Building Wick Systems

A complete system: Tray, blocks, container, wick, planting mix.

The wick container system is an easy way to garden because it is self-watering. It also removes the uncertainty of when to water, requires far less care than hand watering, and it is simple, fast to assemble and inexpensive to set up.

The wick system is based on capillary action. One example of this is a tissue drawing up water from a puddle. The system we are about to set up works on the same principal. Instead of tissue we use braided nylon rope.

Equipment

Starting from the bottom we need a tray that is at least three inches deep and wide enough to support the plant container. The wider the container the deeper the tray should be. For instance, with a six-foot container I use a 10-inch deep tray, but with small containers the trays is only three to five inches deep.

Next we need some blocks to hold the container a few inches above the tray. Some possibilities are 2×4 or 4×4 boards, Styrofoam blocks or an inverted plastic tray.

The container is next. Select the same size container that you would normally use. I have used this system with four-inch containers and eight-foot wide soft containers.

Next is the wick. Nylon braided rope draws up water very well and these wicks last for a long time. I have used some more than 10 years. Select the wick size. The larger the container the thicker the wick should be. A small container needs only a 1/4-inch wick, while a large container, which is deeper than the small can, uses wicks up to 3/4-inch. Wider containers should have more wicks so water is drawn across the entire bottom of the container by the wicks.

Next, the planting mix goes into the container. Almost all mixes work, so you can use your favorite. Once the water is drawn up the wick to the bottom of the soil level, the soil starts wicking it up. You probably have already seen this happen when you watered a plant and excess water dripped into the tray below. A while later, the water disappeared as it was pulled up into the planting mix. The wick system works in the same way.

Installation

• Place the wood or plastic supports in the tray.
• Measure and cut the wick. It should start at the bottom of the tray, go through the drain hole in the container and stretch across the container bottom to the drainage hole on the other side and down to the bottom of the tray. The rope tends to fray at the ends. To prevent this, before you cut, use two twist-ties, one for each end of the rope, to hold it in place.
• If the container is wide, use two wicks, one in each set of two opposite holes. You may have to drill holes in wider containers, such as kiddie pools or wide trays. Figure that each wick drop covers about two square feet.
• Fill the container with planting mix.
• Plant the plant or seeds.

This system was automated using a reservoir and flush valve.

Maintenance

• To start, add water to the container until it starts to drip into the tray.
• Fill the tray with water.
• Refill the tray as it loses water. You can also water the container from the top once in a while.
• The planting mix absorbs water from the wick automatically as the plant uses it.

Holes were drilled in the tray for the wicks. Pallets were used to support tray above the water.

Options

This system can be automated. By placing a reservoir above the container level and placing a flush valve in the tray, the water level can be maintained for a longer time.

A number of trays can be connected to a reservoir so the whole garden is irrigated just by filling the reservoir. The advantage to this system is that each tray receives water only as it needs it.