Want To Get Your Spring Garden Going? Here’s Some Expert Advice
In most parts of the U.S., it’s time to get the garden going for the year. From readying your soil to picking your plants and getting seeds started, April can require a lot of decision-making to set the stage for a successful growing season.
Have questions about choosing containers, hardening your seedlings, or dealing with excess water? Our panel of expert gardeners is here for you. Ira talks to Cornell University Extension’s Elizabeth Buck and Oregon State University Extension’s Weston Miller about common spring troubleshooting, chemical-free pest management, and even how to brace your garden against climate change.
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Elizabeth Buck is a fresh market vegetable Extension Specialist at Cornell Cooperative Extension in Ithaca, New York.
Weston Miller is a community and urban horticulturist with the Oregon State University Extension Service in Portland, Oregon
IRA FLATOW: This is Science Friday. I’m Ira Flatow. April is here, at least in the colder climes like where I’m living. That means it’s time to get the garden ready for planting. We have had so much rain this season that getting my garden ready has been a real challenge. But I am getting the compost in. I am starting with my cold-weather veggies– my spinach, my lettuce, my broccoli family. And I’m actually trying some new raised bed hoop ideas with PVC plumbing pipe and netting, making the hoop out of the pipe. It’s really cool. And then I can throw the netting over and keep the critters out from crunching on my veggies.
I’m also trying to grow flower seeds, like black-eyed Susans and sunflowers especially this time. And you may be getting things in your ground already, depending on where you live. I mean it’s 100 degrees in California this week. So you have your own challenges there. And maybe we can help you out whether you’re cold and damp or hot and dry. Maybe you have questions. I know you do. Like Lynette in California who called into our SciFri VoxPop app.
LYNETTE: We have an enviably long growing season. And I love tomatoes from my garden. But these plants get to be huge. So can you help me with the debate over whether to prune or not to prune?
IRA FLATOW: Oh, yeah. I am familiar with that one in my own tomato patch. What to do with those tomatoes? They’re really vines. Well, we’re in luck. We’ve got two experts on the line today to help answer those gardening questions. Let me bring them on. Elizabeth Buck, a fresh market vegetable specialist with the Cornell Cooperative Extension in East Aurora, New York. Welcome back, Elizabeth.
ELIZABETH BUCK: Hi, Ira. It’s great to be back.
IRA FLATOW: Nice to have you back. Weston Miller, a community horticulturist with Oregon State University’s Extension Service. He joins us from Portland. Welcome back to Science Friday, Weston.
WESTON MILLER: Thank you so much for having me.
IRA FLATOW: Nice to have you. And also we want your calls. Give us a call out there. Our number– 844-724-8255, 844-SCI-TALK. We’ll be talking not only veggies but flowers, and plants, and all kinds of stuff, problems that you may have going on in your garden. Lots of questions– 844-724-8255. Elizabeth, you’re in a slightly different climate zone. I mean, what’s happening in your garden right now. What should people be doing at this point in the season?
ELIZABETH BUCK: Sure, so I’m up in the Buffalo area. And right now, our daffodils are just beginning to bloom. Our bulbs are starting to come up. It’s pretty early here. So in this neck of the woods we’re really looking at that spring cleanup of our gardens. Getting ready to plant our peas, and lettuce, some of the beets, and other crops that we can do really well at this time of year, and watching for our perennials to start coming back to life.
IRA FLATOW: And with all the wet weather we’ve had, I know you’ve had that also. Is there a danger of getting out too early in a muddy garden?
ELIZABETH BUCK: There is. And that’s something called compaction. So compaction happens when you put weight on wet soil. And it basically squeezes the water out and sticks those soil particles together. And when they get stuck together, they don’t come back apart. They create a hard layer, and that’s difficult for the roots to get through. So any time you’re working in your garden, you want to make sure that it bears your weight well, that it’s not squishy underfoot.
IRA FLATOW: OK, so wait for it to dry out a little bit more before we go in there. Weston, you’re up there in Portland. What’s going on there?
WESTON MILLER: Well, spring is a little bit further along here in Portland. The daffodils are starting to fade a little bit. And in terms of vegetable gardening, folks planted their peas and whatnot in March. And in April, the recommendation is to plant the broccoli family plants, and carrots, and beets, and things like that.
Well, we had a question from Lynette, who is thinking further along in the season about her tomato plants, which are– well, you can’t get them started here in the cold weather. And she’s trying to figure out if she should prune her giant tomato plants this year. Elizabeth, what’s your advice on this because we all have that same question?
ELIZABETH BUCK: Yeah, tomatoes are lovely. And there’s two different kinds. They’ve got the kinds that are called indeterminate. And they really want to be vines. They’ll grow feet and feet long if you let them. And then there’s the determinant kind that grow into a smaller plant, maybe four or five feet big. And so what we recommend is that when the plant is little, you pick one or two main branches and you pinch off the side branches at the bottom of the plant, up until the first flower. If you reduce the size when the plant is small, it helps contain how big it gets later in the year. And with the tomato, any time it’s too big, you can just cut the growing point off. That’s fine.
IRA FLATOW: Yeah, because it loves to grow back. Let’s go to the phones. Let’s go to Chris in Tulsa. Hi, welcome to Science Friday. Chris, hi, there.
IRA FLATOW: Yes, go ahead.
CHRIS: Hi, yes, I was calling about– I had planted all heirloom varieties of lettuces this year. We got those from our public library, which offers– you can come by and basically check out these different types of heirloom seeds that grow really well here in Northeastern Oklahoma. And my question was since we did plant all heirlooms, usually we would have some hybridized plants in there somewhere. But this year we went with all heirloom. Is that better for the environment? Is it going to change anything by planting all heirloom varieties?
IRA FLATOW: Oh, good question. Elizabeth, do you want to tackle that?
ELIZABETH BUCK: Sure, so heirloom varieties are old, historical varieties. They’re still bred by somebody. Someone selected traits they liked in that lettuce– maybe it was colored, maybe it was crunch. Hybrid varieties are also based on traditional selection. Someone saw that plant, and they liked it, and they picked that trait, and they crossed it with another plant to keep it going. So in terms of environmental profile, whether you have a hybrid or you have an heirloom, it’s about the same. They’re both equal to the environment.
IRA FLATOW: I hope that answers your question, Chris.
CHRIS: It did. Thank you very much.
IRA FLATOW: You’re welcome. You’re welcome. Let’s go to a question that was sent to us over the internet. Do I need to dump my soil after four years of using a growing box? That’s the same question I have. How long can you get away with the same soil you’ve been using year after year? Weston, what’s your idea on that, especially if it’s on your patio or you’re in an urban environment?
WESTON MILLER: With container plants, the soil certainly is going to get tired over time. For years is probably stretching it. I generally get it to go about two or three years. But I think it’s really important that people also know that– with containers especially– that the nutrients drain out really quickly. And it’s important to add a fair amount of fertilizer along the way during the growing season.
And then to keep it really well watered as well, since the drainage is also really good. And then it also depends on the kind of plant. So with perennial plants in a container, you’re going to want to just keep that going and maybe step it up into a new container and add more potting soil. But for annuals over and over again in a container, at some point, it’s going to make sense to dump it out and start afresh.
IRA FLATOW: I suggest don’t keep adding stuff. Just refill the container with new potting soil, better idea.
WESTON MILLER: Yes.
IRA FLATOW: Yeah. All right, let’s go to the phones to Chelsea in St. Louis. Hi, Chelsea.
IRA FLATOW: Go ahead.
CHELSEA: Hi. I’m calling because I’m wanting to start growing my own vegetables. And I live in an apartment with no access to a yard. So I was wondering what are the easiest vegetables to grow on a patio?
IRA FLATOW: Yeah.
CHELSEA: And when should I start? I’m in St. Louis, and it’s still frosting.
IRA FLATOW: Weston, let me give you first crack at that.
WESTON MILLER: Well, first off, I would recommend talking to your local county extension office about when to start the plants in St. Louis area. And then, overall, with container growing, I would recommend growing herbs. They cost a lot to buy at the store, and they’re also relatively easy to grow– parsley, and then rosemary, thyme, sage, and things like that. Lettuces are also relatively easy to grow in containers. And then, if you want to grow tomatoes, choose smaller varieties and zucchini, smaller varieties as well. There are specifically adapted varieties that do better in containers because they’re a bit smaller type plants.
IRA FLATOW: And, Elizabeth, anything to add?
ELIZABETH BUCK: I would add pole beans. They’re really fun. You can plant three or four of them around a small stick or stake and watch them climb up all season.
IRA FLATOW: Yeah, Chelsea. And they’re really fun to watch.
CHELSEA: Awesome. Thank you guys so much.
IRA FLATOW: You’re welcome. Yeah, I just started putting my beans in the ground indoors. And can you do that? Can you start early and then move them outside?
WESTON MILLER: You sure can.
WESTON MILLER: Yeah, starting them indoors is a lot of fun. You need to make sure that you have plenty of light. Oftentimes, people start plants indoors, and they don’t have enough light, and they get a little bit leggy. So having supplemental lighting or a really good window with lots of light would be recommended.
IRA FLATOW: Yeah, because they grow quick. I was so surprised how fast beans grow, I mean, how fast they germinate. Let’s go back to the phones to Nina in Hancock, New Hampshire. Hi, Nina.
NINA: Hi. How are you?
IRA FLATOW: Hi, there. Go ahead.
NINA: I was wondering if there are any easy fixes for very sandy soil that don’t involve trucking in a lot of new soil and bark since. We live in New Hampshire and our front yard is very, very sandy.
IRA FLATOW: Elizabeth, what would you say?
ELIZABETH BUCK: Sandy soils are excellent because of all the drainage. So your vegetables would love it out there, but it can be a little hard for lawns. Adding any sort of organic matter will help improve the water holding capacity. So you can do simple things like when you mow your lawn, leave the grass clippings there. And over time, they’ll break down. They’ll kind of help sponge up and hold on to some of the moisture. Spreading compost can help too. And it just takes time to build those things up.
NINA: OK, great. Thank you very much.
IRA FLATOW: You’re welcome. Well, let’s talk about the different kinds of fertilizers that people use. A lot of people like to go with the liquid fertilizer that’s turns a little blue when you mix it. And there are other people who like to go with the organic fertilizers. What is the difference, Weston, between the two of them?
WESTON MILLER: The difference between organic and conventional fertilizers is based on the origin of the material. Organic materials are derived from natural sources– including animals, and plants, and minerals. And synthetic fertilizers are synthesized in essence. Plants don’t really care which they get. They Just like the right amount of nutrients at the right time.
IRA FLATOW: That’s good. Let’s go to the phones because there are a lot more questions than I have answers certainly. Bud in Syracuse. Up there, hey, in the neighborhood. Oh, we lost Bud. Well, is there a bad time– let me ask you, Elizabeth. Is there a bad time to put seeds in the ground, when you shouldn’t be doing that?
ELIZABETH BUCK: Probably January when it’s frozen. No, for every season there is something that you can plant out. For a specific plant there may be a bad time. So we’ll take spinach for example. Spinach seed will germinate, meaning it will break out of this seed coat, but if the soil is to warm, if the soil is soils over 80 degrees, that little tiny seedling dies before it makes it up out of the ground and into the light. So we don’t sow spinach in the middle of summer. Instead, we can sow a bunch of different crops, like you could sow zucchini instead. So there’s something for every season but not every crop in every season.
IRA FLATOW: Yeah, thank you. We have Janet who’s asking Weston a question. How do I deal with too much water? We’ve had so much rain, and my house is in a flood zone. Are raised beds my only option, Western?
WESTON MILLER: Soil drainage is really important for most plants and especially vegetables. Raised beds do that really well. You don’t necessarily need to use wood or something to retain the soil. You can mound soil to increase the drainage. And then also adding compost or organic matter to the soil is going to help to improve the drainage as well. And then, if you’re in a really, really wet place, I would recommend growing in containers if the soil is just too wet to work.
IRA FLATOW: This is Science Friday from WNYC Studios talking about how to get your garden up and growing this season. It’s been a really different kind of weather a lot of different places around the country. Around the country this time to Jackson, Wyoming. Let’s go to Valerie. Hi, Valerie. Welcome to Science Friday. Valerie?
VALERIE: Hello? Is this for me?
IRA FLATOW: Yes, this is for you. Yes.
VALERIE: Yeah, well, this is more of a little mystery. I planted about 150 mixed color tulip bulbs about four years ago in the fall, so it’s not a springtime question. But it’s a fall time, spring tulip question. The tulip bulbs were planted in groups of three to seven, randomly. And the foxes kept digging them up over, and over, and over again. So they kept rolling around my driveway every night for about a month. And I kept putting them back in the ground.
When they bloomed, every cluster bloomed the same color. And I just thought, that’s not possible. It’s not possible. It was a mixed bag of colors. They were rolled around so many times in the driveway. How could all of the reds be together, all of the yellows be together, all of the whites be together.
IRA FLATOW: Wow.
VALERIE: I wondered if there was chemical–
IRA FLATOW: Are you blaming it on the foxes digging them up? I don’t know.
VALERIE: So it was either some kind of chemical communication in the bulbs or something. Or, it was an incredibly random and I should have bought a lottery ticket. I don’t know.
IRA FLATOW: Wow. Elizabeth, I’ll let you tackle this mystery.
ELIZABETH BUCK: So color is genetically determined, and it doesn’t really change. So I think you probably should have gone with that lottery ticket.
IRA FLATOW: Well, at least they came up, Valerie, right?
VALERIE: Well, some did, some got chewed to pieces, some disappeared. I only got a fraction. But, yes, a few did.
IRA FLATOW: Keep trying. Thanks for calling.
VALERIE: Thank you.
IRA FLATOW: Bye, bye. Here’s a question on Twitter. Megan says, what is the most affordable way to fill a raised bed with soil for the first time? We moved in the cost of lumber for the beds has gone up a bit and our budget is tight. I have that same question. If you’ve got, let’s say, a 4 by 4, you’re talking about a lot of cubic yards of stuff. Is there a cheaper way, Weston, to put that stuff in there?
WESTON MILLER: First of all, I’d recommend filling raised beds with native soil as much as possible. And then when you need to keep filling from that, going to a local landscape materials yard and purchasing a soil mix specifically for raised beds is a good option. Potting soil would also work if you need to add just a little bit on the top to bring up the level of your raised bed.
IRA FLATOW: Now I’ve seen a lot of bags of soils– I’ve seen a lot of them in my lifetime. And there’s some for potting soil and there’s some for outdoor garden soil. And it says there, do not use for potting soil. The garden soil says that. Why is that?
WESTON MILLER: The garden soil is going to have actual soil in it. And when that’s put into containers, the drainage isn’t quite good enough for container plants.
IRA FLATOW: And what’s the difference between soil and dirt then? What is soil?
WESTON MILLER: Soil is an amazing mix of the mineral parts of the actual soil air, water, and millions and millions of organisms. And dirt is a word that refers to the same thing, but it’s really inappropriate. Soil is a living entity and dirt has implications that it’s not.
IRA FLATOW: All right, we’re going to have to take a break. And when we come back, we’ll talk more about gardening, taking more of your questions. Don’t be afraid to call us– 844-724-8255. Maybe someone will have an answer to that tulip question for us. What happened to all the different colors in her tulips? Stay with us. We’ll be right back after this break.
You’re listening to Science Friday. I’m Ira Flatow. In case you’re just joining us, we’re talking about the challenges you may have as you get your garden ready for spring, from enriching the soil to deciding what to plant and getting those seedlings hardened and into the ground. And we are taking your calls– 844-724-8255. 844-SCI-TALK– with my experts Elizabeth Buck, fresh market and vegetable specialist with the Cornell Cooperative Extension in New York and Weston Miller, a community horticulturist with Oregon State University’s Extension Service based in Portland.
Before we go to the phones, let’s talk about things I’ve been thinking about also. Elizabeth, is it possible– I know it is– to manage pests without using any chemicals. How do we do that?
ELIZABETH BUCK: It is. And it requires a little bit of study and planning. And what you want to do is figure out what pests like the things that you want to grow. So if you’re growing marigolds, they’ll have certain pests. If you’re growing zucchini, you’ll have others. And when you learn what pests they have, you can learn how to prevent them coming in. Ira, you were talking about using netting over your vegetables. You can do it with open nuts for woodchucks and things, but you can also do it with something called row cover. And that keeps bugs off. So it’s making that plan in advance.
IRA FLATOW: Well, wait. Row cover– describe that for me, please.
ELIZABETH BUCK: Yeah, sure. Row cover is kind of like a spun, woven, lightweight blanket. It’s about the same weight as a sheet, but it’s made of tiny, little fibers. And it lets light in, and it lets water in, and it lets a little bit of a breeze through. But it does not let a lot of pests through. And the other nice thing about it is you can use it early in the spring to get a little bit warmer conditions. And you can use it in the fall to help give a little bit of frost protection.
IRA FLATOW: Wow. I’m going to look into that. I know that some people are using fabric tulle. They make dresses out of tulle. That works very well. It’s got tiny, little holes in it. But row cover– I’m going to look into that. Now that we’re talking about chemicals, I want to ask you a question that lots of people have asked me, and I’m wondering myself.
When people are making their raised bed gardens, they’re using wood. In the old days, they said, do not use pressure-treated wood because it had arsenic and other bad chemicals in it. And now, I’m hearing that the pressure-treated wood is not so bad because I think it’s using copper or something safer. Weston, is that true? What should we do about that?
WESTON MILLER: The new pressure-treated wood with copper is allowed for use on raised beds. For people who are strictly organic gardeners, they’d want to avoid it. It’s not allowed in the National Organic Program, which regulates farming in the Organic Standards. I personally wouldn’t buy any used treated wood off of Craigslist or something like that for fear that it could be an older product with arsenic.
IRA FLATOW: Now I know, additionally, that you think a lot about climate change and how we can get our gardens more hardy for severe weather. What should we be doing in anticipation that the climate crisis is a crisis?
WESTON MILLER: That’s true. With regards to gardening, I think what we can expect is that there’s going to be increase in frequency and severity of extreme weather, whether that be an early or late frost, a torrential rainstorm, a drought, a hailstorm, and things like that. So what we can do is I think as much homework as we can to choose plants that are adapted to our area. Know that there might be weather events that will damage them.
For me, in the Northwest, we have a lot of trees. And I have been working with an arborist in my yard to get trees ready for ice storms and things like that. And then, otherwise, I think a lot of it is just hoping that we make the right decisions in terms of the plants we choose and then being prepared to replace them if we need.
IRA FLATOW: That’s great. 844-724-8255 is our number. We have a lot of folks on the phone. Let’s see if we can get this one right. Michael in Louisville, Colorado. Hi, Michael.
MICHAEL: Hi. Can you hear me?
IRA FLATOW: I can. Please, go ahead.
MICHAEL: Oh, great. So I live in Louisville, Colorado where we just had these horrendous fires. And 1,000 homes were lost within seven, eight hours of time. And there was smoke storms of all the debris going in the air, toxic elements from computers and just awful things. And it settled in our gardens.
And last summer I built beautiful raised beds and conditioned my soil. And I’m scared to plant food. And I have worked with the Colorado State University extension. They test soil. But there is great confusion in the town of Louisville. There’s very different answers. Some are saying take all the soil out, just start over. Some are saying take out the first five, six inches. Then, of course, where do you put it. It’s toxic. It’s awful. And we’ve gone through a terrible time. And any help would be so appreciated.
IRA FLATOW: You have my sympathies. Elizabeth, Weston– Elizabeth, let me start with you. What would you suggest?
ELIZABETH BUCK: I think you started in the right place and that was getting a soil test, specifically to look at heavy metals and other contaminants. Once you get the results of those tests, there are really good standards. New York state has a good set of standards. I’m sure Colorado has some too– for what is acceptable for urban soils. And that’s because those contaminants– usually we find them in urban environments not out in more rural places.
So you can follow those guidelines and see if your soil is above or below the guidelines for things like lead, arsenic, chromium, barium, other contaminants. And then, based on where it comes, that’ll help you decide, do I need to remove the soil? Do I need to cover the soil? Or, can I grow in this soil?
IRA FLATOW: Weston, anything to add?
WESTON MILLER: I would agree with everything that Elizabeth said there. And would also say keep consulting with your local extension folks. And they can help you make those decisions.
IRA FLATOW: Good luck to you, Michael.
MICHAEL: Can I just say one quick thing?
IRA FLATOW: Sure.
MICHAEL: When we do a soil test, we’re only taking from like the top five, six inches. The bed is fairly deep. So it’s just very confusing where to take the sample from. And the upper part might read one way, the lower part– since we’ve had snow and drainage– might read another way. So it’s just confusing how to get a final, definitive answer. I hope that makes sense.
ELIZABETH BUCK: It does. It does. And so we’re mostly concerned about the root zone and the zone that you’re going to be turning over when you work your garden. That tends to be the top 8 inches. So that’s the zone that you sample.
IRA FLATOW: All right, I hope that helps you out and good luck. Thanks for calling. Speaking of soil, while we’re still talking about it, Weston. I know that you say we can even use our gardens to help take carbon out of the atmosphere to help fight climate change. How do we do that?
WESTON MILLER: Well, that’s true to a degree. And when we add compost and other organic matter to the soil, it’s going to slowly break down. And it feeds the soil microorganisms that are there. Eventually, some of it reaches a stable, organic matter called humus. And that is known to stay in the soil for anywhere from 100 to 5,000 years or so.
So when we are adding compost and adding mulch to the soil, some of that is going to be captured. Of course, the scale of that’s going to be very small. And it’s going to be very difficult to measure the actual contribution to fixing carbon in the soil. But those are the things that we want to do to soil anyway to improve it for growing conditions, and to help retain water, and block weeds in terms of adding the mulch.
IRA FLATOW: Thank you for that advice. Let’s go to Christine in the San Francisco Bay Area. Hi. Welcome to Science Friday.
CHRISTINE: Hello. Thank you for taking my call. Yes, I have a question. A friend of mine who’s a master gardener, she had asparagus for about five years. And it grew to be really big. She dug it up, and she gave me a good portion of it, which then I broke up and I put into my garden probably about six weeks ago.
And I know it’s still early in the season, but we’ve been having quite a bit of warmth. And I have them in a nice sunny area. And these things still look dead. Should they have started to sprout by now? Should I have seen something coming out of them? Should I just dig them up and start with something else?
IRA FLATOW: You have my sympathies on asparagus. I’ve had challenges with asparagus myself. Well, let’s see if we can get an answer from Elizabeth. Elizabeth, what do you think?
ELIZABETH BUCK: I’m excited for an asparagus question because I have a research trial on it right now.
IRA FLATOW: Oh.
ELIZABETH BUCK: So question for you first. When you split up the asparagus, what stage was it in? Was it throwing up spears? Did it have ferns on it? Was it dormant?
CHRISTINE: It was dormant.
ELIZABETH BUCK: It was dormant.
ELIZABETH BUCK: OK. So the crowns on asparagus are very deep down, usually at least 10 inches, sometimes as deep as 12 or 14. So you want to go all the way down and get the crown that has– you see the buds on the top of a dormant asparagus, and you see the really thick, long routes on the bottom. When we replant asparagus, it’s not unusual for it to take several weeks to come up because it is, again, planted deep. And the plant has to spend a lot of energy to do that. I would say six weeks is getting towards kind the iffy bit. If it has been dry, try giving it some water and see what happens in the next two weeks.
IRA FLATOW: Good luck.
CHRISTINE: Yeah, I have it on a dripper system, so it is getting water regularly. So every other day it gets about five minutes of the dripper system. That doesn’t put a lot of water in it, but it is getting water. But I’m just like it doesn’t look like anything’s coming up.
IRA FLATOW: Yeah, I’m with you on that.
CHRISTINE: I’m out of luck.
IRA FLATOW: I’m having the same problem.
ELIZABETH BUCK: In this point in time, I would do two things. One, I would dig down gently and see if you can see the buds starting to grow. It may just not be time for the asparagus yet. And when you dig down, they’ll either look alive and sort of whitish and thick. Or, they’ll look shriveled and brown. And you will have your answer.
IRA FLATOW: Good.
CHRISTINE: All right.
IRA FLATOW: Good luck.
CHRISTINE: Thank you so much.
IRA FLATOW: Thanks for calling.
CHRISTINE: Bye, bye.
IRA FLATOW: You’re welcome. See how many calls we can get in the last few minutes that we have here. So many people. Joe in Greenwich, Connecticut. Hi, Joe.
JOE: Hi. Thanks for taking my call.
IRA FLATOW: Go for it.
JOE: So I was wondering if you all could speak to the pros, and cons, and any health issues of using local, stable horse manure and cow manure–
IRA FLATOW: Which one?
JOE: –to augment your– well, both to augment your soils in my garden vegetable?
IRA FLATOW: OK. Is there a preference? Let me ask my guest. Is there a preference or just get what you can get, Weston?
WESTON MILLER: With local manures– a couple of concerns. One is food safety. You don’t want to apply any fresh manure to crop areas when you’re going to be eating lettuces and things like that. The general guidance is to wait 120 days or more after adding manures to soil before you harvest anything from it. So if you’re taking care of that, another concern with manures is weed seeds. And I would generally want to compost manures first to try to kill the weed seeds before putting them out in my garden.
And then, a third concern is potentially– especially with horse manure and horse bedding– there can be persistent herbicides that come in through the horse’s food, and then it’s in their manures, and then it still persists after composting. And that can sometimes have a negative impact on plants as well. So with manures, if it’s free, I would ask a lot of questions and make sure that you’re not going to run into any problems with the persistent herbicides particularly.
IRA FLATOW: Thanks for calling. Our number– 844-724-8255. This is Science Friday from WNYC Studios. Seeing how many questions I can get– because there’s so many– in the last few minutes. Let’s go to Florida. We haven’t been to Florida. Let’s go to Mark. And is it hobbit sands?
MARK: No, it’s called Hobe Sound.
IRA FLATOW: Hobe– oh, wow. My screener has got it all wrong. So much for AI. Sorry, go ahead.
MARK: Yes, I have perennial peanuts that I had planted about 12 years ago, just for ornamental purposes. It’s the variety called Arachis glabrata in about an 8-foot wide by 30-foot long section. And over the years, just because of them kind of waning, shriveling up, and so forth, I’ve gone in and put in some new plugs. And it’s that Atlantic ridge type of soil.
And at one point, I put some garden soil in beds. The biggest issue now is weeds coming in and just the horrific amount of pulling, pulling them by hand. And I loathe to spend the money on this stuff called [INAUDIBLE] to apply it to it. Is there any good way to revitalize this bed of perennial peanuts?
IRA FLATOW: Who wants to tackle peanuts? Elizabeth?
ELIZABETH BUCK: I’ll give it a try. So I’m not as familiar with peanuts, but my understanding is that they bloom. And then, the stalk grows down into the ground. And then the peanut works its way down into the soil. So you have a window of time to control the weeds before that peanut tries to push into the ground.
What you can do in that period of time is you can use a shallow tool, like a hoe or I even like a putty knife, and just sort of scratch just barely under the surface and cut off all those little weeds as they’re coming up. And then, once the peanuts are about ready to go down, you can put in a mulch layer of some sort of organic material that they’ll be able to get through, something like maybe a woodchip or something fluffy. And the mulch layer will let the peanuts go through, but it should prevent a barrier to the weeds and just make it that much harder for the weeds to come up.
IRA FLATOW: Well, we have run out of time. Everybody’s gotten in. So I want to thank everybody for calling. And sorry for those who did not get in. Let me thank Elizabeth Buck, fresh market vegetable specialist with Cornell Cooperative Extension in East Aurora, New York and Weston Miller, community horticulturist with Oregon State University’s Extension Service based in Portland. Thank you both for joining us today.
ELIZABETH BUCK: Thanks for having us.
WESTON MILLER: My pleasure. Thanks for having me.
IRA FLATOW: You’re welcome. Wish everybody good luck with the garden.
Christie Taylor was a producer for Science Friday. Her days involved diligent research, too many phone calls for an introvert, and asking scientists if they have any audio of that narwhal heartbeat.
Ira Flatow is the host and executive producer of Science Friday. His green thumb has revived many an office plant at death’s door.