Transcript
00:00 Patty Skinkis
This is the HiRes Vineyard Nutrition Podcast series, devoted to helping the grape and wine industry understand more about how to monitor and manage vineyard health through grapevine nutrition research. I am your host, Dr. Patty Skinkis, Professor and Viticulture Extension Specialist at Oregon State University.
21:00 Patty Skinkis
Vineyard nutrition is a subject area where many growers, consultants, and extension educators often want to learn more. Many want to know how to better diagnose and manage vineyard nutrient issues. However, nutrient issues in a perennial crop like grapes can show up slowly and be hard to fix quickly. It's generally much easier to identify a pest or a disease issue in the vineyard and come up with a spray program that can take care of that pest if it's a mite or insect or preventable disease such as powdery mildew or botrytis. However, it is much harder to give an action plan for vineyard fertilization. This is because grapevines have only so many ways that they can show that there is a nutritional issue. That might be loss of yield, might be color change, which can be confounded or confused with viruses. There can be stunted growth, which could be due to trunk diseases. There's a lot of other things that can cause issues beyond just nutrition, unfortunately, most people think it's due to those other factors before nutrition.
We can look at diagnostic testing of either plant tissues or soils. Then we need to make a decision based on what those reports tell us. Of course, the reports don't tell us perfectly what needs to be done. Sometimes there's fertilizer recommendations, but I see that many people are very nervous about what to do in those next steps. What actions need to be taken to ensure a healthy vineyard from the mineral nutrient standpoint?
Well, to help address this question in season three of this podcast, we focus on the practical side of what people are doing out there outside of the project. I invited Fritz Westover to talk vineyard nutrition with us today.
Fritz is a viticulturist and the owner of Westover Vineyard Advising and the Virtual Viticulture Academy. He also has a podcast known as The Vineyard Underground. If you haven't listened to it, you should tune in. It's pretty good. I enjoy listening to it myself. He's been working in viticulture for more than two decades. He has a Bachelor's Degree in Horticulture from Penn State University and a Master’s of Science in Plant Pathology, also from Penn State. He worked for several years internationally and served as a viticulture research and extension associate with Dr. Tony Wolf at Virginia Tech. Then he went on to Texas A&M and was a viticulture extension educator there. He’s also had some other posts in industry, with The Vineyard Team. He’s got a strong background in both viticultural research and outreach that serves as a strong foundation for his newest ventures as an advisor and an educator in the private sector.
Fritz started the Virtual Viticulture Academy in 2018, and the mission of his work is to help growers improve their practices with approachable, accessible information. He serves many growers of all acreages, so many different sizes of vineyards, so about 2,000 acres and across 35 states and 10 countries.
Thanks for joining us, Fritz.
03:30 Fritz Westover
Hey, Patty, it's great to be here. The last time I saw you was about a week ago yesterday from the time of this recording at the Sustainable Ag Expo in San Luis Obispo, again, with The Vineyard Team who I worked with. It was so great to hear your presentation. You're such a great speaker. It's great to know that I can reach out to you when I have questions, especially for my growers I interact with in Oregon. It's been really great to have you as a resource and a friend.
03:58 Patty Skinkis
Thanks Fritz. I'm glad you were there and got to know a little bit more about the project and what's going on. I want you to tell us a bit about the nutrient-related issues that you face as an advisor and an educator. What do you typically hear from growers that you serve?
04:16 Fritz Westover
Patty, as you mentioned, I work with growers in many states and other countries. I've seen pretty much any nutritional deficiency or excessive nutritional situation that you can come across. I would say it really depends on the region. As you know, every region has different soil, different climate, different varieties and parent material that the soil is comprised of. When I break it down, the most common nutritional deficiencies really depend on soil pH at the basic level. Let's give some examples of that. If I'm working with a grower in Pennsylvania or Virginia, or even East Texas, where we have acidic soils, there tends to be, and I think you remember from the textbook days of soil science, as your soil gets more acidic or a lower pH, you lose the availability of certain nutrients the more acidic the soil. Then if the soil is more basic, you get into deficiency ranges with certain nutrients. There's kind of that sweet spot in between, which is that 6.0 to 6.8 pH--that basic range--where most nutrients should be available if they're there in the soil.
5:22 Fritz Westover
In the eastern United States those examples I gave--Pennsylvania, Virginia, eastern Texas--we tend to see anything from nitrogen deficiency which can be seasonal sometimes. If it's a drought year, there's not water availability, there's not nitrogen moving in the water. That can be a factor. Magnesium deficiency tends to be common. We also see, for micronutrients, things like boron and zinc deficiency in those acidic soils. I'd say if I was going to do a survey of all of the nutritional panels I've looked at from plant tissue tests, those [nutrients] would be the most common [deficiencies] in the acidic soils. When I look at where I'm working, maybe in the Texas Hill Country, or High Plains, or in my growers sites in Arizona where I consult, or if I'm looking at a soil test or plant nutrition data from California where there's a higher pH soil, a basic soil, maybe above 7.0 or 7.2 to 8.5 is that range, we also can find nitrogen deficiency, again depending on the season and the crop load. We can also see, in addition to magnesium, potassium starts to show up as deficient sometimes in those soils. Again, depending on the parent material and that cation exchange and some of the cations in the soil, we sometimes see iron deficiency [in those basic soils], which is not as common in those acidic soils. Again, boron and zinc [deficiency] can show up as well. Those are the main ones. Sometimes manganese deficiency shows up in tissues in those basic, high pH soils as well. Those are kind of the range [of nutrient deficiency], so with my program, I've just found ways to think about what methods the grower has for 1) improving the nutrient availability through maybe manipulating pH, and then 2) what methods they have to apply, and then 3) what their seasonal conditions are. Are they in an area where they get rainfall and are basically dry farming, or do they have access to irrigation? And I think we'll get into details about that as we go through the discussion. But those are the main nutrient [issues] I see. I think that some growers, believe it or not, almost never see deficiencies. There are some growers that just have the right balance of pH, the right balance of—their sum of cations [in the soil] is in balance for [vine] uptake. They get the right amount of moisture during the season to make sure those nutrients get to the roots. The roots are actively growing through the soil, so they're knocking on the door to those nutrients to get those as well. The beautiful situation is where you just monitor, but you don't really have to do anything. That's a magical thing.
07:58 Patty Skinkis
With grapevines, they don't have a huge demand. So that's why it makes it so challenging to diagnose issues when they pop up.
08:08 Fritz Westover
Yeah, compared to other crops, nitrogen and water levels that are needed in grapes are much lower. And if you have high enough organic matter in your soil, as that decomposes and cycles through microbial interactions, you could almost get enough nitrogen for the entire season, just through your organic matter content in your soil. So, we always look at that when we're starting a new site.
08:29 Patty Skinkis
When it comes to dealing with these nitrogen issues with your clients, are they usually something that your clients come to you and say, “I think I have a nutrient deficiency?” Or are they coming to you saying, “I have an issue just with general plant health?”
08:45 Fritz Westover
A lot of the growers I work with in my startups--where I'm helping someone with a bare piece of land—to get their vineyard going, we look into the soil, and we try to determine what's there, what's available through the pH, through the organic matter, through their cations already there. We try to adjust that before planting so we can prevent it [nutrient issues]. But to your point, I do have growers who already have vineyards in the ground before I started working with them. And they'll come to me, not always with nutritional issues. They'll come to me with, “Hey, why are my vines so pale green?” or “Why are my shoots stopping growing before bloom?” or “Why am I not getting a full canopy?” And as you know, if you don't get your full canopy size, you don't have the carbohydrates and the capacity to carry over to the next season or to get the yields that you need. I typically get a grower who sees something that just doesn't look right and it's not always nutritional. In your introduction, you touched on that. It could be they have an old vine with trunk disease and with virus. They could be in a drought situation, which could be a water limiting factor. With limiting water, there's limited nutrient uptake as well.
09:52 I get growers who will come to me with a visual issue and then we start going through the process of diagnosing, and that's one of the things that I think is the most fun. I've been diagnosing problems in vineyards ever since my Extension days, and it's always exciting when you can nail it--and usually with enough testing you can. We'll look at things like disease, water availability, soil issues, and pathogens in the soil as well. But the first thing we'll do is take a plant tissue test and see if there's anything that comes back from the lab deficient. And then of course we'll ask, “is it because there's not enough of it available in the soil?” or, like we said, with nitrogen, nitrogen moves in mass flow, right? You need water to move it around to the roots. If we don't have that happening, the roots may deplete their nitrogen source right around the root surface, and therefore they're going into deficiency mode without proper irrigation or rainfall. We tackle it from a step-by-step process and process of elimination. It's very rare that someone comes to me and says, “I need your help with this nutritional deficiency.” It's usually “I need your help diagnosing what's going wrong and is it nutritional or is it something else?”
11:06 Patty Skinkis
I agree. The troubleshooting list of 20 questions or more is really fun, and I enjoy doing it too and it's cool that you get to do that hands-on with growers.
11:17 Fritz Westover
For any grower listening out there, the better your record keeping is, the more it's going to help us to diagnose it: your fertilization program, your spray program, your irrigation program. Everything you can give us, that's going to help us dissect it.
11:29 Patty Skinkis
Absolutely. Thank you so much for saying that, Fritz, because those sorts of data holes exist—then you have to walk in on the site and look and just try to [troubleshoot]. It's a perennial crop. You've got years and years of factors that will compound on each other, so you have to have that long term, or at least multiple-year data leading up to it.
You mentioned plant tissue samples. What type of tissue do you normally collect? What's the timing? Can you give us a little bit more detail on that?
12:02 Fritz Westover
Soil is the first thing we look at when we're building a new site. Then we want to test to make sure the amendments and treatments we did actually had the effect that we wanted. But beyond that, once the plant's in the ground, my typical protocol is to start testing plant tissues in year two. Year one we'll typically fertilize; I like to fertilize in year one if the soil is showing it's deficient or if the vines are not growing well. I'm a big advocate of giving the vines what they need to get established well, whether it's year one and year two. And then at that point, whether it's two or three years in, I highly recommend that my growers start taking tissue samples. I like to do that twice a year. That's always how I was trained to do it and because throughout the season things are changing. I use the first tissue sample at bloom and then I do another one at veraison because that's where the industry standard charts are giving us the data that we're going to then look at to determine if we have deficiencies or excessive amounts of nutrients. I personally have been following the Pacific Northwest guidelines as you're aware of. I think I even asked you a question about this during your talk on the HiRes Nutrition Program at the Sustainable Ag Expo. Some growers will do petiole testing. We have a lot of data on just the petioles. Then some growers will do leaf blade, where they detach the petiole and send that [leaf blade] in and you're going to get a different set of standards for that. Higher nitrogen and other nutrients should be expected to be higher in concentration in the leaf [blade] versus the petiole. I've actually been doing a whole leaf with the leaf and petiole attached as my baseline. Now, when a grower says, “well, wait, that's kind of two sets of data”, the way I see it, it's one big set of data that gives us a snapshot. If I start to see that a vineyard is having some issues with any one nutrient deficiency and it's chronic from one test period to the next, I'll then start to separate out the petiole from the leaf blade to see if I'm getting consistent readings of deficiency in both the petiole and the leaf blade, or if it's just in one or the other. And I know that can muddy the waters, but when you look at a lot of data and you follow a vineyard, it just gives you one more layer of the of the onion to look at, so to speak.
14:20 Fritz Westover
I do both whole leaf with petiole attached as my baseline and then I separate it out if I think that there's a deficiency or something is showing up in the leaf tissue that I'm just not really seeing in the vineyard. I always like to match what I'm seeing visually. I remember back when I was working at Virginia Tech in 2006, I wrote an article on how a grower should approach their nutrient management in vineyards, and I thought why don't I come up with a clever acronym? That's what everyone wants, more acronyms. I used one that growers would know well in the area because they grow a lot of vertical shoot positioning. So, I said, “let's use VSP as our nutritional acronym.” It stands for Visual, Soil and Plant tissue.
15:01 Fritz Westover
We start with the soil. I only do soil testing about once every three years in a vineyard. Or, if I'm doing amendments like compost or lime amendments to change pH, then I'll go and do a soil test after that to see what the effect was. But generally, I'm using those plant tissues on an annual basis. My philosophy with the plant tissue testing is that at bloom, the growers get their progress report. You and I both have kids; I have one. You want to know that progress report to know if they are doing okay. Do you need to step it up a little before the end of the season? Are you going to pass or are you going to fail? The progress report tells you at bloom if things are where they need to be as you enter into fruit set and to veraison.
Then that veraison sample, and by the way, you still have a chance to add nutrients early on after fruit set and get them to uptake through the soil or through a foliar spray; we can talk about methods a little later. But the veraison report is kind of like that final report that's giving you information on how did for the season. Are you coming into harvest with a major deficiency, like a magnesium or potassium or nitrogen deficiency? Those macronutrient deficiencies tend to be the ones that, in my experience, will limit ripening of fruit and compromise quality of fruit. So, we don't want that to be the case. And then I often times use that veraison sample, which is the final report card, to understand if I need to do amendments not only after harvest but before harvest. You can [make amendments] if you have enough leaf area. I'll give you an example, in areas in the south where I work, like Texas or Arizona, we sometimes harvest in July or August. And then we'll have three to 12 weeks, depending on the season, of active canopy area and root activity after harvest. You could put a fertilizer out, have it assimilated into the plant before dormancy, and it would actually be in the gas tank or reserves, so to speak, for the following season.
17:07 Fritz Westover
Then there are some times where you harvest your fruit in October, like in the mountains in Georgia or Virginia, and you get a freeze the next day after you harvest, so fertilizing after harvest doesn't make sense in that case. But the veraison tissue, back to my point, will tell you if you need to top off the tank, so to speak, for nutrients or anything before you go into dormancy so that the next season you start off with a full tank of carbohydrate reserves and nutrition and everything you need to get the vine started well. I'm an advocate, in some cases, of post-harvest fertilization. It doesn't work in all situations, but at least we know if we have to apply something, perhaps at bud burst. That's where I recommend if you don't have that period of time after harvest, you still can apply something before or just after bud burst so that you'll have that uptake before bloom. We can talk about that because the uptake at bloom is a critical time for most macronutrients.
18:05 Patty Skinkis
I really like the couple of nuggets that you've shared, with the VSP--the visual, the soil, the plant. I love it. It follows a lot of what we talk about in general, and we train growers how to look at nutrient data, to soil [data] every three years; you don't have to do it all the time. But that tissue analysis every year is so helpful, especially at key time points such as bloom and veraison.
The one question I have with the tissues, so putting the leaf blade in the petioles, I want to comment on that a little bit. It's very atypical, just because of how we've done things in viticulture for the last several decades. These recommendations came to look largely at petioles and not the whole leaf and blade with the petiole. Of course, the leaf blade focus came in a little bit later in the time course of research, but it's been done other places, just not here in the US as much, and the leaf blade and petiole together, I just want to comment on the practicality of it. I think it's helpful because anybody who looks at two tissues, two time points: leaf blade and petiole at bloom and veraison, it's data overload. Even for those of us who are doing research. The leaf blade and the petiole don't always align in terms of showing deficiency.
The real question is, I don't know what it would look like if we threw them together. For those listening, what happens is when you take these tissues, you send them off to a lab, they get cleaned to wash residues off, oven dried, and then ground into a fine powder. When you separate the tissues, you've got your leaf blade and your petiole and you can't just say “do the math and just sum them up” because it's a concentration, is what your data comes back as. If you take your leaf blade and you put your petiole with it, you can maybe estimate what those concentrations would be, but it's hard to come with a direct conclusion of what those numbers would look like if you look at a whole leaf blade or a whole leaf versus the two components separate. I think you, and others who do the whole leaf, have a unique data set to work with. It's not to say that you must do sampling these other ways, but pick a way of sampling and stick with it. And over time you'll have a plan for how you use the data. Obviously, it works for you, and you've found guidelines that help you diagnose issues. For listeners out there who are saying, “What? This guy's crazy, he's doing something different.” Or “I do this too.” It's OK. People can do things different, even though we tend to do some of our analysis or our sampling a bit different.
20:50 Fritz Westover
If I could add to that, Patty, that's my go-to protocol, but we definitely use just petioles in some circumstances. And I know the data shows sometimes it's better to do petioles at bloom, and leaf data might be more accurate for things like potassium at veraison or things like that. You'll hear a lot of these conflicting views and even some research reports from that. One of the things that I know they found at Texas A&M with their studies is that leaf blades have more contamination than petioles. If you're spraying any kind of spray product that has manganese in it, like there's growers in the east that use Mancozeb, it's high in zinc and manganese. If you're working on a soil that you believe could have deficiencies in manganese or zinc, you probably want to do petiole tests because that leaf blade is going to be contaminated from those [sprays]. There's always a case for looking into the site, what they're spraying, how they're applying things. If they do standard foliar applications with every fungicide spray, for example, if that's the grower's method, the leaf blade is going to carry a lot more residual contamination, and it doesn't always wash off. That's what some of the studies showed. You can't wash that manganese off. It becomes part of the test. You get growers sending test reports to you who are using Mancozeb in their vineyard and they say, “why is my manganese off the chart?” It's because no matter how good you wash it, you can't get rid of that.
I asked Joan Davenport, who was with Washington State, “why is it that you did these protocols with leaf blade and petiole attached?” And she gave me a very unsatisfying response at the conference. She said, “well, I just thought it was easier that the grower didn't have to detach the petiole from the leaf and they can turn the whole thing in.” And by the way, that's how most other crops do it. You know, fruit trees and others, berries, they'll use the whole leaf with the petiole attached. I love that there was a set of standards created for that. And I use that, but I've actually adapted it a little for each of the regions that I'm in. I think that the key is customization and experience. And what are you comfortable with?
23:04 Patty Skinkis
You're absolutely right. That is what most other crops do. They don't bother separating the petiole and leaf blade. I always say in viticulture, we always want to make things more complicated and there’s reason for that, but that this is maybe one of those other cases. Absolutely and I'm glad you talked about the leaf blade component carrying all of those potential contaminants because, if you think about some of the foliar sprays, you're adding an adjuvant that helps it really adhere to the leaf and it's difficult to get that washed off. That, and not all labs wash the tissues. Those are all very good points.
Next, I wanted to ask, how do you come up with fertilizer recommendations to correct an issue? I know you talked about the troubleshooting process and there's a stepwise approach. This is always what people want to know. Even our distinct challenge in the HiRes Vineyard Nutrition Project is we want to give people better guidance on how they can make recommendations, but you need to know so much in order to do that. It's not going to come out of an Extension publication or one simple talk or even our meeting today. Maybe talk about how you go about that process of coming up with a fertilizer recommendation or an amendment suggestion.
24:23 Fritz Westover
I'll give you all of my secrets right now, Patty, and then I'll basically be unemployed forever because as you know, there's a recipe, right? No, of course not. There's no recipe for fertilizer management or anything like that in the vineyard. It's pretty complicated, but that is job security for us who are helping growers. I approach it from the soil standpoint. If you can get the soil balance of your sum of cations, your pH corrected, that's going to create a scenario where nutrient uptake is going to be more balanced, right?
Let's take that out of the equation. Let's presume the grower did all that, but now they're getting a plant tissue report back from the lab and it says, well, we're a little bit low in nitrogen. And we're a little bit low in sulfur and we're a little bit low in calcium or something like that. What we then need to do is determine what means does the grower have to apply fertilizer?
There's really three main ways. They're either going to apply something to the ground; that's going to be incorporated in some cases or just surface applied. They're going to apply it to the foliage as a solution with their sprayer. Sometimes growers mix in fertilizer with their fungicides or just do a fertilizer spray by itself to do a foliar feed, and that works better for some nutrients than others. And then, if you have the luxury of a drip irrigation system--I find this is one of the most efficient ways to apply a small amount of fertilizer for quick uptake at just the time it's needed is through a drip irrigation injection system. That's my favorite way, but not everyone has irrigation if you're dry farming. Then you're thinking more along the lines of soil application or foliar application. If I see something like, let's say, nitrogen deficiency, and it's not really bad, it's just a slight deficiency, let's say in leaf tissue we want it to be somewhere around 2% or a little above 2% and it's low, I might just recommend that they do a foliar application of nitrogen in some cases. If the vineyard, for example, is high vigor and they're hedging it multiple times, if you add nitrogen to the soil and then it moves in through the roots, it's going to have more of an impact on creating more vine vigor and vegetative growth.
We know from studies at Cornell, and I think there's been studies now at Washington State University, that -- let's say your yeast assimilable nitrogen is low and your plant nitrogen is a little low and you're trying to boost both of those, a foliar nitrogen application can help with both in this case. It's going to get you through that period where you had a slight deficiency. It may be that the deficiency was only because of hot, dry weather. You don't want to put a bunch of nitrogen in the soil. You probably have enough in there, it just wasn't able to get into the plant. We're using it as kind of like a Band-aid to get you through. But if it's a more severe nitrogen deficiency, then you're probably going to need to address that through the soil so you can impact the uptake through the roots and actually increase vigor. If the site is looking low vigor, if the shoot tips are slowing down and they shouldn't be yet, if the foliage is a little pale green, that's a deficiency of nitrogen; if it's uniform across the canopy, it could also be a sulfur deficiency. If those both come back as deficient, then we start thinking, what type of fertilizer do we use, right?
There's lots of ways to get nitrogen into the system. Maybe, if you're going to be at the most basic level, an ammonium sulfate, if that's what you have on hand, has both ammonium and sulfur. Maybe, you tackle both of those issues through the soil with that. Or if you're looking for an organic method, maybe you're going to apply compost in the fall and let that work into the soil, so the next season, you have the organic matter and nitrogen availability in the soil to stop that from occurring again. I would say matching the fertilizer to the problem and then looking at the degree of the problem. If it's severe, I generally would go through the soil and not through foliar.
If it's a micronutrient, let's use that as an example, like boron and zinc are two of the most common nutritional micronutrient deficiencies I run across, I'll try to find a way to put boron into the system in multiple ways. Foliar is the easiest. You can add boron to certain products with your foliar sprays, and you could also add it to the soil through drip irrigation. Some growers even add it to their herbicide tank as they're spraying certain herbicides. Now, you have to be careful with compatibility, but boron's usually pretty compatible. It's a non-charged nutrient or element; it's not a cation or an anion; it's just kind of floating through the system there. Sometimes we'll put it on the ground if we need a long-term fix, and that's what I really like to do if there's something that's chronic, we're seeing it year after year, both in bloom and veraison [tissue samples]. We can't just spray our way out of that [deficiency] on the foliage. We need to add it to the system by adding it to the soil, either a ground applied fertilizer or an injected fertilizer would be the best way to go for a major deficiency.
We could do a whole podcast on just that topic. And I'm pretty sure I've done some on my Vineyard Underground if you go back far enough on methods of application and timing and things like that.
29:39 Patty Skinkis
You’re right. It's always matching what the capabilities are with the grower: what they have available to them and matching that deficiency. But it's work. There's no easy button.
29:51 Fritz Westover
To give a practical example: someone who's dry farming, let's say in the eastern United States, if they know they're chronically low with nitrogen or potassium or magnesium, it's usually magnesium and nitrogen, they can put something down before bud burst on the ground. Usually there's rainfall that will work that nitrogen into the soil. And maybe magnesium [can be applied], which is also know water soluble and moves in the soil. That means by the time they get to bloom, which is the major uptake demand for nitrogen and potassium, and then after bloom when you get into fruit set, there's a little spike in magnesium uptake demand. If you can get [fertilizers] out early in the season and hope that there's some rain to work it in, it'll actually be available at the root interface by the time that peak in demand comes.
However, let's go to an irrigated vineyard. Let's say it's in Arizona or Texas or California. If they're trying to be really efficient and use less fertilizer, you can use a lot less, maybe up to 10 times less fertilizer if you apply it through your drip irrigation and put it right next to the root versus putting it on the whole soil surface and having it trickle down and capture some of the root system and some of it not hitting the root at all.
In that case, I'm going to [reference] Marcus Keller's work where he says, when you get six fully unfolded leaves, you start to draw moisture from the soil because you have transpiration that draws from the root system. If you're putting out something through your drip irrigation before then, it's really not being taken up by the roots because the shoots are growing off of carbohydrate reserves, stored water and pressure. But once those shoots get six to seven fully unfolded leaves, then you have moisture being actively taken into the roots. If we can go through and do all of our shoot thinning and desuckering before six-inch shoot growth, then we can go in and fertilize immediately after we get to that point and we haven't fertilized our sucker shoots or anything that we don't want to put nutrients into that we're removing anyway. And we can put [on] a fraction of the nitrogen. If you're putting maybe 10 to 20 pounds of nitrogen per acre as a broadcast fertilization at bud burst, you could put as [little] as three to five pounds per acre of nitrogen through your drip irrigation at that peak timing right before bloom and then you would serve its need at the time that there is the highest demand by the plant. And that's just one example with one nutrient. Now think about doing that with every nutrient and looking at the timing and looking at the rate of application and looking at the method of application and now you can start to dissect what the best practices are for your vineyard.
32:33 Patty Skinkis
It's not always so easy to do it all in one shot.
32:36 Fritz Westover
Yeah.
32:37 Patty Skinkis
Do you have any recommendations for listeners to get better at their vineyard nutrient management? Any kind of things you wish that growers did, other than collect data? Although if you want to talk about that, that sounds good too. What specific information do they need, if that's one of the key takeaways that you would recommend?
32:58 Fritz Westover
Yeah, here's what I focus on when I'm teaching this topic. I focus on helping the grower understand what we've been talking about, the timing and demand of highest peak for each nutrient by the plant. If you understand that, you understand when you should be applying it. If you know your methods of application, should you be applying it earlier versus later in the season? Then doing the test of the plant tissue, really it's the tissue that I rely on, the tissue and the visual. Like I said, soil is important. If you have chronic issues, you're probably going to fix those through adjusting soil and fertilizing the soil. But the plant tissue is really the key thing. I don't like to just say take the data, and you know data, data, data. Get the data points so that you can see the full picture. But then understand when you're making a treatment with something like nitrogen, that it's mobile in the soil and it can quickly move through. But if you have a deficiency in phosphorus or calcium, those nutrients don't readily move with moisture through soil. That's why when we make applications of lime for an acidic soil, it has to be incorporated to the depth that we want to plant the roots at to make sure we're changing the soil at the depth where the roots are going to be planted because it's not like a row crop, right, Patty?
If you're planting a grapevine, you're burying that root system 12 inches to 15 inches underground, so you need to be able to influence the soil at 12 to 15 inches underground. Calcium will sit on the soil surface, and if it's not incorporated, it's not getting to where it needs to be. Phosphorus will sit on the soil surface, so sometimes we need to actively cultivate those nutrients into the soil and get them closer to the root. And over time, moisture and rain will move them downward. There are some fertilizers you can put through an injector that contain phosphorus or calcium. If we're using those two examples, and if you push them with enough water, they're going to move down that column and get to the roots as well. I think just understanding the mobility of those nutrients in the soil environment and how your application is going to relate to that [is important]. Then also [the movement] within plants because some nutrients are readily mobile in plants or can be taken up through plant tissues, like micronutrients. If you're doing a foliar spray, I generally only will do foliar applications of either micronutrients or nitrogen works as well.
I remember my colleague Joe Fiola from Maryland, you remember Joe, he made the analogy once, “putting potassium out through a foliar spray is kind of like a human sticking a banana in their ear and trying to get their potassium that way.” You just don't get the quantity you need if you have a major deficiency, but you get a little bit, and I think things like nitrogen, potassium, and magnesium are things that I'll put out in foliar feeds to maintain borderline low nutrient levels in plant tissue, and micronutrients on foliar. Learn what the mobility is of these nutrients, learn the best timing for uptake and demand, and then figure out what your methods are going to be, whether it's foliar, irrigation injected, or ground- applied fertilizers. And if you can understand those moving parts there, you can put together a program that reduces your cost for fertilizer by making the uptake more efficient: by applying using a method that is going to be better for uptake through the soil or timed better for uptake through the soil.
That's really where I focus when I'm teaching, especially new growers. I always say to the very new grower, “just make sure your vines have what they need because you're going to be worrying about pest and disease, young vine training”. You're going to have all these things going on, so just don't overdo it. Your vines don't need, like you said, Patty, a high demand of nutrients, but we definitely don't want to start off with deficiency.
36:52 Patty Skinkis
On the flip side we want to baby those vines. I appreciate that you said in years and one and two, feed the need. They're babies, they need some support.
37:03 Fritz Westover
Yeah. If the baby needs formula, give them the formula, because you want them to get established. And then later you can start restricting and stressing and things that you're trying to do for wine quality. But let's get the full vine intact as a young adult first, right?
37:18 Patty Skinkis
Yep, absolutely.
37:19 Fritz Westover
Yeah.
37:20 Patty Skinkis
All great advice.
I want to wrap up with a fun question. I know that you're an avid mountain biker. And I also interviewed Cain Hickey, who you know, we're friends, we're all viticulturists. He also is a mountain biker, and I asked him the same question: What is your favorite place of all time that you've mountain biked and why?
37:44 Fritz Westover
Oh, great question. Yes, I do love Cain Hickey. We've definitely mountain biked before there at Penn State where he's working now, my alma mater. I bought my first mountain bike. I'm going to say I beat Cain to it because when I was busing tables as a 13-year-old, I saved all of my tip money and I bought my first [bike], it was a Specialized Rockhopper Sport. It was an amazing new purchase. The most expensive thing I ever bought in my life at that point.
And I always loved biking in Pennsylvania, but when I went out to Moab and Utah and saw what was going on there, and then started biking in Colorado, I realized--wow, there's some amazing climbing and beautiful views that you can see from those areas. Being in Texas now, it's a little tough. I try to get up to Bentonville, Arkansas once a year if I can. It's a little mountain bike paradise there. But I would say I really have been loving learning the trails in Colorado and seeing the diversity of uphill, downhill, cross country and everything else I love. Some of my best thoughts come to me when I'm climbing up that 2,000-foot climb. It's weird.
38:49 Patty Skinkis
You do your best viticulture work on a mountain bike. That's great.
38:53 Fritz Westover
Yeah, or trail run, whatever gets my blood flowing, you know, gets my creative ideas going.
38:57 Patty Skinkis
Thank you so much for joining us today, Fritz, and sharing your knowledge. I know you're very open to teaching others and sharing your information and you just always seek to learn yourself, which is great and what makes you a great colleague.
Thanks everyone for joining us today and if you want to learn more about the HiRes Vineyard Nutrition Project, be sure to check out our website at highresvineyardnutrition.com. If you've been enjoying this podcast, please take a moment to complete the listener survey. The link will be in the episode information. https://oregonstate.qualtrics.com/jfe/form/SV_bvkyFYGqwy23AWi
Learn more about the HiRes Vineyard Nutrition Project: https://highresvineyardnutrition.com/
Learn more about Fritz Westover
- Website: https://www.vineyardadvising.com/
- Podcast: https://www.vineyardundergroundpodcast.com/
- Virtual Viticulture Academy: https://www.virtualviticultureacademy.com/
- LinkedIn: https://www.linkedin.com/in/fritz-westover-8660797
Related podcast episodes:
- Season 1, Episode 3 | The Grapevine “Blood Test” (Paul Schreiner)
- Season 1, Episode 8 | Honoring the Past, Building the Future (Matt Fidelibus)
- Season 3, Episode 9 | Digging Deeper to Decode Vine Tissue Results (Cain Hickey)
Podcast listener survey: https://oregonstate.qualtrics.com/jfe/form/SV_bvkyFYGqwy23AWi
This podcast was funded through the National Institute of Food and Agriculture’s (NIFA) Specialty Crop Research Initiative Coordinated Agricultural Projects (CAP) grant. Project Award Number: 2020-51181-32159. The continued efforts of the podcast are funded by the Viticulture Extension Program at Oregon State University.
Audio mixed by John Adams.
Diagnosing vineyard nutrient issues isn’t simple. In this episode, Dr. Patty Skinkis and viticulture expert Fritz Westover share practical strategies for soil and tissue testing, interpreting results, and timing nutrient applications for maximum efficiency. Perfect for growers, consultants, and academics seeking actionable insights to optimize vineyard health and fruit quality.
