Sub Irrigated Planter (SIP)

Tonight I made a sub irrigated planter. These are pots that hold water under the dirt and let the pot get watered from the bottom up. Supposedly this gives you better roots as they grow deep, towards the water as opposed to staying near the top.

I built mine using recycled ‘stuff’. The pot is a round plastic tote that was on the deck when we bought the house, so it’s a bit weather beaten, but still in good shape. The tray is part of the plastic back from a rear projection TV I am parting out for parts for other projects. The fill tube is a bit of PVC pipe. The wicking fabric is the only part I actually bought for this project.

Cut out black plastic from the back of a rear projection TV
Cut out black plastic from the back of a rear projection TV

I traced the bottom of the tub onto the black plastic, and made a larger circle around the tub circle to cut along. I then cut tabs up to the tub circle.

Bend the edges 90 degrees so they form legs
Bend the edges 90 degrees so they form legs

I used a heat gun to heat up the plastic and bend the tabs up. These will for the legs of the tray to hold the tray above the water.

It doesn't have to be perfect, just good enough.
It doesn't have to be perfect, just good enough.

 

Cut four slits
Cut four slits

I cut 4 slits a little wider then the saw blade of my jigsaw.

Feed 2 pieces of Thermolam (or somesuch) through.
Feed 2 pieces of Thermolam (or somesuch) through.

The fabric gets cut into strips and fed through the slits.

Make sure the pieces are long enough to touch the bottom
Make sure the pieces are long enough to touch the bottom

Make sure the fabric is long enough to extend all the way to the bottom of the tub. They need to be able to touch the bottom so they can wick up every last drop of water.

Drop the wicking base into the container
Drop the wicking base into the container

The tray gets dropped in feet first and tweaked to fit. This was just a tad to big, but I got it worked out to fit.

Drill a hole for the fill tube
Drill a hole for the fill tube

I then used a hole saw to cut a hole for the fill tube.

Put all the pieces together
Put all the pieces together

The bottom of the fill tube isn’t flat, it was cut by drilling may holes – this makes sure that water can flow out the bottom easily.

The bottom may not sit perfectly flat or well, but that's ok
The bottom may not sit perfectly flat or well, but that's ok
Drill an overflow hole just below the bottom of the wicking tray
Drill an overflow hole just below the bottom of the wicking tray

It’s important to have an over fill drain hole. You don’t want water to get up to the dirt level or you will drown your plant roots.

Put some pea stone around the edges to address the varied height of the tray
Put some pea stone around the edges to address the varied height of the tray

My edges where less than perfect, with a low spot, so I used pea gravel to add some drainage and make sure that the dirt stays above the water level.

Fill the center with damp potting soil making sure to get good contact with the fabric
Fill the center with damp potting soil making sure to get good contact with the fabric

Dry potting soil won’t wick water from what I’ve read, so make sure the dirt is moist.

Fill the rest of the way and plant
Fill the rest of the way and plant

I used most of a new bag of potting soil, and some old stuff that I had but never used. This is a large container, so I am hoping it’s big enough for more than one tomato plant.

I now have a large pot that I don't have to water very often
I now have a large pot that I don't have to water very often

The pot is to go on the deck. Tomatoes and basil. Hopefully they do well, right out the kitchen door.

 

Tonight I made a sub irrigated planter. These are pots that hold water under the dirt and let the pot get watered from the bottom up. Supposidly this gives you better roots as they grow deep, towards the water as opposed to staying near the top.

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