MR. MARC FISHERWelcome back, I'm Marc Fisher of The Washington Post, sitting in for Kojo Nnamdi. Well, remember when a dinner salad consisted of a few veggies, some 1,000 Island dressing and the feature iceberg lettuce? Well, today, grocers give those pale, watery leaves a lot less shelf space, in favor of darker, richer greens like arugula and the so-called superfood of the produce aisle, kale. With advocates like Michelle Obama touting their healthy benefits, leafy greens are red hot. But funny thing happened on the way to the produce section.

MR. MARC FISHERGreens are getting smaller, even micro sized. And colorful leaves with exotic names like mizuna, tatsoi, purslane and bok choy are flourishing at markets near you. It's a leafy greens revolution, at least in some circles stoked by popular demand and led by farmers who can now grow greens year around. So how are leafy greens changing our plates and our palates and which ones pack the biggest nutritional punch?

MR. MARC FISHERIn studio to talk with us, Ann Yonkers is co-executive director of the Fresh Farm Markets which operates 11 farmers markets in the region from DuPont Circle to Boston to Annapolis. Welcome.

MS. ANN HARVEY YONKERSThank you.

FISHERGene Lester is the national program leader for food quality at the U.S. Department of Agriculture's Agricultural Research Service. Thanks for coming in.

MR. GENE LESTERYou're welcome.

FISHERAnd Kip Kelly is the owner of Full Cellar Farm based in Jefferson, Maryland which is in Frederick County. Thank you for coming in.

MR. KIP KELLEYPleasure to be here.

FISHERAnd you have all brought an array of greens from microgreens to kale to beets that is spread across the table here. So any crunching sounds heard during the remainder of the hour, that's what's going on here in the studio. And Ann Yonkers, a few years ago, picking up a bag of spring mix or Italian mix or even arugula sent a message that you are a trendy healthy salad eater. But now the leafy green section at the grocery story seems to be changing, diversifying in extraordinary ways with lots of leaves whose names I can barely pronounce. What is happening and why is it happening?

YONKERSWell, I think that what's one of the important things that's happened is that the leafy greens turn out to be something that the farmers can really rely on, can grow, some of them, year around, the kales and the collards. And that as they -- as farmers markets have set so many trends in this country, I think that the leafy greens are another example of that because they can buy them the year around. And of course they were having these conversations with the farmers, well how do I cook them, how do I serve this?

YONKERSAnd then along the way they're also finding out how -- you know, what great nutritional profiles they have. But probably in our market we have 30 to 40 different varieties of leafy greens. So they go all the way from the microgreens all the way up through sort of the salad and the mesclun which were made popular by farmers markets into the leafy greens.

YONKERSAnd then basically what's happening on the other end and probably the newest trend is that they're being transformed into drinks. So you can eat microgreens and you can eat all kinds of leafy greens and then at the end than you can drink them.

FISHERAnd you can join our conversation by calling 1-800-433-8850 or email us at kojo@wamu.org. Let us know about the greens you're finding on your salad plate. Are your favorite leafy greens more traditional like spinach and lettuce or do you like to experiment with the new flavors and textures? Tell us about your favorite way to cook with greens and tell us about your position on kale. What's the best way to eat it and, well, maybe you can't even stand the stuff. Let us know at 1-800-433-8850.

FISHERAnd Kip Kelly, at your farm, at other farms around the region, this change in people's tastes obviously creates a shift for you in terms of what you grow. How do you make that kind of a change and how quickly can you retool to match tastes? How much are the tastes leading you and how much are you leading the tastes?

KELLEYThat's a great question. We -- I think what we mostly try to do is just respond to what our customers want. In terms of growing greens they're pretty simple. They're not -- you don't need a lot of different infrastructure to grow them so it's an easy shift. And they compliment the beginning and the end of the season very well where you're looking to find something to bring to market. Which is the reason we started to grow microgreens is we didn't have much early in the season and we needed to bring something. So it's been working well and...

FISHERSo they grow earlier in the season.

KELLEYThey do, yeah. They like cool -- most microgreens and most greens prefer cool weather and so we're in that right now. You can go to your farmers market and find that great local greens now. And then in the fall again you'll find another plethora of greens. It's a great time of year to eat healthy.

FISHERAnd is it a simple matter of sensing that people's tastes are changing and you can swap things out that next season or does it -- do you need more lead time than that?

KELLEYIt's fairly simple. I mean, we -- I think for our farm and other farms around, we follow different crop rotations. And it is fairly easy to stick another type of green in when you need to -- if you want to try to grow to appease a different customer base. And some of the ones are just greens we've been growing for a long time, like spinach and kale. It's been around for a while and I think it'll stay for a while. So we always make plenty of space for that.

FISHERGene Lester, from the USDA Agricultural Research Service, is this shift that we're seeing in tastes and in variety, is this happening in all levels of the market or is it mainly a high-end phenomenon? I think about my local Safeway where there's still pretty much iceberg lettuce is the main feature there. So, you know, is what we're seeing in farmers markets reflected throughout the rest of the marketplace?

LESTERWell, we don't do the study in the marketplace. We actually are the laboratory that certifies or basically tells you what the nutritional level is in the food level or the benefit of the microgreens. I think Ann could probably answer that a little bit better than me.

FISHERSure. Ann.

YONKERSYeah, I think that what's happened is that the -- there's a confluence between what the farmers can grow, because think about a kale that was known by Hungry Gap, exactly what -- that's an old variety. You can grow it on the shoulders, the spring and fall. So the farmers know it's reliable. Then you also have nutritionists are saying, wow we've discovered this nutritional super power.

YONKERSAnd then I think -- also think about the fact that many of these greens -- many of the greens that we're talking about like kale and collards, for example, and all the Asian greens, they're cabbages. Those are old traditional -- some of them are storage, some of them are, you know, summer season crops that people have been relying on for a long time. So there's nothing trendy necessarily in them because they've been sustaining life for a long time. I just think our discovery makes it feel like it's trendy.

FISHERAnd that discovery, I guess what I was getting at, is that discovery something that's shared across economic lines? Is it mainly -- you know, you think of the DuPont Circle farmers market for example has a pretty high price point in a lot of the products there. Is that something -- are you seeing the microgreens and kale and so on appealing beyond that high-end market?

YONKERSYeah, we have 11 farmers markets. And in our farmers markets we have a whole range of people coming and buying foods. So I would say that farmers -- or the DuPont market is the showcase but we also have markets, smaller markets like on H Street which are serving a completely different community. And so I would say that you really see people responding to the opportunity to eat. And actually greens, if you're talking about something that's low cost and high nutrition, that is one of the perfect foods.

FISHERAnd kale has been sort of the hot super food. I mean, you say that, you know, these greens have been around forever, and that's true. But there are trends and there are fads. Kale has had enormous popularity and it's grown with advocates like the first lady singing its nutritional praises on TV. So has the demand for kale resulted in greater interest in other less well-known varieties?

YONKERSI would say yes. You know, as I said, people are very -- would be very surprised if this is the cabbage that they thought they hated. And now it's the darling. So I would say yes, that kale has started people looking at these greens which were sort of background and how do you eat those. And we get a lot of questions in farmers markets about how to cook them.

FISHERAnd you can find recipes for greens such as Swiss chard and dandelion greens on our website at kojoshow.org. So you should check that out and might also want to check out an interactive that we have comparing baby greens to adult leaves. That's also at kojoshow.org. Kip Kelly, it used to be that if you wanted fresh arugula or kale in the winter you had to rely on whatever was being shipped into grocery stores. Now we're seeing, as you mentioned, fresh greens in markets most of the year. How are you able to grow these varieties in winter months?

KELLEYA little bit of protection goes a long way. So we grow in high tunnels which are unheated structures that are covered with plastic. It lets the natural light in but it keeps the wind off the plants. And during the day it can be the middle of winter 30-degree day but in your high tunnel you're 80, 90 degrees and you're sweating and you need to take your shirt off so you can stand working in there.

KELLEYSo it's -- and, you know, you're not adding extra fossil fuels to it. You're just using what's naturally there and just enhancing it and keeping a little more protection around those plants. So they grow slower that time of year so you don't -- I think that's one reason the farmers market numbers drop off that time of year. There's not as many markets that time of year and there's not as much variety. But there's -- winter's the best time to think -- for me to eat greens. They're sweeter, they're just so nutrient dense at that point they're a great addition.

FISHERSo you're really more of a year around operation than you once were.

KELLEYThat's right, yeah. Greens are -- you know, you're not bringing tomatoes and sweet corn to market in January but greens are what's filling your plate. And that's -- and they're a great addition.

FISHERAnd does that mean you have more people employed year around as a result?

KELLEYThat's right, yeah. So we have two employees -- great employees that I can't say enough good things about and they work year around. Man, we're able to keep -- this winter was a particularly hard winter. Some crops that we normally have in the spring that survived the winter did not make it. But regardless, we still had -- we're still picking some greens even in the skimpy months.

FISHERGene Lester, you do a lot of research at the lab on the nutrition behind the greens we eat. Let's start with a more practical question about choosing leafy greens. For people who buy their salads from bags or plastic boxes in stores, how do you choose the freshest leaves? How do you know what's been sitting on the shelf for a long time and what's actually pretty fresh?

LESTERWell, one of the things I would go by is, of course, the sale by date. And salad greens tend to, if they stay on the shelf too long will kind of have a wilted look about them. So something that looks fresh and not wilted, it would be your better green to purchase in either a clamshell or a plastic bag.

FISHERAnd I gather you did some research on the salad bags themselves and how much light hits them in the display.

LESTERRight. That was a study done a number of years ago where I was actually at the grocery store and I asked myself, I said, you know, I wonder which bag of spinach is more nutritionally dense, the bag of spinach in the front of the display case that's getting the grocery store light 24 hours a day or the one protected in the back in the dark where it might be cooler and a little more cozy.

LESTERAnd I said, you know, somebody needs to do that research. And then I realized my -- the definition of my job at the USDA was to do that sort of research.

FISHERYou're the guy, right.

LESTERSo we set that study up and we actually simply mimicked the light intensity of the grocery store. We got the plastic boxes that they grow the -- or they have in the grocery store and set it up in the lab. And we did it either 100 percent darkness or grocery store lighting for nine days. And within as much as the first 24 hours you started seeing an increase in vitamin K and vitamin B9 which is folic acid. You saw an increase in vitamin E and particularly in carotenoids and the maintenance of vitamin C. Because we understood in the research that once you harvest, vitamin C starts to drop off immediately.

LESTERSo actually able to maintain the levels of vitamin C under light post harvest is new information.

FISHERSo the -- let me get this straight. The products that had the increased vitamin content were the ones that were exposed to the light...

LESTER...to get continuous light, yes.

FISHERAnd the one at the back of the shelf suffered...

LESTERRight. It was either dropping off or there was not much change to the vitamin level.

FISHERSo grab the one in front.

LESTERGrab the one in front, yes, right.

FISHERAnd...

YONKERSBut not with microgreens.

LESTERThat's true. Right.

FISHERAnd what's the difference there?

LESTERWell...

YONKERSWell, Gene should say.

LESTERYes. We did that study also. And of course, even though these vitamins we're talking about are all part of photosynthetic process, without them photosynthesis wouldn't happen. But the microgreen leaves are not a true leaf. So it holds true for true leaves but like asparagus and microgreens, because the microgreen is designed by the plant to get the plant up and going and then drop off and die away, so the regular leaves don't have any competition.

LESTERAnd you're basically speeding up that senescence process or that dying process of the microgreens if you keep them under continuous light. The best bet is keep those in dark under cool temperatures once you've harvested them.

FISHERSo take us back a step. What are microgreens?

YONKERSLittle plants.

FISHERAnd previously people didn't much eat them or why are they -- what's new about them?

YONKERSWell, I think what -- I think it's also one of those trends that we were talking about before the show. Does the trend -- where's the -- so many of these trends that have to do with vegetables and the way food is grown have started in farmers markets. And they just -- even though they're a small part of the actual vegetable growing farmers in the whole country, they've had a huge impact.

YONKERSAnd so I think -- so our question was, was -- I think that that trend was a combination of the fact that people were seeing probably in the last eight or ten years microgreens on plates coming out of fancy kitchens. And they were always -- they'd been used typically just as a garnish. And then so that sort of sparked an interest. And then the farmers like Kip who can basically figure out how to grow anything well -- and it's a short harvest period of about -- isn't it just about ten days?

KELLEYYeah, it's not much.

YONKERSTen to twelve days, figure out, oh I can grow that. And then, you know, once you start having something in abundance then the public starts saying, well how can I eat that?

FISHERAnd so Kip Kelly, was there a time before this when basically microgreens were just left in the field or...

KELLEYYeah, we -- actually this is our first season of growing them intensively. And it kind of came out of desperation for us just because we had some early markets starting and we did not have a lot of greens that were ready just due to the cold season. And so we said, well, they're easy to grow. And one of my employees was very interested in trying them out. And so we said, let's give it a shot. And it's been a great success and we'll keep doing it.

FISHERLet's hear from Patrick in Washington. Patrick, you're on the air.

PATRICKHi. My name is Patrick Kenny and I have a question. What is the best combination of greens for people with diabetes?

FISHERGene Lester?

LESTERWhoa, I -- well, I'm a little overwhelmed by that question because I'm not a nutritionist. So I hesitate asking that but I would say probably just fruits and vegetables are pretty good anyway simply because they aren't going to give you a spike in sugar like sweets are, for an example. So I would imagine probably most of them are pretty good, at least from the leafy green vegetable standpoint for people with diabetes.

FISHERAnd what about cooking greens? We have this beautiful spread of greens here and they're all fresh and, you know, they'd be great in a salad. But when you start boiling and otherwise cooking greens, are you blanching them of their nutrients?

LESTERTo some degree. What you're going to lose are going to be some of your water soluble vitamins. And that's going to be your vitamin C for an example. And to replace that I would just simply squeeze some lemon juice on your blanched greens. But as far as your fat soluble vitamins, which are you carotenoids, your vitamin K, your vitamin E, your vitamin D, you have very little to worry about. You're not going to lose those in the blanching liquid. So with the exception of pretty much vitamin C, you're pretty good to go.

FISHERYou can join our conversation by calling 1-800-433-8850. Tell us about the greens that you've been trying lately, how you've been experimenting with cooking them and what you've noticed in your local markets, especially in the colder months. We have some microgreens here. Tell us about what we have here.

YONKERSWell, we have -- back here in the back we have a rainbow mix which is raised hydroponically by Bay Water Greens in Maryland. And then here's something interesting which is really probably not technically a microgreen but it's claytonia which is a green that is sometimes called miners lettuce, very nutritious. And it's mixed with mustard greens -- baby mustard greens. And then Kip, you have...

KELLEYYeah, then in front of you, Marc, there is a radish called the China Rose Radish. And then another kale called a red Russian kale that we harvested this morning.

FISHERWow. And Ann, you have a farm on the eastern shore. Do you grow microgreens there?

YONKERSYes, we do. We sell those in our Fresh Farm Market at St. Michaels.

FISHERAnd how -- if you want to do this at home how do you go about doing that?

YONKERSWell, we do -- we find -- our most popular microgreen is pea shoots which people love to -- you can -- and one of the advantages of pea shoots is that peas are, you know, precious. I'm waiting -- we just got our first strawberries in the market, which is always a great mark from Southern Virginia from Barajas, wonderful farmers down there in the northern neck.

YONKERSAnd so peas are the next big thing that we're waiting for but, you know, one of the things that's advantage about a pea shoot is that you get a lot more shoots than you get peas. So you get tremendous amount of benefit from growing the greens. And then you can also cook them. They're fantastic, for example, if you're making an omelet and tuck those little pea greens right into the omelet and it's yummy.

FISHERSounds great. We have an email from Jessica in Burke, Va. She asks, "What exactly is a mesclun mix? Is it always a mix of certain greens or is it whatever's fresh on the farm that day?"

YONKERSI think the answer is both. I tend to be much more of the purist. I have a culinary training and mesclun is sort of a holy word for a very limited number of very tender young greens. And -- but I think you find at farmers markets now I would call it farmers choice, which is basically whatever looks great in the greenhouse and goes together, let's put that in.

YONKERSAnd so one of our farmers at DuPont Circle Hinds Toma from Next Step Produce, he has his mesclun which is sort of, for me, the Holy Grail. And then he has a salad mix that tends to be more, I would say, liberally interpreted.

FISHERWe have an email from Parker in Ranson, W.V. who says, "I cannot eat cooked greens. It's a texture thing. But my girlfriend makes an awesome kale salad," and he loves that. So kale is one of those polarizing products where you get people who absolutely love it and people who just cannot fathom why anyone would go there. Kip, do you agree with that?

KELLEYI agree, yeah. I think it's -- some people are hot or cold. And I have to hand it to farmers market customers though. They really are very adventurous often. And I know people -- well, there's a lot of different kales. We have some that are regular green curly kale and then a red Russian kale. And there's ones that have different textures and different looks to them. So sometimes what they think of as the kale they don't like, they're willing to try a different kind of kale that maybe has a different texture, a different flavor.

KELLEYAnd I would say even different times of the year kale has very different flavors. So if you're not big on kale I would recommend holding off and waiting until the fall where it's just very sweet. And November kale, about one of my favorite things to eat, very concentrated sugars, very sweet, tender, hard to say no to that.

FISHERWhen we come back after a short break, we will go maximum with microgreens. That's coming up on "The Kojo Nnamdi Show." I'm Marc Fisher.

FISHERWelcome back. I'm Marc Fisher sitting in for Kojo Nnamdi and we are talking about leafy greens and microgreens and lots of new things showing up at farmers markets and on salads around the country. Ann Yonkers is the co-executive director of Fresh Farm Markets, which operates 11 farmers markets in the region. Gene Lester is the national program leader for food quality at the USDA's Agricultural Research Service. And Kip Kelly is the owner of Full Cellar Farm in Frederick County, Md.

FISHERWe have an email from George in Falls Church who asks, "What do microgreens taste like? Are they weaker than a regular bunch of arugula, my very favorite green?" And Gene Lester, I think you would say they're not weaker, they're stronger.

LESTERThey're much stronger. We've done a study and I don't want to say too much because the research paper's in the process of going through a viewer to be published. But as a panelist on that sensory study that we conducted at the USDA here outside of Washington, D.C. we found that if it's cilantro or it's naturally peppery or it's got a very unique flavor characteristic, it's in its mature form, it's going to be punched up much greater in its microgreen version.

FISHERAnd so the microgreens are actually the seedlings, right, that crop up in the first few days of growth?

LESTERYes, they are. Right.

FISHERAnd...

LESTERNow they're different than a sprout. A sprout will have a seed coat attached to it which has some food safety issues. A microgreen, the seed leaves have fully expanded and have turned either green or red or yellow or magenta or some very exciting color, and they're quite crunch as a matter of fact in most cases. So you've got a taste and a texture and an aroma going with it as well. And that's what makes it very exciting for a lot of the chefs.

FISHERWe have in front of us the radish microgreens with do have a spiciness and a taste that is much more intense than that of the parent plant, right.

LESTERAnd you can say so because you just tried it.

FISHERI did. And then we also have these kale microgreens. What's their taste relationship to the actual kale?

LESTERWell, if it's going to have a kind of a mustard or a peppery type characteristic, which is characteristic of a lot of the brassica or cabbage family plants, you're going to find that to be the case. Now if, for an example, you're not one that can handle cilantro and that seems to be a certain number of people in the population, don't go near cilantro microgreens because you'll really hate it. So if you like cilantro, then put cilantro microgreens on your food.

FISHERWe have an email from Ama in Alexandria who says, "I'm seeing a lot of different kinds of kale at my local market but what's the difference between things like red Russian, dinosaur, red boor and other weird kale names I've been seeing," Ann?

YONKERSWell, there's -- I would say that the lacinato kale which she's calling dinosaur kale is the mildest form of kale. Red Russian would obviously have its roots in Russia and would be more cold tolerant. And I would think the green kale, the green bor kale is also pretty similar to that. Structurally they are pretty much the same. I think that the collard, which is -- she's not mentioning but that is also probably the most cold tolerant so that it actually can make it through the winter as can some of the kales.

FISHERNow a dissenting voice we hear from an email from Richard who says, "I love all the variety available now for salad greens but I can't seem to get a good head of romaine, which is the basis for my salads. What happened? All I find is something that should've gone to the dumpster several days before." Kip Kelly, are -- is there a lack of emphasis now being put on some of those old standby lettuces?

KELLEYI think -- maybe a little bit. We've yet to grow an iceberg lettuce but we still grow green romaines and they're popular I think. We just try to do the best to make our customers happy so -- and really what we find is people like some romaine but they like trying other stuff too. So we'll try butterheads and crisps and lolo lettuces in different varieties that you don't see all the time.

FISHERAnd some of these microgreens are pricier than a head of romaine, you know, per leaf or however you measure it. Is that because it takes more effort and care to raise them or is it just because of the demand?

KELLEYA bit of it's demand. Some of it is they're a little bit higher cost in some ways and that they're -- you know, they're -- each little green that you get is a seed. And your seed costs are much higher to grow a pound of microgreens than it is to grow a pound of romaine where it's just one seed. The benefit of microgreens is it's such a short time. You're planting and harvesting sometimes within a week or ten days, not much time. So that's the benefit.

KELLEYI think sometimes it's just a different kind of item. You're not going to eat a whole salad full of microgreens. You're going to use it as an emphasis, pair it with a protein or something like that. So it's -- doesn't eat a lot.

FISHERLet's hear from Sam in Baltimore. Sam, you're on the air.

SAMGood afternoon. Thanks for having me. I have to say as a macho man I was definitely a skeptic in terms of jumping on the microgreen bandwagon. But I just tried, it was a blend of even parts baby kale and arugula and it was awesome. I waited way too long. And for everyone else who's a skeptic and listening, I really have to say go for it. And go organic with it. It was super tasty.

KELLEYGreat. Well...

YONKERSGreat. That's...

LESTERWell, that's what...

YONKERSYeah, ditto.

FISHERThat's what these folks like to hear.

LESTERGeorge, what we're finding is that the kids in the restaurants find them interesting if not cute. And men don't see it as a vegetable so they're not afraid to eat it.

FISHEROkay. Let's hear from Kathy in Washington. Kathy, you're on the air.

KATHYHi. My question is about production of these greens, and I'm glad that you're doing studies about them and experiments to see the nutrition. But what I want to know is, as a horticulture student I had an internship with a grower who was producing lots of greens but they were grown in raised beds that had pressure-treated wood all around them. And they were using a pro-mix, an artificial growing medium and dousing them with chemical fertilizers.

KATHYI also went to a farm when I was at the farmers market and he ran out of tomatoes. And I went to his farm and he had a greenhouse. And again I saw raised beds, pressure-treated wood. They were called organic tomatoes. In this case the soil medium was again artificial but the fertilizer was organic, therefore tomatoes were organic. I'm wondering how these growth methods are regulated and how they affect the nutritional value of the greens that we're eating that should be really healthy for us.

KELLEYThat's a great question. I think there are organic standards that farmers adhere to who are organic. And we're not certified organic but we do follow those principles. And, you know, because we're not certified we don't claim -- we don't call ourselves organic microgreens. But we'll tell you how they're grown. And I think, you know, it's like every -- anywhere. There's some people who do a little bit better job than others. So I think that's the benefit of a farmers market is you can go and talk to your farmer and say, hey, how did you grow these?

KELLEYAnd if you are worried about pressure-treated wood or worried about using synthetic fertilizers you can say, you know, what'd you do? And it sounds like you can talk pretty well so I think a lot of customers are okay with a very general answer. But I love it when people ask me the details. And I love to get into it with them. So I think your best bet is just to talk to somebody.

FISHERWell, speaking of knowing the details, here's a farmer of microgreens, Mary Ellen in Purcellville. You're on the air.

YONKERSMary Ellen is...

MARY ELLENHi, Ann.

YONKERSHi, Mary Ellen.

ELLENHello. I'm so glad we are talking about microgreens. As you know, I think they're pretty maxi. And I just wanted to share, my research has said that an ounce of microgreen kale or broccoli or cilantro would be the equivalent of six cups. So people who have difficulty eating the kale or, you know, little people who need just smaller portions, those microgreens are the first two cotyledons of the seed. And from there those cotyledons...

FISHERWhat are cotyledons?

LESTERSeed leaves.

ELLENThe first leaves of the seed.

YONKERSSeed leaves.

ELLENAnd from there the seed then dispenses all of the nutrients and flavor to the rest of the plant. So when you grab it, science is now showing us in those first two leaves you get all of the flavor and the nutrition of a mature plant. So like that radish leaf that you just ate would have all of the nutrition of that plant of that mature radish, which I just think is remarkable. Chefs have always known, you know, how great they were for flavor. But now we're also learning the science of them. So they're amazing.

YONKERSAnd I think one really interesting thing that Mary Ellen has just gotten, a kip...

ELLENKiva.

YONKERSSorry, a Kiva, a loan through Fresh Farm Market to raise -- to buy some more shelves for raising microgreens. And her production has doubled. And it's also true of Bay Water Greens who I was talking to on Sunday, 50 percent increase. So there's a real rise in demand.

ELLENAnd you don't need land to do that. You can do these in upright shelves. So it's awesome add-on products for us. And ability not to have to have so many acres to get this great food.

LESTERRight. It's a new way of farming in America.

FISHERGene Lester, in that farming, I mean, could you potentially make a microgreen out of any edible plant?

LESTERPretty much so, yes.

ELLENYes, you can. Yeah. Excuse me, doctor.

LESTERThat's all right.

ELLENYeah, that's the amazing thing. And you can do it hydroponically. I grow mine on burlap with flowing water. No pesticides.

FISHERGene Lester, if baby greens are good for you, I would imagine microgreens are even better. What have you learned about the nutritional value?

LESTERWe've learned quite a bit because we have studied directly at the USDA. And we found that if you go from the older leaf to what's called the baby leaf or the baby greens, you're going to increase the nutritional density. And that can even go to the microgreens, which in some cases you're going to have anywhere from four times to eleven times greater density in the nutritional concentration of microgreens compared to its more mature leave counterpart.

LESTERSo, for an example, we based everything on 100 grams. And if an apple or an orange -- your average apple or orange is about 100 grams, which it is, you're going to need maybe about an equivalent, as the last caller said, about 20 to 25 grams of microgreens to meet your recommended daily intake of most of the phyto-micronutrients that you need, in the vitamins that we studied anyway.

FISHERWe have a comment from Georgia who says, "Who would've thought everything old is new again? Kale is hip and collards are cool. Am I really hearing that the old dark southern greens like collards and kale are the healthiest for you?"

YONKERSYes, you are, absolutely. You're listening well.

LESTERYes. And they're outstanding. And we've done some studies on that recently also. And the mustards, the turnips and the collard greens are outstandingly nutritionally dense. And there's a lot of seed savers out there in the southeast part of the United States. And we haven't maximized at all the variability in the nutritional density of that very wealthy salad green mix.

FISHERYou can see an interactive that compares the nutrition of microgreens to their mature counterparts at our website at kojoshow.org. And let's hear from Carol quickly in Kensington. Carol, you're on the air.

CAROLHi. Thanks for taking my call. My question is that a lot of my friends and I have started making kale chips out of kale. And children love to eat it and it's a great way to get them to eat greens. I just wonder -- it reduces so much in the oven and I just bake it at 350 with a little olive oil and salt and that there's so little left of it by the time you eat it. Not that it isn't delicious but I just wondered about what's the nutrient content still? Is it still pretty high if you're baking it in a 350 oven for 10 to 12 minutes, say.

FISHERGene Lester.

LESTERWas it kale, Carol?

CAROLYeah.

LESTERCarol, you're not going to lose anything with regards to the minerals. That's not a problem there, so don't worry on that. You're carotenoids are going to hang in there. Your vitamin E, your vitamin K's going to hang in there. The only one that's going to -- you're going to lose I'm afraid and that's very -- the heat-sensitive vitamin C. So most of your nutrients are still going to be there with the exception of your vitamin C.

YONKERSI have a suggestion. Is the next time you go to the farmers market, but three bunches of greens and not one. And then when you make your kale chips, you'll have some left over for the kids that love it so much.

FISHERSpoken like a true market person. So, but Ann Yonkers, I have a -- you mentioned at the start of the show the fact that people are drinking greens more than juices and that sort of thing. When you see those being sold for 6, 7, $8 a pop, does that have any rational connection to anything?

YONKERSIt has to do with the sheer concentration of plant material that's in a bottle. So it's hard for people to think if they compare it to a sweet drink or tea or something, they can't understand why the prices are as high. But basically if you have a pound or so of a combination of vegetables and fruits in a bottle that's a pint bottle, you basically have a very high concentration of nutrients in a liquid form.

FISHERSo I shouldn't resent that price as much as I do.

YONKERSWell, it's just to understand what's happening. I mean, you know, actually if you want to save money go buy bunches of greens and cook them yourself. But if you...

FISHERAnn Yonkers is co-executive director of Fresh Farm Markets, a nonprofit that operates 11 farmers markets in the region including the one at DuPont Circle as well as Boston and other places. Gene Lester is national program leader for food quality at the USDA's Agricultural Research Service. And Kip Kelly is the owner of Full Cellar Farm in Jefferson, Md. Thanks to all of you for joining us. I'm Marc Fisher of the Washington Post sitting in for Kojo Nnamdi.