Wicking is THE most efficient way of watering plants, because the plant actually sucks up exactly what it needs. That means using less water, and also the convenience of being able to fill a reservoir and walk away for weeks at a time.
Wicks can be made from many sorts of rope. This summer, community gardens across Kāpiti will be experimenting with different wicking systems. See them in action at Paekākāriki School Garden, Matai Community Garden in Raumati, Ōtaki College, and at Kāpiti Community Centre in Paraparaumu.
This simple bottle wick, ideal for pot plants, is adapted with permission from David Bainbridge’s Gardening With Less Water. He also describes how wicks can be used in outdoor garden situations, with larger containers such as 10-litre pails.
You will need:
|The tubing needs to be slightly larger than the rope. For instance I used 10mm clear vinyl tubing (old hoses also work well) and 8mm cheap polypropelene rope. The tubing covers the rope for areas between the reservoir and the plnat roots where you don't want water to drip or leak.|
1. Wash the rope to remove any oils. If doing this in the washing machine, use a laundry bag to stop it getting tangled (or use a bucket of hot soapy water)
2. Cut a piece of tubing to reach 2cm into the soil, then into the reservoir bottle.
3. The rope needs to be long enough to reach the bottom of the reservoir, then around the roots of the plant being watered.
4. Melt the ends of the rope if needed to keep it from fraying (being careful not to brun your fingers- melted rope is HOT), then thread it through the tubing. Use a piece of coat hanger wire if needed.
5. Near the top of the bottle, cut small cross-hatches with a sharp knife and push the tubing through. Make sure the wick reaches the bottom of the bottle.
6. If using the wick to water a pot, gently push the other end of the wick down around the roots, using your finger or a long screwdriver. For a new pot, coil the wick around the pot about half way down at time of planting.
7. Fill the bottle and walk away. Refill as needed (should last for weeks)
You’ll get a faster flow if the bottle is higher than the pot (eg. resting on the soil surface, or on a higher shelf) but these systems can even make water flow upward, eg. if the bottle is on the ground next to the pot, through capillary action and the suction of the plant roots.
I’ve been using this system with indoor plants for almost a year now and have only needed to refill the bottle once, but I imagine tomatoes in full sun would use more water- a larger bottle or reservoir bucket might be needed before going on holiday.
And while these systems are easiest to install at time of planting, to get the wicking rope right down at root level, they can also be put in afterwards if need be. Use a long screwdriver or notched stick to gently poke the rope down among the roots.