Rich soil coupled with intensive gardening practices are what make raised bed gardening so successful. Intensive horticulture has been practiced for centuries in many parts of the world. In America, one of the best-known methods is French intensive gardening. Intensive gardening methods all have their own disciplines, but all use raised growing beds, close spacing between plants, careful attention to building and maintaining soil fertility, and succession planting to make the best use of available growing space.
Applied skillfully, intensive growing methods can (and consistently do) produce harvests 4 to 10 times greater than might be expected from a conventional garden. But intensive gardening also demands more initial work, planning, and scheduling than row gardens. If you wish to convert to intensive methods, it’s best to start gradually. For example, you could try building one or two raised beds each gardening season for a few years.
Plantings managed using intensive planting systems require fertile, well-balanced soil rich in organic content. Without plentiful additions of compost along with soil amendments, intensively gardened soil soon loses its vitality. Cover crops or green manures also help keep the soil fertile.
Close Plant Spacing
One reason that raised beds are so productive is that they are planted intensively, putting as much as 80 percent of a garden’s surface area into crop production. Pathways and spaces between crop rows make up the remainder. Plants are placed close together over the entire bed, usually in a triangular or staggered pattern, so that their leaves overlap slightly at maturity. This allows for more plants per square foot and produces a continuous leafy canopy that shades the bed, moderates soil temperature, conserves moisture, and discourages weeds. Close spacing also means plantings must be carefully planned according to each crop’s growing habits, including root spread, mature size, and water and nutrient needs.
Another technique used to maximize harvests in raised bed gardens is succession planting, which is the practice of rapidly filling the space vacated by a harvested crop by planting a new crop. This can be as simple as following harvested cool-season spring vegetables, such as peas or spinach, with a planting of warm-season summer crops, such as beans or squash. Once harvested, those crops could be followed by a cold-tolerant fall crop such as spinach. Another technique is to stagger plantings at 1- or 2-week intervals to prolong the harvest. Advanced intensive gardeners also interplant compatible short-, mid-, and full-season vegetables in the same bed at the same time. They then harvest and replant the faster-growing plants two, three, or even four times during the season.