Asked by: Gopala Stempliewiczhome and garden landscaping
Do wine barrel planters need drainage holes?
Also question is, how Big Should drainage holes be in planters?
In Purdue's bulletin on container gardening (http://www.hort.purdue.edu/ext/HO-200.pdf ), they say: "To provide drainage, drill three or four small (1/4 inch) holes in the bottom of the container. Holes larger than 1/4 inch in diameter will allow too much soil to escape.
Similarly, what do you put in the bottom of an outdoor planter for drainage?
Poking sphagnum peat moss or cheesecloth loosely into the drainage holes of your planter won't plug them but will help keep soil particles from washing out. Commercially made discs of coconut fiber, polyester or plastic filled with hydroponic rock also are available to place over drainage holes.
Rocks aren't all bad. Rocks added to the bottom of large pots will reduce the volume of potting soil required to fill a container. So, while they won't increase drainage they will help to save a few bucks on soil.