Can You Compost Potatoes? Or Will They Start Growing?

By Paul Smart •  Updated: 11/09/21 •  6 min read

Can You Compost Potatoes? Composting is a great way to process waste and also develop nutrient-rich soil that can be used for growing plants. However, many people want to know what foods can be composted. While most fruits and vegetables can be composted, some plants like potatoes have tubers that can start to grow, so can you compost potatoes?

Potatoes can be successfully composted. However, potatoes have a tendency to grow into new potatoes if left intact. To avoid this the potatoes need to be chopped up to avoid turning the compost bin into a growing pile for new potatoes. If the potatoes have any signs of blight, it’s best to avoid composting. The virus or spores may not be killed by the composting cycle. However, potato peelings and skins will rot down quickly and can be composted safely.

Composting Potatoes

Since potatoes grow underground, composting them appropriately will ensure that they don’t turn into more potatoes, but instead break down into nutrient-dense humus. Starchy tubers contain moisture as well as a source of nitrogen for healthy soil. Since nitrogen-rich waste is great for composting microbes, potato scraps are actually a great option when it comes to organic debris in the compost bin.

To optimize the composting of potatoes though, some additional work is needed. Take the time to prepare any old potatoes or scraps before adding them to the compost pile. Chop or shred any large potatoes or chunks that are at least 1/2 inch or smaller in size which can be done with a trowel or shovel.

Any potatoes that are molded or appear blighted should not be put in the compost bin. Sprinkle the pieces of the potatoes across the top of the compost heap. Cover them with a few inches of a carbon-rich compost material such as straw, shredded newspaper, or even wood chips. This speeds up the composting process by making the nitrogen content of the potatoes more available to compost microbes that will break them down.

Considerations for Composting Potatoes

When adding potatoes to the compost pile, the amount added does make a difference. Any nitrogen-heavy waste shouldn’t overpower the rest of the bin. No more than half of the waste in a compost pile should be made up of a nitrogen-rich source, such as grass clippings or fresh plant cuttings.

The other part of the waste should come from a carbon-rich organic material, which includes things such as paper, cardboard, or brown garden waste, as both of these elements are essential to create a successful compost. If too much of either nitrogen or carbon is in the compost pile, it may slow down the degradation of the materials. Although larger piles typically have a mix of materials, be cautious with any smaller compost bins where the balance may be more delicate.

To ensure that the composting goes smoothly, it’s also best to watch for moisture and mixing. Keep the compost pile about as wet as a kitchen sponge that’s been wrung out. The compost can also be mixed with a garden rake or similar tool about once a week in order to introduce fresh oxygen to the mix.

Potatoes Growing in the Compost

Although it’s best to chop up potatoes, you may miss a section and end up accidentally growing potatoes in your compost bin. When this happens, you may find that you enjoy having the potatoes. However, if not, then dig out the potato plants. You can discard them or chop them up again and add them to the compost bin. They will break down over time. Avoid overloading the bin with too many potatoes at one time.

Avoid Composting Potatoes with Blight

Since potatoes are prone to certain diseases, always check potatoes that may not be good before adding them to a compost pile. Potato blight is common. This fungus-like spore-borne disease can affect potatoes, tomatoes, and peppers. The disease starts in the leaves of the potato plant but can infect the potatoes themselves over time. Blight can damage an entire crop and since the spores are long-lasting, you want to avoid getting them in your compost pile.

When chopping up potatoes for composting, check to see if they have any brown spots, rot, or mold. If you notice this on the potatoes, throw them away. Do not add them to the compost pile. The spores are long-lasting and can continue to damage other plants if you use the composting soil in your garden. Since it’s difficult to eradicate blight, prevention is the key.

How To Compost Faster

To get materials to break down relatively quickly there are a few things that you can do. The first thing is to run a hot compost heap rather than a cold one, which for some people is not always practical. To create a hot compost heap you need to have a heap that is at least 35 cubic ft (1 cubic metre) in volume.

At these volumes, the temperature of a compost heap can reach a peak temperature of around 150°F (65°C). To monitor the process of your heap you can use a specifically designed compost thermometer. These are relatively cheap and can be purchased from Amazon, click here to see the latest price.

The second thing that can be done is to ensure that any materials that you add are cut up as finely as possible. This will increase the surface area of the materials added and accelerate the rate of reaction. To minimize the size of the garden waste you can use a specifically designed garden shredder or simply run over the waste with a lawnmower.

The third thing that is highly recommended is to spread the materials evenly across the surface of the compost pile in thin layers alternating between nitrogen-rich materials and carbon-rich materials. The benefit of doing this is that all of the nutrients that the microbes need are in close proximity to them.

To get additional tips on how to make and use compost I highly recommend watching the videos from Charles Dowding. He is a well-known market gardener that has over 35 years’ worth of experience.

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Paul Smart