Self Watering Window Boxes





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.



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    24 Discussions

    use an arduino with some relays, moisture sensor and a light sensor. you can increase your system efficiency. with those timers you cannot predict how much water you need for your plants in a certain amount of time.

    I have designed a self watering system that is very adaptable to different kinds of growing spaces. It is based on an Archimedes water lifter and I have used it for starting seeds, growing plants in my living room windows, flowers on the patio, and vegetables in my community garden plot. Here is a link..

    Hello, everybody!

    I just wrote an instructable about self-watering indoor plants: really self-regulating, and no powering needs.

    It is here:

    Hope someone find it useful.

    Best wishes,

    Arrgh. Every time I go to a self-watering planter instructable, I lose an hour or two following links...
    This is interesting - I've been trying to figure out how to make windowboxes self-watering, for shallow things like lettuce. I grow tomatoes in a couple Earthboxes, and have been working on DIY variants for other things, but the lettuce does poorly in the Earthboxes because it's so far from the reservoir to their roots (I think - they wilt and die, even with a full reservoir). This would solve that nicely.

    wow! very nice idea. I always ask my neighbor to water plants when we all go out for a week. Add timer or remote control over phone (available in market) will be very useful thanks for the great idea

    In larger containers, an inverted plastic water bottle with the bottom cut out works as a fill tube. I've built many sub irrigation boxes using the info from this site:

    1 reply

    What a great site!!!! Thanks for posting the link. Keeping the pots watered in our brutal Texas summers is a major challenge.

    Not putting down your work, but you can buy pots that do this electricity free. A reservior at the bottom provides water by osmosis to the dirt & plants. It's a maintenance free solution too.

    1 reply

    I believe the pots you're referring to actually operate using capillary action, not osmosis.

    It'd probably be pretty easy to modify these instructions to build the capillary action version. Just replace the pump + tube with something that will wick up water. A short piece of rope could work, or you could even just wrap the entire reservoir in additional felt. You just want to make sure that whatever you use will wick up water well, that it reaches the bottom of the reservoir, and also makes good contact with the felt in the bottom of the soil compartment.

    Thanks everyone for your ideas! Now what do you do when soil / debris plugs your pump? I folded my wire up on 1 end and used a single piece of left over landscape cloth. This solves 2 problems your clear tubing can rest on top of your soil. ( or about 1/2 as much ) and you can now see your water level. or use cardboard on deep pots. It will last the season and it is compostable

    If you put in a water detector that would alert you to the low level of water in your tank, you could really improve the system cheaply.

    check out 'water detector' or 'leak detector' kits and you'll see what I mean.

    One issue would be over filling. If you use the PVC fill pipe idea, simple dipstick could be used with a mark on it below the wire support. Some auto watering pots use a foam float on the bottom of the stick. Cut the stick so that when the water level is low the top of the stick is flush with the top of the stand pipe and a full mark on the stick.

    For people using this outside it will be necessary to drill a overflow hole in the side of the container below the level of the wire. Otherwise rain could over fill the container and drowned your plants. Or you could drill a hole near the bottom of the container and mount a elbow with some clear plastic tubing standing straight up to act as a site glass. Cut the tubing to the proper length and it will act as an over flow.

    One more question..what happens if you have a bunch of these outside, when you are away and it rains ? What would prevent them from flooding ? Hope I haven't missed something obvious, but if I have, enlightenment would be welcome.

    Love the details of your instructible. I like the comments on adding a PVC fill tube. I would go one further for a level check device. Put the PVC pipe in the corner through the wire mesh with some notches cut out of the bottom of the tube to allow for the water to pass through. Next get a rubber stopper or cork and a length of plastic or fiberglass rod. The rubber stopper or cork diameter needs to be smaller than the inner diameter of the PVC tube so it can ride freely within the tubing. Have the rubber stopper/ cork on the end of the plastic rod, and the rod cut to an inch longer than the PVC tube. Put the stopper/rod combination into the PVC tube with the stopper on the bottom. This is now a float level. Mark of for a critical level to fill the planter. With enough water in there, it will happily float in a good level, as marked. When the water level gets too low, it will lower the float into a fill level. And the float can be removed while filling.

    1 reply

    This would be very useful on deeper planters, especially.. I've seen a similar set up on some commercial self watering planters, but they are often so poorly made they don't last long. Never thought of using a bit of cork to replace the floating bit that always seems to fall off or break.

    This is a brilliant idea.. I have to go away often, to visit my mom in a nursing home, and getting the plants watered is always a hassle. This would work even in much bigger planters, I'd think. Is there any worry about backpressure damaging the pump ? I've read this can be a problem with some pond pumps, if the outlet get gunked up. Wouldn't the same thing happen with the holes in the tubing over time ?

    Love this! I've done something similar to this on a larger scale with a Rubbermaid tote for tomatoes, copy of the Earth Box, which are too expensive. I do like your water circulation on a timer idea! I wouldn't worry too much about the roots not getting deep enough. They will probably go right through the felt in their search for more moisture. Gonna have to give this a try this year.

    It is a great idea, sort of like th earth box but with a more reliable way of pumping. If you wld add a piece of pvc pipe (like for electrical wiring), it is easy to see how high the waterlevel is. You would not want yr pump to run dry.

    Great idea

    Cool idea. I think I have all the parts for one of these laying around. You could add a vertical piece of tube in the corner to make water re-filling easier.