Root proof raised redwood garden beds

Redwood planter boxes with root protection

Last summer Stephan and I were tasked with designing and constructing some raised garden beds in Los Gatos. There were existing beds on the property that had become overrun with roots from a large oak tree in the back yard, rendering them useless and causing the old beds to break apart. Tree roots have a way of working their way into pretty much everything and can certainly become an issue in the garden as well, especially when they can find an area that is irrigated during the summer months.

2x6 frames before final assembly

Keeping this in mind, we had to come up with a design that would prevent root intrusion into the raised beds, which is impossible if the bed has any openings in the bottom. The standard procedure of covering the bottom with gopher wire wasn't going to work for this application.

In order to alleviate these concerns and to ensure the beds will last for many years to come, we enclosed to bottom of the beds with redwood 2x6 decking, turning them into large planter boxes, leaving a small space for expansion between each board, which is a must for any outdoor construction project using wood.

Assembled frames on pickup

There was concern over having adequate drainage into the existing soil with the bottoms in place as well so we opted to elevate each box using pressure-treated lumber. To prevent the boxes from sinking into the mud the weight was distributed onto 5/8" pressure treated plywood below. The use of pressure treated material normally isn't acceptable for use in vegetable beds (see linked post) but is fine here because it does not come in contact with the soil inside the boxes. The end result was four extremely durable large redwood planter boxes on bases that will last for decades.

These boxes are made entirely from construction-heart grade redwood 2x6 decking, which gives them a lot of flair. The top rails provide a working surface or a seat for those tending the garden and also add some strength to the boxes. Making all of the cuts and assembling all of the pieces takes a lot more time and skill, but the end result is well worth the extra labor. If you want to turn heads with your new raised beds or planter boxes, this is the way to go.

Robert carefully screws the bottom boards on

Inside view of the box