Getting Your Raised Bed Garden Soil Right, Part II



In our last Blog Post, we covered the basics of the type of soil and soil amendments you may want to add to your raised bed garden! In Part II, we are going to cover how to calculate how much soil you need depending on the size of your bed, and some other helpful tips!

We know that creating a good soil mix will be important for garden success. If you are on a tight budget, you can use topsoil from your yard, once you remove grass. You can then strain the soil through a screen and mix in compost to equal 25% of the topsoil. Mix compost and topsoil, and any other additions such as peatmoss and vermiculite, on a tarp or in bins BEFORE adding it to your garden bed. A great foolproof mix is equal parts peat moss, vermiculite, and compost added to your topsoil.

Calculating how MUCH (i.e. in cubic feet or in cubic yards) soil you will need depending on the size of your garden box can be done by:

Cubic Feet=  multiply the bed’s width, length, and height and then divide this number by 1728 (which is the number of inches in a cubic foot). For example, if you have a 4x4 foot bed (i.e. 48 inches x 48 inches) x6 inches in height : 48x48x6= 13824 inches/ 1728= 8. So this bed would need 8 cubic feet of soil.

Cubic Yards= multiply the bed’s width, length, and height and then divide this number by 46,656 (number of cubic inches in a cubic yard). So continuing with our 4foot x 4foot x 6inch bed, this would be 13824 inches/ 46,656= 0.29 cubic yards.

When filling your garden bed, mound the soil slightly so it forms a shallow slope to the bed’s sides. Overfilling your bed will cause some soil to run out on rainy days. Depressions in the soil surface will end up holding water. You may need to level the soil surface again, especially after you plant.

Maintaining your soil year after year is also needed for continued garden success. Add compost each fall or early spring to renew nutrient levels that may be depleted after growing veggies that are “heavy feeders.” At the end of the season, clear out any overripe veggies, plant stocks, and leaves in case any disease or pests linger. Mulching with straw in the fall will help suppress weeds from sprouting the following spring and will help keep your soil in one place during windy, cold months.

Getting your soil mix and nutrients right in your raised bed will set you up for success! Consider some of the above when doing your garden planning! Happy Gardening!



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