Written by Kaisha-Dyan McMillan and Ramsey Nubani

What is crop steering?

Crop steering is a cutting-edge plant growth management practice that strategically adjust the environment (light, climate, irrigation) to encourage plants to grow in specific patterns. Next to light intensity, it’s the most important agricultural tactic you can use to manipulate yield.

How does crop steering work?

Crop steering is not new. It’s been practiced by growers of hydroponic vegetables for years. About seven years ago, we brought it over to the cannabis industry. We saw these practices in hydroponic vegetable production, where growers were able to really direct the way that their plants grow, and shape that plant literally just by changing irrigation tactics, changing a little this or that about the climate, any one number of little tiny tweaks that would then have this huge effect on these plants.

As we took it into cannabis, we kept tweaking the process to perfect it for each strain, in each grow environment. One of the first trials was just hammering plants with tons of shots of water, just going as absolutely vegetative as we could, because we knew that was the way to get plants to grow the quickest.

Doing that from day one of veg and keeping with that hyper-vegetative signaling all the way through the end of flowering, we saw we could get the plants to get to 12 feet tall. It was a total gamechanger. We’d never seen plants grow that tall, that fast before. (We only got in trouble when they started leaning over our neighbor's fences.)

So we started playing around with the technology a little bit. Toying around with the osmotic potential and/or the matric potential, depending on what you have. If you're into natural soil, you have matric potential to play with. If you're in a hydroponic, you really don't.

Matric Potential v Osmotic Potential

Taking it a step back further, the matric potential is the force that the roots have to overcome to absorb water from the soil. Osmotic potential is the force they have to overcome to extract water against a really high EC (electrical conductivity) environment. The inside of the roots is at a certain EC, and it's held higher than the outside of the root, so that that water flows naturally with that osmotic gradient. So if you raise that EC, it makes it harder for the plant to absorb that water.

We use some specific irrigation tactics to get the plant in a state of simulated water stress. There's all the water in the world for that plant to drink, and it has all the resources it needs to grow as fast as it possibly can, but what we're doing is we're just telling the plants: "Hey, your water is not always going to be there." This puts it into a generative state that has it focused on reproductive parts. And so when we say generative versus vegetative, that's part of what we’re changing when we talk about toggling crops back and forth between vegetative and generative.

Vegetative v Generative Phases

There are two grow phases: vegetative and generative. Vegetative growth is where plants establish themselves with more leaves, top growth and longer roots. Generative growth is where plants produce flowers and fruits. In crop steering, you’re cueing your plants to lean more heavily in one of these two directions. Maintaining a proper balance between the two stages is vital for healthy plants with a high yield.

Vegetative growth is characterized by:

• Focus on leaf and stem production

• Increased plant size and structure

• Development of a strong root system

Environmental conditions that promote vegetative growth include:

• Higher humidity levels

• Lower electrical conductivity (EC) in the substrate

• Higher water content in the growing medium

• Lower vapor pressure deficit (VPD)

• Consistent, moderate light intensity

Generative growth is characterized by:

• Focus on flower production

• Slower overall plant growth

• Development of trichomes and increased resin production

Environmental conditions that promote generative growth include:

• Lower humidity levels

• Higher EC in the substrate

• Lower water content in the growing medium

• Higher VPD

• Increased light intensity

Crop Steering Made Simple

Knowing how—and when—to manipulate light, climate and irrigation is essential to balancing high yields and high quality. Here’s a rough guide for every type of growth.

Crop steering utilizes vegetative and generative cues through three main pillars: Light, Climate and Irrigation. Through all these cues in combination, you can encourage plants to produce bigger flowers and higher quality.

Generative is just targeted intentional stress, and the resulting behavior of plants is to focus on reproductive parts so that they can finish getting their DNA out into the world before they die, basics of evolutionary selection. And so the vegetative, on the other hand, is removing all of that stress, and just treating that plant to the absolute maximum that you can so that it can grow at the fastest speed that it can.

In crop steering, we use the timing of those when we apply, which, one, to get the plants to put on more bud sites, well, almost double the count of bud sites typically, versus just not doing anything or going vegetative as opposed to generative during that time. And then using it to really bulk those flowers out once they're there and the plant has that focus, and we don't need to force that focus anymore. We can just get that thing pumping up those flowers as big as possible.

The Importance of Precision Crop Steering

One of the big things we notice is the fine line between being too vegetative or being too generative in terms of quality and yield. Every specific cultivar has its own feeding needs. This is why automated crop steering is so essential for the future and how we progress as an industry.

Using crop steering tech will allow you to bring out the most of your cultivar. For instance, if you look at craft cultivator 1.0 eight months ago, and he's in these rooms and he's picking up his pot, he's got his little petri dish under the plant, it's catching its run-off, and every night he's pouring his run-off into his milliliter cup and taking his notes and dialing that all in, he gets his test, he's excited.

Then you fast forward seven months to craft cultivator 2.0, and you start looking at what the different crop steering method brings out in the cultivar. You start seeing the terpene analysis rising, you see your THC rising, your total cannabinoid rising. Hitting these specific water content moisture levels and drying back to these precision amounts, and bouncing back and really steering that battleship through these rough waters, it's going to bring the most out of the cultivar that you're working with.

Once we stress plants out, then we’re steering vegetatively to try to bulk, bulk, bulk. We want to see good quality bud and plants that aren’t too leafy. Every strain has this balance of maximizing yield, and maximizing the quality. For each (approximate) 12-week growth period, it’s vital to nail the first three weeks to set the plant up for success for the rest of its nine weeks.

The first three weeks are really the plants’ launch point. If you miss the boat there, that boat's gone. During that bulking phase, there's definitely a point of pushing too hard. You can see it when you get the white hairs in week seven. You can avoid that by just backing a little bit off of the frequency, and maybe letting the EC creep up a little bit more or something like that, and then you usually find that sweet spot.

There's a little bit of balancing act to do with each genetic so that you can really push that thing to get bulk, the best quality, and the best yield that you can possibly get out of it. And there's always the potential to get more yield, but it may not necessarily be the yield that you want. It might not be the product that you want to yield that much of.

At AROYA, we’ve seen many, many rooms that are getting four, four and-a-half pounds of light, or 80-90 grams a square foot and the quality is still just absolute fire ... just 35 plus cannabinoids, all that good stuff. With precision crop steering, there is definitely the capability to get large yields and quality at the same time.

The AROYA Approach

Getting the right data is so important. What we've done at AROYA is we've been able to create historical data and utilize that information to enhance each one of these phases of growth. Vegetative steering tends to be lower electrical conductivity (EC), higher water content, lower VPD, lower light intensity. Generative cues tend to be higher light intensity, higher VPD, bigger dry backs, lower water content, higher EC. So in conjunction with each other, we are able to steer the plant through the different phases to produce the flower to be bigger and better quality without losing any of our production.

We make cutting-edge sensor technology, the telemetry systems to install and use these, and we make the software layer that turns the data into insights. That deep expertise is specifically tailored to the needs of the cannabis grower. Plus our market-specific platform and resident experts can help you get the most out of your crop steering with the least amount of nutrient burn: time after time and at scale.

Our platform includes sensors that measure accurately throughout the cultivation process, and we can help you monitor every variable: Light intensity, pest control, soil nutrient content, atmosphere, air flow, air quality, water quantity, water quality and water frequency. We put you in control of the entire growing process to get the largest quantity at the highest grade, guaranteeing increased yields of at least 5g per square foot of harvest.

And that's AROYA's goal, is to help educate and work with each one of you as growers because each one of you has a different facility, a different strain, and different steering capabilities. And through our historical data, we build the knowledge of your crop and your strain in each one of your facilities, and that's what we're able to drive forward to you as a grower.

At AROYA, we've been able to create historical data and utilize that information to enhance each one of these phases of growth. So in conjunction with each other, we are able to steer the plant through the different phases to produce the flower to be bigger and better quality without losing any of our production.

It's not just a phase

Knowing how—and when—to manipulate light, climate and irrigation is essential to balancing high yields and high quality. Here's a rough guide for every type of growth.

Crop Steering Chart: Use this chart tool to manage your crop more effectively.

Putting Crop Steering Into Motion

Here is a quick summary to be successful. Cultivators respond to generative and vegetative cues in the following key areas:

• Electrical Conductivity (EC): The amount of dissolved fertilizer in a solution as determined by the ease at which electricity can move through the water; EC is a direct measure of the amount of water that roots can access immediately for transpiration and growth. For a deep dive into EC, check out our video.

• Drybacks: The difference in volumetric water content (VWC) - expressed as a decrease in VWC% - from the last irrigation event of a given day (maximum saturation) to the first irrigation event of the following day (lowest VWC level).

• Field capacity: The point after/during irrigation at which a substrate can no longer hold any more water. Check out this video for more about field capacity.

• Leachate: The solution that is not absorbed by the medium during an irrigation event once it has reached its maximum potential saturation; also known as runoff.

• Shot size: The volume applied during an irrigation event, or shot - usually expressed in total volume (mL) or as a percentage of the total media volume. For example: a “3% shot” means the volume of the irrigation water applied is equal to 3% of the total substrate volume.

• Volumetric Water Content (VWC): The volume of water per volume of substrate, expressed as a percentage (%). Check out this video for more on volumetric water content.

• Water Content (WC): The volume of nutrient solution (water + nutrients) in the substrate.

Crop steering is an approach to craft cultivation that allows growers to have greater agency over their plants. Being able to steer plants toward a target outcome doesn’t just empower cultivators - it also makes their lives easier.

That’s our reasoning for developing AROYA, the ultimate cannabis cultivation platform. With sensors that see inside the substrate and a platform that tracks and monitors your grow at every stage, cultivators get all the insights they need to be able to steer their plants successfully.

The Importance of Dry Backs

Drybacks, the decrease in substrate water content between irrigations, are crucial for cannabis crop steering. They promote root growth, oxygen availability, and can influence plant development phases.

Root Zone Management: The Core of Effective Crop Steering

Are you looking to maximize your cannabis quality through crop steering? The secret lies beneath the surface - in the root zone. Let's dive into the world of root zone management and discover how it can revolutionize your cultivation practices.

Why Root Zone Management Matters

Root zone management is a critical component of successful crop steering in cannabis cultivation. Growers must carefully monitor and control four key factors: substrate water content, electrical conductivity (EC), root zone temperature, and oxygen availability. Optimal substrate moisture levels promote healthy root development and efficient nutrient uptake, while preventing root diseases and nutrient lockout. Proper EC management ensures balanced nutrient availability and prevents salt buildup. Maintaining ideal root zone temperatures, typically between 65°F and 75°F (18°C - 24°C), is crucial for nutrient absorption and root metabolism. Adequate oxygenation prevents root rot and supports overall plant health. Effective strategies for root zone management include selecting appropriate substrates with good water retention and aeration properties, implementing smart irrigation techniques like strategic dry-backs, utilizing technology such as substrate sensors and automated systems for precision control, and making data-driven decisions based on trend analysis. As Josh Ginsberg from SOZO explains, "We are able to get live dry back and EC data at any given point, which really enables us to dial in each cultivar to its full potential." By focusing on these aspects, growers can optimize plant growth, prevent common issues, and maximize both yield and quality in their crops.