Last summer we had significant drainage problems with the pots on our balcony. Some pots did not drain, filling up with water and killing the plants–a boxwood, in particular–that were in them. Other pots drained so well they drained right onto the furniture–and one time a person–on the balcony beneath us.
In both cases the problem was too much water. You might say we were over watering (and maybe in the case of the boxwood we were), but it was a very dry summer and we wanted to make sure the plants did not die due to lack of water.
To solve the problem of too much water–in the pots and on our neighbors–we have now implemented a pot drainage system. We removed the drainage trays from pots that have plants and placed these pots in larger pots. Any holes in the bottom of these larger pots have been sealed, and a drainage spout has been added to each. The drainage spouts are connected to pieces of PVC pipe that run along the edges of the balcony. This PVC pipe has one open end that points off the back corner of our balcony so water can drain into the landscape bed that is three stories below.
To prepare the larger pots (that would hold the smaller pots), I added a “spout” to the bottom of each. Part of the spout is a threaded 1/2″ PVC female adapter, visible in the bottom of the photo below. I drilled a 1″ hole in the pot using a spade bit, which was just right for the adapter to fit snuggly in the hole.
Once the spout was in place, I caulked around the edges (with silicone caulk) to make sure it was sealed and water would not leak at the seam between the adapter and the pot. I also screwed a threaded 1/2″ male barb into the adapter so I could connect the pot to the main drainage pipe using a short piece of flexible PVC tubing. Finally, I caulked any drainage holes that were in the pot so water would only drain out of the spout and not out of the bottom of the pot.
Next, I put together the main PVC drainage pipe. The drainage pipe runs along two sides of the balcony, with a valve on the end that hangs off the edge so we can stop the flow of water if need be. I figured out where on the patio each pot would go, and put a 1/2″ threaded female T at that point. I screwed a threaded 1/2″ male barb into each T so I could connect the other end of a piece of flexible PVC tubing that was connected to the male barb on each pot.
Finally, I put everything on the balcony and connected each pot to the main drainage pipe using about a 6″ piece of PVC tubing connected to the male barb on the pot and the male barb on the drainage pipe.