I’m in the process of setting up a fully automated greenhouse with its own growlights, heating, ventilation, dehumidifier and water supply and am theorizing automated nutrient solution making.

My plants grow in 10L mayonaise buckets (waste product from snackbars) filled with clay pebbles.

The idea is to mix Nutrient A, Nutrient B and plain water with peristaltic pumps as they can be both accurate and the pump mechanics do not come into contact with the solution. For instance it would pump 10000mL water, 25ml A and 25mL B into a vat and mix it using a motorized mixer.

The freshly made solution can then be fed to the plants. Some issues come to mind, the nutrient solution is heaven for algae and bacteria. Would a UV led strip suffice for this? Currently I pump an excess to the plant buckets and anything that overflows goes back into the storage tank. The nutrient solution in the storage tank loses nutritional value as well as grows bacteria and algae.

Does the nutrient solution even need to be stored? Right now I prepare nutrient solution in a 10L bucket and use that for a month. Nutrient could be made directly as well, just the perfect amount so the plant bucket does not overflow. I would need to measure moisture levels in the plant pot to calculate the amount of nutrient to be made. No storage means less waste but more complicated.

The idea here is to use peristaltic pumps for really small volumes so that instead of 10L for a whole month, it makes only 200mL total volume with for instance 0.5mL nutrient A/B. Small volumes are no problem for peristaltic pumps or syringes. Mixing is the bigger challenge.

Have any of you ever made or theorized about this? I’m looking for some inspiration.