoil. This utilizes those nutrients which travel downward through the soil and are normally lost to shallow-rooted plants.
The raised bed method can be adapted to power hand tractors. Larger four-wheeled tractors could also be used, but hand tractors or hand cultivation is most suitable for soil preparation, maintenance and care in the intensive raised beds.