Lynne Forbragd, Extension Master Gardener in Anoka County.
Spring is an excellent time of year to build a raised garden bed for the upcoming growing season. Raised gardens can be a single bed or multiple boxes clustered together. The width is usually three to four feet wide so reaching into the garden bed is minimal and eliminates the need for extra space for paths through the garden. A number of border materials can be used. Some examples of materials are timber, cedar boards, landscaping border materials, rocks and galvanized water troughs with many kits and products available on the market. Straw bales are also used for a raised garden. With any type of material for the border you choose, make sure that the material will not break down over time and is food safe if you are planting edible plants. Do not use green treated wood, old railroad ties or plastics that may leach chemicals into the soil.
There are many benefits to installing a raised garden in your yard. Soil temperatures in the beds will warm up earlier than a traditional garden bed. This allows seeds or plants to go into the ground earlier and extends the growing season. The soil does not get compacted because garden beds are small and gardeners don’t tend to walk on them, giving the roots ample room to grow and not get damaged. Since there is no need for paths, weeding is minimal because plants are grown closer together. Raised beds can be placed anywhere in your yard with an optimal soil mixture making it a more productive garden. Gardens can be built on a platform at a higher level for people with physical limitations.
Any type of herbs, vegetables, fruits and flowers can be planted in a raised garden bed but just like a regular garden, follow the planting instructions to provide the proper spacing for the plant and the amount of sunshine and water it needs to grow.
Typically the soil depth can range from six to twelve inches. The recipe for the soil mixture is a combination of 1/3 top soil, 1/3 compost and 1/3 peat moss. This mixture provides the needed nutrients for new plants and will prevent the soil from compacting in the bed. When the season is over, remove any plant debris and top the garden with a half inch of compost to enrich the soil for the next year’s plants. No need to mix it in, this will keep the soil structure intact and keep the microbes working to maintain a healthy soil.
Raised garden beds can add a new dimension and design to your yard. Try experimenting with some of these ideas this spring season. For more information, see: http://www.extension.umn.edu/garden/yard-garden/landscaping/raised-bed-gardens/ .