Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall. 

What does it take to keep your lawn looking green and healthy? A lot of people say you need to use fertilizer. But do you really? And what’s the cost of using this stuff on our grass?

Megan Hall: Here to tell us more are Luci Jones and Fatima Husain from our Possibly Team. Welcome, Luci and Fatima! 

Luci Jones: Hi, Megan! 

Fatima Husain: Hello! 

Megan Hall: What exactly is fertilizer? What is it supposed to do? 

Luci Jones: So, people add fertilizers to the soil to help plants, like grass, grow. They usually have three key ingredients: phosphorus, nitrogen, and potassium plus a bunch of other nutrients.

Megan Hall: And how are fertilizers made in the first place? 

Fatima Husain: Some fertilizers are made from stuff you can find naturally like compost or cow manure. 

Luci Jones: But there are a lot of human-made, or synthetic, fertilizers. And those are created with fossil fuels.  

Megan Hall: What happens when we add fertilizer to our lawns? 

Luci Jones: Well, when you add them to soil, they DO help plants grow, but they don’t always stay in your yard.

Fatima Husain: When it rains, or when you overwater your lawn, fertilizer can drain from the soil into water bodies near your house. 

Luci Jones: To learn more, we talked to Wenley Ferguson, the Director of Restoration at Save the Bay in Rhode Island. She says… 

Wenley Ferguson: Think of your yard as a sponge, and try to have as much of the water that hits your yard stay in your yard.

Megan Hall: But, what if I don’t live near a river or a lake?

Fatima Husain: Well, even if you can’t see a body of water near you, wherever you live, you’re close to what’s called a watershed.

Megan Hall: What’s that? 

Luci Jones: Wenley describes them this way: 

Wenley Ferguson: A watershed is like a large sink. And the water body is the drain.

Fatima Husain: Basically, watersheds are lands that channel rain and melted snow into a specific body of water. Wenley says you’re almost always on top of one.

Wenley Ferguson: When when you're driving down the road and it says you are entering a watershed area, I always kind of laugh because you just left a watershed too. Every drop of water that hits the earth is going to drain someplace.

Luci Jones: So for instance, here in Providence, Rhode Island, our water drains into the Narragansett Bay watershed. But in Washington County, people live in the Coastal Pond watershed.

Megan Hall: Okay… so, because I live in North Providence, that means, when it rains, any fertilizer in my yard drains into the watershed, and then into Narragansett Bay? 

Fatima Husain: Exactly! 

Megan Hall: What happens when my fertilizer gets into the water? 

Luci Jones: Wenley says two things happen. First, you know how fertilizer is designed to help plants grow? When it’s in the water, it causes algae -- tiny, tiny plants -- to grow a little too much. This can make the water toxic for humans and animals.

Fatima Husain: And when there is a really big algae bloom, and the water conditions are right, the breakdown of all those algae can remove oxygen from the water, which can kill fish. 

Megan Hall: Is there any way to prevent our fertilizers from getting into the water ? 

Fatima Husain: Yes! You can grow plants that don’t need fertilizer, use it sparingly, or opt for the kind labeled “slow release,” which lets out fewer nutrients at a time. 

Luci Jones: And don’t be afraid to let your lawn go brown in the summer. Wenley says, a brown lawn isn’t a dead lawn, it'll green up again when the weather gets colder and wetter.

Fatima Husain: These individual actions can make a big difference, but Wenley says what we really need are local bans or limits on fertilizer. 

Luci Jones: So the last thing you can do is spread the word about what happens when fertilizer gets into our water and advocate for landscaping choices that prevent this kind of runoff. 

Megan Hall: Got it! Thanks, Luci and Fatima! 

That’s it for today. For more information, or to ask a question about the way you recycle, use energy, or make any other choice that affects the planet, go to the public’s radio dot org slash possibly. Or subscribe to us wherever you get your podcasts. 

Possibly is a co-production of the Institute at Brown for Environment and Society, Brown’s Climate Solutions Initiative, and the Public’s Radio.