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Flowers, Fruits, and Frass

Raised Beds: Benefits and Considerations

With a little spring preparation, your garden season can be more rewarding than ever: raised beds simply make gardening vegetables and herbs easier.

When gardeners choose to grow in raised beds, the soil stays looser which means the roots are happier. And every gardener knows happy roots means happy shoots. The soil also warms up faster and stays warmer; this helps with germinating seeds and allows them be planted earlier than they could go into the ground. Coupled with better air movement for disease prevention and less pest pressures, the warmer and looser soil in raised bed gardening gives you a higher yield of goodies during the growing season.

Consider the following when planning your raised bed:

  • Ensure that your bed gets at least 6 hours of sun to grow most vegetables and herbs. If you have dappled shade, limit yourself to salad greens, swiss chard, kale, mustard, parsley, lemon balm, mint and chives.
  • To prep your site, kill off existing vegetation with cardboard or moist newspaper at least 6 sheets thick.
  • Build as close to the water source as possible, and consider adding drip irrigation. Drip irrigation is relatively affordable, and makes mid-summer watering less of a task. In 2018, Reid Young, Program Coordinator for University of Illinois Extension, installed a large drip irrigation system for raised beds at the Unity Community Center for $250. A smaller home system can be much less expensive. Reid tells me "with a little forethought, it's not too difficult to install. And it saves a lot of time and water compared to watering with a garden hose." Installation was completed in an afternoon.
  • Raised beds can be as short as 6 inches tall, but I would recommend building 12-24 inches high. Build no wider than four feet or you will have difficulty reaching all of your plants. If your beds will be longer than 12 feet the, boards need to be reinforced or they may warp.
  • Lumber treated with arsenic was phased out in 2004. Lumber is now treated with copper and is approved for growing food, but be sure to wash vegetables well. Untreated cedar is an excellent choice for rot resistance and durability, but can be very expensive.
  • Reinforce corners with corner brackets of pieces of wood.
  • Soil should be one-third topsoil, one-third organic matter, and on-third vermiculite and perlite. No more than 35% topsoil should be used, as it will hold too much water and will not provide the benefits of excellent root growth.
  • To find the volume of soil you need, multiply length by width by height. Remember to use actual dimensions, and consistent units of measure! Soil is sold in bulk by the cubic yard, and by the cubic foot in bags.

For in-depth information on raised bed vegetable gardening, search for our Four Seasons Gardening webinar Growing Vegetables in Raised Beds or Containers.