This is an almost free self watering planter box anyone can build themselves, and it will barely cost you anything, and it will take you about 30 – 60 mins depending on how slow you are at doing things. I got the inspiration from a Brisbane man who appeared on the ABC’s Gardening Australia program.

The Brisbane man had created these self watering boxes which i just had to try to recreate, and create a blueprint for. They are portable, highly effective, almost free, and require barely any space, easy to make and will provide you with plenty of vegetables or herbs without having to water daily. To watch the episode, click here.

What do you need?

You will need the following items to build this self watering planter box:

A foam box without holes + the lid (you can get these from your local greengrocer or seafood shop, and they will just give them to you).

A PVC pipe (ready to cut to size)

A saw or cutting implement to cut the PVC pipe

A pair of scissors and a Stanley knife

Waterproof tape

Stick (free from your garden)

How do i make it?

Firstly get your foam box. You can get these foam boxes from any green grocer, supermarket or seafood / poultry shops. Be brave and ask (you don’t get if you don’t ask) and most places will be glad to get them off their hands and give them to you, and no one will want any money for them. If they want money or make it an issue, move on and get them somewhere else. In 1 day i was able to get about 5 from a supermarket down the road, all free.

Get the lid and cut around the inside lid following the groove using a stanley knife. This is the best implement to use when cutting into the foam.

Once you have finished cutting out your divider from the lid, it should look like this.

Next you want to measure the PVC pipe ready to cut to size against the foam box. This will be used for adding water when needed, and to house the float which will tell you when you need to add water to the box.

Once you have measured the pipe, cut it down to size, as shown below. It should be the size of the foam box itself.

Next what you want to do is cut 3 pieces of the PVC pipe, 2 as supports to hold the foam divider in place (it’s up to you on the length you want to cut, remembering that water will only go as high as the PVC pipe length you cut. The third piece needs to be slightly taller than the other two as it will be used as the wicking pot. Cover it with netting using anything to secure the netting in place.

A wicking pot acts like a candle but upside down, and with water instead of fire. Confused? Basically a wicking pot is used to draw water up into a garden bed from a water source below. This allows the plants to draw water when they need it provided there is enough water in the reservoir from where the wicking pot is drawing the water from.

To allow the wicking pot to work, you’ll need to cut a hole in the divider so the wicking pot will fit in it. Simply just cut out a hole using the PVC piping as a guide and with a stanley knife.

Once you have finished, it will look like this.

Insert the wicking pot into the divider so it looks like this.

So now you need to cut a hole in the divider for the water pipe so it can be inserted into the planter box. Use the PVC pipe as a guide and cut around it with a Stanley knife.

Congratulations, you’ve now completed the majority of the work, and it’s really more about assembling and the finishing touches. So to get ready to assemble your planter box, place the two support PVC pipes in the bottom of the foam planter box, and the water pipe as shown below.

Ok here’s the satisfying bit, when you finish assembling the planter box by adding the divider, and you realise you have just created something awesome that’s going to give you some great produce without having to water it all the time, and it’s barely cost you anything to make.

So now you’ll want to add your overflow hole which will allow water to overflow out of the planter box, and not fill up higher than the divider and drown your plants. Determine where your overflow hole should go which should be just under the foam divider, and use scissors to carve out a decent sized hole for the water to overflow out of.

Cool, that’s pretty much it. Now, before you do anything else, determine where you are wanting to put the planter box and put it there before you start adding in soil and water. It can be difficult to move when full of soil and water without a trolley.

Now to add in the dirt and start prepping to add in your seedlings. You should start with filling the wicking pot with soil so the water has something to get sucked up with, and then cover the rest of the of the divider with soil.

Add in as much soil as required. I think the foam divider can handle any amount of soil without breaking or caving in.

Now get your seedlings ready so you can plant them in your planter box. I’ve chosen Rhubarb seedlings that i’ve grown from seeds in my awesome greenhouse. Can’t wait for Rhubarb crumble!

Once you’ve added your seedlings, you may want to mulch. I like to mulch, i think it has to do with conserving water, and keeping the soil moist. I think you’re also meant to water the soil before adding mulch, but i’m not sure. I’ll leave that to you to research.

So once finished, your planter box should look reasonably similar to the planter box shown below.

Ok, a self watering planter box requires you to add water to it, unfortunately it’s not automatically replenishing, so add your water by adding the water through the water pipe.

You’ll know when you’ve added enough water when it starts dribbling out of your overflow hole.

So how will you know when you need to add water to your self watering planter box? Simples, create yourself a float using some of the foam scraps, and a stick from in your yard.

So put your float in the water pipe so it can float on the water, and you can use the stick as a gauge to whether the planter box needs water or not. You will have to remove the float when you add water to it otherwise you may break your float.

OK, so this step should really have been completed when the planter box is empty. You’ll need to mark the stick at the point that shows the float being at the bottom of the planter box (showing that the planter box is empty and needs water). this can be marked by using colored tape.

Now when you see the tape level with the top of the PVC pipe, you’ll know you need to top up the planter box with water. Simples!

And that’s that, you’ve created yourself a self watering planter box that will tell you when you need to add water, and it barely cost you a thing, and you’ll barely have to water your plants, you lazy stingy bastard you. No seriously though, congratulations, you’ve recycled, and saved yourself a decent amount of money, and you’ll have a bumper crop to show for your efforts, well hopefully anyway.

Hope this helps, and please share with your friends, don’t get duped into spending lots of money for something that’s ridiculously easy to make and is helping the planet by recycling.

Your helpful gardener.