Permaculture
How to make a DIY wicking container
DIY wicking containers provide consistent moisture, so they keep your precious plants alive for long periods without you watering every day. They’re great for when you go on holidays, or for those of us who are just plain forgetful about watering our plants! So how does wicking work? At its most simple, water is drawn up from a reservoir through the soil to the roots of your plants. You can build wicking systems from many containers—foam boxes, closed pots, wine barrels, or large food-grade Intermediate Bulk Containers (IBCs)—but they all rely on this same principle. In this project we demonstrate a simple example using a cut plastic bottle.
Materials Needed:
- Plastic bottle (1.25-litre works well), hard is better than super soft plastic
- Special potting mix: compost, perlite (or other free‑draining material), and a little manure
- Garden gloves
- Scissors and box cutter
- Cotton rope, string, or natural fibre fabric strip, about 5 cm long
- Plants
- Gesso, and non-toxic acrylic paint (if you want to decorate it)
Important safety issue: To cut the bottle, make the first incision with a box cutter, but be careful! This can easily slip and cut your hand. Use gloves for this stage and keep your fingers and body well out of the path of the blade. Once you’ve made that first incision, you can safely complete the rest of the cut using scissors.
Step-by-Step Instructions:
- Clean and Cut: Wash the plastic bottle and remove labels. With gloves on and taking care with the blade cut the bottle about three quarters of the way down. Then cut the capped section in half.
- Prepare the Cap: Poke a hole in the bottle cap, large enough for the wick to pass through. Again take care with the blade.
- Insert the Wick: Thread the cotton wick (about 6 centimetres long) through the cap, leaving a few centimetres on both sides. Tie a knot at the top end to keep the wick in place.
- Assemble and Fill: Screw the cap back on. Place the top half of the bottle upside down (cap down) into the base.
- Planting: Place the plant into the top section, ensuring the wick is surrounded by soil, then fill any gaps with the special potting mix.
- Add Water: Half-fill the bottom reservoir with water, ensuring the bottom of the wick is submerged. Now gently water in your plant from the top – don’t overdo it, just a gentle sprinkle. (This ensures the soil settles well around the plant.)
- Decorate: If you would like your wicking container to match your decor, you can paint the plastic with Gesso. Gesso is a non-toxic primer that helps paint adhere to the surface. Once the gesso is dry after a few hours you can paint your container how you like.
General information on wicking containers
Plants that grow well in wicking beds: Plants that thrive in consistently moist, well-aerated soil. Thirsty plants: leafy greens, tomatoes, zucchini, eggplant, capsicum, basil, mint, parsley.
Plants that don’t grow well in wicking containers: Those that prefer dry conditions or require wet/dry cycles, like, Mediterranean herbs, succulents, cacti, plus seeds can rot in highly moist conditions so plant mainly seedlings.
Note on optimal soil levels:
For water to wick properly in a large wicking container, your soil should optimally be around 30 centimetres, no more. Any more and the wicking effect is lost.
Anatomy of a self-watering (wicking) container: An example of a wicking bed made using a simple pond liner to capture the water. Water beds using the pipe that feeds into the water reservoir. A weed mat separates the soil from the pebbles. Care needs to be taken not to use sharp pebbles, which will pierce the pond liner. An overflow pipe allows any excess water to flow out of the system.
To add nutrients:
You can feed your wicking barrel, bed or pot by adding a worm tower. This can be as simple as a brown cardboard tube, ag pipe or an old clay water pipe. Whatever food-safe material you can find is fine (note that cardboard will need to be replaced eventually, and there is some debate about whether cardboard is safe, please do your research on this). Bury a short section of pipe about 10 centimetres deep, leaving a few centimetres of the pipe above the surface. Add your worms and well-cut veggie scraps. Take care to always cover the scraps with extra soil to prevent smells and reduce the chances of attracting flies. Then place an upturned pot or lid on top so vermin cannot climb in and eat your veggie scraps!
Other wicking projects to try:
- How to make a wicking box: https://www.milkwood.net/2011/05/09/how-to-make-a-wicking-box-mini-wicking-bed/
- How to make a wicking barrel: https://tinyurl.com/wicking-barrel
- How to make a wicking bed: https://www.milkwood.net/2010/05/11/how_to_make_a_wicking_bed/
