I have several plants hanging in my balcony from something like this, so when I water them, the residual water naturally spills to the floor. So I was thinking of building a wood planter, similar to the image below, to pick up any residual water.

I'll be building this planter with treated wood. So two questions:

1) Should I drill some holes at the bottom of the planter so that the plants in there don't rot from too much residual water?

2) If I do drill some holes, what can I do to avoid so that the residual water from the planter doesn't spill to the floor?

3) I've read that there are materials I can put at the bottom of the planter to absorb any water. Would this be healthy?

4) Is there any special paint or treatment that I should use with this wood so that it doesn't rot from the combination of moisture, soil, water, humid & hot weather, etc?

5) Any other creative ideas on how to pick up any residual water from the plants above? I particularly thought about this because I can use it to add more plants.

Any help is appreciated.


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2 Answers 2


I was going to say apply PVC pipe aquaponic theory.

Since you have board boxes:
you should drill about 4 holes per foot approximately the size of a hanging basket to pass the water to the bottom container.
Use the bottom container with a few small holes out the side to take out excess water slowly.

There is a rubberized 2 part paint that is used on ships that you could use if you worry about wood rotting that much.


Yes, you will need to drill holes in the bottom for drainage, about quarter inch across, probably about 8 to 10 holes, evenly spaced out, for a container the size of the larger one in the picture. The only way to solve the water seeping out the bottom problem is to also make a tray that fits beneath the box which you then empty out after watering so the trough and its contents are not sitting in water. If you could make the trough with short, stubby legs, say about 1 or 2 inches long from top to bottom, then stand it in a tray, that would assist with drainage, and you'd be able to see easily whether the tray needed emptying or not. Using materials inside the container to soak up excess water isn't a great idea - even commercially made self watering window boxes tend to be too wet at the bottom most of the time, which is good for neither most plants nor the wooden container.

I think you may have already bought wood to make the trough/s from, but there are woods that resist rotting for longer such as teak and cedar, and do not need treating other than a coat on the outside occasionally if you don't want the wood to fade to an ashy colour, see link for more information


The depth of your planter is quite important - if you want to grow only summer bedding type plants, then containers as shallow as the ones in the picture are fine, but should you want anything permanent with some height, say up to 3/4 feet, then an internal depth of 10 to 12 inches would be more appropriate, more for taller plants.

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