Great question. Here’s the scoop. When we poop, we’re getting rid of a bunch of stuff that we can’t digest or that our bodies can’t use. But there are lots of useful nutrients still in the poop. All living things are made of cells. And those cells are made of molecules. And those molecule are built out of nutrients. If you look on a bag of fertilizer, you will see words like “nitrogen” and “phosphorus.” Those are nutrients that plants can use to build their molecules and cells. And poop is full of those nutrients.

We don’t usually use human poop as fertilizer because germs and parasites could get into our food. But we do use poop from cows, chickens, and bats. Often the poop is left to rot a bit so that bacteria, fungi, insects, and other decomposers get a chance to break things down. That makes it easier for plants to get the nutrients.

Why do you think decomposers are so important in ecosystems? Hint: recycling.

You may want to study ecology.

There are useful things in poop for plants. Our bodies don't use all the food that we eat, and bacteria in our intestines make other useful molecules out of the food and wastes in our intestines. These make useful fertilizer for plants.

My husband got a load of chicken poop put on his new garden, but the plants died. The poop had some strong chemicals in it that killed the plants. One needs to let the chicken poop sit out in the sun, or water it a lot, or do something to it before one can use it as fertilizer.

I put guinea pig poop on the plants on my balcony, and they seem to be doing fine. Guinea pig poop comes out in dry little pellets, so I think they're getting air and water and time to make them safe before they soak into the soil around my plants.

Some animals like to eat their poop. Wikipedia says people think that bacteria in the animal's intestine make vitamins that the animals get when they eat their poop.

Poop, or manure, can help plants grow because it enriches the soil that they grow in. Plants are just like us; we need nutrients to help us grow. Manure supplies nutrients like nitrogen, phosphorus, potassium, which speeds up decomposition and lowers the pH of the soil. This helps the plants grow faster!

Poop contains phosphorous, which plants need but which isn't in the air. Poop also contains nitrogen, which is in the air, but the form of nitrogen in the air is not in the form that plants can use either, so again plants can get it out of poop.

Thanks for the great question.

Animals eat food to grow bigger and for energy, but they don’t use everything in the food. Animals get rid of the food they don’t use by pooping. This means that animal poop, or feces, contains lots of nutrients, or things that all plants and animals need to grow.

When animal feces are added to dirt, it is called manure. Manure has all sorts of things plants need to grow, like nitrogen. These help to make the ground fertile, or a good place for plants to grow. Manure also makes the ground hold onto more water, which is also really good for making plants grow.

Manure is so helpful to plants that we wouldn’t have nearly as much food without it.

Thanks again for the question!

Poop, which I’ll call manure for the rest of this explanation, does a lot to help plants grow. Plants, like us need nutrients in order to grow and sometimes the soil that plants naturally grow in doesn’t have enough. Manure actually has a lot of the nutrients that plants need to grow. In addition to this, adding manure as fertilizer also heats up the soil, which speeds up the breakdown of dead plants and animals, which plants can then feed off of. Thank you so much for your question!