Practices for Growing Larger, Firmer Blueberries

Good afternoon, friends. Welcome to our webinar on blueberry management. Like to. We have a slightly different format this time for our webinars. We have a smaller audience and targeted specifically towards a blueberry conversation. So I want to welcome all of you to the discussion because we have a smaller group and we wanted to focus. I also wanted to be able to have the interaction be a bit more personal. So, yeah, we have a couple of the AEA consulting team joining us here as well. With me showing up now at this point is Jim Dunlop, who's one of our agronomists and consultants from the Pacific Northwest in Washington, and Kevin Tolle as well. Hi, Jim. Hi, Kevin. Welcome along. Howdy. Hi, Jim. Jim and Kevin have both done some work and continue to do a fair amount of work with blueberries in the Pacific Northwest. I wanted them to be able to be here and participate as well. So I'm going to kick off with some initial, initial outline of some of the things that we've observed and working and learned about working with blueberries over the last seven or eight years and then open it up for questions and answers and talk about any questions or concerns that you might have. And there'll be. There's two options. One is at the bottom of your screen. You should be able to see a Q and a box where you can type in any questions that you have. If you type in any questions during the course of the discussion, then I'll respond to those. And also when you go into the participants section, you'll be able to show where there's an icon where you can raise your hand. And at any point during the course of the conversation, if you have any questions, you can raise your hand and Anna will unmute you and you'll be able to ask the question verbally as well. So hope you take advantage of that option because I really enjoy the interaction and enjoy the conversations that emerge. And it's a lot easier to have those discussions live in person than it is by typing in questions. I think it's a lot more practical as well since we have a smaller audience and a smaller group of people. So without anything further, I'm just going to jump right into some of the pieces that we wanted to speak about. There have been a lot of questions that have emerged over the last year or two as we've learned more about oxidation reduction and supplying nutrients at key stages of blueberry development. There have been a lot of questions about how to get, how to optimize nutrients and nutrition for blueberries. So I want to Talk about a couple of pieces that we've learned. One of the things that we've observed is growers being able to produce a high degree of fruit uniformity and sometimes also if it's desired, when it's desired, condense the harvest window where this is particularly valuable for fresh market blueberries. If when we're hand picking instead of having a 16 week harvest window, being able to condense that down to perhaps a nine week harvest window gives us a lot better, a lot better labor efficiency, etc. So want to speak about some of that, of what we've been observing and some of the things that we've been working with. So what we've observed is that developing condensed harvest windows and uniform maturity is a function of developing a high degree of bud uniformity in the fall. So it's we've observed some quite exceptional successes in being able to condense harvest windows on extreme examples. Perhaps the most condensed harvest window is one blueberry grower who has been this is machine harvest for processing. So with a machine harvest, instead of doing formally before we begin working with him, he was doing six passes through the field. After working with him for two years, he was able to harvest 90% of the berries on a plant in a single pass to such a degree that he was not even planning to take a second pass through the field on fresh market for hand pick. We've been able to observe reduction from 16 week window down to a nine week window. And of course there's variations from variety to variety. What we've observed in general is that we can, for most varieties, we can condense the harvest window by about 30%, which can be a really big deal. Of course now there's also it's possible to delay the entire harvest window, still have it in a condensed period of, let's say nine weeks instead of 16 weeks, but push it back to the latter part of that 16 week window or it's possible to bring it forward to the front part of the 16 week window based on how we manage plant nutrition. And if you have any questions about that, I'm happy to expand on that and elaborate on a little bit more. So the question is, how do you develop a high degree of bud uniformity? If you want uniform buds so that you have a condensed harvest window, how do you achieve that? And of course bud uniformity. Reproductive buds are being set in the late fall as we go through as the plants and the bushes enter dormancy and after I say after dormancy, after leaf drop. And the only way that I know of at this point is to develop a high degree of bud uniformity, is to make sure that the plants have a surplus of energy so that the buds that are the closest to the growing tips are equal in size to the buds that are closest to the base. You can't really reduce bud size at the base. The only thing you can effectively do is increase bud size farther away. And to do that, we need to make sure that the plants have a surplus of energy to have abundant energy. And obviously this means having adequate nitrogen. One of the things that we observe is sometimes not having enough nitrogen. But of course, nitrogen needs to be in the right form so that we don't introduce any cold susceptibility or frost susceptibility. And also, very importantly, at this particular stage, plants really benefit and the buds really benefit from having elevated levels of calcium. So I want to talk a little bit about how we can contribute calcium at this stage without having a negative impact on soil ph and everything else that's happening within plants. The second piece that we've really become known for in our blueberry work is being able to develop very high degree of fruit firmness and very strong fruit. So that packs well and that ships well. And this is also related to calcium supply, both in the fall during the bud development period, but then also in the spring during blossoming and pollination and during the fruit development, the fruit fill period. So when we look at the nutrition that is required during fruit development, there's two different stages which I'm sure you're intimately familiar with. The first stage is what is referred. This is immediately after a blossom pollinates, the fruit embryo gets into the cell division stage. Actually, before I jump into this, I want to go back just a moment to talking about bud uniformity. If you notice this photo and this example is, this is an example of a cluster with a high degree of uniformity. The majority of these buds will all open and blossom and pollinate within a very condensed time window, which then gives us the capacity to have a high degree of fruit uniformity as well. So once we have the high degree of fruit, you know, or bud uniformity, and we want to achieve really firm fruit, then we need to manage nutrition during the cell division and cell expansion phase. So for cell division, for blueberries, this can, I've listed here, 10 to 14 plus days. And for blueberries, particularly for some varieties, in some climates, this can extend to sometimes being as long as 30 days. And what we want to have happen during the cell division period is to produce the greatest number of cells possible. And while we're producing the largest number of cells possible, to also have really strong cell membranes, because the more cells that we have, the larger and the firmer the fruit can be. And the number of cells that is produced and the cell membrane integrity and the cell membrane strength that is produced in this during this cell division period, Limited by the calcium supply and limited by calcium availability. So the when we are successful in supplying a lot of calcium during this cell division window, during the cell division period, we can produce really firm fruit that is really strong and that is also really large. When we look at some of the varieties that are exceptional at producing large fruit size, Duke being one that comes to mind, it's common. One of the characteristics that we've observed in SAP analysis is these varieties often produce a larger berry size, partially because they are quite effective at absorbing calcium from the soil profile, Perhaps more effective than other varieties which are planted on similar soil conditions. After the cell division, of course, the plants switch to cell expansion for the remainder of the fruit field period. And this is what determines the actual berry size. And the berry fill for the duration of the fruit fill period is going to be limited by potassium availability. And I've spoken a lot recently about why this is important to manage and the fact that calcium and potassium have a strongly antagonistic relationship, A challenge that we have in a lot of tree fruit crops and blueberries as well, and actually blueberries in particular, because of their relationship to calcium and high or low calcium soils, that often we have a surplus of potassium that is limiting calcium absorption, and this becomes extremely important. And actually blueberries have the capacity to manage this when they're supplied with enough manganese, which often doesn't happen. I want to describe this in just a moment. So what we have observed in our SAP analysis, we've collected quite a large number of blueberry analysis from a number of different growers all over the country. And of the hundreds of samples that we've looked at, kind of across the board we look at, we've developed desired values for blueberries based on what we are observing the healthiest and the highest yielding crops to be. So the desired values that we've established are not laboratory averages. We don't care about growing an average crop. Instead, the emphasis has been on crops that are the highest yielding, the highest performing. And the general trends that we're observing across much of the data is that we're seeing low levels of phosphorus, nitrogen, calcium, manganese and iron, as well as other trace minerals. It's not uncommon to See zinc and boron and copper levels below as well. But in particular, these five elements are consistently showing to be quite low. And then we're also seeing elevated levels of potassium and chloride. And in fact, I believe, as I was describing just a moment ago, the high potassium levels that are showing up on the SAP analysis are actually contributing to the plants not absorbing calcium very effectively. And also the elevated chloride levels are contributing to plants not absorbing nitrogen and phosphorus very effectively either. But that's something that we can unwrap. So how do we, how should we, knowing all this within this context, how should we manage blueberry nutrition differently from what we might manage other crops? And I think in order to be able to answer this question and also this question, how to supply nutrients in a challenged PH environment where we don't want to have alkaline soil pHs, we need to really understand soil reduction oxidation a little bit better. So I'm sure that all of you are familiar with ph, a scale that measures acidity versus alkalinity on a scale from 0 to 14, with 7 being the neutral point. And we also need to be cognizant, particularly for blueberries of EH or redox, which is a measurement of reduction versus oxidation on a scale from 0 to 42, with the neutral point being 28. And understanding EH is extremely important for blueberries. It's important for all crops, but it's particularly important for a blueberry crop because of the environment that blueberries have natively been adapted to. So when you think about examples of reduced environments would be blueberry or cranberry, bog apple, cider vinegar, yogurt, corn silage, sauerkraut or rice patty. These are all very reduced environments. The opposite end of the spectrum from a reduced environment would be a very oxidized environment. So oxidized environments? Well, oxidation is just the natural weathering process whenever you begin weathering soils or minerals. So anything that will basing anything, essentially anything that will rust, sheet metal is a very strong oxidizing effect. So if you add sulfuric acid, for example, to sheet metal, that's a very rapid oxidizer. And blueberries, really, there's this entire conversation around blueberries requiring acidic soil pHs. And when you look at the environment that blueberries have adapted to, being a native blueberry, bog peat, soil, etc. Many are some of the sandy soils, many of these soils do have acidic pHs, but they have something else as well, which is that they are extremely reduced. And in fact, you can find some environments where blueberries are growing natively that are very reduced but are not acidic, which is not common, but it does occur occasionally. So the reason this is important is because all the metal trace minerals, such as with the exception of zinc, but particularly manganese, iron, copper and cobalt, absorbed by blueberry plants and are most active when they are in the reduced form. And in fact, blueberry plants have adapted to have extremely high requirements, particularly for manganese and for iron, because they've adapted to being in a naturally very reduced environment where there is an abundance of manganese and iron. So the. When we look at a SAP analysis and we look at what defines the ultimate in plant health and performance for blueberry crop, the manganese and iron levels are sometimes as much as three to four times higher than they are for other berry crops such as caneberries, because of their adaptation to being in a blueberry bog and to being in a very reduced environment. So the key commonality between all these reduced environments that are described is that they have anaerobic digestion. So I wanted to describe reduction versus oxidation a little bit and what we are observing from a microbial perspective and also how that translates to nutrition management. So a very key point is that reduced environments and acidic environments sometimes correlate in biological systems. In fact, I would say that they usually do. And when we're. Whenever we have a biological system soil biology, or take yogurt, for example, or sauerkraut, or corn silage, or any of the examples that I mentioned, the elements that they have in common is that not only are they very reduced, but they're also very acidic. And it's common for biology in reduced environments to produce microbial metabolites that are quite acidic, Such as if we use corn, corn silage, or yogurt, for example, these, this anaerobic fermentation or anaerobic digestion process, this reduced digestion process is resulting in the formation of a lot of lactic acid, which has the effect of reducing the ph. And so generally in biological systems, when biology has a food source to digest and consume in an anaerobic environment, they will also tend to produce acidity, which is why we've developed the idea that blueberries thrive best in acid ph soils, and why that has also generally been observed to be true. However, this correlation between reduced environments and acidic environments is not necessarily true with chemistry. So it's possible to have acidic materials which are very oxidizing, and it's possible to have alkaline materials which are very oxidizing when we look at it from a chemistry perspective. So an example would be Limestone. Limestone as calcium or magnesium carbonate, the oxygen in the carbonate. So carbonate we have CO3. And the same was true for bicarbonates, where we have HCO3. Because of the presence of oxygen in carbonates and bicarbonates, those materials are very oxidizing and they produce the soil environment in a blueberry root zone that we don't want because they suppress the absorption of manganese and iron and phosphorus and because they have an oxidizing effect which blueberries don't like. However, another oxidizing material which is very acidic is sulfuric acid. So sulfuric acid, very acidic, but is also very oxidizing. And the optimal, where we've really observed, or I personally have observed, some extraordinary blueberry health and high yields, is when growers applied materials that were both acidic and also reducing. And one example of that would be acetic acid or apple cider vinegar. Apple cider vinegar, very acidic, and it's also very reducing because of the result of the fermentation process. So obviously, depending on the soil environment and the context which we're talking about, it's not always practical or appropriate to consider acetic acid as a replacement for sulfuric acid, but in the situations where I have observed that it's been exceptionally successful in delivering extremely high quality. So I think it's certainly something worth considering. When we look at the macronutrient anions, these are materials which have very large redox swings in the soil profile. So if we look at nitrogen, for example, or phosphorus, sulfur for sulfur, we know that all of these have different, a number of different forms. So phosphorus, we have phosphates, phosphides, phosphites, nitrogen, we have nitrate, nitrites, ammonium, urea, etc. So there are different. These can be in different oxidation states as well. In addition to they can have oxygen elements added or subtracted to them, PO4, PO3, etc. When we consider oxidation versus reduction from a nitrogen perspective, we have nitrate which is oxidized and which we can see in the chemistry Formula as being no 3. So we have the presence of oxygen. And this is why this is another indicator. Blueberries are adapted to thriving in reduced environments, which means that they are dependent on absorbing their nitrogen in the form of ammonium. They don't have the nitrate reductase enzyme and the nitrate metabolism pathways that enable them to convert nitrate, which is why they can actually get nitrate toxicity from over applications of nitrate. So that's another indication. Rice has a similar characteristic, the same characteristic. So it's another indication of a plant that has adapted to thriving in a very reduced environment. So when we look at oxidation, reduction in, when we look at nutrient availability on this EH scale, 0 to 42, the zone, there's a zone slightly below the neutral zone, slightly below 28, which is the optimal environment for blueberry nutrition. And this is also the zone where we have the peak availability of manganese, iron and phosphorus. And it's also the zone where all of the nitrogen that is present in the soil profile is going to be formed in the form of ammonium. When you go above the neutral line and move into the oxidized territory is when you're going to have nitrates showing up in the soil profile. In addition, there's another conversation around soil biology, particularly within the domain of biological and organic agriculture. There has long been a conversation that we need soils. Healthy soils are aerobic soils. We need to have the presence of oxygen. And I can't find any evidence in the literature to support this hypothesis. The idea that this might be true, in fact, quite the opposite. And instead what I find is that the really healthy soils need to be primarily populated by these two groups of bacteria in the center, which are termed the facultative aerobes and the facultative anaerobes. These are really the strains of bacteria that lead to the development of disease suppression. When we describe and talk about developing disease suppressive soils and also producing reduced minerals, so producing very available manganese and iron in the soil profile, these are the two groups of bacteria that have this effect in the most pronounced fashion and that contribute the greatest to disease suppression. So for blueberries in particular, for crops in general, but particularly for blueberries, it is not that they require a soil that has an abundance of oxygen. Instead, they require soil that has a good gas exchange. But for blueberries, this is true of crops in general, but blueberries in particular are adapted to living in soils that are right on the edge of being saturated for a great deal of the time. So when we take all of these various pieces into consideration, and we think about the need to supply calcium during the bud development period, during late fall at leaf drop, as we enter the dormancy period, when we think about the need to supply calcium during the cell division window, and we think about the nutrient trends that we're observing in blueberries, we look at all of this and think about reduction versus oxidation. How do we supply the best nutrients at the optimal timing to produce the greatest crop responses? What's the where can we apply the least amount of material to produce the greatest effect? Here's some Strategies and some ideas to keep in mind. First of all, I would suggest that we avoid applications of oxidizing materials, particularly carbonates, bicarbonates. You already know about nitrates. And in general, I think, from. From what I've observed so far in my experience, it is really the carbonates and the bicarbonates that have the most substantial negative impact on blueberry production. And I have a question mark about sulfuric acid. Obviously, many blueberry growers are using it very, very successfully, and who am I to argue with success? So there's a question mark. I would like to better understand how sulfuric acid, how the possible oxidizing effects of sulfuric acid are being mitigated. And I think we need to conduct some experiments and to better quantify the effects of other forms of acid that perhaps don't have a strong oxidizing effect as sulfuric acid. The challenge that we have to deal with, of course, is economics. And where's the economic threshold, what makes sense? We're using acetic acid or citric acid or not, and we may need to continue to use sulfuric acid at this point. I've observed some pretty interesting things, but we don't yet have enough information. And I, for one, am not comfortable making the recommendation that we should discontinue the use of sulfuric acid until we know a bit better what is happening with soil biology and what the true effects of sulfuric acid are, how that might be replaced with acetic acid, and whether there's economic viability in doing so once we start managing some of these other minerals. So I think there's a lot more homework to be done there. I don't have a good answer for that at the moment. Another thought that I would have is that we need to. For blueberries in particular, we need to supply generous irrigation, particularly when we're growing blueberries in substrate. We need to supply irrigation almost to the saturation point because blueberries love it. They have a root system that has adapted. It's a fairly shallow root system. It's adapted to an environment in which it's being constantly saturated. And so if we can keep that environment almost to the saturation point, the nitrogen that's in the soil profile is naturally going to remain in the form of ammonium. And we're going to have the greatest availability of manganese and iron and phosphorus, which these plants need very high levels of. And then the last point is that I would suggest we also apply any of the missing nutrients as foliar applications. And my reason for emphasizing foliar Applications. Blueberries, even though they have this glossy, waxy cuticle on the leaf surface, they can absorb some nutrients very well. So when a foliar application is properly designed, meaning that the nutrients are chelated and the foliar application has a high point of deliquescence. So what's point of deliquescens? I think it's perhaps important for me to discuss this because it's not a topic that's frequently described. A point of della quescence describes the point, the humidity point, at which a droplet will dry out on the leaf surface. What you want is a foliar spray, which has a very high point of deliquescence, which means that a droplet, as the droplet begins concentrating on the leaf surface, it begins absorbing and pulling humidity from the air and will remain liquid on the leaf surface for a much longer period of time. So it's possible for some, for a properly designed foliar spray that has a high point of deliquescence, to remain liquid on the leaf surface for up to 96 hours, in fact, even longer than 96 hours in some cases, and depending on the humidity of the air, of course, and whereas other foliar applications will dry out completely in as little as eight to 10 hours. And of course, this is all dependent on temperatures and humidity and a number of different factors. But you can find some interesting information online about the point of deliquescence. The summary being simply that there has been this idea for some crops that have this glossy, waxy sheen on the leaf surface, such as citrus and brassicas and blueberries, that they don't absorb foliar nutrients very well. What we've learned is that they do actually absorb foliar nutrients very, very well. When the foliar is properly designed, when it's not properly designed and it dries out quickly on the leaf surface, then they don't absorb it very well. My reason for emphasizing foliars, so you might ask, why not an application in the irrigation system or soil application? I am also an advocate of irrigation applications and soil applications. I'm not discounting those all. I think they're essential, they're very important. But for the, for the applications of particularly of manganese and iron and also of phosphorus, when we have soils that are not reduced, the soils are already oxidized, perhaps because of applications of sulfur, perhaps because of soil management practices, and the soil has really dried out, whatever the case might be, when we have very oxidized environments and we apply manganese and iron to the soil, even though if it is in the reduced form, it quickly oxidizes and a plant roots do not absorb it. We see very little plant absorption response from soil applications of trace mineral metals, manganese and iron. And for those cases in particular, we see the greatest crop responses and the most economic responses from foliar applications. So I think those are the that's one of the substantial advantage of foliars that we need to harness and take advantage of. So those are the thoughts that I wanted to share. I spent a bit more time reviewing those than I expected to. So I'd like to open it up for questions. Jim, I'm going to go to you. I know you and I have had a couple of conversations about blueberries over the last couple of days. What questions do you have or what comments do you have? Is there anything that you've observed or learned that you think is important to contribute to the discussion that I missed? Yeah. Just based on what you're just talking about, I wondered if there was a strategy of when you're applying your nitrogen through your drip, if you could use that as the time that you tried to keep the soil more saturated for a longer period of time. The short answer is yes, and I think, I'm sure many growers already know this. But of course you want to apply your nitrogen in the form of ammonium. And I think it's it's also important to constantly spoon feed the ammonium rather rather than putting on a large shot all at once. So if we put on and again this is dependent on soil and cultural management practices, but we have to also take the nitrification cycle into consideration. So if we apply 100 pounds of ammonium sulfate all at one shot, then particularly on soils which dry out or that are exposed to higher temperatures that are warmer during the summer months, then some of that ammonium sulfate is going to convert to the nitrate form which can lead to the blueberry plants absorbing nitrate and eventually lead to nitrate toxicity, which can really nitrate toxicity is it has to become pretty severe before it shows up on plants, although it does show up. But even when plants are absorbing just a very small amount of nitrate, plant doesn't have the blueberry plant doesn't have any way of metabolizing that and converting it once it's in the leaves. So a couple of things happen. One is it substantially increases susceptibility to diseases and insects when it's present in the leaves and even very small concentrations. And secondly, it really it's, it presents a tremendous energy drag and yield drag on the plant so you can really slow down yields a lot by having even just a very small amount of nitrate in the system. It's better to just avoid it altogether. And that means spoon feeding ammonium through the system or through the season as needed. Good question, Jim. All right, we have a number of questions coming through here, and also if any of you want to ask questions live, you can go into the participants section. I see we have one raised hand here, so actually I'm going to go there first. Darren, I think you are now permitted to speak. You have to tap on mute. Hi, Darren. Glad to see you here. Hey, how's it going? It's actually, I'm with Elon as well, and he has a couple questions for you regarding in particular, our substrate production. Blueberries. Yeah, I think I also have questions on the Q and A. So I don't know if you may have them in front of you, but the first one was just about how might dissolve oxygen levels in the irrigation water affect crop health and overall oxidation. That's a very good question, Elon. And I. I don't. The short answer is I don't know. I would expect. I mean, oxygen obviously is a very strong oxidizer, so I would expect that it would have an effect. But your question actually leads me to think of something else, which is that I mentioned carbonates and bicarbonates just in the presence of fertilizing materials such as limestone. But actually the presence of carbonates and bicarbonates in the irrigation water can also have a very substantial oxidizing effect. So water quality for blueberries becomes particularly important. Regarding dissolved oxygen, you can actually. You can measure the redox values of water itself directly, and I think that would give you an indication of whether it is having an effect or not. I don't know the answer directly. Okay, very good question, though. Did you have another question as well? Yeah. He wanted to know how soil moisture might be altered through the production cycle. Because, you know, we're growing in substrate and we can. We can affect our watering and tension in the soil through the growth or expansion, bud formation, fruit set, etc. If you have any recommendations for optimizing those different cycles. Yeah, so when we have saturated soils or soils that are just on the edge of saturation, they're essentially at field capacity, then those soils will tend to be reduced, which will mean that we will have peak availability of phosphorus, ammonium and manganese and iron. And when you think about those elements that I mentioned, each four of those nutrients has a strong reproductive effect in that they will trigger bud initiation or reproductive bud initiation. They will trigger strong bloom and they will trigger and increase the cell division and fruit fill and cell expansion process. So in general, when you have, for many crops, when you have saturated soils, it'll tend to increase reproductive effects rather than vegetative effects. Did that answer your question? Yeah, yeah, yeah, definitely does. Awesome. Thank you. All right, we have other questions. Questions coming through in the Q and A. Michael Guffey asked us a couple of questions. Hi, Michael. Have you experimented with amino chelated iron and or manganese as a foliar and or as a soil application through the drip? Yes, Michael, we have experimented with amino acid chelates and organic acid chelates pretty extensively. We generally find. Our general observation has been, of course, there's a number of different products available in the marketplace, but our general observation has been that the organic acid chelates seem to be absorbed more effectively than the amino acid chelates. Although the amino acid chelates generally are quite good as well. And almost invariably a foliar application will outperform a soil or drip application. It'll outperform in terms of speed of plant absorption and overall crop response. So I'm very strong in favor of foliar applications. Soil applications make more sense when we're dealing with substrate grown blueberries, but whenever we're dealing with real soil, there's simply too many unknowns that we don't know enough yet about soil biology and all the, the interactions that I have with minerals. And invariably we find that when we apply these trace mineral metals in drip irrigation systems, we get, we get a response, but we get a delayed response and a smaller response than we do from a foliar spray. So it's better than nothing, but it's not as good as a foliar. Michael asked a follow up question. If calcium carbonate is not a good liming material because of its oxidation potential, what liming material do you supply suggest? So this is an interesting question, Michael, because for blueberries, of course, we don't often think about adding liming materials. Our usual challenge is the need to decrease rather than increase soil pHs. So with that consideration, unless you have extreme negative or extremely acidic soil pHs that you need to deal with, there are, I can imagine a possible situation where it might be appropriate to add calcium carbonate, although I've never encountered one. In general, when we need to supply calcium to blueberries, which happens frequently, our two preferred sources are gypsum calcium sulfate, which also, because of the presence of the sulfate, has very, very slight oxidative potential. Much, much less than limestone and, or calcium silicate, which can be a mine source, sometimes referred to as wallocinite. And that can be a very effective form of supplying calcium for blueberries without, without having an oxidizing effect. And then Michael asked the follow up question in regards to using citric acid being in a saturated environment, wouldn't its byproduct of CO2 lead to high bicarbonate in the soil solution, thus leading to oxidation? Michael that's, that's not my understanding. If my understanding of the interactions of citric acid in the soil is that it does lead to CO2, it also leads to the formation of carbonic acid and some of it remains as citric acid as well. So releasing CO2, of course, is not a bad thing because it benefits plant growth and plant development, assuming the plants are healthy enough and photosynthesizing and capable of absorbing it. So the CO2, many of the crops that we deal with are actually CO2 is one of their biggest limiting factors to increasing yield and increasing quality. So I don't see the formation of CO2 as being a negative or to the formation of carbonic acid either being a negative. Each of those. With my current level of understanding what I currently know about citric acid and carbonic acid soil, my understanding is that it's only a positive. Catalyn asked the question, can we measure the EH level in our soils? And please talk about delaying the harvest window. So the short answer is yes, you can measure eh. It's. I'm using the technically correct terminology, but a different way of referring to EH is just simply to measure redox. So you can purchase inexpensive redox meters for probably in the neighborhood of 90 to $100. I think while it can be for many crops, I don't think it's important to measure EH or redox. For blueberries, it can be useful to measure that, particularly when we're growing in substrate. And I think perhaps the more important piece in the actual chemistry itself is the soil biology that is present, which can have either a reducing or an oxidizing effect. So it's very important. I haven't spoken much about the biology, but it's very important to manage the biology that substrate as well and in the, in the soil profile, because some biology, what I referred to as the disease suppressive biology. So the facultative aerobes and the facultative anaerobes, during their development process, they will actually reduce the minerals, the trace mineral metals such as manganese and iron in the soil profile and increase their plant availability. So it's important. And so the really healthy and beneficial bacteria will have that effect. Aerobic bacteria, the oxidizers will tend to have an oxidizing effect. So it's not just about the chemistry. It's also about the biology that is present in the soil profile. Spencer. Hi, Spencer. Glad to see you here. Recent published article states that foliar applications of calcium chloride help with Draper drop on Western Washington blues. Which organic substitutions would you recommend for calcium chloride? Spencer, you've identified one of the anomalies of the organic certification process. Crazy as this sounds, and it is really crazy, there is an organic calcium chloride that is. I think it might even be Omri listed. It's a product called Calcium25. It's really expensive and has. Has a whole set of challenges all its own. So there is actually, or there used to be. I haven't received any updates recently, but I believe to the best of my knowledge, there is still calcium 25 available, which is organically certified calcium chloride. I have no idea how they got that through the regulations, but they got it passed somehow. And a substitute for that would be. Well, the simple substitute would be our holocal, which actually we've done a bit of work with Holocal in coastal Oregon and observed substantial improvements in calcium mobility into the fruit, embryos into the fruit, which is actually something interesting to speak about when we go back to thinking about cell division versus cell expansion. The standard knowledge has been for a long time that almost all the calcium that moves into a fruit will move into the fruit during the cell division period. And after cell division, calcium absorption and calcium movement of the fruit, for all practical purposes, essentially stops. There might be a slight trickle, but there's very little calcium that moves into the fruit past that point. And. We found that to not be true when we've used Holocal. So applications of a holocal as a foliar, where the calcium remains in the chelated form, we've actually been able to document calcium movement from the leaves into the fruit, which has been really interesting and really intriguing. It's something that we would expect with a good chelated calcium. And so I don't know whether that would specifically help with the Draper drop that you described and that you asked about, but I do know that it will be effective at moving calcium into the fruit. It's a very good question. Meredith asked the question, do I have any thoughts on specifically on low bush or wild blueberries? Also in the context of reduction oxidation, do you recommend against application of lime as a calcium source for blueberries. So regarding lowbush or wild blueberries, these the low bush blueberries haven't natively adapted to reduced environments to the same degree that the highbush blueberries have, so they are less dependent on having a very highly reduced environment. They also have lower nutritional requirements for manganese and iron and phosphorus as a result of that. But they they still are related, of course, and they still do have a similar root system pattern, etc etc. And ammonium applications as well. So for the in general, for the lowbush blueberries, I would make similar recommendations, similar agronomic recommendations as I would for the highbush. I would generally recommend avoiding limestone calcium carbonate as a source for calcium. Again, unless you have extremely acidic phs that you need to address. My preference would be to use gypsum or to use calcium silicate, which will either one, but gypsum in particular, or both of them depending on the quality, will provide all the calcium that the crop needs and still maintain the optimal soil environment that we're looking for. So I think I've answered all the questions that came in in the Q and A. I see there's a couple here in chat as well. Actually, before I answer these in chat, Kevin, are there any comments that you'd like to add from your experiences or questions that you have? Hi John, you know, I might just ask the question I asked you the other day and maybe if you could speak to applying a biological soil program in the fall on substrate and how that differs from applying to a regular soil. Yeah, so managing the soil biology for blueberries becomes extremely important because of the need to have a reduced.