Wick Systems are passive, meaning that they have no moving parts. This makes them easier and cheaper to maintain than active systems such as Ebb and Flow, but they also have the drawback of being less efficient and not well equipped for high-maintenance plants, or large plants that consume a lot of water. The best plants to use in this system are fast-growing lettuces or herbs. Herbs such as rosemary that don’t require a lot of water are the best choices, while thirsty plants such as tomatoes would not do well. A Wick System works in a similar way to the Lettuce Raft Method because the roots are always in contact with water. The difference is that a Wick System uses two or more wicks to deliver water from the reservoir to the roots via capillary action, while in a lettuce raft, the roots are submerged in the reservoir itself. There are four main components in a Wick System: the grow tray, reservoir, wick, and aeration system.
The Grow Tray
The grow tray in a Wick System differs from other hydro setups in that it does not use net pots to hold the growing medium. The growing medium fills up the entire tray, with seedlings transplanted directly into it. The best kind of growing medium to use in this system is one that will not drain too fast and will utilize the capillary action of the wick most effectively. Vermiculite, perlite, and soilless mixes are all good choices—they have good wicking abilities but will not become soggy like traditional soil.
The Reservoir
The reservoir is much the same as in any other system. It is a large container of fertilized water that sits below the grow tray and supplies water and nutrients to the plants. The water in the reservoir must be refreshed every week or so because the strength of the nutrients diminishes as the plants absorb them.
The Aeration System
The most common aeration system is an air stone and pump. The air stone, much like those found in home aquariums, is placed in the water and connected to an air pump outside the reservoir. The pump pushes air through the stone, which blows out tiny bubbles to distribute oxygen through the water. It is essential to the health of the plants that their roots are oxygenated. In traditional gardening and active hydro systems, this is accomplished partially by letting the roots dry out in between waterings. Active systems also use air stones to oxygenate the water, but in a Wick setup, the aeration system is especially important because the roots never have a chance to dry out completely.
The Wicks
The reservoir is connected to the grow tray by two or more wicks. The wicks utilize capillary action to transport nutrient solution into the growing medium and to the roots of the plants. The easiest wick to use is a cotton rope, but after a while, it can be susceptible to mold or rot. If you plan on using the system for extended periods of time, make sure to check the rope periodically. Alternatively, nylon rope is very effective and does not mold or rot. The wicks are inserted into the grow tray through small holes. You may want to either add a rubber connector or make sure that the holes are slightly smaller than the wicks to prevent any growing media from falling through the holes. The number of wicks used depends on a number of factors—the total system size, plants used, growing medium, and wick material will all have an effect. A good rule of thumb is to use one wick per plant and make sure that the tip of the wicks is placed near the roots. For water-hungry plants and large systems, two wicks per plant may be necessary. If you were setting up a Wick System in the classroom, a fun experiment would be to test different types of rope to see which has the best wicking ability. Just stick the ends into a cup or bowl of colored liquid and measure how fast and how much liquid each sucks up. Washing the rope can have a significant impact on its wicking ability, so make sure to test all of your wicks both washed and unwashed and compare the difference. Depending on your results, you can decide how many and which type of wick your system will need to be effective.
Nylon ropeWool rope or stripBraided polyurethane yarnPropylene stripsMop head stringsStrips from old clothes or blankets
The shorter the wick length, the faster and easier the water will travel from the reservoir to the plants. Thus, it is best to keep the plant right above the reservoir in a wick system. The main disadvantage of Wick Systems is that they can be less efficient than other types of hydroponic systems when it comes to nutrient delivery. The wicks can sometimes become clogged or saturated with water, leading to poor plant growth.
Step 1: Cut wicking cord (six to eight sections, each 15 to 20 inches long).Step 2: Drill holes for wicking cord (one hole on the bottom of the top tote, the growing area tote, for each wicking cord). Each hole size should be equal to the diameter of each cord. Space the holes out to provide moisture across the growing area.Step 3: Drill drain holes (several around the bottom of the growing area tote), to allow excess moisture to drain back down into the reservoir.Step 4: Run wicking cords through each of the drilled wicking holes (see Step 2). Make sure that the cords hang down far enough to touch the bottom of the bottom tote, the reservoir tote.Step 5: Cut out the inner section of the lids that come with the totes, to keep the top tote from sliding down into the bottom tote.Step 6: Drape the wicks over the lip of the top bucket, then put on the cutout lid to secure the wicks while you fill the bucket with media. This keeps the wicks from falling down and getting covered up.Step 7: Add expanded clay pebbles or small river rocks (rinse them first to remove dust) to the bottom of the growing area tote. This will act as a filter to keep perlite and vermiculite (see Step 8) from draining into the reservoir.Step 8: Make a 60/40 mix of perlite (60%) and vermiculite (40%). Rinse thoroughly to remove dust before using.Step 9: Add the perlite/vermiculite mix to the top tote. Keep the wicks in position so that the media doesn’t push them to the sidewalls.Step 10 (optional): If you’re using an aerator, drill one hole on each side of the bottom tote, about 2 inches below the handhold. If you’re cutting air lines, keep them the same length so that each line gets the same amount of pressure.Step 11: Add 2 to 3 gallons of water to the nutrient reservoir (bottom tote). Mix nutrients according to the needs of the plant you’re growing. Adjust the pH as needed. If you’re using an aerator, test it to make sure it works correctly. Install the lid on top of the bottom tote, slide the top tote onto the bottom tote, and make sure all the wicks drop down into the bottom tote.
