030: Richard Vollebregt - Cravo Equipment Ltd. (Part 1)

In this episode Joe and Nick interview Richard Vollebregt, President & CEO of Cravo Equipment Ltd, a company that develops retractable roof production systems to enhance berry, cherry, cannabis and vegetable production for growers worldwide.
His background in economics combined with 30+ years of experience designing automated retractable roof greenhouses, knowledge of plant physiology and my worldwide experience in many crop industries allows me to be very effective in designing crop production systems and then creating financial models which bench marking again conventional greenhouses, tunnels and open field production.

More about Richard Vollebregt:
Website: https://www.cravo.com/en

More about Joe Swartz:
Website: https://amhydro.com/
Twitter: https://twitter.com/HydroConsultant

More about Nick Greens:
Website: https://www.nickgreens.com
Twitter: https://twitter.com/InfoGreens

Transcript

Hey everyone. Welcome to another episode of the poly greens podcast. I'm your host, Joe Swartz from am hydro, along with the host Nick greens of the Nick greens grow team. And we're here to talk to you again about all things controlled environment agriculture, and just based on that and controlled environment.

That's one of the big hot topics and how to, how to control the environment around the greenhouse for optimum crop growth. There maybe be. More appropriately, how to steer crop growth. Um, we've gotten today one of the innovators of greenhouse system. Um, as we talk about technologies, we've talked in the past, we've talked about the different, uh, levels of technology in terms of the, the, uh, high tech versus low tech approach.

The economics that relate around that. And we've got someone that's put a very interesting and very effective spin. On the greenhouse structure, a lot of people have heard of the craveable retractable roof greenhouses, but we're going to talk today, um, to Richard Vola Brecht, uh, CEO of  and see what his approach is and see what type of successes that they're having in terms of providing optimum environments for, for, uh, whatever growth, uh, you're looking for.

So, Richard, thanks very much for joining us today. Uh, Joe and Nick, uh, thanks for the invite. Real pleasure. And an honor to be, uh, one of the esteemed members of your podcast. Very cool. So again, you have a, an interesting background, if you could just kind of tell us a little bit about, obviously you come from a, of an economics background, which, uh, in, in the farming industry is actually I think undervalued, but certainly not exactly what you would traditionally think of as, as a background for getting into controlled environment agriculture.

So can you tell us a little bit about, uh, your backstory and how you got to where you are? Sure. Um, yeah, so my formal training is economics and business. Um, I joined Prevo after university. Um, my father started it 45 years ago and, uh, came in basically from the business side. Um, but I'm also got a very good mechanical mind.

I can connect dots very quickly and we were doing retractable curtain systems as our core business, uh, insight, shape systems, energy curtains, and then we, uh, Started developing actual retractable roof houses, which would then be the structure of the drive system, the roof covering and the manufacturing processes to make all the components.

But there was no control systems. Um, and so, uh, after several years of waiting for the other computer companies to develop controls, I decided, okay, if no one else wants to do it, we're going to develop the controls for the retractable roofs. And since my economic Mike's background, didn't really train me on plant physiology.

I took 18 months away from the business and I studied plant physiology. I joined the international society of horticultural scientists. Got connected to university of Arizona with gene Giacomelli and Merle Jensen. And basically try to understand the problems that are in conventional greenhouses, the problems that are in open field and in shade houses.

Because what we learned is if I can open and close a roof completely. I can create a greenhouse environment. I can create a shade house or I can create an open, natural open field environment. And so I wanted to understand how do we measure and what do we measure to understand how to create the right environment?

And, uh, so that led me to kind of combine economics with mechanics, with plant physiology. And then eventually I ended up using my economics again, because now we create and design production system globally. And we always tried to create a financial model to forecast the return on investment. By looking at what crop are we growing?

What time of the year are we trying to target the harvest and what CapEx and a cost of production are we facing? Now when I first heard many years ago about retractable roof greenhouses. So just to kind of give everyone a little bit of a background, we have a greenhouse structure, obviously the glazing, whether it's polyethylene, polycarbonate glass is separating the greenhouse growing environment from the external environment.

And especially as it relates to pest control, that's very, very important to be able to. Isolate or to keep the, the two for lack of better terms, a little bit of the outside world from getting into the greenhouse. And so the concept to me of a retractable roof, greenhouse, that now opens up into the natural environment, suddenly opens up this whole world of the introduction of.

Pests from outside into the greenhouse and it suddenly causes the grower to lose control of that specialized environment, but that's really not at all the case. Can you, can you tell us a little bit about how that works? Because that was originally kind of that intuitive thought that came to my mind and I was horrified and, uh, learning about the retractable roof queen houses and all the things that go with that.

Um, the, the exact opposite really is true. Yeah, sure. Joe, that's a fantastic comment, uh, because this is all about perspective. So if you retract the roof, your initial comment was I'm going to let all the bad stuff come in and I'm going to say first, we're going to let all the good stuff come in. And what's the net effect of the good stuff.

So if I retract a roof and I get full spectrum, sun radiation, so full UV, full inferential. Full par light. First of all, I got more glass, more light coming in than a glass. That's when the roof is retracted, I have direct UV, which means I'm sterilizing the leaf surfaces to kill the spores. If I'm growing lettuce, micro verbs, I I've got the UV to create the coloring that I want.

And most importantly, I've got full spectrum, infrared radiation, which is now heating up the leaves. And if I'm heating up the leaves, what am I doing? I'm drying them off. And if I'm drying them off my foliar disease, just plummets, because my leaves are dry. I'm not creating a suitable environment for foliar disease.

Well, what else is happening? I'm driving the transpiration rate up and if I'm driving the transpiration rate up now I'm moving all the nutrients through the full body of the plant and I'm helping to prevent nutritional deficiencies. Well, what else is happening? And here's the part that most people did not understand.

It's actually changing the plant structure to being more like an outdoor plant. What does that mean? It means you have a thicker cuticle on the leaf. So when you expose the plant to that full spectrum of UV and infrared, Is causing the plant to develop a thicker layer of wax on the leaf, which is a more effective barrier to high transpiration rates.

But it's also a more effective barrier to sucking insects. Cause sucking incidents always look at they're looking for the sickest weakest plant because it's easier to penetrate a weak plant than a strong plant. And so this was the biggest learning we had. Is we're changing the plant structure when we retract the roof.

And by changing the plant structure, it's changing your foliar disease. You're great of insect attack, but it's also now going to change plant quality, number of flowers, fruit size, fruit, firmness, bricks, all of those things, because they're connected to plant temperature and transpiration. Certainly there's a lot right there to unwrap real quick.

So, so obviously, and a lot of people think, especially in a glass house environment, they think you're getting full sun. You're getting everything that is coming from the sun directly into your crop. And it's not, there's a lot, that's, that's not making it through and UVA and UVB, infrared light. Those are all critically important parts to our.

Proper lighting environment. And even that exchange, even the exchange rate on the air, right. The air exchange rate, right. It's probably so rapidly exchanging that you have fresh air all the time available for the plants. Yeah. And, and so the, and as Richard had mentioned, so not only are you. Increasing the, the light to diversity, to the plants and, and through the air exchange and through the environment, you're now developing a plant with a thicker cuticle, with a thicker cell wall structure.

And, and, and when we talk about controlled environment products to market, um, and consumer demands, one of the challenges that some people have, especially in the leafy greens industry is a lettuce that. May have good flavor, may have beautiful aesthetic qualities, but doesn't have the, the, the textural quality, the crunch, the, the, um, uh, The, the F the flavor is, is greatly impacted by texture.

And sometimes people don't always know that. And so now all of a sudden we're with, with what Richard had said, we're adding all of these different elements, not only to the health of the plant, um, the growth rate and the economics, of course, which we'll talk about, but also the flavor profile and nutritional profile.

So there's a lot there to what Richard had just said. It's really important to our controlled environment, ag products. I think Joe, there's an important comment that needs to be made here. And that is there's, you know, we shouldn't really talk about high tech, low tech. We should always talk about what's the appropriate tech.

Perfect. And that really starts with what climate are you in and what crop are you growing? So greenhouses were really developed for cold dark places. Holland Canada, Russia, UK, where you have a shortage of light, you have a shortage of heat. So the greenhouse is designed to maximize light transmission and heat retention during the cold dark winters.

And in that situation, a retractable roof doesn't work. You need a glass house to Excel and be profitable in that climate during that time of the year. So retractable only fits in the colder climates as a three seasons solution spring, summer fall, which really puts you more to the Berry crops. As an example.

I mean, we do a lot of work in perennials and bedding plants, but sticking on the food crops, uh, in the Northern climates, it's really, you know, season extension for berries. But as you move to the warmer climates, whether it's Texas, Florida, Arizona, the Gulf coast countries, uh, South Africa, Australia, et cetera, they're not dealing with dark and cold.

They're dealing with sunny and hot. And so Nick, when you mentioned about you open the roof, you got great air exchange. You actually can have too much. You can quickly lose your microclimate. If you retract the roof. And you have the sun beating on the leaves and the relative humidity dropped to 20% and the air temperature outside is 95 degrees or, you know, uh, 35 Celsius.

All of a sudden you're dealing in a situation of creating excessive plant stress from putting the plant in an adverse condition. And this is where. The learnings over these 40, this 38 years that I've been doing, this has really come into understanding how do you actually know how to optimize the environment?

And you start by focusing on the plant. And this is one of the most critical learnings that I had over the years, because when, because retractable roofs were not in existence, we were really the pioneers working with pioneers. And there was no, no nothing that you could refer to. Everything was learned by trial and error.

And so when you're in a glass cells, your two most important sensors are your air, temperatures and sensor and your humidity sensor. Because if you're under a covering leaf temperature and air temperature will be similar. Cause there's no direct sunlight on the leaves, but the moment you get direct sunlight on the leaf, I can warm up the leaf surface very fast in direct sunlight, which means if it's spraying conditions direct, sunlight's a positive.

If it's summer conditions at one o'clock in the afternoon, direct sunlight is a negative because it's going to cause excessive transpiration. And so the, the, if I had to say, what was the most important thing that I learned over all these years is the job of a manager of a growing facility to manage the climate or manage the plants.

Am I successful because I hit my target air temperature and humidity, or am I successful? Because the plant developed the appropriate quality. Hmm, those are excellent. Excellent points. Let's just, let's go back on that for a second. So again, is, is what Richard is saying is, is, is it more important to, to manage the temperature or is it, and humidity and other environmental factors, or is it more important to get a specific result from the plant or a specific outcome?

And that's a really important point that I'm hoping, uh, Richard, you can build on that a little bit as far as did that. Sure. So when, when somebody buys a Cray boat house for the first time we have set up, what's called grower success meetings, which are basically weekly or bi-weekly meetings between the growing team and our, uh, our, uh, agricultural engineers at cradle where I will say, okay, don't talk about the climate.

We're going to talk about the plants. So send me pictures or videos of the crop, and then tell me what you like and tell me what you don't like. And after you tell me what you like, and don't like, we're going to talk about, what do you think is the root cause for why the plant's developing that way now?

So I'm going to talk climates. I'm going to say the humidity was too high or too low, or the air temperature was too high or too low. And let's assume that irrigation and nutrition are under control. Let's focus on climate, not on irrigation, nutrition. Okay. So I can hit target and humidity and air temperature levels, but that doesn't guarantee the plants developing the way I want.

So what are the two most important things that I'm actually managing? I actually need to manage the plant temperature and I can change the plant temperature more by closing or retracting the roof or closing or retracting a shade screen because I'm altering. The direct sunlight and I can have a leaf temperature that's easily, 10 degrees Celsius or whatever that is 20 Fahrenheit warmer than the air, simply by letting the sunshine on it.

And if I'm measuring air temperature, I will never know that the plants warmer in the sun. And if I'm growing in a black container, like an easily have temperatures of 140 Fahrenheit. Sitting in black, in direct sunlight. So we, you don't look at air temperature. We look at plant temperature, we use infrared handheld thermometers to measure the plant temperature.

That's the first thing. The second key lesson was we're not managing humidity. We're managing Crespo operation. Because the transpiration is going to change the plant activity. Change. Nutrient absorption distribution changed cellular structure changed the balance between vegetative and generative growth.

And if I can open and close the roof, going back to the next comment, I can dramatically change my humidity levels. I can drop them down. I can get direct sunlight on the leaves. I can warm them up. I can get the wind blowing across the leaves so I can drive transpiration up. And typically in a, in a covered greenhouse, your challenges, eight o'clock in the morning, you have insufficient transpiration, but I can solve the problem by retracting the roof.

If the temperatures outside are sufficient, but then because I'm in warm climates, typically I need to go quickly into. A protective mode. So just this week we were having a discussion with growers in the United Arab Emirates. And they had outside temperatures of 46 Celsius, which I'm not sure, probably 120 or 110 Fahrenheit.

And they had a 10% humidity outside because there's no pattern fan cooling. So, um, in that situation we didn't build a retractable greenhouse. We built a retractable cooling house. Hmm, which is using a white coat covering this design actually to cool and reduce temperatures and radiation rather than increase the transmission of light and heat.

So a greenhouse is designed to maximize heat and light transmission, a cooling house. When the roof is closed, it designed to block it more, just like when you have a cloudy day automatically your leaf temperature, air temperature drops. When the cloud passes by the sun. So we're growing, uh, crops in the middle of the desert at these temperatures with 2010, 20% humidity outside by closing the roof, we're letting the air temperature get really high, but we are forcing the humidity up.

Because I need to stop the plant from running out of water. So you're keeping the VPD range proper rather than the relative humidity. Exactly. This is all focused on transpiration, so I don't really care what the humidity is. I care as the plant running out of water or not. So when you think of plants have a fixed capacity to absorb water, the roots can only absorb so much water.

So let's assume a plank and absorb one court or one liter of water in a day. We have to make that quantity of water last the entire day. So if I'm growing lettuce and south Florida or the desert, I need to make sure that that plant doesn't run out of water because I don't want tipper. So I need to reduce the radiation sufficiently, get the relative humidity high enough so that I'm actually managing the transpiration.

So we don't talk air temperature so much. We don't talk humidity so much. We'd foot. We talked plant physiology. Our focus is we manage the plant, not the environment, the environment we manipulate, but that's not the goal. The goal is to think like the plant. Am I trying to make the plant warmer or cooler?

Am I trying to make it lose more water or lose less water? And when you get that concept in your head, and then you understand how you can change plant temperature and transpiration by opening and closing a roof or a shade curtain, you have power to do things that no one could ever do before, which is why we're very active in mild and hot climates because we're helping to solve the problems that people struggle with.

And those climate zones when they're using a conventionally covered house yeah. Based temperature and relative humidity really are kind of kindergarten. And now understanding now that we understand a little bit more about what's going on with the plant and we, we understand how to drive that. So how do you, how does Crable approach.

Controls to do that. So in other words, you know, obviously we have an aspirator box measuring a temperature or a relative humidity. How do you go about then starting to quantifying and, and monitoring and adjusting based on the plant response? Ah, there is your key question. My friend million dollar question right there.

Yes. So in a conventional greenhouse, your two most important sensors are air temperature and humidity inside now. Our philosophy is different. So in a glass house, let's say, for example, if the air temperature is too hot or too humid inside, we start to open the vents. Right? So we are, we are opening when in outdoors, sorry.

When insight is adverse. Now, if I'm in a retractable roof, we start with the philosophy that mother nature is best. So when outdoors is optimal, we are outdoors. So what does that mean? Well, whenever the plants thriving outside, we don't want to interfere with it. Thriving. We only want to protect when outdoors is diverse, but what does that mean?

Well, if I had temperatures below freezing, that's not good. We know that. So too cold is not good. Two. Wendy's not good. Right? If you have too much wind blowing across an outdoor crop, that's a negative, you get physical damage, but you also cause high transpiration rates or this demonic closes up a hail, not good rain, hard rain, not good.

And also too hot, not good. So we start with the premise of plants should be outside. Between say 55 cells, 55 Fahrenheit and 80 Fahrenheit, or call it 17 Celsius and 28 Celsius. So in that range, plants, roadside. Now where's your rain sensor. It's outside, right? It's not insight. So I have a rain sensor outside.

That's going to say it's raining. Close the roof. I have a wind sensor outside that says it's raining close the room. When it comes to temperature, I'm not measuring inside. I'm measuring outside. I want to know when outside is getting too cold, close the roof. And when is it getting too hot? Close the roof.

So this was the most important development in the whole retractable roof program, because if I said to you is sunny and 55 outside, too hot for the plants you go. No, if it's 90 degrees and sunny. Is it too hot for the plants you go. Yeah, but it was sunny in both cases. So sunny, didn't tell you how, if the plant was too hot or not.

Well, let's try it. Let's try, you know, uh, air temperature. So if it's, um, if it's 85 Fahrenheit or call it 35 Celsius and it's sunny is my plant too hot. Yes, if it's that same temperature, but overcast is my plant too hot. No. So air temperature, didn't tell you the plants too hot and light levels. Didn't tell you the plants too hot.

So how are you going to know the plants too hot? So we developed a black plate sensor, which is a piece of steel painted black that's up on the weather station. And just like a pot in the sun or the asphalt is always hotter than the air. The black plates heating up faster than the air. And it's telling me, what is the plant temperature going to be?

If it's in the sun, you're on mute by the way, juror, uh, Joe. Yes. Um, the black plate is forecasting. Whether the plant temperature is gonna go up or down. If the roof has retracted and the moment the black plate gets too hot, it's telling me my leaf temperature is going to get too hot. And my transpiration rate is going to get too hot.

So in a very simple way, you are now monitoring and understanding what the leaf tissue temperature is. So again, as you said, what the air temperature is while there is impact on the leaf temperature, the air, the air temperature is functionally irrelevant, right? It it's it's, I'm not measuring the air temperature by managing the plant.

And I just need to know when is the plant temperature going to get too hot? So I could have an early morning spring day where it's cool outside, but it's sunny and the black plate temperature could be 10 or 15 degrees warmer than the air, which is telling me get that right roof retracted because I want more light coming in.

I want to dry off the leaves. I want to activate the plant. Because that's going to increase my quality, my photosynthesis, and reduce my chance of fully or disease. Are you calculating or, or predicting transpiration rate functionally based on leaf temperature. Um, I can say this way as a general rule, when we're talking about highlight crops, um, you know, blueberries, strawberries, um, things like that.

When the leaf temperatures exceeding 31 Celsius, we know transportation's going to become too high. And what we have to think about is even ourselves, if we have a hot day and we're outside for half an hour, no problem. But if we're outside all day and we're dehydrating, we're not going to have a good day, the same with the plants.

They can take high transpiration rates for a short period of time, but not for an extended period of time. And so what we're trying to do is we basically say to, to a new user of a retractable roof, okay. Here's a handheld infrared thermometer. I want you to get a chair. I want you to go sit in the, in the retractable roof house, and I want you to watch the plants and the roof is going to be retracted in the morning.

And I want you to tell me, when is that plant starting to show signs of excessive transpiration, because at that point, as you go now, I need to move into a protecting mode and I need to reduce plant temperature and reduce transpiration. So you look at the plant. And then adjust your control systems. And so the, there is a, there is a relationship between black plate temperature and humidity and transpiration, right?

So the higher, the air temperature, more transpiration, the lower the humidity. So what we've learned is particularly by going into these arid or tropical climates, we're really needing to regulate. The humidity in order to optimize the transpiration rate. So our, our, our thinking is always, there is no target humidity per se.

We're looking at the plant going, what do we need to increase humidity or decrease? So we've got crops that are growing in 40 degrees, Celsius conditions, but we've pushed the humidity up to 70% because I need to keep that plant full of water. For those five hours of the day where it's really hot and the rate of drying out is too great.

How do you most commonly supplement humidity? If you need to Mr. Fog. Mr fog, Mr. Fogg. Yeah. Yeah. And you know, when you're, we've got different rules that we've learned, if you're in a, uh, uh, tropical environment, you still benefit from HAF fans because the thing is, it's more difficult, obviously in a tropical environment because you can never really dry out the plant as easy as you can in a desert climate.

So it's easier to add humidity. It's more difficult to take it away. But if we think back to transpiration, um, if I have 80% humidity and I want to increase transpiration, what do I do? Let more sun shine on the plant and I'm going to cause an increase in transpiration. So again, the goal is transpiration or either trying to increase it or decrease it.

And here's what the one phenomenon that we learned, uh, It's a common knowledge that foliar disease risk is higher in a covered structure. And if you go, why is that? What is the fundamental science behind that risk? Now we talked earlier about, if you walk on a beach or walk on the asphalt, it's hot in the sun, which means exposed surfaces are warmer than the air.

Right. So the air might be cool, but I can burn my feet. Walking on bare sand is telling us that infrared radiation and direct sunlight heats objects. Now, if I walk into a greenhouse or the plants warmer or colder than outside. Oh yeah. I thought you were asking me metaphorically. So you're asking us, what do you think?

So if you're out, say that again, please. Okay. You're outside. You have plants outside and it's sunny outside and you put them in a poly house. Are the plants warmer inside or outside of the leaf temperature is going to drop when they go into the poly house. Right. But the air temperature went up.