Home Growers & Small Indoor Operations – Large Containers
Pressure Compensating (PC) Spray Stakes
For uniform water and nutrient distribution over a broader surface area and extremely effective in larger pots with loose, soilless media. Used for larger containers/pots over 25 gallons and/or with a wide diameter and grow bags. We recommend one spray stake for every 1.5 sq. ft. of container surface area. This sample system layout can irrigate:
- 50 large containers/pots with 15” to 18” diameters
- 25 large containers/pots with 20” to 36” diameters
- 15 large containers/pots with 28” to 32” diameters
Sample Layout for Large Containers with PC Spray Stakes
- 1 Spray Stake for pots with 15” to 18” diameters
- 2 Spray Stakes for pots with 20” to 36” diameters
- 3 Spray Stakes for pots with 28” to 32” diameters
Best Practices
The above shot volumes and run times are aimed at vegetative growth. When going from the vegetative stage to the generative stage, you may need to double the shot volume and double the time in between shots. This results in a slightly lower water content (WC) and higher EC in the substrate, which steers the plants in a generative direction. It is unknown how strong the effect is, but maintaining a root zone close to saturation with lower EC generally steers plants towards vegetative growth, so we want to do the best we can to steer towards reproductive growth when it is desired.
Always maintain the same volume applied per irrigation “shot” (say either 101.25 mL for veg or 202.50 mL for flower in a 6” cube) and add additional irrigation events to achieve the desired runoff % and EC content of the rockwool substrate. For the first week or two, you may only need to water once a day. However, it is perfectly normal to reach a point where your plants will need to be irrigated with these small shots upwards of 20 times per day, especially for outdoor and intense light greenhouse applications or very large plants in small cubes.
Begin with the first shot roughly 1-3 hours after sun-up (or lights-on) and stop irrigation events 1-3 hours before sun-down (or lights-off) to allow a bit of dry-back overnight and to prevent root rot (1 hour for vegetative stage, up to 3 hours for generative stage). The purpose of this ‘multi-pulse’ method is to maintain the root zone at the ideal balance of water content, oxygen and available nutrients at all times, preventing the plants from becoming stressed due to low water content, deoxygenation, or unbalanced nutrition/salt buildup in the root zone.
