Raised-bed vegetable gardening takes very little space and allows vegetables to be grown closer together.
Raised-bed gardening is a great way to grow vegetables -- especially if the garden soil is poor or compacted or has poor drainage. And there's no bending over to pull weeds or harvest vegetables.
Raised beds take very little space, and can be built right over a concrete patio. Drainage in a raised bed is superior to that in an in-ground garden bed. A 12"-deep bed provides ample room for most vegetable roots.
The soil in raised beds warms up more quickly in spring so planting can be done earlier. And if the bed is narrow, 3' or less, there will be no need to step on the soil and thus it prevents compaction. It's much easier for roots to grow in loose soil.
Don't build a raised bed on a wooden deck: when the bed is full of soil and water, its weight could cause structural damage.
If the raised bed sits directly on the soil, line the planting bed with hardware cloth or chicken wire at building time to prevent visits from burrowing animals such as gophers and moles.
The bed may be made of wood, stone, brick, cinderblocks or any other material from which you can build a base at least 12" deep. Choose a location that gets at least six hours of direct sunlight each day. Almost any type of vegetables can be grown in raised beds. Exceptions are potatoes, whose roots need a lot of room, and corn, which would grow so high that harvesting would be difficult.
Here's how to plant a raised bed:
1. Fill the bed with good-quality potting soil or compost, and rake the surface smooth and level. Remove any rocks or debris.
2. Plants in raised beds may be spaced a little closer together because fertilizer and manure can be concentrated in the small gardening area.
3. Plant lettuce by poking holes in the soil with your finger at 6" intervals, and sprinkle a few seeds into each hole. Once the seeds germinate, thin to one seedling per hole.
4. You can also broadcast seeds over the surface of the raised bed. If you plant carrots, apply fine-textured potting soil over the top of the seeds. Carrots will attract some species of butterflies to your raised beds.
5. Cucumbers may be planted along the edge of the raised bed, where they can trail over the side. Cucumbers will grow right on top of your patio.
6. Water the garden well immediately after planting.