The puncher roller
The puncher roller can pierce through plastic mulch or mark out lines in the soil for sowing or transplanting. This tool is very adaptable: you can choose the spacing between each plant and the number of rows you require for holes or markings.
The puncher roller consists of a frame with a roller made up of several wheels with spikes. You pull the tool as you walk along the side of the bed. You can also push the roller to ensure a better perforation of the plastic mulch.
The frame can be made using scrap metal, such as old polytunnel poles. The metal parts suggested here as just given as an example. The dimensions of the parts don’t matter so much, as the pressure exerted on the tool is minimal. You can assemble old polytunnel poles in a number of different ways. It’s useful to flatten out the poles using a hammer and a vice in order to increase the contact area of the metal plates. You can weld the parts together but it’s hard to do a neat job of it. Another option is to completely flatten the pole and attach the sections together by drilling in holes and screwing them together, but the frame will be less sturdy as the metal parts will have lost their structural resistance.
The shaft is made of a square 40mm metal plate onto which the wheels slide on. It’s the shaft that drive the wheels. The central part of the wheels is a square metal plate 45mm wide and 2mm thick, which gives a 1mm play.
The wheels are 410mm in diameter and are made by bending a flat 60mm x 5mm plate. Drill only after the plate has been bent, to ensure the surface of the wheel stays smooth. With forty holes spaced 32mm apart, you have a big choice of adjustments for the spacing of your plants, sowings or holes. The wheel is kept in place on the shaft with a large wing nut. The roller can be used with 2, 3, 4 or 5 wheels. You can also have a single wheel with spikes while the other two flat wheels are used to stabilise the roller (for squashes and courgettes for example).
The spikes are made by welding two bevelled corner pieces back to back beforehand. 1 to 8 spikes can be fixed onto each wheel.
The lightness of the tool means it doesn’t always perforate the plastic mulch properly. It’s sometimes necessary to add weight to the frame, but this will increase the work involved in pulling the roller. Pushing rather than pulling can help, and it also allows the user to have better visibility of the work being carried out.
The shape of the handle bars means you can work along the edge of a polytunnel without knocking into the sides of the tunnel.
Documents to download
- The technical drawings are currently only available in the Self-build guide, with additional information and research for permanent bed cultivation. Once the Guide has sold out, the technical drawings will be available as open source designs, free for all to build and modify! Order Self- build guide here
The entirety of this article, including descriptions, photos and technical drawings, are available for all to use under a Creative Commons licence. They can be distributed and modified as long as the user mentions their origins (Atelier Paysan) and ensures that all related tools and documents are also under Creative Commons.