Fertilizing plants in hydroponics requires fertigation—the process of delivering nutrients through irrigation. Growers can either add nutrients to their hydroponic systems manually or use an automatic dosing system to regulate how much is added to the water.
Nutrient dosing systems work with almost every type of hydroponic system and suit a range of cannabis operations, from hobby grows to large-scale grow-ops. In this blog post, we’ll cover the benefits of these automatic systems, how they work and best practices for using them.
Benefits of nutrient dosing systems
As with most types of automation, nutrient dosing systems require minimal human intervention and can operate continuously. This saves time and labor.
Even small grow rooms can benefit from nutrient dosing systems because they reduce the risk of human error. By measuring and dispensing nutrients precisely, they eliminate the risk of over- or under-feeding.
These systems also offer customization, giving growers the flexibility to create nutrient solutions tailored to the specific needs of their strain and its current growth phase. In addition to fertilizer, these systems can inject:
- pH-adjusting solutions
- Enzymes
- Chlorine
- Wetting agents[1]
- Plant growth regulators
- Insecticides and fungicides
- Beneficial microorganisms
- Liquid organic fertilizers
Benefits of nutrient dosing systems
As with most types of automation, nutrient dosing systems require minimal human intervention and can operate continuously. This saves time and labor.
Even small grow rooms can benefit from nutrient dosing systems because they reduce the risk of human error. By measuring and dispensing nutrients precisely, they eliminate the risk of over- or under-feeding.
These systems also offer customization, giving growers the flexibility to create nutrient solutions tailored to the specific needs of their strain and its current growth phase.
In addition to fertilizer, these systems can inject:
- pH-adjusting solutions
- Enzymes
- Chlorine
- Wetting agents[1]
- Plant growth regulators
- Insecticides and fungicides
- Beneficial microorganisms
- Liquid organic fertilizers
How nutrient dosing systems work
Nutrient dosing systems can be used with several hydroponic systems, including deep water culture,[2] nutrient film technique,[3] ebb and flow, aeroponics and drip irrigation. They also work with both inline and batch fertigation methods:
- Inline: Nutrient concentrate is added to water during irrigation.
- Batch: Nutrients are premixed with water and stored in reservoirs prior to irrigation.
Some systems are simple setups powered by water pressure and require no electricity. Others are more complex, using timers and sensors to adjust fertilizer dosing or pH as needed to maintain optimal conditions. While exact setups vary, most systems share the same basic components and follow a similar process:
- Irrigation water is introduced into the system.
- Dosing mechanisms, such as pumps or boosters, draw precise amounts of nutrient concentrates from reservoirs or stock bottles. Injectors then mix the concentrates into the irrigation water. A separate reservoir may be used for mixing.
- Some systems include a control panel connected to sensors that monitor the EC, pH and flow rate, adjusting dosing as needed.
- The nutrient solution is delivered immediately to the plants (inline) or stored in a reservoir for later use (batch).
Getting started with nutrient dosing
Choosing the right nutrient dosing system depends on the grow room’s size and setup. The components need to be near the water source—and if required, a power supply.
Our grow consultants recommend placing the system as close as possible to the cultivation area to prevent pH drift and biofilm buildup. Ideally, use a dedicated fertigation room where the nutrient dosing system can serve specific cultivation zones.
For larger operations, we recommend separate systems for different growth phases, since plants in the vegetative phase require different nutrients than those in flower. Switching between nutrient recipes can be time consuming and often requires flushing the irrigation system. Separate setups work best for those using our two-part series—Cali-Pro Grow A & B and Cali-Pro Bloom A & B—formulated specifically for the vegetative and flowering phases, respectively.
If separate systems aren’t feasible, use Emerald Harvest’s three-part series: Grow, Micro and Bloom. This flexible system allows growers to tailor blends for each phase by adjusting the dosage rates.
Once the system is set up, test it before full deployment to confirm that it’s operating correctly and that hoses, pumps and valves are leak-free.
Finally, maintain regular irrigation hygiene. Prevent biofilm buildup by cleaning the system proactively and flushing out harmful residues before dosing the plants. Use enzymes and other cleaning agents as needed.
Getting started with nutrient dosing
Choosing the right nutrient dosing system depends on the grow room’s size and setup. The components need to be near the water source—and if required, a power supply.
Our grow consultants recommend placing the system as close as possible to the cultivation area to prevent pH drift and biofilm buildup. Ideally, use a dedicated fertigation room where the nutrient dosing system can serve specific cultivation zones.
For larger operations, we recommend separate systems for different growth phases, since plants in the vegetative phase require different nutrients than those in flower. Switching between nutrient recipes can be time consuming and often requires flushing the irrigation system. Separate setups work best for those using our two-part series—Cali-Pro Grow A & B and Cali-Pro Bloom A & B—formulated specifically for the vegetative and flowering phases, respectively.
If separate systems aren’t feasible, use Emerald Harvest’s three-part series: Grow, Micro and Bloom. This flexible system allows growers to tailor blends for each phase by adjusting the dosage rates.
Once the system is set up, test it before full deployment to confirm that it’s operating correctly and that hoses, pumps and valves are leak-free.
Finally, maintain regular irrigation hygiene. Prevent biofilm buildup by cleaning the system proactively and flushing out harmful residues before dosing the plants. Use enzymes and other cleaning agents as needed.
Nutrient dosing system example: Dosatron
Let’s walk through how a nutrient dosing system works with a liquid hydroponic fertilizer lineup like Emerald Harvest. In this example, we’ll show how it can be used with Dosatron fertilizer injectors, which work in a variety of installations and configurations.
To determine which Dosatron products to use, you need to know how many cultivation areas the system will feed and how many zones there will be per area. Different plant genetics and growing media should ideally be in separate zones, since they’ll likely have different nutrient and irrigation needs.
Once you’ve determined your cultivation areas and zones, add up how many plants you need to feed. This total is used to calculate the flow rate:
Flow rate in gallons per hour (GPH) = Number of plants per zone ´ Drip emitter’s GPH rate.
For example, if you need to irrigate 100 plants and your drip emitters have a 2 GPH rate, you’re using 200 gallons per hour per zone. To convert this to gallons per minute (GPM), divide by 60. In this case, the flow rate is 3.33 GPM. If you use two emitters per plant, multiply the GPM by two, resulting in a 6.66 GPM flow rate per zone.
Now that you’ve calculated your system’s flow rate, you can identify which Dosatron injectors fit your setup based on each model’s minimum and maximum GPM capacity.
Let’s say you are using the Dosatron Lo-Flo system to deliver our two-part Cali-Pro Grow series during the veg phase. The system uses D14MZ3000VFBPHY injectors, which dose nutrients at 1.25‒11 mL per gallon, operating within a flow rate of 0.05‒14 GPM. Mixing chambers (HYKMC34) ensure proper blending, while filters help prevent clogging and maintain system cleanliness. Along with Emerald Harvest base nutrients, supplements like Emerald Goddess, Honey Chome and Root Wizard are also injected, followed by a pH buffer to stabilize the solution if needed. This setup ensures consistent nutrient delivery, healthier vegetative growth and reduced manual labor (Figure 1).
Figure 1. Emerald Harvest’s two-part Cali-Pro series and supplements set up in a Dosatron nutrient dosing system. Image source: Dosatron, dosatron.com.
Conclusion
Nutrient dosing systems are an effective way to ensure plants receive the right amount of nutrients at the right time. They save time and labor and reduce the risk of human error. More advanced systems can even adjust pH and EC, maintaining optimal conditions in the hydroponic system so plants have their best chance to produce high yields with excellent quality.
Emerald Harvest Team
