[0003]-[Video 2. Arizona Gutter System for Greenhouse Strawberry Production]-[jTJuqPjHa5s].mp4

So we're here today at the University of Arizona's Controlled Environment Agriculture Center with Mark Progle and Mark, it's strawberry planting time. It is. And you have two different systems here that you're using to grow your strawberries in the greenhouse. That's right. I wonder if you'd walk us through these two systems and maybe take this one first and just kind of explain for us what it is, how it works, how you put it together and maybe all the way up to the point where you plant your strawberries. Okay, this is the one we've been working with for the longest. It's a styrofoam trough system and the important thing is that it's a gutter. It's a continuous gutter and it's filled with soil for the whole length of the gutter. But this fact that a styrofoam is an added benefit and that styrofoam gives us a little insulated property so the substrate we're using, the temperature doesn't fluctuate so much. But really it's still just a continuous gutter and that's something to remember. This particular trough system has the styrofoam. There's a plastic liner that protects the styrofoam from all the nutrient solution that we use. There is a drain tube that helps facilitate drainage away from the substrate. There is a plastic grid that goes above the plastic film but below the wheat root barrier that you'll see. And that allows actually air to enter in all the way through the bottom of the root system. And then we have a root barrier. What I have here is just 12 year weed mat. It works pretty well to keep the roots out of that drainage system and keep them up in the substrate. So the layers you have first, you have your styrofoam trough. Then you have the plastic protector. And then you put in the drain tube. There's a perforated drain tube. And then next, that flexible plastic grid that serves to allow air to enter below the entire root zone. And then there's the weed mat which we use as a root barrier to keep the roots from growing down into the drainage and plugging everything. Otherwise they're going to grow in and clog everything. So then once that's all in place, we put the plants in. Typically for our purposes we pre-grow our plants in small pots. That allows us to establish the plant, get rid of ones that aren't going to grow well, and give us a nice uniform planting. In a university research system that's maybe a little more important than a commercial system, but that's what we do. A commercial grower though might receive different types of propagation material, right? You can receive dormant runners. You can use tray plants which are plugs. You could take any of those and grow them up to a larger size or plant them immediately. All those options are available to the grower. They wouldn't have to pre-grow them the way... They would not have to and they probably would not. Right, right. That'd be a lot of space and time and money. Exactly. So we'll arrange the plants on the spacing that we want. The linear spacing down the trough. And we typically use a six inch spacing between each plant. And that's six inches for one plant, six inches to the plant on the next side of the trough. As you see, we alternate to the side of the trough that we plant on. Okay, so that on a given side it would be 12 inches? It would be 12 inches. But then they're staggered, so... Okay. Exactly. Now when we plant, we plant the plant so that it's at an angle and sort of leaning, if you will. Because that downwards, that will help the plant promote the flower development out and down from that plant. So it's hanging over the edge of the trough. We want our fruit to hang over the edge of the trough, not be to the internal of the canopy. Well, I would imagine it also just opening that up for sonic light exposure and air movement. It probably has a lot of benefits, no? It has those. Eventually that canopy is just going to close solid. But initially, at least it gets some of those initial fruit trusses out to the edge of the trough. So you've spaced them out here now, and you've laid them out. You're going to come in with your media or your substrate. Tell us a little about what you use in the way of your substrate here. Okay, what we're using is a coconut core, peat moss, and perlite blend. Okay. We've come upon this because we like coconut core. It has lots of favorable properties as a substrate. But ball by itself, it's too wet and the pH tends to be too high. So we add peat moss for a little bit of pH management. It helps keep our pH down in a manageable level. It also has some nice characteristics of disease suppression. Right. But then you're not having to add any type of calcitic or dolomitic limestone to that. No. You're doing a pH adjustment with the two components. Right. That ratio of one part coconut core, one part peat, and then we have two parts of perlite as our aggregate. But that one-to-one ratio of coconut core to peat gives us a pretty good pH balance. And what is that starting pH you're going for? Well, we want to keep the root zone in a range of 5.5 to 6.5. Almost all our nutrients are available in that range. And with chelated iron, we can get towards 7, but we really want to stay in that 5.5 to 6.5 range. Okay. So you've got your substrates, you've laid your plants out here. What are we going to go? Well, now typically what we would do is we would just water in that substrate just using tap water. And that will, one, wet it. Right. And also settle the substrate around the roots of the plants. And then if we have to, we'll come and backfill again with a little more substrate to get a nice even layer on the top. So once that's settled in, in fact, we'll irrigate with water over the top for a couple of days. We won't be applying nutrient right away. We just want the plant to settle in and not be stressed. But once that's all done, then we lay down an irrigation line. Well, before you do that, now you talk about coming back and backfilling. It's going to settle. Let's talk a little bit about what the appropriate planting depth is for strawberries. Would growers bring those in? Because that can be an area you can really do some damage if you don't get that right. You cannot bury the crown, but you don't want the crown too high. Basically, what you would like to see is the soil right about a little bit above the roots so that the crown is just slightly buried, but most of the crown is exposed. Okay. So don't bury that crown. Don't bury that crown. That's going to cause problems. And if you leave the crown too exposed, that's a problem too because new roots form at the new leaf axils and they won't grow into the soil then. So you've got to have close proximity of that crown to the soil. But again, it can't be too exposed. Right. So now you've come in, we've got the plants planted, you've got them at the right depth, you've backfilled if you needed from settling. Now we're ready to come in and lay the drip tube or the drip line that you're going to use to irrigate and vertigate the crop with. What are you doing there? Right. Well, what we're using is what we have. We have, for all our hydroponic systems, we use this half-inch black poly and we use these pressure compensated emitters. And we're putting one emitter per plant. And these are two liter per hour emitters and just lining them up so that they're in line with the plant. So we're applying the nutrient directly near the plant. Initially, that's important. Later on, it will be less important. But initially we line them up because we want that water source to be near the plant. So again, we're just using this black poly, these emitters. On this line, you see short little sections of drip tube. I added those just because as that irrigation line in this system may settle a little bit, if that emitter is too close to the soil line, roots will actually grow up into the emitter and just plug it up. So those little bits of drip tube help elevate them above the soil and prevent the roots from growing inside. Now, could a grower also use drip tape? I would use drip tape if I had a preference. I probably would use two strips of drip tape, one on each side of the trough. I believe they come in spacings that would fit this kind of planting density. And then having two also just is sort of assurance that enough of those drip tape emitters are functional. Well, if you have clogging, you've got to stand by. So drip tape's nice. It sets flat. There's no, you know, protuberances sticking up. I think drip tape would work pretty well. So they've got a couple options. Right, they've got options. This system works, but if you've got drip tape or you're willing to buy, use it. Now, after you've laid down your irrigation or your fertigation line, whatever that is, whether that's tape or emitters or what have you, you've now come here with a white plastic cover white plastic mulch. This is panda plastic. It's white on black. So we're doing a couple of things. White on black prevents light transmission into the soil. So that's going to prevent algae from growing on the surface of the media underneath the plastic. That's the white on black aspect. The white reflects more light back up into the canopy, at least until the canopy is closed. Initially, it gives us that that reflective of light property. And in the winter, that's important. The other thing is that you need something to keep your fruit off that substrate surface, because if a fruit is sitting on that substrate, which is always at least moist, that fruit quality is going to degrade and the fruit probably going to rot. So you've got to have something of a mulch to protect your fruit, to cover your soil. Just leaving bare soil is not a good idea. Right. So just summary, that white on black plastic, it's reflecting light. It's helping keep your substrate cooler. It will. It's also helping keep your fruit cleaner. Exactly. Okay. So it really pays off there. Now, this is one system that I see you have here, but you also have a second system in another part of your greenhouse that looks very different from that. Can you walk us through that? Sure.