Lasercut Capilliary Windowsill Irrigation Tray

Making a lasercut subfloor to convert a small tray into a capillary irrigation system. Germinating Broad Bean seeds in perlite allows for good moisture control whilst also providing some air around the seeds to prevent potential mould growth.

Using a capillary tray means that you can leave these propagators on a sunny windowsill and not have to worry about keeping them watered for a week or so.

The small size of the trays was chosen so that the trays could be made and used by a group of children, taken home and allow the children access to a convenient method of growing seeds.

This project is suitable for a School Eco group, community garden, forest school, scout group or home schooling group.

https://meadoworchard.org

1. Offcut of 3mm Acrylic sheet
2. Acrylic cement (Tensol 12)
3. Capillary matting
4. Micro-Perforated polythene sheet
5. Garland Super 7 Module
6. Green Single Brick Floral Tray (for Oasis)

Using a Glowforge Lasercutter to cut the attached svg or pdf file from 3mm Acrylic sheet. If you don't have access to a lasercutter you can carefully cut the acrylic sheet from the pdf template using a jigsaw and fine tooth per inch blade suitable for plastic.

The support legs slot together from the lasercut parts. Add a small amount of Tensol cement to the slot in the parts prior to assembly. Add a dab of Tensol along the edges of the cross shaped cutouts in the subfloor and assemble the support legs to the top. Leave the assembly upside down until the solvent cement takes hold so the legs don't fall out.

Cut out a piece of capillary matting to the same width as the subfloor, cut it so there is approximately 50mm longer (2 inches) longer than the subfloor so the ends can wrap around and dip into the tray at each end.

Cut the Micro-Perforated sheet to the same length as the capillary matting but 50mm wider. This allows you to fold the edges around the capillary matting for a neat finish.

If you pre-soak the capillary matting it's easier to wrap the Micro-Perforated sheet around the matting as it will stick to it and keep it flat.

The Micro-Perforated mesh helps to reduce evaporation so the irrigation tray wont need to e topped up as often.

Flip the assembled subfloor over and lay centrally onto the capillary matting. Make sure there's approximately 25mm at each end.

Place the subfloor into the Oasis Floristry tray. It's easier if you angle the tray and push one end in first and then carefully lower the subfloor into place. Try to keep the capillary tray flat for a neat finish.

In this photo we are using the capillary trays to germinate broad bean seeds. Using slightly dampened Perlite and placing the broad beans on top and covering with a thin layer of perlite.

The broad bean seeds should germinate after around 7 - 10 days. If it's a little cool, they might take a little longer. Once the beans have started to sprout a good root you can transfer into a multipurpose compost. Cardboard toilet rolls are great for this as they allow a good depth for the roots.

Alternatively if you would like to observe the seeds growth leave a few in the perlite until they have developed their first seed leaves. After this, they will benefit from being placed in compost and potted on.

For more information about this project and propagating the Beans, please visit our website below:

https://meadoworchard.org/2025/02/13/mini-windowsill-propagator/