Pushing THC Potency to Infinity and Beyond

Conversation with Matt Schwarzkopf of 420 Kingdom

Interview with Matt Schwarzkopf, Cultivation Director at 420 Kingdom

By Lance Griffin


Terpenes and minor cannabinoids influence the cannabis consumer experience. The entourage/ensemble effect has inspired producers to craft products with diverse chemical profiles. But tetrahydrocannabinol (THC) remains king in many markets, and THC potency still drives demand and price. With this in mind, Matt Schwarzkopf, Cultivation Director at 420 Kingdom, is producing flower with ~36% total THC and ~43% total cannabinoids. He envisions total THC in the 40-50% range.

The 420 Kingdom operation relies on the advanced aeroponics system from AEssenceGrows. I caught Matt between overlapping harvests for a conversation about THC potency and cannabis cultivation. He even shared his all-time favorite cultivar.


Why are you cultivating plants with such high levels of total THC?

Honestly, as a cultivator, I’d be happy with anything over 20%. That’s a high-testing, good quality cannabis. Not everything needs to be in that 30% range. For your everyday consumer, some people may like a more mellow product. Out here in California, especially where we are in Kern County, the market is after high THC. We have a delivery service; the first thing that someone calls and asks about is ‘what’s the highest THC that I can get?’

Some people do ask about specific terpenes, but it’s mainly potency. In California, the flower market is driven by potency. For high-quality craft indoor flower, potency is huge. We’ve been on the cutting edge for a while. Utilizing our growing methods and practices here, we’ve been able to keep boosting cannabinoid levels every harvest. We’re dialing it in better.


Can you tell me about your operation and how you’re able to maximize total THC and total cannabinoid potency?

It comes with trial and error. Not all cultivars act the same depending on the initial vetted genetics. We work with clone nurseries and directly with breeders. They have a very selective process for the cultivars they distribute to license holders. They give us plants that they know are tried-and-true high producers. Most come from tissue culture. Working with scientists and labs, they have these genetics on point. It’s not a random guy giving us clones out of the back of a truck.

We also get tissue culture in vitro plants—plantlets in Petri dishes sealed up like clamshells. In the bottom is agar, and there are no roots. We root them here using our AEssence Cloner, which is a 4-tier aeroponic cloner. We can fit 3,000 clones. We put tissue culture plants in there. That’s where the Grapes and Cream cultivar came from (see certificate of analysis below). We did a tissue culture test and saw that it worked, so we ordered more. We vegged them in our 2.1 AEssence Atrium then moved them to flowering tables. They kicked butt. That’s a cultivar we’ve got going again right now, repeating that same process.

Additionally, I’m able to design grow plans. These are the recipes the machines follow throughout the grow cycle. Grow plans are done using AEssence’s software, Guardian Grow Manager, to control the equipment. The software is my favorite thing about AEssence—I can control my grow from anywhere in the world with an Internet connection. When you’re at home and it’s midnight, if you’re worried about something, you can always log in for peace of mind. You’re not wondering if the table is overflowing. You’ll get alerts if there’s an issue. The system also tries to correct itself, and if it can’t correct itself, it will shut itself off. I’m able to fix it remotely or address it asap without walking in the next morning to see that there’s been a catastrophe.

The software allows me to create these recipes. We’re looking at different nutrient solutions, different concentrations, frequency of fertigation, and other parameters I can control—everything from water temperature, pH, nutrients, light intensity, air temperature, humidity, etc. I control the whole room.

Each time we grow, we look at data. The system takes data points every five seconds. I analyze graphs to see when and how much the plants are eating. Then I make predictive changes. For example, if I see a trend over a few days that the plants are eating aggressively, I’ll up the nutrients a little. If they’re taking a little longer, I’ll give them a lighter concentration. We feel the plants and look at what they want. The plants tell you what they want—we’re able to use data to back that up. We make constant adjustments every time we grow a cultivar to boost yield and potency.

Grapes and Cream CoA


Biscotti CoA


What is the most important cultivation strategy to push potency?

The precision control is one of my favorite parts about this operation. We’re not mixing up nutrients in a bucket and pouring it on top of soil. With that method, you don’t know what the plants are getting. Here, we know exactly what we’re feeding to the plants and what’s coming back. We’re constantly dosing, recirculating, and monitoring. There’s no soil or media around these roots; nothing’s being buffered out or getting caught up. That’s how we’re able to feed these plants aggressively and get this explosive growth and super-high testing flowers. We push them to their genetic potential.


What are the advantages of using tissue culture plants?  

The genetics are guaranteed. We know they’re pathogen free. They screen them for hop latent viroid, which is probably the worst pathogen going through the cannabis industry right now. The tissue culture clones are certified hop latent free and pathogen free because they are grown in a sterilized environment on agar.

We know we’re not bringing in powdery mildew, Fusarium, or other diseases. That’s probably the biggest downfall of traditional clone nurseries. Whatever nursery you go to, you can find an issue. There’ll be a little powdery mildew, fungus gnats, aphids… They maintain warm, humid environments because that’s best for the clones. But that’s also best for pests and pathogens. We know our tissue cultures are clean, disease-free, with guaranteed genetics. There’s nothing that we’re unsure about with tissue-culture clones.


Is it possible to push total THC to 36% with an outdoor grow in soil?

I’d say it’d be hard but doable. Generally, these higher numbers come from indoor facilities with precise control on the environment and fertilization. Then you can feed plants more frequently than in a traditional outdoor soil-based setting.

The nice thing about aeroponics is that we can feed higher concentrations more times throughout the day to drive the plants to produce. We control vapor pressure deficit (VPD) to keep plants thirsty and wanting to eat and grow. We compliment that with fertigation. Outdoors, you’ve got a lot of nutrients locked up in soil slowly being released over time as you water. There’s not as much nutrition provided at the rate it is in an aeroponic environment.


You have a cultivar producing 43% cannabinoids… What’s the plan to get to 50%?

You can only go as far as the genetics let you go. You can’t do anything past genetic potential. We’re working with the top tissue culture labs and top breeders in the industry for the newest, most potent genetics. These cultivars are rigorously tested for potency. We find the best genetics and then create our own genetics. We find genetics that give us constant 40%+ cannabinoids and look at crossing these.

The other strategy is dialing in our systems and perfecting the recipes for cultivars. We don’t hit 40% cannabinoids the first time we grow a cultivar. It usually it takes a couple of cycles. We grow it the first time, and realize, for example, that we could’ve fed it a little more during mid flower. We watch how it responds. After one cycle, we have a good idea; after two cycles, we have an even better idea. With Watermelon Mimosa, every cycle has been better. We’re constantly improving the cultivar.


What techniques in your cultivation operation boost energy efficiency and sustainability?

Light-emitting diode (LED) lights use less energy and don’t create as much heat as standard high-pressure sodium (HPS) lights. You don’t have to use as much HVAC [heating, ventilation, and air conditioning], which also saves energy.

We use much less water than traditional cultivation methods. Each of our flowering rooms has 10 reservoirs and 10 rows. There’s anywhere from 7-8 beds on a row, and they all share water from one reservoir. Water goes through a pump and high-pressure line, sprays on the roots, then comes through a drain pipe right back into the reservoir. It recycles.

That is really helpful because we’re in central California. Water’s always an issue. A lot of cultivators are draining to waste. They’ll irrigate the plants and runoff drains out of the building. We’re able to reuse and save water.


With the system updating every five seconds, have you ever had a crisis situation?

We’ve been alerted to power outages. The system will stay on for a couple of minutes after the power cuts out. We had a truck hit a big transformer near our facility.

The AEssence system controls our HVAC, but our HVAC is from a third-party company. If the HVAC stops working—something happens to the fan coils, say—we’ll start getting alerts that the temperature’s not being maintained, or the humidity is getting too high. That lets us see if there is a down dehumidifier, down air conditioner, etc. Once it goes out of the range where I’ve programmed it, it will text me. It doesn’t care if it’s 2 AM—it’ll text me 300 times. Whether I like it or not, it tells me that something’s gone wrong.


Are you targeting any minor cannabinoids or terpenes with your genetics and grow operations?

The Los Angeles market (where we wholesale and distribute) is more in the terpene stage; they’ve been through the high potency stage. They’ve been educated through dispensaries. They’re looking for a combination of cannabinoids and terpenes. But up here where we’re at, the legality and infrastructure are a little different. The general consumer isn’t as up to date with education.

Terpenes are something we are chasing. Our highest terpene content to date was on Marshmallow OG at 2.3% terpenes.

We’ve been trying different drying and curing recipes and methods. We don’t want to lose terpenes at the drying stage. You can ruin months of hard work in a few hours in the dry room. We’re looking at methods to preserve terpenes and cannabinoids—we don’t know what we’re losing throughout that process. We take samples before and after to compare things; we’re still working on it. We think that we’re onto a couple of new methods. We’re in the middle of a data-gathering drying trial right now. We’re gravitating toward a low-and-slow strategy.

Primarily, it’s THC and then terpenes that we’re trying to optimize. I personally look for CBG [cannabigerol], the stem cell cannabinoid. Just looking at the medical benefits, I think CBG is an important cannabinoid that’s often overlooked.


What is the biggest challenge when cultivating your cannabis?

You have to be ready to tackle issues asap. We’re not growing with any soil or medium around our roots; we’ve got a few hours before plants show serious signs of stress.

We’ve had multiple instances where our power has gone out. We never know how long it’s going to be out. It could be five minutes or six hours. Once, we resorted to spraying roots by hand with mist water bottles. You always have to be ready for any type of failure or emergency. These plants can’t go overnight without being watered. For this reason, we have back-ups and fail-safes.

The other challenge is pathogens. If pathogens spread through here, it’s going to be quick because all the roots share the same water. If one plant has some type of fungal root rot, it’s going to spread. These plants are in close proximity. The water splashes all the different roots in that same bed.

That’s why we’re using certified clean tissue culture plants. You can never tell, coming from a nursery, if a root has Fusarium, Pythium, etc. It’s hard to spot issues among hundreds of clones.

We do environmental monitoring and testing as well as tissue sampling from our own plants. We send root samples and water samples. We do swabs inside the plant tubs, on the walls, on the tabletops, and all over the room. We send those out to ensure we’re disease free. If we do find something, we have action plans to get rid of it. By staying on top of our cleanliness, we’re able to prevent pathogens from getting in and taking hold. If a pathogen were to get in, it could wipe out a lot of the plants.

Cleanliness is key to our success. Our technicians and employees wear scrubs, hairnets, beard nets, gloves, etc. The second we stop maintaining this clean-room environment, the second something will pop up.


How have technology and innovation transformed cannabis cultivation?

Growers are going from the gray market cowboy days to GMP [good manufacturing practices]-like facilities. Good cultivation and laboratory practices have become huge—especially with the rigorous testing that cannabis goes through to reach end consumers in legal markets.

Using AEssence equipment, we’re minimizing the contaminants that come in through soils. It’s just roots, water, and air. There’s a lot of hard work that goes into maintaining the equipment, but it’s made out of metal and plastic, which are easy to clean.

I’ve seen a push towards precision sensor-controlled cultivation. People are starting to get into the science to optimize plant growth with data and precision. When it comes to mixing nutrients, I’d rather have a calibrated machine than somebody mixing it by hand. Humans make mistakes. Generally, a machine won’t make mistakes as long as its calibrated, maintained, and designed properly. Cannabis is a very high value crop. It pays to optimize and make everything fail proof with multiple redundancies.

Controlling the environment is another big one. Many people grow outdoor, greenhouse, or mixed light, but environmental controls have been improving. Such controls make a big difference when cultivating cannabis at the commercial scale.

We’re in a tech world right now. It makes sense to incorporate this tech into cultivation. Cultivators are debunking myths and focusing on science.


Where do you the see the cultivation industry in the next 5-10 years?

Cultivation is going more indoor. There are a lot of places you’ll have trouble cultivating outdoors, whether it be in a cold, northern state with snow on the ground half the year, or an extremely hot state with an unfavorable environment for the plants. Indoors, you can cultivate 365 days a year. Your season never ends.

Cultivation costs a lot of money. Bigger companies are buying warehouses or industrial parks and turning them into campuses.

Also, testing is constantly evolving. In California, we have harsher testing laws for cannabis than for cigarettes.

Constant research and development will drive this industry forward. Cannabis had a lack of support for years. Now we’re finally starting to see scientists, doctors, and universities doing the research that needs to be done.


What’s your all-time favorite cultivar?

That’s like asking a chef what their favorite food is! I had a cross of Peanut Butter Breath and Cherry Garcia. That was probably the best I’ve ever smelled and tasted. The flavor on that was amazing—just one of the best I’ve ever had the pleasure of growing. Luckily, the cultivar still has some seeds around. We’re going to try to get that into the facility. That’s one I never forgot.


How high do you think you can push the potency?

No comment. I honestly can’t tell you. I have seen total THC percentages in the 40s. I’m coming for that!

Every harvest is better than the next. We’re going up after each harvest. I have an excellent team surrounding me. We’re all striving to push each other for the next goal. We’re doing groundbreaking work. It’s fun and incredible.

About the author

Matt Schwarzkopf of 420 Kingdom

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