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Build Your Own Self-Watering Planter

Save water and grow healthier veggies and flowers with a self-watering planter. This attractive cedar design uses perforated drain pipe to store and distribute the water.

By the DIY experts of The Family Handyman Magazine

About self-watering planters

I love to grow fresh salad greens, tomatoes and herbs. But growing veggies during high summer means daily watering, which becomes a problem when we go away for vacation. In the past, we’ve hired the neighbor kid—sometimes he remembered, and sometimes we came home to withered veggies. Last summer I decided to build “self-watering” veggie planters that I could leave for a week without watering. The results were amazing. The planter boxes themselves were gorgeous, they kept rabbits and other critters from munching on my greens, and I went for weeks on end without having to water. I watered three times all summer long (no kidding), and we had garden-fresh salads until frost. In this article, I’ll show you how to build one for yourself. The secret is in the perforated drain pipe.

Self-watering planters are sometimes called “sub-irrigated planters” or SIPs, because your plants get to “sip” water whenever they want. Our version uses inexpensive perforated drain pipe with a fabric sleeve in the bottom of the planter. Once you fill the drain pipe reservoirs, they allow air to circulate and water to wick up to your plants’ roots whenever they need it. When plants are watered from below, the roots stay consistently moist, there’s less evaporation and you don’t need to water as much. The vinyl tubing allows any overflow water to drain. There are many commercial self-watering planters available—the EarthBox (earthbox.com) is one but you can easily make your own.

Build a self-watering planter

Build a self-watering planter

Top 8 Reasons to Build This Self-Watering Planter

  1. It saves your back and knees.
  2. You’ll have fewer weeds.
  3. It waters your plants while you’re away.
  4. It saves water.
  5. You’ll have fresh veggies steps from your back door.
  6. It’s easy to create the perfect soil.
  7. It protects your veggies from hungry critters.
  8. It’s a handsome addition to your patio.

Self-Watering Planter Basics

  • Choose a spot that gets at least six hours of sun. If your planter is against a wall, you can get by with less sun because of the reflected heat.
  • A 4-ft.-wide planter is ideal for harvesting from both sides. Keep it to 3 ft. wide if you’re placing your planter against a wall or fence.
  • Line your planter with a “fish-safe” rubber membrane. It will prolong the life of the wood without leaching chemicals into the soil (and your food). You can buy fish-safe pond liners in different thicknesses and materials at home centers, garden centers and online retailers.
  • Don’t use garden soil or a heavy potting soil in your raised garden. Use a light, fluffy “soilless” blend that will retain moisture without compacting or becoming waterlogged. You can also buy potting soil specifically formulated for self-watering planters.
  • Mulch your containers to keep weeds down and to slow evaporation.
  • For more great ideas for building sub-irrigated planters (SIPs), visit insideurbangreen.org.

Build your own planting box

Photos 1 – 6 show you how to build a handsome wood planter box. The total cost of my 3 x 6-ft. cedar planter was $330. If you use treated wood, the price would drop to about $250. And I used a thick EPDM pond liner, which cost $120. (You can buy thinner versions at home centers for about $35. All the other materials are available at home centers or garden/landscape centers.) To give the box a nice finished look, we routed the boards and sanded the faces and cap. We left the cedar unfinished, but you could seal yours. After we built the basic box, we moved the planter to its final position and then added the self-watering system, soil and plants. Even without the soil and plants, this planter is heavy!

Photos 7 and 8 show you how to construct the self-watering system. Once you’re ready to plant, add a soilless mix to just below the top of the planter.

Once your plants are in, fill the drain pipe reservoirs through the fill tube until water runs out the drainage hole (this can take a while). The water will slowly wick out of the perforated pipes into the potting mix packed around it and eventually up into the potting mix and plant roots above.

You’ll have to experiment to see how long your planter will stay moist. Fill the drain pipes whenever the soil feels dry 2 or 3 in. down. When I set mine up, I filled the drain pipes and gave the plants an initial surface watering and then mulched around them. After that, and despite a record hot summer, I refilled the pipes only three times over the summer and I had herbs and greens growing until the first frost!

Figure A: Self-watering Planter

Figure A: Self-watering Planter

Figure A: Self-Watering Planter

Overall dimensions: 3’ x 6’ x 23 1/2"

For Material List, Cutting List, and Plant choices for containers, see Additional Information below.

Note: We notched the flooring to fit (Photo 5). You can also fit the floor within the 2x2s as shown and let the liner span the gap.

Building Tips

  • When assembling the box ends (Photo 1) and sides (Photo 2), leave gaps between the planks to allow for expansion and contraction. I used 1/16-in. washers as spacers.
  • To determine where to put your planter floor (Photo 4), add together your soil depth, the flooring thickness and the height of the drain pipe and add an inch to that so the soil level will sit an inch below the top of the box.
  • For greater strength, use 2x2 horizontal cleats (33 in. long for our planter) for each end and 2x4s for the center two joists.
  • Don’t miter the top cap—miter joints open with changes in humidity. Butt joints will look neater than miter joints over time.
  • Wedging the ends of the drain pipe against the planter will prevent potting mix from getting into the pipes.
  • Wedge the CPVC fill tube tightly into the top of the drain pipe. It should be long enough to poke out of the top of your soil once your container is planted (Photo 7). You only need one—the water will flow into all the drain pipes.

Video: How to Build a Sub Irrigated Planter System

If you like fresh vegetables and herbs from the garden, but don't think you can have a garden, Elisa Bernick, an editor at The Family Handyman, shows you how to build a sub irrigated planter system (also called a self-watering planter) that will allow you to grow your favorite foods and keep them watered, even while you are on vacation.

 
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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

    • Clamps
    • Miter saw
    • Cordless drill
    • Countersink drill bit
    • Combination square
    • Level
    • Drill bit set
    • Framing square
    • Hacksaw
    • Jigsaw
    • Stapler
    • Router
    • Safety glasses
    • Utility knife

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

    • See Additional Information

Comments from DIY Community Members

Share what's on your mind and see what other DIYers are thinking about.

1 - 15 of 15 comments
Show per page: 20   All

April 22, 9:21 AM [GMT -5]

FLEX-Drain 25' Perforated Drain Pipe with Sock is sold in 25' lengths. Is there any reason why it needs to be cut into 4-6' lengths rather than simply kept as one continuous pipe, looping back around the box? It would seem to fill faster.

April 19, 9:14 PM [GMT -5]

How big should the perforations in the pipe be? The holes in the pipe I bought seem awfully small.

April 15, 9:30 PM [GMT -5]

I assume from comments that perforations on pipe should be facing up? This just seems to go against everything I know about leach pipes but I know the purpose is the wicking of the water. Just want to make sure I am doing these correctly. I also agree that running a few PVC connectors to the pipes would speed up the process of filling them. Has anyone tried that?

Thanks

March 25, 10:53 AM [GMT -5]

So I chose to take the deepest depth for my plants and I estimate I have about 18 cubic feet of space to fill. Could I fill this entire planter with a CoCo Peat Mix?

March 20, 12:11 AM [GMT -5]

Only the video mentions the landscape cloth. Is this to keep the roots from sitting directly in the water reservoir part? Is the water supposed to wick from the watr half to the upper half through the fabric?

March 19, 3:24 AM [GMT -5]

J17MD -

True that treated lumber can leach chemicals, but this bed is lined with a pond liner so the soil is never in contact with the wood.

March 18, 8:58 AM [GMT -5]

"If you use treated wood, the price would drop to about $250" This is a HUGE mistake if you're growing food. I'm shocked that a warning isn't in the article.

**I REPEAT IF YOU PLAN TO GROW FOOD DO NOT USE TREATED WOOD!**

March 18, 2:43 AM [GMT -5]

As written, the second pipe leeches water from the surrounding soil. So, you fill - wait for water to equalize, then top up.
An alternative is to run a small tube (like the runoff tube) between the 2 main water-holders, allowing them to both fill faster.

As for that runoff tube: connect it near the BOTTOM of you main pipe, take it straight out of the box, then run it UP the side... presto! You now have a water level indicator, just like a boiling water urn! Snip the top to allow overflow, tack the tube to the side, and you can see water level at a glance.

svc

March 17, 5:31 PM [GMT -5]

The list of materials along with exact instructions for them were not included in the of materials/shopping list - like the pipes need to be perforated, the length of the pipes, etc. It's a fun and doable project but we need list of materials. Thanks
Sonia

March 16, 9:24 PM [GMT -5]

the material and cutting lists are downloads after you go to the print section. I am going to build a couple of these this spring. Thanks

March 16, 7:24 PM [GMT -5]

Wouldn't it be more efficient to join the four tubes with connecting tubes than to wait until the bottom fills/seeps into the three remaining tubes? Seems like this is a flaw in the design. But other than that I like the concept and it could be used for smaller planters too. Now to source out some 'cheap' pond liners...

February 24, 2:49 PM [GMT -5]

I'm not sure why no one is answering the above questions, so I will: The soil will absorb as much water as it can, then the rest will seep into the other pipes through the perforations. It's kind of like osmosis, but has to do with pressure/gravity. When the plants drink the water, the soil can absorb more and draws it out of the pipes. You only need one fill tube.

October 08, 2:28 PM [GMT -5]

How are the 3 remaining pieces of drain pipe suppose to be filled with water? The instructions call for only 1 piece of CPVC tube to be inserted into 1 drain pipe and not all 4.

August 29, 9:35 PM [GMT -5]

Is the perforated drain pipe snaked through the bottom of the box as one piece or laid as pieces next to each other. And if so, are they connected in some other fashion to allow the water to pass from one to the next?

July 14, 4:28 PM [GMT -5]

You are missing the materials list for this project.

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