How to Make a Self Watering Planter from a Plastic Storage Tub

Husband and I want to grow bitter melon this year. Unfortunately, bitter melon will not grow next to any of the other plants in our garden.

Fortunately, our south facing patio is the perfect place to grow bitter melon. Unfortunately, we are better at watering the plants in the front of the house than the plants on the back patio.

A self watering planter would solve this problem nicely. Then I priced self watering planters. Great googly moogly! The price is not so nice.

 Pin this easy gardening tutorial for later and to share with your friends!

    

I did some research and saw a bunch of different designs and directions for self watering planters. There were a lot of you musts and you shoulds that contradicted other people's you musts and you shoulds.

I turned to Rob of Rob’s World AKA the King of Building Self Watering Planters and peppered him with a bunch of questions. Who basically said either way is fine on any of number of things I questioned him about.

I went with using a tub from BPA free #5 plastic (polypropylene) I had on hand to keep the cost down. I'd like something that looks a little nicer and won't potentionally tick off the Bitter Betty neighbor to report me to the Home Owner's Association. I’m considering building a wood surround to make it look a nicer. Eventually. It's on my massive DIY List.

How to Build a Self Watering Planter

 You will need:

1 20 gallon plastic storage tub and lid like this one

4 plastic plant pots (pre drilled plant pots like these will make your life easier)

1 bamboo or metal tube (I cut down a bamboo tiki torch)

Zip cable ties

Tape measure

Marker

Drill and drill bits (I used a ½:” and 1’ drill bits)

Jigsaw

Heavy duty scissors

Window screening 

Optional: Mosquito doughnuts, plant stakes and twine for trellises

Disclosure: I included affiliate links in this post for your convenience. 

Make it:

1. Measure the inside of the plastic storage tub and the plastic lid. Use the marker to draw a cut line on the plastic lid so the cut plastic lid will fit inside the plastic tub.

2. Use the drill and 1 inch drill bit to drill a start hole. Then use the jigsaw to cut the center out of the plastic tub. Keep the outside rim of the plastic tub intact, you’ll use that part later.

3. Use the drill to drill a bazillion or so holes in the plastic lid.

Tip: use a low voltage drill such as 15volt drill or if you have variable speed drill use a lower setting when drilling through the soft plastic 

4. Drill several holes in the sides of the four flower pots.

I used the 1/2 inch drill bit to drill these holes.

Then cut several notches in bottom of the flower pots to make two wicking chambers. This will allow the soil to wick water.

5. Drill holes in the top of two flower pots that match up with the holes in the plastic tub lid.

6. Do a dry fit. Place the four flower pots that will act as supports and wicking chambers in the four corners of the plastic tub. Put the plastic lid on top of the flower pots and adjust them accordingly if needed.

I had to cut down my flower pots to size because they were too tall for my plastic tub.

7. On the outside of the plastic tub, measure the height of the flower pots, add ¼ inch, and use the drill to drill a water overflow hole at that measurement.

8. Trace around the two flower pot wicking chambers with the marker on the plastic tub lid. Remove the flower pots and lid from the tub and use the jigsaw to cut two holes for the wicking chambers in the plastic tub lid.

9. Attach all four flower pots to the plastic lid using the zip cable ties. Drill extra holes in the lid or flower pots as needed.

It isn't pretty but it works. In a few more steps no one will see it anyway.

10. Optional. West Nile Virus is a concern where I live. I cut a piece of window screen to cover the overflow hole, which will be held in place by the tub lid. I also added a mosquito donut to the bottom of the tub which will hold the water.

11. Place the flower pots attached to the tub lid inside the plastic tub.  Flower pot side down.

12. Cut the bamboo or metal tube to the height of the plastic tub plus several inches to make the watering tube. Most plans call for using PVC. I don’t want the possibility of PVC leaching chemicals into my food plants. Copper pipe was not in my budget. Instead, I bought a $5.00 bamboo tiki torch and cut the torch to length.

13. Cut a notch in the bottom of the watering tube to allow the water to flow from the watering tube and into the water chamber. This is another reason why I used a tiki torch. It already had the notch cut into the bottom of the bamboo tube.

I was feeling clever about this until I got to step fourteen

14. Optional: If you are using bamboo, make sure you are using a hollow tube of bamboo. If not, you may have to drill a hole into the knots to make it a functioning hollow water tube like I did. A flower pot full of dirt helped steady the bamboo while I drilled it.

15. Trace around the bamboo tube with the marker and cut a hole for the watering tube in the plastic tub lid with the heavy duty scissors. Put the watering tube into the hole. Optional: To keep my water chamber from being a mosquito nursery, I covered the top of the watering tube with a piece of window screen and a cable tie.

16. Cut two pieces of window screen to fit inside of the wicking chambers and fill the wicking chambers with potting soil.

The wicking chambers will draw the water in the bottom of the planter up and into the soil you will place on top of the holey tub lid and to the roots of your plants.

17. Optional: I cut the plastic tub lid a little too small for it to fit snugly and keep the potting soil from falling into the water chamber. I cut a piece of window screen and put that on top of plastic tub lid to fill in the gaps.

You see the window screen poking out from the first few handfuls of dirt I tossed on the screen to steady it before I dumped the rest of the potting soil into the planter.

18. Fill the planter with potting soil. Add fertilizer if desired. I use fish emulsion fertilizer instead of a chemical based fertilizer and my plants love it!

19. Optional: Put the outside of the plastic tub lid onto the plastic tub. Drill two holes into the tub lid rim, place bamboo or wood dowels into the holes, and run twine or attach more bamboo horizontally between the dowels to make a trellis.

20. Plant your seeds, water them, and watch them grow!

You can water your self watering planter using the watering tube to send the water directly to the water chamber in the bottom of the planter or just by watering it from the top as you would with a regular potted plant.

If you'd rather buy than DIY, check out the following ideas - and more!- below!

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