You’ve been growing cannabis on a small scale for years, and now you’re ready to step up to a larger grow. But are you really going to commit hours of labor into hand-mixing fertilizer blends and distributing them to a warehouse full of plants?
You don’t have to. Like many aspects of a large grow, fertilizing can be automated, thanks to devices that do all the measuring and scheduling for you. These nutrient injection systems, often known as “dosers,” can take the guesswork out of feeding your plants.
What’s so important about dosing? The answer might not be immediately obvious to cultivators who’ve mastered the art of growing in tight spaces.
“Many people in the cannabis world started growing in their attic or basement or garage, and they grew in small quantities,” which meant they could hand-mix their nutrients and water each plant manually, said Morris Brink, business development manager for Surrey, British Columbia-based Argus Control Systems Ltd.
“But as growers scale up … it’s very important to be consistent in everything you do and eliminate human error,” he said.
To complicate matters, fertilizing can be tricky. Many cannabis growers like to use a spectrum of recipes, each tailored to a different stage of the growing process. For example, a grower may have two fertilizer recipes for the vegetative stage and five for flowering stage. Recipes may change as often as every five to 10 days, Brink said.
Dosers eliminate the need to manage that complex system manually. They can mix the recipes for you and distribute them to plants on schedule. The rack-mounted system sold by Argus, for example, draws from eight separate stock tanks, plus acid and base injectors, “to create as many recipes as the grower needs” for the plant, Brink said. “It’s automated. It’s consistent.”
As the plant matures, the injection system will automatically swap out recipes. The system collects data during the process, and it can alert the grower if there’s a problem, he added.
What kind of nutrients can you put in the doser? It depends. Some growers use a generic hydroponic mix, with some additives blended in during different stages of the growing cycle. Others prefer to mix their fertilizers using raw salts, like potassium and nitrogen. If you’re looking to save money, the latter approach could be your best option. Fertilizing with raw salts can save you up to 90 percent of your fertilizer costs compared to using pre-mixed hydroponic solutions, Brink said.
Dosers are often used with hydroponic systems, but they can also be adapted to soil-based grows, too. It just depends on your technique. Some cultivators grow in soils rich with microbes and other biological elements, which they irrigate with plain water. For these growers, a doser may not be the best investment, Brink said.
However, if you’re adding liquid fertilizers to amend the soil throughout the plant’s life, then a doser might be a good option, he added.
In addition to saving time and hassle, dosers may save you money. If you eliminate the need to hand-mix or hand-irrigate, you reduce labor costs. Dosers can also help you cut down on over-watering, too.
“With this system, you can dose the plant in small quantities repeatedly throughout the day with very little drainage,” Brink said. He added that reducing drainage also cuts down on water and fertilizer use.
Scale is the most important factor to consider when determining if a doser is right for your grow. A nutrient injection system usually isn’t a good fit for grows contained to a couple hundred square feet. However, it does make sense for a larger operation, Brink said.
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