How do I set up an auto-dosing system for my plants?

Q:

I recently started a job that requires some travel, so I need to autodose my indoor garden. It seems quite involved. Do you have any advice for setup and dosing? It looks like it will be pretty efficient once it’s set up and running.

A:

At first glance, autodosing does seem complicated, but it can be simplified. You probably know how it works: you set up tanks of your pH adjustor and fertilizer concentrates (you should store your calcium nitrate solution separate from the other fertilizer or it will precipitate) and hook the tanks up to peristaltic pumps.

The autodoser acts like a thermostat; define the levels you want for pH and EC, and it will pump in solutions to keep it at those levels. Growers can “set it and forget it”, saving several hours per week of maintenance and freeing themselves up to focus on growing healthy crops.

Here are a few other questions that are often forgotten.

How much maintenance is actually needed? Growers will want to calibrate the probes about once a week and occasionally check the water manually, just in case. You’ll want to check the concentrate levels once a week so that empty tanks don’t sneak up on you.

How much does it cost? Monitoring-only units will typically cost between $250 and $400. For instance, an all-in-one handheld meter may run at $280. When you add dosing and remote login capabilities, the price runs closer to $2,000. The benefit of a monitoring unit is that you could simplify the dosing task for someone taking care of your farm. If you want to leave it without extra help, however, you’ll need the complete version.

Don’t forget that although the autodoser will manage pH and EC, and sometimes temperature, you might need a water top-off as well. If your sump doesn’t hold enough water, you’ll either want to upgrade it or install a tank to “top off” the water when it gets low.

The latter can function in one of two ways. The first is to use a sealed tank and an open valve just under the ideal water level. As the water level decreases, the open valve will let water into the tank. The second is to have a secondary tank (you can use this for return water if you’re running a recirculating system) with a float valve that turns a pump on or off.

If you’re using aquaponics, a solids-lifting overflow in the fish tank(s) can also safeguard against low water levels.

Note on traveling: It’s wise to still have a trusted friend check in on your system if possible. Autodosing takes care of pH and EC, but problems like leaks, pest outbreaks, or power outages could still prove catastrophic if left unattended for a few days.

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Written by Amy Storey
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Amy Storey is the content coordinator at Bright Agrotech, a company that manufactures vertical high-density farming equipment. Amy and the Bright Agrotech team provide modern growers with ZipGrow technology and tools like Able (able.ag) to build a fresher, more distributed food system.  Full Bio