Introduction: Self Watering Window Boxes

If you are out of town frequently or have your hands too full to keep up with plant watering, this is an easy solution.

Make your own Self Watering Window Boxes.    

Here's how...

Step 1: Step: Gather Your Supplies

You will need:

-A 24" plastic Window Box Liner  
 (available at Lowe's in the Gardening Section)

-24" Galvanized Cage Wire  
 (available at Lowe's in the Gardening Section)

-A small submersible water pump  
 (available at Harbor Freight Tools for under $10)

-4' of vinyl hose sized to match the diameter of your water pump nossel  
  (available at Lowe's in the Plumbing Section)

-Potting Soil
-Plumbers Putty
-Two pieces of felt
-A Dremel with your smallest drill bit
-Wire Cutters
-Automatic Timer 

A note about the water pump... Water pumps are rated based on how high they can lift the water and how many gallons per hour they can pump.  This water pump will only need to lift the water a few inches, and will won't be required to cycle lots of gallons of water.  The tiniest water pump you can find will probably suffice.  

Step 2: Step 2: Cut and Fold the Cage Wire to Create the Support

CAUTION: Cutting the wire can result in some sharp edges.  
You may wish to wear leather gloves and safety glasses for this step.  

Using your wire cutters, cut a piece off the spool of cage wire that is 12" wide.
Then trim this piece down lengthwise so it is 12" x 21".

Gently press the cage wire until it is flat.
Fold the edges down 3" in from edge.
Once folded, the piece of cage wire should sit nicely in the bottom of the window box liner. 
Test fit it in place and keep shaping the wire as needed.  

If you are planting a plant that needs a trellis support, cut your cage wire piece to be 25" x 21".  Fold the extra 13" vertically. 

Step 3: Step 3: Drill Holes in the Tubing for Water Circulation

Time for some Dremel action!

Layout your tubing and drill holes with the Dremel about every inch or so.

Once the holes are in place, plug one end of the tubing with Plumbers Putty. 

Attach the hose to the water pump. 

Step 4: Step 4: Set Up the Pump

The pump has four little suction cup feet on the bottom.  
Wet them and adhere the pump to the bottom of the window box liner.

Once the pump is in place, replace the cage wire support and run the tubing up through it. 

Step 5: Step 5: Lay in the Felt and Set Up the Tubing

Lay the two felt pieces on top of the cage wire support.  
Cut a hole for the tubing and the power cord to come through.
The tubing will lay on top of the felt.

The felt will act as a support for the soil.
It will allow excess water to drain back into the resevoir without letting the soil pass through.
(Note: By using the bottom half of the window box as a water reservoir, your plants won't have as much depth to grow.  This is fine for plants that you will transplant into a larger container later or plants that have a shallow root structure)

Step 6: Step 6: Test Out Your Handywork

The area under the felt and cage wire support will act as a large water reservoir.

Fill the bottom of the window box liner with water.  

Testing out your water circulation system could get a little wet, so protect your workspace. 
Be careful not to get the power cord plug wet while you are adding the water.  
Make sure there is nothing around that would be damaged if it gets wet accidentally. 

Plug in your pump to test out your new system!

If the water is circulating nicely, Congrats!
If some of the holes aren't letting water through, unplug the pump, and re-drill the holes a little bigger.

Step 7: Step 7: Add Dirt and Plants

Once you know your water pump and water line are circulating water, it's time to add dirt and plants.  

The tubing will get buried in the dirt so it delivers water directly to the roots of your plants. 

Step 8: Next Steps...

Once every week or so add a gallon of water to keep the water reservoir filled.
Pour the water into a corner so it won't drown your plants and will just drain down into the resevoir.

You may wish to add a some fertilizer to the water supply to give your plants a boost.  
There are lots of liquid fertilizers available at

For super easy plant maintenance, consider plugging your water pump in with a automatic timer. 
Set the timer to come on for fifteen minutes once each day.
This should be enough to water the plants, while allowing the excess water to drain back into the water resevoir.

If it's not warm enough for your window box to go outside yet, add a grow light. 
Set it on a timer to come on for 16 hours each day.