How to Make a DIY Self-Watering Planter Box & Bonus Summer Garden Hack

Growing flowers can be a joy, but keeping them watered can sometimes feel like a chore. That's where a self-watering planter box comes in handy.

In this guide, I'll walk through the steps to create your own sub-irrigated planter using simple materials and tools you might already have at home.

Plus, I'll throw in a bonus outdoor summer project to protect your newly planted flowers using waste bins from the dollar store.

This post was transcribed by a member of the Hometalk editorial team from the original HometalkTV episode.

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Tools and Materials:

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Upcycle your plastic bottles for a DIY self-irrigating planter box

1. Gather Materials from Recycling

Before you begin your self watering planter, rummage through your recycling bin because you're going to need to upcycle a few plastic bottles for this DIY.

Upcycling plastic bottles tutorial

Find yourself 4 milk jugs and a plastic drinking bottle to get started.

Homemade self-watering plant container

2. Waterproof the Container

First things first, let's ensure our container is waterproof.

Step-by-step self-watering planter tutorial

Place a milk jug inside the tub and mark the tub just above the jug level.

DIY self-irrigating flower pot instructions

Drill drain holes on the sides of the tub.

How to waterproof your container

Roll out heavy gauge builder plastic, and cut it to fit inside the tub.

Ensure your container is waterproof for a successful sub-irrigated planter

Secure it with duct tape.

Waterproofing techniques

Staple the plastic at each corner.

After the tub is lined, puncture holes in the plastic where the tub drain holes are located so that the water can drain out.

Separate soil from water with a sturdy screen

3. Creating the Screen

Now, create a screen to separate the soil from the water.

Follow these steps to create the perfect barrier for your planter

Place a milk jug inside the tub and measure just above it.

Screen creation process

Cut cedar strips to create a square wood frame.

Easy homemade sub-irrigated planter

Add additional strips to fill in the sides.

Self-watering flower box how-to guide

Then attach old window screen to the top with screws.

Cut long slits into one side of each jug.

4. Making the Water Reservoir

Next, make a water reservoir using milk jugs.

Construct a water reservoir

Then flip the jugs around so the cuts face down.

Learn how to make an efficient water storage system for your planter

Holding two milk jugs together, trace around the spout of one jug onto the other.

Plant hydration strategies

Then cut the circle out with an X -Acto blade.

Plant irrigation system

Repeat for each jug, remembering that the cut side should face downwards.

Eco-friendly gardening projects

Attach all the milk jugs by pushing the pouring spouts into the cut holes.

Homemade self watering container tutorial

Lay them down horizontally.

Craft a feeder tube to supply water to your plants

5. Assembling the Feeder Tube

Now it’s time to create a water feeder tube. Use a felt pen and the top of the drinking bottle to mark around one of the milk jugs and cut out the hole.

Discover how to assemble a reliable watering system

Slice off the bottom part of your water bottle

Watering system setup process

Insert the drinking end of the bottle into the jug.

Plant hydration strategies

Drill holes along the tops of the milk jugs for plant roots to gravitate towards once filled with water.

Self-sufficient gardening ideas

6. Planting and Testing

Add about 1 inch of potting soil to the bottom of the tub, then place the milk jug reservoir inside.

Expand your DIY gardening repertoire

Twist off the feeder tube, set it aside, and place the screen on top of the reservoir.

DIY self-watering planter box

Cut a feeder tube hole through the screen and reattach the feeder tube.

Plant your flowers

Add soil under and on top of the screen until it is deep enough to plant flowers.

Self-watering plant diy

Fill the feeder tube with water

Test your self watering planter

Ensure the irrigation system is working by checking that water seeps out through the drainage holes in your tub.

Self-watering plant containers

Remember to periodically check the feeding tube and top up with water as needed.

Ready to take your gardening skills to new heights

Explore this DIY Flower Tower tutorial for another ingenious way to nurture your blooms!

Bonus Summer Project: Protect Your Flowers with Waste Bins

Clever gardening solutions

1. Prepare the Flower Bed

Clean up the flower bed by removing dead debris and weeds.

Garden hacks for flower beds

Use a half-moon edger to create a sharp edge and plant flowers.

Waste bin plant protector

2. Use Dollar Store Garbage Cans

Cover each newly planted flower with a dollar-store garbage can for protection against wildlife and harsh weather.

Protective measures for new plants

These bins are easy to lift for inspection and can remain until the flowers are stronger.

Follow these steps for a thriving garden with minimal effort

How to Make a Self-Watering Planter

Congratulations! You've created a sub-irrigated planter box that takes care of your flowers with minimal effort.

Plus, you learned a neat new trick to protect your plants from critters.

Let me know how your project turned out in the comments below!

Donna at Funky Junk Interiors
Want more details about this and other DIY projects? Check out my blog post!
Frequently asked questions
Have a question about this project?
  3 questions
  • Mfitz Mfitz on May 08, 2024
    How do the overflow holes in the tub work? How does the water actually get through the heavy plastic that was taped along the sides? Thank you for a great idea, it is one of the best ideas I have seen.
  • Jan Jan on May 09, 2024
    I don't understand. The water is below the soil. How does the soil keep from driving out?
  • Sheila Bishop Sheila Bishop on May 09, 2024
    I wouldn’t cut the slits in the bottom of the jugs. They will never fill up. Instead I would drill holes in the sides so the water is evenly distributed in the soil. Maybe I’m not understanding how this is supposed to work?
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