Learn how The Perennial Farm implemented a drone spraying program

Alex DeJong, IPM manager at The Perennial Farm, says 2025 was a year of new ideas at the Maryland nursery. There were two big projects happening in his world. First, The Perennial Farm teamed up with Koppert to overhaul the nursery’s biological program and beneficial insects. Second, he began using a DJI Agras drone sprayer at the nursery and worked it into their existing IPM strategy.

“It’s taken about a year so far to be able to really kind of play with it, figure out the spray patterns, to kind of figure out and dial in how many gallons per acre am I trying to spray,” DeJong says.

Trial and error

One of the biggest challenges of setting up a drone spray program was the change from using a 200-gallon tank under the previous system to a 2-gallon tank.

The goal was to achieve the same amount of reach with the drastically smaller spray tank that is light enough for the drone to carry on its flight.

DeJong says The Perennial Farm uses the same chemicals with the drone program that it did before, just at a higher concentration. The grower has been working with the University of Maryland Extension to determine the amount of gallons per acre that are truly necessary for the product to work effectively. Currently, DeJong is using 10 gallons per acre. Other variables he’s been tweaking are the speed and height at which he chooses to fly the drone.

Per label, everything he sprays is at a maximum height of 10 feet. DeJong has found that the sweet spot is about 8 feet above the crop.

The Perennial Farm’s DJI Agras drone has an autonomous feature that allows DeJong to customize gallons per acre, feet covered per second, height above crop and much more, all through the remote control.

“If I wanted to go spray a C25 over here, I could easily just map it out using the remote controller, hit the go button and it will spray it,” DeJong says.

When a grower maps out a field or container plot using the provided software, the drone will fly the programmed route and spray the product at the programmed rate. The drone’s system even adjusts automatically for edges or borders. One of the settings with this specific model will send the drone back toward the corners after it finishes its full spray rotation, ensuring full coverage across the mapped area.

“It’ll take it in a little bit to kind of compensate for drift and overspraying,” he says.

When he measures the new system against the old way, sending those large tanks or workers with backpack sprayers down the rows, he believes the new procedures handle the job just as well.

“We’re still very much testing and learning its capabilities, but as far as efficiency and coverage, it’s pretty much on par,” he says. “If anything, I would even suspect that with some more research and some more testing, it’s even better because we’re coming from the top down as opposed to our tanks, where we’re coming from the side.”

While he’s been experimenting with the technology throughout 2025, he’s excited for the 2026 season.

Safety first

Applicator safety is a big advantage to drone spraying. The only time DeJong has to wear PPE is when he’s mixing chemicals. He says drift possibility is minimal, as well.

“As far as safety goes, it’s incredible,” DeJong says. “And as far as efficiency goes, it’s a great tool for us.”

When he’s ready to spray, he loads the tanks and zips the drone over the storage building and off to whichever row he’s scheduled to spray that day. The drone can cover a full bed in less than 10 minutes.

That’s a good thing, though, because the battery life is also about 10 minutes. However, it only takes about 10 minutes to charge. Alex has three batteries to cycle through that power the drone and two tanks to swap out, as well. He’s learned to plan his workflow to swap them out together and keep charging and refilling as he moves through areas of the nursery.

He’s also been helping the University of Maryland Extension research spray patterns. With the spray being pushed down by the propellers in some areas, the researchers are looking at how that impacts chemical contact rates.

Some plants are tougher than others to cover with the drone sprayer. Asclepias presented a challenge to dig into the canopy, with the downward force of the propellers creating a sort of vortex.

Finding the right drone

DeJong says the nursery tested multiple drones, but picked this specific one because it was the smallest. Larger drones had more powerful propellers, but those posed a problem in a nursery container operation: flying low enough to maximize coverage without blowing over the pots. The small Agras hits the sweet spot as the perfect size for The Perennial Farm’s current scale.

Larger drones also typically have more options, like rotating discs and adjustable micron size. This particular drone is used for spraying only. The nursery has a camera drone, and DeJong has been keeping tabs on research on drones for inventory counts or to measure disease pressure or drought.

He took the initiative to learn how to operate the drone on his own time. He found a mentor after seeing a presentation that showed the potential of using drones in a nursery setting.

He also handles maintenance.

“Every time we boot up to fly, I do a little pre-flight checklist to make sure everything’s good,” DeJong says.

He has repair parts on hand for his specific DJI model. He did not buy direct from DJI, but through a dealership on the West Coast.

“If there’s any sort of issues, you can call them right up, and they’ll be able to walk you through it,” he says.

But he hasn’t had to rely on them for any support in year one of drone ownership.

The Perennial Farm has applied bioproducts through the drone, including different amino Bacillus products and biofungicides. He hasn’t tried beneficial insects yet, although a spreader attachment exists, so the potential is there. He currently uses a handheld Natutec Mini-Airbug to apply beneficial enemies. The device’s advantages are uniform application of the natural enemies of The Perennial Farm’s problem pests, including flea beetles, which “have been a big pain for us,” he says.