How to make your own container with water reservoir

Using old recycling boxes and pvc piping

Step by step instructions 

All ready to plant.... and the perfect size for growing squash, potatoes, vine tomatoes, runner beans or any other large, hungry vegetable crop.

In this post you'll learn how to make a long lasting, high performance container with water reservoir.

Level of difficulty: moderate

Water reservoirs make watering easier and dramatically improve yields.

You can add reservoirs in various ways. One simple way is to add a reservoir to an existing container. Or with a little more time and effort, you can create a far superior system using two plastic boxes and some PVC piping.

Old recycling boxes are perfect for this project because:

• They are large (usually 40 – 55 litres), ideal for hungry vegetables like squash, tomatoes or potatoes.
• The plastic is UV treated - it will last and not disintegrate in the sun.
• The plastic is strong - and can withstand all the drilling.

The main drawback of recycling boxes is what they look like - see below for ideas on how to make them more attractive. If you don’t have recycling boxes, you can use the same method with other plastic containers or buckets. 

To make one self watering container you need:

• 2 old recycling boxes (In the UK you can often source supplies of old, used recycling bins from council recycling centres if you ask them.)
• 30cm (1 foot) PVC drainage pipe for the wicking feet – ideally 11cm (4.3 inches) diameter  (often found in local skips)
• 50cm of pvc pipe for the filling pipe – anything from 3 – 8 cm (1 – 3 inches) in diameter (again frequently found in skips).
• 13 plastic cable ties.
• 2 small sachets of Sugru or a silicone sealant.

And the following tools:

• A power drill with a 6mm (1/4 inch) drill bit, a 12mm (1/2 inch) drill bit
• A hole saw large enough to cut a hole for your wicking feet (you can cut the hole without a hole saw but it makes the job much easier).
• A hacksaw for cutting the plastic pipe.

Collecting together the materials and tools. The attachment on the end of the drill is a hole saw, used for cutting out circles. PVC piping like this is common in skips (it will often need a good clean before using).

Step by step instructions

1. Waterproof your reservoir.

One of your boxes will become the water reservoir. As recycling boxes nearly always have holes in the bottom, you’ll need to fix these. The easiest and neatest way is to use Sugru, a cool new product that is easy and pleasant to work with. Just press it into the holes, making sure these are clean and free from dust, then leave overnight to dry. Alternatively, you can use a silicone sealant.

Left: recycling bins usually have holes in the corners. Right: these can easily be blocked up and made water proof with Sugru (pictured) or silicone sealant.

2.Make your wicking feet

Drill plenty of 6mm (1/4 inch) holes in the drainage pipe. It’s easier to drill these before you cut the pipe. Then cut off two 15cm lengths using a hacksaw or mitre saw. These are your ‘wicking feet’. They will sit in the water reservoir and water will enter through the holes and then wick up into the main container.

It's easier to drill the feet in the PVC drainage pipe before cutting it into 15cm lengths.

 

3. Prepare your soil holding container

• First, using a hole saw the same diameter as your  wicking feet, drill two holes in the bottom of one of the recycling boxes (not the one you just waterproofed!) – see picture below – and keep the two round offcuts (you’ll need these in the next step). If you do not have a hole saw, you can rent one from some hire shops. Alternatively, you could try and cut the hole with a hand held key hole saw. I do not recommend trying to cut hard plastic with a sharp knife like a Stanley knife – the knife can slip too easily (I know someone who had a serious accident this way).
• Then drill three equidistant 5mm (1/4 inch) holes round each of the large holes – you will use these holes to attach the wicking feet with ring ties.
• Then drill a bunch of further 5mm (¼ inch) holes in the bottom of the box – these holes will enable air to travel into the soil and reach the roots of your plants.

 

The large holes are easiest to cut with a hole saw. The size of the hole saw for the feet should be as close to the diameter of the pipe as possible - but it will still work if its a little bit bigger or a little bit smaller.

4. Attach the wicking feet

• Attach the round offcuts to the bottom of your wicking feet using three ring ties. This will prevent soil falling out of the bottom. Drill three holes at equidistant intervals round the bottom of the pipe to thread the ring ties through.
• Attach the wicking feet to the bottom of the container using three more ring ties for each foot. Drill three equidistant holes at the top of the foot to thread the ring ties through.

 

The red ring shows highlights one of the cable ties attaching the foot to the container. The piece of wood has been added here to give additional support to the container - and to spread the weight of the soil.

5. Make the overflow hole

Drill a 1cm (1/2 inch) overflow hole 12 cm from the bottom of the water reservoir. This will ensure that there is always an air gap between the bottom of the soil and the water – this helps get air to the roots. The overflow hole also prevents the possibility of overwatering.  This makes this type of containers great for community projects.

 

The overflow hole is essential to prevent the container getting water logged. It also helps to create an gap between the water and the container, enabling air to pass into the soil and the roots.

6. Add the fill pipe

Using a hole saw, drill a hole in the bottom of the soil holding container to slot the fill pipe through (see image under 3. above). Cut the fill tube to the right length – you want it sticking out of the top of the soil at the top – and cut the bottom at an angle to help prevent it getting blocked.  I’ve used 8cm diameter PVC piping (that's what I found) but any piping 3cm (1 inch) in diameter or wider does the job fine.

 

The bottom of the fill pipe is cut at an angle.

Slot the reservoir underneath and you’ve now finished building your container!

Finished!

7. Fill it with compost

Fill the wicking feet first. Use a soil based compost (this wicks water better) and firm it down lightly to make sure there are no air gaps in the feet.

Then fill the remainder of the container. I like to use a mix of 50% soil based compost and 50% peat free compost.

 

Use soil based compost to fill the feet and press it down lightly to ensure there are not air gaps.

Make it beautiful

Use your creativity to make your containers look beautiful. For example, you might:

• Arrange them in attractive formations, circles perhaps or on bricks (or old pallets) to create different levels.
• Hide the container behind a façade – perhaps old scaffold boards, floor boards or willow hurdles.
• Grow some trailing plants (eg nasturtiums) to hide the containers.
• Decorate the containers with leftover paint.

 

If you make these, please do send images of your handiwork – all the best will be posted on this blog and / or  the Vertical Veg Facebook page.

 

I’d like to thank Alternatives and the Rooftop Garden Project for their invaluable guide where I first learnt how to make these. If you are using a different type or size of container, please refer to this guide for the formula on how to calculate the number / size of wicking feet you need.