If you need to produce large quantities of cannabis, it’s essential that you automate your irrigation system. Not only will this save you time and reduce your labor costs, but it will allow you to scale up more easily as your cannabis cultivation operation grows. This is especially true for commercial facilities with extensive crops. The good news is that automating cannabis irrigation is easier than you may realize.
Start With Irrigation Basics
If you’re already a seasoned cannabis grower with a decent drip irrigation system (complete with spaghetti tube and drip stakes), you might just need to set it on autopilot. All you really need to get started is a pressure regulator (included with most standard drip systems), a water filter, and a timer
Invest in a battery timer that works with your system, and place it between your spigot and main hose. This type of timer can usually be purchased for under $50.
If you’re seeking more control, spend a few more dollars and invest in a commercial controller that allows you to precisely control your watering durations, intervals, and even individual crops (a capability that’s especially important if you’re growing different strains with different watering needs).
Use a Fertigation System for Large-Scale Grows
Fertigation has become the standard for large-scale cannabis grows. A combination of the words “fertilization” and “irrigation,” a fertigation system combines the necessary water and cannabis nutrients in a single system.
The system uses the same type of tubing and drip emitters common in conventional drip irrigation systems, but the water is treated to promote the optimal nutrient absorption. In this sense, it works similarly to a hydroponics system whereby the nutrients are delivered via the flow of water. However, a fertigation system still relies on soil and uses different substrates than hydroponics (including coconut coir mixes).
Fertigation systems may be manual or automated, but it’s always worth investing in the latter, especially if you run a large commercial operation. With an automated fertigation system, you can even set up a pH doser to add base or acid when the pH balance is off.
Perhaps the best part of having a fertigation system is that you can customize both the necessary water and nutrients to different crops. There are more than 700 strains of cannabis, each with its own nutrient needs, and it can be tedious to manually cater to a dozen different varieties.
Use the Proper Irrigation System
When choosing a fertigation system, it’s best to opt for a top-feed system. This method delivers the water and nutrients from above, much like hand-watering. Not only does this allow you to see how much water is being applied, but it allows you to achieve the necessary runoff. A small amount of runoff is necessary to flush out excess salts.
The presence of runoff also indicates that you’re completely saturating your soil, another essential component of fertigation. Each time your crops are watered, you want to ensure total saturation to prevent salt build-up.
Implement Anti-Tampering Safeguards
The downside of automating your irrigation system is that the entire operation rests on a single set of components—and often on a single spigot. If the system is shut off by an unassuming passerby, none of the cannabis plants receive their water or nutrients.
The best way to circumvent this issue is to inspect your system daily to ensure that it’s up and running. Also, if the system is connected to a water spigot, remove the handle to eliminate the possibility of someone accidentally turning off the water.
Apply a Wetting Agent
Automated irrigation water should be treated with a wetting agent to ensure better penetration and saturation.
A good wetting agent will help to ensure that all areas of the plant—including those not directly in the path of the drip line—will receive the necessary water and nutrients, thereby reducing your total irrigation requirements by as much as 30% and promoting a healthier, more robust plant.
Not only will a wetting agent reduce water surface tension and increase nutrient uptake, but it will also help to prevent the dripper nozzles from clogging, thereby prolonging the life of your system. In most cases, you’ll apply the wetting agent once to twice per month according to the manufacturer’s recommendations.
Don’t Neglect Your Reservoir
Automatic fertigation systems are equipped with a reservoir that houses the nutrient solution. If not properly maintained, this reservoir can become a breeding ground for bacteria like Pythium. Over time, the bacteria can seep into your crops, infecting them and contributing to root rot.
Some cultivators will fight off the bad bacteria by introducing beneficial fungus like Trichoderma. This is a viable solution, but you can also kill off the bacteria using periodic applications of hydrogen peroxide. Do this whenever you change your reservoir, about every one to three weeks.
Water Your Crops Occasionally by Hand
Just because your irrigation system is automated doesn’t mean you can just set it and forget it. You need to inspect your crops on a regular basis, assessing the growth, feeling for any dry spots, and looking for signs of insects and pests.
In addition, it’s a good idea to occasionally hand-water. Not only will this ensure total saturation of your cannabis crops, but it will help you to identify potential problems more easily. Do this at least once every couple of weeks.
Use Air Pruning Pots
There are many container types that you can use when growing cannabis, and each one has its merits. When automating your irrigation system, you need to be especially diligent about using pots that drain well and that support optimal root growth. Air pruning pots are designed for these purposes. You never have to worry about overgrown roots or root circling, and you can always count on consistent, unobstructed airflow.
It’s also important to opt for tall, narrow pots, as they promote better saturation as the water travels downward through the soil. This is especially true for top-feed irrigation systems, which receive their water from above.
Manage Your Waste Responsibly
One of the biggest challenges you’ll face with an automated fertigation system is what to do with the fertilizer waste.
While organic nutrients and organic fertilizers (those consisting of plant matter, animal waste, or natural minerals) can be discarded or composted like any other waste, this isn’t an option If you’re using a traditional chemical fertilizer that contains nutrients like nitrogen, phosphorus, and potassium. Chemical fertilizers are classified as hazardous wastes and must be discarded according to the rules of hazardous waste disposal.
When cleaning out your reservoir and discarding fertilizer, keep it separate from your other refuse. To get rid of it, your main options are to compost it or to set it aside for hazardous waste pickup. The easiest solution is to opt for a cannabis waste disposal service that specializes in hazardous waste for the cannabis industry. In addition to rendering and eliminating your standard waste, they’ll be able to manage all of your hazardous waste streams including—but not limited to—your chemical fertilizers, non-organic wetting agents, and discarded bulbs.
When It Comes to Irrigation for Cannabis, Never Stop Experimenting
Finally, the great thing about having an automated irrigation system is that you can test different nutrient formulas, watering durations, and watering intervals under precise conditions to determine the most effective approaches. You can constantly fine-tune your cannabis cultivation efforts and discover how to maximize your yields and perfect your crops. It’s all about finding the sweet spot.
Even small adjustments can make a big difference for your recreational or medical cannabis cultivation, so always read up on the latest techniques, experiment with new methods, and discover which approaches work best in your facility. Since you’ll already be saving a ton of time on watering, you’ll have plenty of time to play and learn.