How to Garden for our Rivers with Master Gardener, Maisah

Do you find yourself dreaming of the garden on the coldest days of winter? I do. Planning and scheming for this year’s growing season is one of my favorite winter activities. As a Master Gardener, I am always searching for new, exciting plants to grow that will be a feast for the eyes and the appetite. But did you know that the decisions we make as gardeners also have an impact on our rivers and local waterways?

If you’re a River Citizen, you know that many issues are facing our rivers. This Q&A blog focuses on three issues facing our rivers where gardeners can have the most impact: reducing fertilizer pollution, reducing plastics pollution, and increasing resilience to climate change.

“But did you know that the decisions we make as gardeners also have an impact on our rivers and local waterways?”

Q: Is my garden in a watershed?

Yes! Whether or not you live right next to the Mississippi River, we are all connected by water, and we all live in a watershed. Our Mississippi River’s watershed is tremendous. All or parts of 32 states and two Canadian provinces drain into the Mississippi River, totaling over 40 percent of the contiguous United States. Look at the map of the U.S. below. The lighter shading illustrates the watershed of the Mississippi River. In my home state of Missouri, every drop of water that falls is within the Mississippi River watershed. Thus, my garden in St. Louis is part of the Mississippi River watershed.

Image: Map of the Mississippi River watershed, including the main stem of the Mississippi and major tributaries. By Jon Platek.

Is your garden in the Mississippi River watershed like mine? We all live in a watershed. If you do not live within the watershed of the Mississippi River, you live in the watershed of another waterway. Look up your watershed by visiting the U.S. Geological Survey’s website of North American watersheds here.

Q. What is fertilizer pollution?

If you’re a gardener, you already know that proper quantities of nitrogen and phosphorus are essential elements for healthy plant growth. But what we have going on in the Mississippi River basin is way too much of a good thing. Over-application, improper application, and increasing runoff all contribute to excess fertilizer ending up in our waterways instead of being taken up by plants. The image below illustrates the pathways for how excess fertilizer pollution (also sometimes called “nutrient pollution”) ends up in our rivers and oceans.

When excess fertilizers end up in our waterways, they have the impact of triggering massive algal growth. These algae rapidly use up all the oxygen in the water, robbing life-giving oxygen for anything else. This results in a “dead zone,” where no aquatic life can survive.

Image source: https://fnfsr.org/fertilizers-algae-blooms-and-fish-kills/

What’s more, sometimes the algae themselves are dangerous to humans and pets. These “harmful algal blooms” (or HABs) can result in beach closures, hospital visits, or long-term health impacts. The Iowa Environmental Council has excellent resources on HABs here.

Q. How can I reduce my garden’s contribution to fertilizer pollution?

Reducing your garden’s contribution to fertilizer pollution begins even before you plant the first seeds; it starts in the planning stages. The popular saying “right plant, right place” is a good mantra to keep in mind as you’re planning this season’s garden. A healthy, happy plant requires fewer inputs like fertilizer to thrive. Taking the time to observe and then plan your garden so that each plant is in the right place will not only save you time but also keep you from helping a weak plant along with added inputs. For example, are there places in your garden that remain muddy for weeks after the snow melts? Does a fence heavily shade part of your raised bed on sunny days? These subtle differences in moisture and light can be the difference between a thriving plant and a struggling plant. Invest time in observing your garden space before planting.

“The popular saying “right plant, right place” is a good mantra to keep in mind as you’re planning this season’s garden.”

On a larger scale, increasing the number of native perennial plants in your garden is another way to plant the right plant in the right place. Native plants benefit from being adapted to your local and regional conditions. After they are established, native perennial plants need little to no inputs like fertilizer to thrive. What’s more, many native perennial plants have extensive and deep root systems that help filter pollutants, prevent soil erosion, and decrease runoff. Plenty of non-native perennial plants can also have long, fibrous roots – check with your local nursery, botanical garden, or Master Gardener group for state-specific recommendations. “Right plant, right place” is a straightforward, common-sense mantra that significantly impacts the environment.

Q. What is plastic pollution?

Did you know that we dump about one garbage truck’s worth of plastic directly into our oceans every minute? At least 11 million tons of plastic find their way into our oceans each year, and our rivers act as a sort of conveyor belt that transports our plastic waste into our oceans. You can learn more about plastic pollution here.

Plastic has only existed for the last 60-70 years, so we are learning more every day about its impact on the environment and our health. Given that it is a relatively new material, we are also still learning about how plastic degrades over time. We know that most plastic materials take decades (if not hundreds) of years to break down entirely.

Image Source: World Economic Forum

Q. How can gardeners reduce their contribution to plastic pollution?

If you think about it, everyday gardening uses a lot of plastic. Starter plants often come in six-packs made of black horticultural plastic. Where I live in St. Louis, I cannot recycle this horticultural plastic with my other residential single-stream recycling. In addition to plant starts, everything from plant tags, packaging, and tools use plastic. Think about the last time you organized your gardening supplies or had a large gardening haul. How much of it was plastic?

It can seem daunting, but the first step to reducing your garden’s impact on plastic pollution is to commit to refusing plastic whenever you can. You’ve heard the saying “reduce, reuse, recycle,” Right? Time to add “refuse!”

Here in the St. Louis area, we’re lucky to have a local plant shop that offers plastic-free options for buying starter plants. The Maypop Shop’s “No Pot, No Problem” program uses a paper-based liner called “elle pots” instead of plastic. Do you know of any local nurseries with similar programs? If not, have a conversation with your go-to nursery about considering plastic-free options for plant starts.

After you’ve considered your options for rejecting the use of plastic, let the remaining “three Rs” —reduce, reuse, and recycle — guide you. Here are a few ideas to get you started:

• Reduce your use of new plastic by making your own pots out of newspaper or other biodegradable materials.
• Wash and reuse your existing stash of horticultural plastic containers (and plant tags) season after season
• Reuse other plastic containers (yogurt, takeout, or beverage containers) in the garden as pots, watering pails, labels, or storage.

Finally, find the proper facilities to recycle your extra horticultural plastic. Sometimes your local botanical garden or plant nursery will have horticultural plastic collection facilities. You can also reach out to your local community or school gardens before the growing season begins to see if they need clean horticultural plastic.

Q. How can I make my garden more resilient to climate change?

The impacts of climate change are being felt all along the Mississippi River. In our region, climate change is bringing more extreme weather events, floods, and periods of drought. As experienced gardeners in the region, you may have already noticed changes in your growing season over the last decade. One well-known example of how climate change is impacting gardening and growing is captured in recent changes to the U.S. Department of Agriculture’s Plant Hardiness Zones.

To adapt your garden to a changing climate, focus on resilience. In this case, “resilience” refers to the ability of your garden to thrive in both very wet and very dry conditions. As mentioned above, taking the time to plan and design your garden space with careful attention to the “micro-climate” of your backyard will make your garden more resilient in the long run. What’s more, the perennial plants with deep root systems mentioned above are also good plant choices to build resilience; many plants with deep root systems not only absorb large amounts of water but are also hardy in drought conditions.

The practices and tools used in rainscaping can also build resilience in your garden. Climate change is expected to intensify storms and lead to greater precipitation across the entire Midwest region during this century (source). When water enters the Mississippi River basin faster than it can be absorbed, it leads to flooding. Rainscaping allows rainwater to be intercepted and/or absorbed right where it falls, rather than being quickly carried away (often carrying pollutants along the way) into local waterways.