Building Better Boxes

Now that I have been living with my easy wooden planters for two weeks I can say that some are better and some are simply functional. All will survive the season, but the warping induced by the wet soil on one side of the wood, and sunny dryness on the opposite side of the wood is causing problems. As was anticipated, some woods handle this environment better than othrs.

I made boxes with four types of wood planking: Poplar, Pine, Redwood, and Cedar.

Above, you see that the poplar plank is pulling away from the framing on the bottom of the box. Did I miss a screw? No matter, additional screws may solve this problem.

The poplar is also most prone to warping. In the above photo, you see that the top planks are pulling away because the planks rose two inches above the top of the framing. The solution is to make sure the framing members rise all the way to the top.

The pine box is hanging in there, showing just a little warp stress.


The redwood and cedar boxes are both performing well —as expected.

As this post makes evident, if you want to make boxes that do not warp so readily, pick redwood or cedar lumber for your planters. There are also some tropical hardwoods, like ipe and teak, that will hold up just as well, or better, than cedar or redwood. These woods cost more than cedar and much more than pine.

As for structural improvements, heavier structural framing (2 X 3 instead of 2 x 2) and sinking more decking-type screws per plank could strengthen up these boxes without too much extra effort.

Professionals are likely use exterior-grade, treated plywood for the interior box and then use tongue and groove planking for the exterior fascia. Many would add trim pieces to accentuate the planter while concealing the screws and corners. The wood may be stained, painted, or sealed to protect their workmanship from the harsh environment or for aesthetic purposes.

See How-To Build An Easy Wooden Planter