How To Make A Sub Irrigation Planter That Is Ideal For Gardening In Small Spaces

You might think that living in a small apartment with a tiny deck or backyard might discourage you from gardening, but with this clever project you’ll be able to grow any number of plants without needing a plot of land. Consider it urban farming for cheap!

This do-it-yourself sub-irrigation planter was posted on Imgur and this urban gardner walks through the steps for creating a planter from a few everyday items.

“There are lots of ways to make sub irrigated planters out of reused materials,” writes ikewulf. “This build uses an 18 gallon storage tote, 4 half gallon milk jugs, and one tall plastic bottle.”

“The tools I used were a hobby knife and a drill with a 1/2 inch bit. These planters can be ideal for small spaces such as rooftops or apartment decks, especially since they do not drain from the bottom or require trays since the water reservoir is internal.”

To start, build the reservoir from milk jugs and mark with a pen where you want the irrigation holes. “Pictured here is the side of the jug that will be facing upwards when placed in the tote. The small holes cut in top serve as an entry point for roots to reach into the reservoirs.”

Next cut two large holes on the sides of the milk jugs. These holes will allow the jugs to be interlocked so that they create one large reservoir. “To size this hole trace around the mouth of the jug on a piece of paper and then use it as a template.” Don’t worry if they fit snuggly together, they should lock into place. You’ll see exactly what this is as the process goes on!

This side of your jugs will be facing the bottom of the tote. Cut a long open slit. This serves as an entry point for water that has accumulated in the bottom of the tote to enter the reservoir.

Cut the small holes on the top of the jugs with a hobby knife and then make the holes bigger by pushing a pen through them.




Here is the mouth and neck of one of the jugs inserted into the body of another. “The plastic should be flexible enough for you to squeeze the neck in, and then when it flexes back into original shape it should lock itself into the hole.”

Now you need a tall, skinny plastic bottle to be the access “spout” where you pour in water. A large water bottle is great. Next, you will cut a hole in one of the 4 milk jugs that’s large enough to place the neck of your tall skinny bottle.

“Remove the bottom from your tall skinny bottle, and check that everything fits correctly. You’re now ready to assemble the entire reservoir tank.”

When you assemble the milk jugs and water bottle you should have something that looks like this. You won’t need to seal around the milk jug necks as any small gaps will be filled by the soil.

Now it’s time to prepare the tote. ikewulf likes to use a 1/2 inch drill bit for this part. If you have another tool to make the overflow holes, go ahead and use it. “You want to make sure your holes aren’t so small they get blocked up. These holes will be placed on the sides of the tote, do not put holes in the bottom.”

The overflow holes are in case it rains and the tote starts to hold too much water. The placement of the overflow holes should be about level with the top of the reservoir. Basically, put them up about as high as the half gallon milk jug laying on its side.

ikewulf put 4 large holes on the wide side and 3 large holes on the narrow sides.

Now we’re ready to start filling up the tote. Put about an inch of potting soil (mixed with a bit of vermiculite if you want) in the bottom before adding the reservoir.

Add the reservoir tank and start filling the tote with potting soil. Use potting soil not garden soil for the best results. You may want to add more vermiculite or perlite to allow for better drainage if the potting soil doesn’t have enough for you.

When you have filled up your tote with soil it should look something like this. You can use the reservoir access tube to see into your reservoirs. “During dry periods achieving even watering is as easy as pouring water into the end of the bottle,” writes ikewulf. “You can also peek in there and see how full the reservoirs are after getting some rain.”




Now you’re ready to plant. You can plant all kinds of things in the container: tomatoes, peppers, melons, etc.

What a cool and inexpensive gardening solution for a compact space! Share this homemade sub-irrigation planter with your friends and family!

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