Creating Swales and Berms in an Allotment

This is some notes on building swales and berms on our south facing sloping allotment.

We got the plot in December 2019 when it was overgrown with couch grass and bindweed and have been gradually cultivating it and observing it. In 2020 we decided to create swales and berms to retain the water across the slope and to provide flat paths and raised beds that could be no-dig beds going forward.

This shows how we constructed and planted up the top berms in 2020. The plants you see labelled are the same plants in the plot to show how the surrounding plants developed.

Swales are ditches dug across the contour, hence you see me using a spirit level A-frame to create them. In 2021 the swales were filled with wood chip.

We created swales and berms for a few reasons:

• digging/planting and harvesting is hard work on a slope so we wanted to create level surfaces to both walk on and plant in.
• it’s a sheltered south facing slope that gets very hot and dry and there is no water supply so water conservation is a priority. Swales slow the water runoff across the slope and the north side of the mounded berms provide a cooler edge to plant salad crops.
• it seemed a fun thing to do!
• the wood chip added to the swale will rot over the year and provide a mulch and fertiliser for future crops when we will replace it with fresh wood chip. This way we get a path/composting system.

So far it’s working well.

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