“Do you offer a solution for monitoring the nutrient supply including automatic dosing/correction that would eliminate making manual corrections on a daily basis?”
The question is from one of our customers. To answer the question, let’s have a look at the nutrient supply in Bifarm’s precision aeroponics setup.
As some of you might have known, for commercial setup, the Bifarm Raised Bed comes with one drain and two intakes — one for nutrient and one for water. Water can be used for auto-cleaning purpose among other usages. All intakes are controlled by solenoid valves. The drain is also assisted by a powered pump. And each of our grow system is equipped with pH and EC sensors.
But noticeably it doesn’t come with auto-dosing capacity. Why? Is it difficult to build auto-dosers? Considering the system controller provides comprehensive interfaces for thermostats, CO2, grow lights and others, adding auto-dosing capacity shouldn’t be difficult, right?
The answer is more complicated than most of people think.
To do proper auto-dosing, we need to know each ingredient concentration. Solely based on EC reading alone, there is no easy way to adjust for each ingredient. The EC value is used as a proxy to monitor the concentration of the nutrient salt as whole. Since there are many types of ingredients, and each has different impact on EC (Electrical Conductivity), there is no accurate way to rely on EC to do auto-dosing. Universities and research institutes use very expensive equipment to analyze the nutrient content.
In practice, farmers use nutrient company’s feeding table to estimate. Most the dosing-system will use pre-set the formula ratio for dosing, with EC as reference of low / high of the contraction, or dose based on pre-set time schedule, or “topping off”.
This type of nutrient dispensing method could cause issues. As plants take in nutrients at different paces over time, the concentration ratio of each ingredient will be hard to predict, if not impossible. “This can lead to burn and deficiency” as one grower puts it.
This is the approach Bifarm is taking. At any time pH and EC sensors detect the nutrient content is out of safe range, the system will dump the nutrient and draw a fresh batch. Also, systems can flush the nutrient periodically (every 1 or 2 weeks), even pH & EC readings are in the safe range.
As Bifarm grow systems are using aeroponics method, the amount of nutrient water used is much less than DWC. It is much practical way and cheaper way to ensure nutrients are always balanced.
In commercial facilities, grow systems are managed by groups, by rooms for example. It would make sense to have one main nutrient reservoir to supply the grow systems running with the same schedule. In this case, the fresh nutrient in the main reservoir can be adjusted according to the stages of the plants in the schedule.
Let me know if you have any thoughts or questions.