Are raised beds necessary for higher yields?

Posted by Sapan Behar

May 20, 2008

An avid subscriber of this blog recently emailed me and asked this question. He is getting ready to plant about 5 acres and wanted to know if he should plant on raised beds. Someone had suggested to him that planting on raised beds increases production.

The advise that was given wasn’t entirely correct. Raised beds do not mean an automatic increase in production. In some cases they may lead to lower production. To answer this question, we need to first understand what the purpose of raised beds is.

The main reasons some farmers plant on raised beds are:

their field has poor drainage
they plan to machine harvest

Although raised beds are not an absolute must for machine harvesting, they do raise the plants about 12″ to 14″ above the aisles. This puts the catcher plates of the harvesters at the base of the plants and less fruit is dropped on the ground.

To understand the other reason, we need to look closely at the roots of a blueberry plant. A blueberry plant has a fine, fibrous and shallow root system. These roots are unable to survive in standing water for more than a few hours. Hence where drainage is a problem, farmers usually plant on raised beds. These beds are about 8″ to 12″ high, and keep the shallow roots (or the majority of the roots) above the water.

Now when a field meets the above criteria (drainage issues) keeping the roots above water will naturally lead to a higher yield. On the other hand, during the growing season, a field with raised beds will be irrigated more often than one without raised beds. Raised beds will also not hold nutrients as well, as they will be washed away by water. In this case (assuming that there were no drainage issues) a field that isn’t irrigated enough and doesn’t receive the required fertilizer applications, to compensate for the raised beds, will have a lower yield.

Share and Enjoy: These icons link to social bookmarking sites where readers can share and discover new web pages.