• Wick System: trays are used to hold plants in this passive grow system to deliver the nutrient solution from the reservoir with a wick.
• Drip System: grow trays are used to hold plants. The submersed pump is used to drip a nutrient solution onto the base of each plant by a small drip line.
• Ebb and Flow: the ebb and flow system temporarily floods the grow tray with the nutrient solution and then the solution drains back into the reservoir.
• Nutrient Film Technique (NFT): nutrient solution is pumped into the growing tray that’s usually a tube and flows over the roots of the plants. This system also has the solution draining back into the reservoir.
• Deep Water Culture: doesn’t use grow trays, but rather a platform that holds the plants. The platform is usually made of Styrofoam and floats, with the roots submerged in the nutrient enriched solution.

Irrigation Systems

In these irrigation systems plants grow in individual rockwool blocks in shallow flood trays. The rockwool cube and roots of the plant get wet with nutrient solution when the tray is flooded. The solution drains back out to allow air into the cube and to then dry out. Irrigation usually only takes a few minutes because the rockwool acts like a sponge absorbing the nutrient rich solutions quickly.

Hydroponic flood methods such as NFT and Ebb and Flow, require flood tables for the solution to be cycled through on a regular, daily basis. Flood tables can be used for herbs, flowering ornamental crops, chili plants, and even cherry tomatoes.

Crops rooted in rockwool can be transplanted into potting soil, larger rockwool blocks or NFT and aeroponic systems which makes this application a popular process for large-scale commercial grow systems.

There are wide variety grow trays to choose form depending on what size you will need.Feature Image: Hydroponic grow trays for microgreens. Image via HydroponicGardeningCenter.com.