It’s nice when something gross turns out to be useful (like how sheep sweat, lanolin, makes chewing gum softer). So I’m happy to report, in answer to a reader’s question some time ago, that, yes, Eurasian watermilfoil harvested from area lakes can be used in helpful ways, including as a soil amendment, fertilizer and even mulch.
First, though, if you’re not sure what Eurasian milfoil is, it’s that stringy, slimy plant that those big, blue boat harvesters remove from the lakes every summer. First detected in Minnesota in Lake Minnetonka in 1987, it is an invasive aquatic species that has spread to waterways across the state. The plant produces thick mats on the surface of the water and tangled stems and masses below, making it difficult, if not impossible, to swim and boat enjoyably. It can also disturb aquatic ecosystems by displacing native aquatic plants.
Acres of watermilfoil are removed from Minneapolis’ Chain of Lakes annually by the Minneapolis Park and Recreation Board’s mechanical harvesters. The machines usually cut off the top 3 to 4 feel of the plant, which can grow up to 15-feet long (super spooky to swim through). If you walk the paths around the lakes, you’ve probably seen (and smelled) piles of it onshore or at the boat launch.
Too Much Trash
Rachael Crabb, the Park Board’s water resources supervisor, says that once the milfoil is harvested, it’s dumped in small piles in a designated spot to dry out. Though terribly unwieldy when wet, milfoil is much easier to handle once it shrinks and composts down a bit. Until recently, the Park Board stored drying milfoil at a site at Fort Snelling. This worked well for the forestry division because whenever they needed to add organic matter to a soil mix, they could just take some from the piles.
The only problem, says Crabb, was—trash. In the lakes, all of that tangled milfoil acts like a magnet for all manner of garbage that winds up in the water in one way or another. Trying to separate the trash from the drying piles was time consuming and inefficient. So, last summer, the Park Board started looking at other options and found that the Minnesota Landscape Arboretum was happy to take the milfoil off their hands. “It’s a trek out there, but it’s the best option we have right now,” Crabb explains, adding that the first delivery is scheduled for later this year.
Soil Building and Mulching
As it happens, the arboretum has been using milfoil from the Lake Minnetonka Water Conservation District as a soil amendment for about a decade. “After it dries and turns into a nice compost, we usually use a manure spreader to put it on the research fields in November,” Peter Moe, director of operations and research, told me. In addition to supplying a bit of nitrogen, the milfoil makes a good amendment because the organic matter helps loosen the arboretum’s clay soil, improving its water-holding capacity and fertility.
In addition to being a good source of free organic matter, Moe says milfoil harvested from area lakes is desirable because it doesn’t have any weed seeds in it. “It’s such a valuable material, even if there is some trash to deal with, we would be very happy to have whatever the Park Board delivers,” he explains. “Our soils here in Carver County are very difficult to plant in if you don’t have enough organic matter, especially in the spring.”
It’s not a pretty sight, but Eurasian milfoil can be used as garden mulch (if you don’t mind the fishy smell as it dries). While researching this story, I talked with several gardeners who’ve tried it successfully. But here’s the thing, because it is an invasive species, it’s not a good idea for all of us to go running down to the lake to collect Eurasian milfoil for our gardens. Seeds and fragments could easily end up in waterways and spread the problem. In fact, Crabb pointed out that the interconnected storm sewer network could even transport milfoil to lakes that aren’t yet infested with it.
While it would of course have been best to keep Eurasian milfoil out of our waters, now that it’s here, it has proven to offer a few benefits. Even where there are thick milfoil mats on the surface of the lake, there are areas where native plants with low light requirements can grow intermixed with the milfoil stems below. Eurasian milfoil also helps make lakes clearer by keeping sediment settled out and using up dissolved phosphorous that would otherwise become food for algae.
And although native plant communities are always preferable to an abundance of Eurasian milfoil, thick milfoil growth can provide good habitat for young fish, as well as protection from large predators. “Milfoil has a more difficult time dominating where a diverse community of native aquatic plants is growing,” says Crabb, who, as part of her job, does aquatic plant surveys of Minneapolis Park and Recreation Board lakes. “We found 10 or 15 native species in Lake Calhoun a couple of years ago, so there are still a few areas in the lakes where native plants have been able to thrive, which is really amazing and a good sign that the lake is healthy even though we have Eurasian Milfoil,” she says.
I generally try to avoid writing a lot about the same issue for fear of boring people to death or seeming like a nutter who can’t stop ranting about one thing or another. In the case of neonicotinoid pesticides, though, I’ve received so many calls and emails on this topic since I started writing about it a few months back, I feel like updates are wanted and needed. So I’m going to go with that feeling and tell you more about what I’ve learned lately in hopes that this will help answer some questions you may have now that you’ve likely learned more about this issue too.
First, here’s a quick recap for those who don’t yet know about neonicotinoids. Neonics, as they are often called, are a class of pesticides that have been linked to the decline of bees, particularly honeybees, over the last decade. Because they are safer for humans than some other pesticides, neonics have become widely used in the nursery trade as a pre-treatment for annuals, perennials, shrubs and trees. They are also found in many of the common pest control products gardeners buy off the shelf and use every day for everything from Japanese beetles to emerald ash borer. (Neonic pesticides include: imidacloprid, acetamiprid, clothianidin, dinotefuran, nithiazine, thiacloprid and thiamethoxam.)
Now that studies have shown that small amounts of neonics can harm bees feeding on the pollen and nectar of treated plants while larger doses can kill, more and more gardeners are making it a point to stop using products that contain neonics and to shop for plants that haven’t been treated with the pesticides. I’ve heard from a lot of people who have called, visited and emailed garden centers and nurseries locally and nationally asking about the use of neonics.
Stories vary widely with some places eagerly sharing their plans to discontinue their own use of neonics and to seek out suppliers who will do the same. But I’ve also heard reports of a fair amount of denial and defensiveness. What you need to know is that it isn’t enough for a retailer to say THEY are not using neonics any longer on the plants that they grow. You also need to know whether the plants they get from outside suppliers are neonic free. Getting that information will take willingness and time on the part of the nursery and from what I’m hearing, it’s clear that not everyone is putting in the effort.Read More»
Of all the things in our landscape, I think the galvanized cattle troughs (also known as stock tanks) in our backyard get the most attention. Even in the winter when nothing is growing in them, their shapes and sheer size turn heads and provoke questions. We added them to what we’re now calling “our little farm” a couple of years back when we lost a huge oak, and I figured I’d take advantage of the sun to grow some vegetables. After starting with one trough, we added another last year and we’ll be getting one more in the next few weeks.
If you want to grow some food on a small, urban lot, you can’t beat these troughs for being easy to get going. You don’t have to build anything, and you don’t have to deal with turning depleted urban soil into something safe, nutrient-rich and workable enough to grow food in. They’re also affordable, durable and tall enough to be out of the way of hungry critters and peeing dogs.
People ask all the time where we got the troughs and how to turn one into a raised bed garden, so even though I wrote briefly about this a couple of years ago, I thought I’d explain the process more in-depth here since it’s the perfect time to get raised beds going for the season. Let’s start with where to buy them. Unless you are literally made of money, do not go to a boutique garden center for a livestock trough. You want to go where farmers buy stuff—Tractor Supply Co. and Fleet Farm.
If you want to grow things like tomatoes, peppers, beans and squash, get yourself a large trough. One of ours is four feet long and the other is six feet. Both are 2 feet wide and 2 feet deep, and they cost about $80 and $110, respectively. Aside from getting the things home in the back of the car, the biggest job is drilling holes in the bottom for drainage. Use a bit that can drill through metal that’s about the size of a dime of nickel. We drilled holes every few inches all around the outside edge along the bottom, and then added many more holes going across the bottom of the trough from end to end and side to side. Remove the drain plug, too, since you won’t be needing it.
Once you’ve got your holes drilled, flip the trough over and put it wherever you want it because once you fill it with soil, you won’t be able to move it around without taking most of that soil back out. We don’t like things looking all kittywampus so we used a level to make sure the trough was lined up properly once we got it situated. (You don’t have to do that unless you’re bugged by such things.) Now comes the soil part. My advice—don’t cut corners. Good soil makes all the difference when you’re growing anything.
Because these are containers, albeit huge ones, you want a mix that’s going to drain well. You also want to provide plants with some nutrients that you’ll boost over time by adding compost and fertilizer. You’ll save some money if you make your own mix by combining 1 part topsoil, 1 part compost and 1 part coconut coir or coarse sand (also known as builder’s sand). I’ve done this by combining these things in batches in a wheelbarrow and it worked well. But I’ll admit, it’s a heck of a lot less work to call someone and have a quality potting mix delivered to your driveway. That way, you can just shovel it into a wheelbarrow and take it right over to your trough and other containers.
What do I mean by a quality mix? As I’ve said in the past, I’ve learned a lot about soil and compost over the last few years and I’m now opting to go with products that are organic or at least produced by a company or farmer who is willing to explain their process so I can make an informed decision about whether to use it. (For much more on that topic, see my blog post on safe compost.
Local organic growers give products from Purple Cow Organics, COWSMO and Mississippi Topsoil high marks. Other local sources that come highly recommended are Kern Landscape Resources and Kelley and Kelley Nursery. Compost from our Linden Hills organics recycling program is also pretty good. But because it includes packaging, paper and other odd bits, I don’t use it to grow edibles. That’s just me. Keep in mind that even though it’s costly to fill your trough with quality potting mix the first year, in subsequent years (unless you get some dreaded disease like early blight of tomatoes) you’ll only need to add a bit more compost to keep soil healthy. If you feel like you’re having drainage issues, add more coir or sand. With the hard part behind you—all you have to do is keep growing.
I just want to take a minute to update my recent post, “In Search of Plants That Won’t Harm Bees.” I’ve now had the chance to talk with Bachman’s CEO, Dale Bachman, as well as John Daniels, Bachman’s vice president of production, about how the company is dealing with neonicotinoids (neonics), a class of pesticides that is harming bees.
As of 2014, while various entities continue to research the role neonicotinoids play in the decline of bees, Bachman’s has decided to take the “precautionary step” of removing all neonicotinoid products for home use from their shelves. That includes imidacloprid, a popular neonicotinoid pesticide used for all sorts of things like rose and lawn care, as well as to protect trees from emerald ash borer. (Of course, homeowners can still buy these products elsewhere and hire professionals who use imidacloprid to treat ash trees.)
They have also stopped using neonics in the production of Bachman’s-grown nursery stock and outdoor plants, which means most of their shrub roses and perennials will be neonic-free along with some annuals. As for plants from other suppliers, they are currently talking with vendors about discontinuing the use of neonics and Dale and John says the outcome may cause them to rethink some of their suppliers. Even as they said that, though, they stressed that the neonics issue is much more complicated than it may seem — a fact that becomes more and more clear to me as I interview people on this topic.
For example, in many instances neonics and other pesticides are used in compliance with regulations regarding moving plants and the potentially invasive pests they may harbor across state lines. In the case of large-scale suppliers, discontinuing the use of neonics will mean switching to other pesticides that will come with their own problems and consequences. For now, shoppers looking for neonic-free plants at Bachman’s should seek out a salesperson for help locating plants the company has grown since implementing their new policy.
Take a deep breath. Buying plants at places that many of us like to shop is going to take more work and patience than usual if we want to help bees. If you start to feel frustrated about the slow pace of change, remember that we are part of the problem. Gardeners have come to expect perfect plants on store shelves, so every entity in the plant supply chain has done everything in its power to kill every bug and wipe out every disease imaginable to make us happy. Moving away from chemical treatments that harm people, pollinators and the planet will be costly and difficult for those who care enough to do so. And we’re going to need to learn to live with more mites, aphids and other things than we’re used to. Who’s in?
A few weeks back I did a short presentation in Pine City, Minn., on how to build good, healthy soil, and a woman in the audience asked: “How do I know if the compost I’m using is safe?”
I’ve been wondering that same thing, I told her, explaining that I’ve been researching the topic so I have some answers, but many more questions, too. This prompted more people to weigh in on the subject, asking: Was it important to use organic compost, especially when growing edibles? How do you know that even organic compost is safe?
Does composted manure from conventional farmers contain pesticide and herbicide residue that could cause problems in their gardens? Should you have compost tested to find out what’s in it before you use it on food crops and, if so, where? And what about GMOs? Is it safe to use composted manure produced on conventional farms on which cows eat things like Monsanto’s genetically modified Roundup Ready corn and alfalfa?
Complex questions like these are difficult to answer definitively for a lot of reasons. Sometimes, there aren’t many studies, if any, on a particular topic. Or maybe there are numerous seemingly reputable studies, but many of them conflict with one another. For example, as a journalist who interviews people for a living, I can tell you that for every scientist I’ve talked to who dismisses the French study that came out last year linking a genetically-modified strain of maize to huge tumors in rats, I’ve got another scientist saying the study should be given serious consideration.Read More»
People have been talking about straw bale gardening for years and, I admit, I haven’t really paid much attention. It’s not that I wasn’t curious about the idea. It just wasn’t on the top of my list of things to try until recently when I got the opportunity to talk with Joel Karsten about his new book Straw Bale Gardens: The Breakthrough Method for Growing Vegetables Anywhere, Earlier and with No Weeding.
Karsten isn’t just another gardener talking about straw bale gardening. He invented straw bale gardening. That’s right; he came up with the idea for a growing technique that has now become an international sensation. And it all started when he was a kid growing up on a farm right here in Minnesota.
Farmers, he told me, have no need for piles of wet, unruly straw. So when a bale would break open for one reason or another and get rained on, his family would push it up against the barn to break down over time. “I always noticed that those stacked up, broken bales would have the biggest, tallest weeds growing out of them, so I knew there was nutrition in there,” Karsten recalls, adding that he didn’t think much more about it until 15 years later.
By then, he had earned a bachelor’s degree in horticulture from the University of Minnesota, and he and his wife Patty had just bought a house in Roseville. After looking forward to gardening at their new home, they were disappointed when they realized that their whole lot consisted of little more than construction debris in which nothing was going to grow well. Then, Karsten remembered those straw bales. “And I thought, what if I just line those bales up and try growing vegetables in them as they decompose?” he recalls.Read More»