Community Spotlight: Installing Leaky Pipe Irrigation

The Kitchen Garden workshops are back in full swing at Brockwell Park Community Greenhouses. Today, we discovered how to lay irrigation in plant beds using a leaky pipe.

The idea is that with leaky pipe irrigation, you can water your plant beds all at once simply by turning on the tap. Water seeps through the porous pipe, laid in rows, and directly reaches plant roots. In this way, you minimise the amount of water lost to evaporation, and in contrast to the way sprinklers work, water doesn’t get splashed around where it’s not needed, like on footpaths.

The Greenhouses had experimented with the leaky pipe method on a few plant beds last year, and it proved so successful that they are extending it to all of the edible garden. Winter is also a great time to lay this irrigation system because the beds are still empty.

Labouring away

Soon enough, we set to work on one of the extremely long beds. We first broke apart the soil with large plastic rakes — the frost we’ve been having had frozen the top layer, but raking helped to break it apart.

Ideally, the spacing between two leaky pipes running parallel should be 60cm. This is because each pipe delivers water to up to 30 cm on each side. Because our raised bed was quite narrow, the spacing was less than 60cm. We simply laid three pipes spaced apart equally.

We dug three trenches, about 10cm deep, in which to hide the pipes. Digging the trenches, all along the bed, was probably the hardest part.

Let’s assemble it!

We put plastic stoppers at the ends of each pipe and used corner and T-junctions to assemble the top piece. These junctions were actually quite tough to slot into the pipe. A little trick: to make the pipe more malleable we submerged it in hot water for a few seconds, which made it flexible enough to slot the connectors in. Finally, we laid the hoses in the trenches and secured them with metal tent pegs.

We used standard snap-on hose connectors to feed the whole system from the main tap. Our test of the system proved a success! The water spurted out in little fountains all along the length of the leaky hose. A larger leak had erupted by the central connector, but after some adjusting, it seemed to work perfectly. We backfilled the trenches with soil.

Happy with the results?

It looked like nothing had ever happened! Save for the one connector poking out of the bed. It’s important to keep the main connector dirt-free when not in use. Otherwise, it could block the entire system. We wrapped it with some plastic wrap to keep it clean.

Repairs to the leaky pipe system are also quite easy. If a part of it gets ripped, say by Mr. Fox, all you need to do is replace that part of the pipe by cutting a new section and attaching it with the plastic connectors.

This leaky pipe was provided by a manufacturer called Leaky Pipe Solutions, chosen by the coordinators specifically because they had measured the precise flow rate of water through the pipe: 4L/meter/hr at 2bar of pressure. Using this flow rate, the coordinators can precisely calculate how long to run the water to ensure the plants gets a good soak.

As a last step we raked the soil to a fine tilth.

I thought leaky pipe was such a clever method of watering, especially if we are to have another extremely dry summer. It saves on both the time and money spent on watering. I wish I could lay this sort of irrigation at the allotment, but we are not allowed to use pipes, nor have we the water pressure necessary to make this system viable. Only a refillable water tank and some buckets.

What about the bees?

I met several new people at the workshop today. There seems to be someone new every time I come. With one of them, an exchange student from Germany, I had lunch and made frames for the beehives. This was a whole new skill for me.

One of the community volunteers showed us how to take a kit of wooden sticks and assemble it into a frame with nails and hammer. We slotted a yellow matting inside the frame made of natural wax. This matting would give the bees a head-start, allowing them to use their energy for honey production rather than to build the initial wax.

Hiding in the forest

We also discovered a hidden section of the garden, tucked away behind the greenhouses, called “The Green Woodworking Workshop”. I’d never seen it before, but it looked like a small magical forest filled with all kinds of strange-looking traditional woodworking tools. Including this incredible pole lathe.

What I found most interesting is that they never use nails for their projects (today, it was stool-making day). All the joints fit together perfectly due to the natural properties of wood. The stool-making workshop did have to take place over two weeks to allow the wood time to dry out and shrink, so that the joints would fit snugly.

There was more irrigation to lay in the front borders, so we finished late in the afternoon. Of course, with a cup of tea and chocolate biscuits! Let’s see what next week brings. ?

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