Maine Farmcast


On this episode of the Maine Farmcast, Dr. Glenda Pereira, Assistant Extension Professor and State Dairy Specialist for the University of Maine Cooperative Extension, has a conversation with Dr. Lily Calderwood, UMaine Extension Wild Blueberry Specialist and Associate Professor of Horticulture. During this conversation we talk about the history of wild blueberries in Maine, Lily’s research and how to grow and tend your own wild blueberries at home. 
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Creators and Guests

Host
Colt Knight
Colt grew up in a coal mining family in West Virginia where they also operated a small family farm and show horse stable. During academic breaks and between schools, he worked in strip mines across the country. Colt earned his B.S. in Animal Science at the University of Kentucky, M.S. in Animal Science at Angelo State University, and his Ph.D. in Animal Science at the University of Arizona in 2006, 2012, and 2016, respectively. In the fall of 2016, he worked on a postdoc with Dr. Derek Bailey at New Mexico State University. Since 2017, Colt W. Knight works as an Assistant Professor of Extension for the University of Maine where he serves as the State Livestock Specialist. He teaches Introduction to Animal Science (AVS 145) and runs the Maine Grazing Behavior Lab. The core focus of the Grazing Behavior lab revolves around designing and manufacturing livestock tracking collars, engaging in applied grazing behavior research, and assisting other researchers with technology to interpret animal behavior. Dr. Knight’s research is broadly focused on selecting animals uniquely adapted to landscapes and promoting sustainable agriculture. Colt is the current chair for the Society of Range Management Livestock Foraging Behavior Committee, as well as, the North East Region Chair for the National Association of County Agricultural Agent’s Teaching and Educational Technology Committee. He also serves as an Associate Editor for the journal Ecological Processes. Colt is actively engaged in outreach and has delivered over 150 seminars on livestock production since starting his career at the University of Maine.
Host
Glenda Pereira
As the University of Maine Cooperative Extension Dairy Specialist, Dr. Pereira conducts applied research and develops educational programs for dairy and livestock producers across the state of Maine and New England. While the Holstein breed is near and dear to her heart, Dr. Pereira admires the Normande breed and her favorite dairy products are sour cream and ice cream.

What is Maine Farmcast?

The Maine Farmcast features weekly conversations with experts from across the country sharing insights and advice for both new and seasoned farmers running operations of any size. Hosted by three livestock specialists from the University of Maine Cooperative Extension, the show brings you world-class expertise paired with practical advice about how to apply cutting-edge research to improve the efficiency and sustainability of your farming operation.

Glenda Pereira:

Welcome to the Maine Farmcast. This is your host, Dr. Glenda Pereira an assistant extension professor and Dairy Specialist for the University of Maine Cooperative Extension, as well as an Assistant Professor within the School of Food and Ag. I'm really excited to have our guests in the studio today. We have Dr. Lily Calderwood, who is our wild blueberry specialist among many other things.

Glenda Pereira:

She's an expert in blueberries and integrated pest management, which I think is really exciting.

Lily Calderwood:

Thank you so much for having me, Glenda. Yeah. So my name is doctor Lily Calderwood.

Lily Calderwood:

I'm the wild blueberry specialist at the University of Maine, which means I'm an associate professor of cooperative extension and horticulture in the College of Food and Agriculture.

Lily Calderwood:

I wear a lot of hats, and there are a lot of needs within the wild blueberry industry between pest management and nutrient management. But I also dabble in fresh pack and helping farmers to have economically sustainable businesses and trying to come up with ways to have them move forward with their packing or harvesting of the berries in a way that will help them produce a higher quality product.

Glenda Pereira:

Right. Because the growing season is very specific, and then you want consumers to be able to enjoy that product for the rest of the year. Right?

Lily Calderwood:

Right. Right. So wild blueberries are harvested in, late July and August, and it's about a three to four week harvest window, which is a very short time to bring in, between 50 and a 100,000,000 pounds of blueberries just in Maine. And so all those berries come in, and about two to 5% of them are sold fresh. The rest are sold frozen.

Lily Calderwood:

And the crop is wild, which means that there's a lot of genetic variability across the fields themselves that makes the crop it it lends itself to frozen. Right. Because it's hard to process a very high quality fresh berry. Yeah.

Glenda Pereira:

And so you mentioned those production metrics in the state of Maine. Wild blueberry is a significant crop to our agricultural industry.

Lily Calderwood:

That's right. So wild blueberries are the one of the top three agricultural commodities in Maine. And it the value the value of the industry is about $250,000,000. And it it's also culturally an important crop in Maine. It's a historic crop in Maine.

Lily Calderwood:

There are indigenous people here still who grow this crop, and they are the first people, the Passamaquoddy tribe and the Mi'kmaq tribe in Nova Scotia and New Brunswick. They were the first people to grow wild blueberries, and, they still grow wild blueberries today. And it's a really special part of this industry to be able to work with them and learn from them and and see them grow even today.

Glenda Pereira:

So some of your role, like the other specialists we've had on the podcast, some some of your role as specialist within Cooperative Extension includes working with all of these folks you mentioned. And there's a Wild Blueberry Commission as well, so you you work with alongside them as well, and they kind of voice some of the needs of the growers and and kind of give a voice to the growers here. Tell me more about how long the year so you've been here for a little bit over six, seven years. Tell me how some of, the programs that you have conducted have addressed the needs of the growers because it's the growing season, is short, but every year, it differs. Right?

Glenda Pereira:

We have such extremes here in the state of Maine that it can pose some challenges, and I know that you and your team have been working to address some of those needs. So let's talk about your program.

Lily Calderwood:

Sure. We have a pest management group of projects, I would say, that are more focused on managing weeds in wild blueberry fields. And then, we have a group of projects that are focused on holding moisture in the soil, and this is really mulching. So spot mulching and whole field mulching are two NRCS practices. So I've worked quite closely with NRCS, which is the Natural Resource Conservation Service, and with farmers who have voiced their interest in mulching whole fields to hold moisture in the field.

Lily Calderwood:

And so in partnership with NRCS and several growers, we've done research to identify the thickness of wood chip softwood wood chip mulch applied to the whole field rather than just spots. And it's worked quite well so far, and it's reduced the prevalence of certain pests. Leaf spot disease and titmage have have dropped because of the mulch being applied, which are, like, side benefits to increasing soil moisture. So it's become a practice that farmers are actually adopting. But the only reason that they're able to actually adopt it is because NRCS is paying for it.

Lily Calderwood:

Right. It's an expensive thing to Right. Put quite a bit yards and yards and yards of mulch across a whole blueberry field. So blueberry fields are big. It's like for people who haven't seen one of these lowbush blueberry fields before, they're wide open.

Lily Calderwood:

It looks like a hay field, but it's growing many, many blueberries. And the crop doesn't get any higher than eight to 10 inches. And we manage it like a field crop. We are fertilizing with a fertilizer spreader.

Lily Calderwood:

We drive across the fields. We're applying this mulch with a manure spreader. People can be organic certified. They are there are plenty of conventional growers who are spraying with boom sprayers. Even though it's a wild tech wild crop, we are required to follow food safety standards.

Glenda Pereira:

Yeah. That gives us a good idea of the landscape of the wild blueberry, management here in the state of Maine because folks generally think of blueberries that we buy at the store, but they are not the same. And you tend to see more consistency with those. But like you mentioned, because these are wild, there's just so much variability with wild blueberries. So something that you mentioned was what these fields look like.

Glenda Pereira:

And, yeah, I've driven down East, and that's predominantly now correct me if I'm wrong, but that's predominantly where a lot of the blueberry fields are here in the state of Maine.

Lily Calderwood:

We consider there to be three regions, Mid Coast, Ellsworth, and Down East, because there are soil type differences and there are different weather patterns in these places. The fields in Midcoast Maine are very hilly. The fields are really on top of hills, small mountains, or they're on the on a hillside. In Ellsworth, in Blue Hill, they're on very ledgy soils, very rocky. And then Down East, the blueberry fields are on what we call, glacial outwash plains where the so the glaciers melted ten thousand years ago from this state and region in Canada too.

Lily Calderwood:

And as they melted, they created there there are rivers coming down as the glaciers are melting. And the River Deltas were are what became the blueberry fields that are down east. So they are, very sandy, gravelly soils. And because the blueberries have inhabited that space, that is a harsh environment. It they're very acidic soils across the state, wherever they're grown.

Lily Calderwood:

But especially Down East, there is this harsh environment where nothing else really wants to grow. And so the blueberries thrive, and they stayed there as this early successional species. And there there are very large fields out there. They're they can be up to a thousand acres in one piece.

Glenda Pereira:

So I wanna put a plug in for the Wild Blueberry Week. It's coming up.

Lily Calderwood:

Yeah. Wild Blueberry Weekend is the first weekend in August. And, this is an event that the Wild Blueberry Commission has organized, and they can or people, anyone from the public can go and visit a wild blueberry farm on that weekend, and you can buy blueberries.

Lily Calderwood:

You can participate in different events, and it's a really fun time. It's, you know, it's been an effort to get the public excited about wild blueberries and onto the farms to connect people to their food. Yeah. And so

Glenda Pereira:

we'll be attending some of those events that weekend. And it's funny. My husband previously in Machias, we made blueberry pizza with wild blueberries from a company Right. That was there. And it was like a dessert pizza.

Lily Calderwood:

Yeah. It's fantastic. It's so good.

Glenda Pereira:

It was such a delicious treat.

Lily Calderwood:

Yeah. And, you know, I feel like the reason why there's they are so delicious is because they're so small. And they're little berries. And so often they're used like, yeah, on a dessert pizza or in baking because it's not such a big bite of blueberry. You're getting, like, a little blueberry that and and that's, like, true for our tastes Yeah.

Lily Calderwood:

In home baking, but it's also true in the industry. So they're selling a lot of these frozen blueberries to companies that make baked goods. And Right. You know, it's an ingredient.

Glenda Pereira:

So how do you, Lily, freeze or extend the shelf life? Because at some Extension events that we've had in the winter, you've brought us some wild blueberries and they're always fun to enjoy. So how do you at home preserve, wild blueberries?

Lily Calderwood:

Yeah. Great question. I do what we call fresh frozen, which means there are fresh pints that are sold and I'll or five and ten pound boxes of fresh berries, and I'll put those directly in the freezer. And, so a farmer also does this. And so they will this allows them to continue selling blueberries throughout the year.

Lily Calderwood:

They'll sell everything they can fresh. And then what they don't sell fresh, they'll put in the freezer and store it there and sell it throughout the winter in five and ten pound boxes. And so, yeah, I get a pint and I just bring it home. I don't wash it because if you wash it, the berries will clump together. And so you would put them into the freezer dry.

Lily Calderwood:

And then when you take them out, you can wash them, or you can just put them into your yogurt or ice cream or thaw them and make a pie or Yeah. Whatever. So if you buy berries from a stand, you can put them in the fridge as soon as possible. But it does change the taste, and it does change the flavor.

Glenda Pereira:

Yeah. That's a really good tip. I didn't know that. But you're right. Adding moisture back in definitely changes, how that product will freeze.

Glenda Pereira:

So that's a really good tip. Don't wash your wild blueberries if you're going to be freezing them. They need to be dry.

Lily Calderwood:

Yeah. Yeah. Or they'll clump up and it'll be a big brick. Yeah.

Glenda Pereira:

So, lastly, you were mentioning that a lot of your work, is to conduct some research and and extension work outreach based on the needs of growers. Right? So what does that look like for you?

Lily Calderwood:

Right now, we have, a lot of interest in improving the harvester and improving the quality berry that comes out of the field. And so we're approaching this in a few different ways. One is nutrient management. And so one project I have is looking at identifying the amount of nitrogen fertilizer that you would apply for a fresh pack stem versus a frozen stem. So if you want to sell frozen berries directly, they don't need to be as perfect as a fresh berry sold directly to a consumer.

Lily Calderwood:

And so the frozen stem can have more branches. It can have more leaves and therefore more berries. And a fresh stem, the way that we harvest with a with raking mechanically is the stem will go through the the tines of the rake and get crushed if there are too many branches. And so for a fresh pack, high quality berry that's not crushed or bruised, you want to have a stem with just one cluster at the top. And so if the more nitrogen we add, the closer we can get to having more branches and more berries per stem.

Lily Calderwood:

But a field that you wanna harvest for fresh, you wanna have fewer branches per stem and be able to go through and pick, you know, really cleanly. We're kinda trying to tailor the fertility rate to your end market, and, we could call that precision agriculture.

Glenda Pereira:

That is so cool. I didn't know you were doing that.

Lily Calderwood:

Yeah. It's really cool. And so then the other side of it is that the harvesters themselves are damaging berries. So they come through the field, and we're we collected data last year that shows we're losing 40% of the berries to the ground. So how can we improve these machines that haven't been improved in sixty years to collect more berries and not damage them as much.

Lily Calderwood:

So we have a Maine Technology Institute grant that we're working with the Web Blueberry Commission on and engineers in the mechanical engineering department and the AMC, the Advanced Manufacturing Center at UMaine. And me and extension to identify harvester innovations that farmers have made around the state and how can we incorporate those into a new harvester and studying a prototype versus the current best harvester

Glenda Pereira:

to try to reduce that loss. So, yeah, that seems like an economic need. Right? It's And it's 40% of your product can make a big dent in your profit per year.

Lily Calderwood:

And let's see. Another project we're doing, I have a master's student working on a drone project where we'll talk more about it another time, but we're trying to reduce the amount of herbicide applied to fields, which, therefore, reduces the amount of money a farmer has to spend on herbicide. And so these fields, you know, it's a full, it's a field. And so the farmer would broadcast an herbicide across the whole field. But the this is a perennial crop, so the weeds are also perennial.

Lily Calderwood:

So we have, like, patches of grass and patches of perennial other weeds. And so you could spray just those patches. Right. And that's what we're trying to do, create maps with the drone so that we have a map that can communicate to a tractor or to a drone so that they have the data to only spray these patches.

Glenda Pereira:

Right. Yeah. Yeah. That's exciting. And like you mentioned, we'll have you back on the podcast to talk more about these innovation projects because we wanna really dive into them and learn more.

Lily Calderwood:

So I also want to, reach out to anyone listening who has a patch of wild blueberries on their own land. Because I get a lot of questions from homeowners, landowners in Maine about so I've got this piece of land that has wild blueberries on it. How do I bring it back to be a stronger patch? How do I foster this patch to be healthier? So the first thing to do is that your patch is probably very weedy, or there are probably small saplings growing up, which means that the field has started to the the habitat has started to become an early succession. It's turning back into forest.

Lily Calderwood:

And so the the first thing to do is to cut those trees out. And you'll really want to, remove them with your tractor and a chain attached to it. You can rip out those saplings by the root ball, then you don't have to come back. But you need to get these saplings out because they're young trees that are gonna become big trees, and you can't manage the blueberry field until you get these out. So you got the trees out, and then you wanna take a soil sample.

Lily Calderwood:

And a soil sample will tell you what the pH of your soil is in this whole patch. And so, you can send a soil sample to the University of Maine who is familiar with wild blueberry soils. That's what I would recommend because on your, test result form, it will say you should apply this much sulfur. And just like you apply lime in a vegetable garden to increase your soil pH, we apply sulfur in wild blueberry to decrease the soil pH to make it more acidic. You need to reduce your soil pH to get rid of the other weed species the other plant species because the blueberry can't compete well against other plants.

Lily Calderwood:

It's a slow growing perennial, and it likes an acidic environment, whereas grasses and broadleaf weeds do not like an acidic environment. And then the second key piece to managing this type of patch or a few acres is to prune it every other year. And so you need to create a two year production cycle, which means that so about 75% of the plant is underground, and you need to cut back to the ground. You're leaving about an inch of stubble behind after the harvest. So you have your harvest.

Lily Calderwood:

You've you've picked your blueberries, and then you wait for a frost event in the fall. Once you've had a frost event, the carbohydrates from the leaves have gone down into the root system, and the plant is ready to be dormant. It has the energy it needs for next year underground, so you can cut back the whole field. We do this in commercial farming with a flail mower or by burning. Homeowners, I would not advise you to burn.

Lily Calderwood:

This is something that you need to learn from an expert, and you need to contact your fire warden to even get a permit. But you can use a lawn mower at the lowest setting and just mow. If you have a lot of brush, I would use a brush hog to go through first and then a lawnmower to get it down to ground level. And you so once you've done this pruning event in the fall after the harvest, that following season is what we call the prune year. So there's no blueberry production.

Lily Calderwood:

The plants are just growing stems, and they're growing buds. And then the next year, those buds will bloom and create Your berries. Yeah. Yeah. There will be green berries, and then those green berries will turn blue, and the cycle starts over again.

Lily Calderwood:

Yeah. And so if somebody has a patch, they wanna get blueberries every year, then you can split the field in half. You can, you know, cut it down the middle and say, okay. On the left side, I'm going to prune in even years. And on the right side, I'm gonna prune in odd years so that you go back and forth.

Lily Calderwood:

You flip back and forth and harvest on both sides every other year.

Glenda Pereira:

Yeah. That was such awesome information that I don't have a patch, so I'm not lucky enough to have a patch myself. But if I did, that's really knowledgeable information because I'm sure folks haven't potentially ran across this resource. And I'll share the resource because I know you have one Yep. Already, readily accessible.

Glenda Pereira:

So I'll tag it in our show notes so folks can read more about it. Have fun, everybody. Thank you so much, Lily. This was fantastic as we sit down with you and learn from you, once more. If folks have questions for Lily, or comments, concerns for Colt and I about our farmcast topic suggestions.