By Sydney Pahle, Research Assistant
Sofia Van Wingerden has deep roots in local agriculture. She’s a third generation Carpinteria greenhouse farmer, but to fully trace her family’s farming history, you have to rewind all the way to the 1600s in Holland. Whether growing flowers, tomatoes or cannabis, the Van Wingerdens are at the forefront of Dutch farming techniques that allow efficient use of space to farm ag products for markets near and far.
In this interview, Sof spills on what it takes to convert from flower farming to cannabis farming. She has been a leader in the Carpinteria cannabis farming space since 2015. The rules and regulations for the new crop are tighter, leading to cleaner, more modernized practices — think efficiency in irrigation and biological pest controls. As a horticulturist and business woman, she has her finger on the pulse of inputs and climate control needed to keep her plants happy and healthy in the competitive world of cannabis farming.
Q. How long has it been since your greenhouse (GH) switched over from growing flowers? Did the transition require purchasing a large amount of new equipment or technology?
A. We switched over completely about three years ago. Our infrastructure was ready-made for the conversion, so we did not have to buy a lot of new equipment in the greenhouse as our system already lent itself well to cannabis farming. We did have to install black-out curtains and cleanse our entire greenhouse environment from top to bottom to remediate historical pesticide use. We also installed an effective odor abatement system.
Q. What do blackout curtains do?
A. The blackout system controls the amount of light our crop is exposed to, thereby controlling growth patterns. In later phases of the growth cycle, we block out sunlight to induce flowering. When the plants are babies through teenagers, we want the plant to grow (and not flower), so we use energy-efficient LED lights to trick the plant into believing its summertime. They need about 16 hours of light per day to grow and not flower during what we call “veg.” That’s when the blackout curtains are used to prevent light from escaping the greenhouse.
Q. Why did you have to clean up the GH?
A. We had to clean our GH & pipes because we used to spray pesticides during the many years we grew flowers. Chemicals found within these sprays can hang around for years if you do not take appropriate steps to remediate the environment. This new crop must test within 1 Part Per Billion in order to be released to consumers, so we keep it very clean now. It’s really a way to modernize agricultural practices to 2019 standards that protect both the environment and consumers.
Q. Cannabis plants are grown hydroponically in a growing medium. Can you explain best irrigation practices?
A. We use a closed loop system that’s designed for efficiency. We first have to cleanse our water through Reverse Osmosis, because the plants are picky too. We mix our water with some naturally occurring fertilizers and feed the plants through drip lines to ensure all plants get watered evenly.
Our property is set on a gentle slope that allows gravity to send any water the plant has not used into our catchment system and into our recycling tank. The unused ‘dirty water’ will be re-injected through the RO system and recirculated. We have a lot of piping in our greenhouse.
Q. How much water ends up being used per plant?
A. Weather conditions dictate the needs of plants, so we are constantly monitoring the climate inside the greenhouse for a variety of reasons. On a humid or rainy day the plant will receive fewer irrigations, and on a hot and dry day we will give them more. Each irrigation is about 180 milliliters of water per plant. There is anywhere from 3 to 7 irrigations a day, so with an average of 5 irrigations, it is about 900 milliliters of water per plant, per day. The excess water that the plant does not use (30-40%), drips out the bottom of the pot and is reused.
Q. How do you feed the plants all the nutrients they need to be healthy?
A. We rely on both fertilizer and an optimal growing medium to promote healthy plant growth. We rely on the medium specifically to house and promote growth from the roots. We’ve tried a few different mediums, like a chunky coco, a thick peat moss and a 50/50 of each. I think it really depends on the grower and what their goal is — how long do they want to keep their plant in a pot for? What kind of water retention are they looking for? Right now we have a nice blend of coco and peat moss and we really like the healthy root structure we are seeing. We experiment and test regularly to determine fertilizer mix balancing.
Q. How effectively do biological controls work to prevent mites, aphids, gnats (the bad bugs) from damaging your crop?
A. They are very effective. We apply our beneficial insects proactively and spot treat for any clusters that have developed. Our insect vendors have great advice and can supply us with specific insects on an as-needed basis. You definitely have to apply them strategically and keep a close eye on the plants during all stages of growth to make sure there’s a balance of good bugs and bad bugs. That way the plants don’t get damaged and the good bugs are present to go about their work of slaying the bad bugs.
Q. Which beneficial insects are used the most here?
A. We use Swirskii, Hypoaspis, Feltiella, Eretmocerus, and Aphidius. We also use just a little bit of pollen as food for Hypoaspis mites. They eat the pollen and grow stronger and sometimes create their own colony, and that’s good! There are strict rules in California for what bugs can be introduced to an environment, so our experts have to stick to the list.
Q. What are the benefits of using biocontrols?
A. There are so many benefits! We’re not using pesticides, so that’s the biggest one. Pesticides are a great “kill all” which is convenient, but I think we’re all aware of the cons to using pesticides in ag. Using beneficials is a bit more work and you have to do more ‘bad bug hunting’ but like I said, sometimes they will develop their own colony and continue to replicate on their own.
Q. What climate conditions are needed inside a cannabis greenhouse? Fairly warm, right?
A. We keep our greenhouse between 20 and 22 degrees celsius, which is the ideal temperature. Humidity should remain around 70 percent.
Q. How do you control the temperature?
A. We use an automated climate control system. Basically we just set the parameters and the sensors send the commands. If the sun is out and the greenhouse reaches 24 degrees, then the sensors send a command to open the windows for air exchange, and the greenhouse will begin to cool down. If it is too cold, the vents will stay closed and the boiler will turn on. The boiler sends hot water through a completely enclosed system of pipes. There is also a CO2 system that works with the boiler, which is really great. It recycles the CO2 created from the boiler and sends it out to help grow a more robust crop.
Q. How many stages are there for the plants in your greenhouse?
A. We have four stages. There is clone growing, hardening, veg, and flowering. The cloning begins from a cutting off of a veg plant. ‘Hardening’ is the stage between cloning and entering the GH environment; the plants adjust to leaving the highly controlled climate of the clone dome and get ready to move to the greenhouse, where they will experience sunlight and nighttime. This stage also promotes more root growth, so when are plants are ready to grow in the GH, they are growing from a strong foundation.
Q. Is there a specific number of weeks when harvesting occurs?
A. This depends on the grower and their method. We currently harvest more frequently from smaller plants. Some prefer harvesting from larger plants at different times of the year. We have tried various methods and find that each has its advantages.
Q. Is everything harvested by hand?
A. Yes. We have a harvest team that goes through and cuts the plants at the base of the stalks, weighs them and send them to dry.
Q. What is the purpose of weighing everything?
A. For State tracking and for our own internal use. It’s pretty cool, once you start tracking everything, how much data you can glean and learn from at all stages.
Q. Do you have any goals to improve the sustainability of your greenhouse, or do you feel you have done most of what you can?
A. I think there is always room for improvement and efficiency. Fortunately, Holland does most of the heavy lifting when it comes to R&D in Ag Technology – so we make sure to stay in close contact with the Horticuluralists and Engineers out there.
Efficiency is always a win-win situation. The more water we can save, the better it is for the environment and the better it is for our costs. The more we can promote ecosystems for the predatory insects, the fewer bugs we will need to buy. The more efficient we can get with our nutrients and soil, the less fertilizer we have to add in. The better our structures are, the better the ecosystem for our plants. Plants are very similar to humans. We just want a warm environment, with plenty of hydration and some good food!