- Test capillary wetting at high and low reservoir levels.
- Manage medium moisture and salt accumulation.
- Identify when passive delivery is inadequate.
01 / The wick is the delivery system
A wick bridges a lower reservoir and a container of moisture-retaining medium. Capillary movement supplies water to the root zone while the plant removes it. The crop is rooted in medium rather than hanging directly into an aerated bath.
This simple layout suits small plants with modest water demand when the wick can keep pace. A large leaf canopy, a tall lift or a poorly wetting wick can exceed passive delivery. The correct comparison is measured wetting and crop demand, not whether the wick feels damp at one end.
Reading: Hydroponic Gardening ↗
02 / Build a measurable prototype
Use a stable upper pot with drainage, an opaque lower reservoir, clean compatible wick material and a moisture-retaining medium. Keep a service gap between the reservoir lid and the pot so overflow cannot saturate the crown. Support the upper pot independently of the wick.
Prepare the wick and medium according to their suppliers. Avoid reused fabric of unknown treatment or containers that held hazardous substances. Place wick ends throughout the intended root region instead of bunching every strand under one point.
- Pre-wet the wick and medium uniformly. Fill the lower reservoir with plain water for the first test.
- Mark water level and the vertical lift from the surface to the medium. Verify the wick remains immersed at the lowest planned level.
- Observe several points in the medium after a consistent interval. Compare the top, center and far edge for dry pockets.
- Repeat at a lower reservoir level and under the intended light and airflow. Capillary supply must remain useful as conditions change.
- Only then add a complete crop nutrient solution and transplant a small healthy seedling.
03 / Nutrients and accumulation
The wick moves solution upward; it does not guarantee that all salts leave the upper medium. Evaporation can concentrate salts near the surface. Measure and manage the root zone as well as the reservoir, using the medium’s recommended extraction or runoff method.
Keep a record of reservoir refill, measured EC and crop response. Use a complete hydroponic feed compatible with the crop and source water. Nutrient strength is not a substitute for insufficient water delivery: a dry plant needs the delivery problem corrected first.
Reading: Soilless Growing Mediums (HLA-6728) ↗ · Electrical Conductivity and pH Guide for Hydroponics ↗
04 / Recognize the method’s limit
Check the wick for algae, deposits, loss of contact or roots that make it hard to replace. Maintain the planned solution level without flooding the upper container. If larger plants repeatedly wilt while the lower reservoir remains full, compare wick capacity, lift and root distribution.
At harvest, inspect whether the roots occupied the whole pot or clustered at wick contact points. Clean both containers, replace degraded wicks and record the dry areas. Choose DWC or active irrigation if the required crop demand cannot be met reliably.
FIELD QUESTIONWhy does a full lower reservoir not prove the plant is watered?
The wick is a transport bottleneck. It may have poor contact, excessive lift, deposits or inadequate cross-section; the upper root zone can remain dry above a full tank.
Parts & buying criteria
Build your own parts & cost worksheet →
Showing wick-fed culture. Quantities describe the teaching model. Specify real working volume, support, fittings and instruments for your installation.
01Nutrient reservoir1 · illustrated quantity+
Stores the measured nutrient solution beneath or beside the growing area.
Inspect: Compare the surface with the wick ends and the lowest intended operating level; freeboard is deliberate.
Maintain: Record level before refilling, keep light out and verify temperature, EC and pH.
Opaque, cleanable, intended-use container with volume marks and service access.
Check size, materials and operating conditions with your chosen supplier before ordering.02Upper planter1 · illustrated quantity+
Holds a moisture-retaining root medium above the lower reservoir.
Inspect: Inspect the drainage holes, the wick passages and how the planter sits above the reservoir without resting on the wicks.
Maintain: Compare the top, centre and far edge of the medium for dry pockets and surface salt; a full reservoir does not prove even wetting.
Stable upper pot with drainage and wick openings, supported independently of the wicks and reservoir lid.
Check size, materials and operating conditions with your chosen supplier before ordering.03Root-zone mediumFor illustrated containers · illustrated quantity+
Stores moisture and air around the roots in the illustrated containers.
Inspect: Compare the medium surface with irrigation and drainage.
Maintain: Inspect wetting at several depths; prevent fines from reaching drains and emitters.
Prepared, stable grade matched to the irrigation method and crop.
Check size, materials and operating conditions with your chosen supplier before ordering.04Capillary wicks2 illustrated · illustrated quantity+
Bridge the nutrient bath and upper medium by capillary delivery.
Inspect: Compare wick immersion at high and low reservoir levels.
Maintain: Check wetting and deposits; a full reservoir does not prove adequate delivery.
Clean compatible material tested at the intended lift and crop demand.
Check size, materials and operating conditions with your chosen supplier before ordering.Evidence beside the lesson.
Source checks: September 2026. The geometry, inspection exercises and worksheets are original teaching material. The named organizations have not endorsed or reviewed this site.
Published recipe rates and planning ranges retain their source context. Calculator equations are accounting tools; they do not predict uptake, yield, toxicity or safe stocking. Model dimensions, water speeds, roots and fish counts are illustrative. Verify species, crop, source water and product labels for a real system.
- NC State Extension · Pender County Center (Extension Master Gardener volunteer post)Hydroponic Gardening ↗
Brief comparison of wick, ebb-and-flow, drip, deep water culture and NFT systems; notes the wick method suits small plants.
- Oklahoma State University ExtensionSoilless Growing Mediums (HLA-6728) ↗
Physical properties and limitations of common growing media.
- Oklahoma State University ExtensionElectrical Conductivity and pH Guide for Hydroponics ↗
Water analysis, salinity, pH and monitoring.
The next useful connections.
Reservoir management and solution replacement
Use a water-and-nutrient ledger to distinguish top-ups, rebalancing and a complete batch change.
Interactive tool · 6 min + guided practice →Media & propagationChoose media by water, air and service
Compare coir, mineral wool, expanded clay, perlite and propagation plugs in the system that will irrigate them.
6 min + guided practice →