There are many advantages to planting in raised beds. Raised beds increase your plants' health, flower blooms and vegetable crops by improving soil drainage, keeping the soil loose and aerated, preventing invasive weeds and insects from entering the garden bed, as well as warming the soil earlier in spring. Several types of raised garden beds exist, each with its own advantages and specific uses.
Shallow Raised Beds
Shallow raised garden beds, also called "raised ground beds," are the most common type of raised beds for larger gardens. These beds are raised less than 1 foot from the ground level, providing just enough raised soil above the ground to keep the soil warmer and easily cultivated. Shallow raised beds are contained using a wide variety of materials, including landscaping or railroad timbers and other types of lumber, stones, bricks and concrete blocks, as well as vinyl, plastic and rubber edging materials. Some shallow raised beds for flower gardens are constructed in a circular shape, but most beds for vegetables are rectangular or square.
Deep Raised Beds
Deep raised beds are those that are built higher than 1 foot off the ground, often made at chest- or waist-level for easy access to tend to the plants without bending down. Like shallow raised beds, deep beds are also made with a wide variety of materials and in different shapes. Deep raised beds are commonly constructed in areas where the native soil is extremely poor, allowing the entire root area of the plants to grow in the above-ground soil contained in the bed. These raised beds are also commonly constructed for gardeners with physical disabilities that make it difficult or impossible for them to bend over or reach the soil surface to tend the plants.
Elevated garden beds are raised beds that sit on stilts or legs off the ground. These raised garden beds are usually shallow and made of wood, often used for annual flowers, herbs and shallow-rooting vegetables. Elevated beds are often used for areas where soil diseases and insects are rampant or for gardeners with physical disabilities. Some elevated beds are built into garden benches as well.
Terraced Raised Beds
Terraced raised beds and retaining walls are built into slopes and hillsides to make the area usable as a garden space. Some terraced garden beds and retaining wall beds have the dual function of also stabilizing hillsides and preventing soil erosion. Terraced raised beds are built into a hillside in a series of small raised ground beds, creating wide steps up the slope. Stairs or steps are often built between the raised beds in the terraces, allowing easy access for tending to plants. You can use terraced raised beds to grow any type of plant, from vegetables to flowers to creeping or cascading plants. Terraced raised beds are most commonly created using brick, stone or concrete materials, but they may also be made with timbers.
Temporary Raised Beds
Temporary raised garden beds are those with no permanent walls to hold the soil above the ground level. Over time, the temporary raised bed will spread out to level with the ground. To create temporary raised beds, you simply mound up the soil in rows in the garden space so that the soil is at least 6 inches higher than the ground level. These types of raised beds need to be re-created each spring.