Can You Compost Pistachio Shells? (And Are They Biodegradable?)

When someone tells you ‘you must be nuts!’, do you get mad or feel bad about yourself? Well, don’t! Nuts are known to contain essential nutrients and can aid weight loss and heart and gut health. Some of the world’s most famous nuts include peanuts, walnuts, almonds, cashews, macadamia, Brazil nuts, hazelnuts and of course pistachios.

Pistachio nuts are not only tasty and fun to eat but also super healthy. They contain healthy fats and are a good source of protein, fiber, and antioxidants. Apart from the nutty and sweet part that is consumed, the other common thing with the pistachio is the exterior shell. They are not edible and are most likely thrown away or used for decorative purposes. This article looks into composting pistachio shells and tries to explain if they can be composted.

Are Pistachio Shells Compostable?

Luckily for you, pistachio shells are compostable. Nutshells like pistachio shells are good for composting. Using compost, including that made of pistachio shells, is one of the best ways to nourish your plants.

Not only does it retain moisture, enrich the soil, and fight against insects and plant diseases, compost is better for the environment than many commercially produced fertilizers. Compost also lowers your carbon footprint by reducing the use of chemical fertilizers.

The shells may take a few years to decompose, so they make the compost less heavy, even though they add bulk. Pistachio shells also help with water retention. The compost might not be applicable for use for sowing small seeds or potting on delicate baby plants, but the shells can make good compost, fine for your vegetable patch or flower beds.

You should be careful not to add the shells as a whole as they are directly into the composting bin. If you add them whole, be prepared to wait for two years or more before they completely decompose. Instead of simply tossing them like that, be sure to crush them first. If they are broken into pieces or a fine powder, they decompose more quickly.

You should also use unsalted pistachio shells for the composting bin or pile. Salted pistachios are not bad while in the bin unless you are composting only a few and if the pile is large enough. Too much salt in the composting bin will contaminate the soil. The salt also kills any microorganisms and natural bacteria in the compost, delaying the composting process.

As such, to be on the safer side, just use unsalted pistachio nut shells in your compost. You can also soak the salted shells overnight to get the salt off the shells. Oh, and for the record, other nuts and nut shells can be used in the compost bin, but then again, avoid salted nuts and nutshells.

Pistachio shells are a terrific bulky ‘brown’ material for compost. Browns are materials that are carbon-rich and will add structure to your compost and aeration to the pile. They are hard and slow to degrade, but you can speed up the process considerably by crushing them up before tossing them in.

Another option is to soak whole shells in a bucket of water overnight to soften them. The next day, dump the pistachio shells, along with the water, into your compost heap.

Composting pistachio shells reduces the levels of methane emissions from landfills, reduces the need to use chemical fertilizers and encourages the production of beneficial fungi and bacteria that break down organic matter to create humus. Composting also helps the soil retain moisture, enriches it, and suppresses pests and plant diseases.

Are Pistachio Shells Biodegradable?

Definitely. Pistachio shells are biodegradable. The fact that they are biodegradable is what makes them excellent candidates for the composting process. They decompose quite slowly, but the process can be hastened if the shells are broken into smaller pieces.

When the shells biodegrade, they add to the carbon side of things. The pistachio shells may take a few years to decompose, so they make the compost less heavy, even though they add bulk. Pistachio shells also help with water retention.

Instead of simply tossing them in your compost bin, be sure to crush them first. If they are broken into pieces or a fine powder, they decompose more quickly. The result is compost rich in nutrients and one that can do a lot for the soil and the plants.

Are Pistachio Shells Good For the Soil?

Yes, pistachios are amazing for the soil. In itself, composting helps the soil retain moisture, enriches it and suppresses pests and plant diseases. It also reduces the need for using chemical fertilizers, lowers the emission of methane from landfills and lowers your carbon footprints.

It also encourages the production of beneficial fungi and bacteria that break down organic matter to create humus, the rich nutrient-filled material. Composting pistachio shells helps with keeping the soil from draining out the hole as the water drains out if you have household plants. The shells can last in the pot for as long as two years and they do decompose so you should change them every year.

Pistachio shells can also be used as mulch for plants and shrubs that require acid soils. The shells help to conserve moisture under the plants, discourage weeds, and improve fertility. However, you should soak the shells overnight for the best results. The shells can also be used as a medium for orchids.

Pistachio shells, primarily the salted ones, can be put around the base of plants to deter snails and slugs. There are other households uses for the shells, that make them ideal for the home.

For instance, they can be used as a fire starter along with a little bit of crumpled paper as they are high in oils and can be used if you do not have a kindling. The shell  can also be put around the base of plants in your houseplant or garden to cover the dirt, making the cats unable to dig up the dirt

How Long Do Pistachio Shells Take to Decompose?

If added to the composting pile whole, without being broken down into smaller pieces, the shells can stay up to two years without them decomposing. Another source suggests that pistachio shells can take even longer than 3 years to biodegrade in the outdoors.

Where the compost is prepared well, aerated well, moistened as it should be and turned regularly, with the pistachio shells crushed before being added to the mix, the process can take between eight and twelve months to complete.

Pistachio shells are a member of the browns so yes, pistachio shells are compostable. The next time you are having them as a snack you put them in a bag to add them to the compost pile. They are a terrific bulky brown material.

7+ Unique Ways to Use Old Pistachio Shells

1. Mulch

You can save up your pistachio shells and mix them with wood chip, bark, leaves, or other organic mulch before scattering them over the garden. Covering your garden beds with a generous layer of mulch is not only aesthetically pleasing, but also helps keep the soil moist, boost fertility, and suppress weeds.

Remember, whole pistachio shells are fairly tough and hard and will take ages to fully break down. As they do, they will slowly release carbon, fats, proteins, and carbohydrates to feed the earth

2. Fire kindling

Pistachio shells are made of woody materials that make them ideal for fire-making. To start or revive a dying fire, toss a handful or two of pistachio shells to get things going. They are a great kindling for enclosed fire pits and wood stoves.

Be careful before adding them to an open campfire, as the nutshells contain fats that pop and sizzle when exposed to high heat. Therefore, give the open fires plenty of space after adding the shells.

You can also make a fire starter by crumpling pistachio shells up in newspaper before tossing them in. This will help stop them from jumping out of the flames.

3. Making crafts

Ingenious crafters have uncovered numerous ways to incorporate pistachio shells into their do-it-yourself projects. The shells have a curved shape, and they can be made to look like beautiful flowers that will never wilt and die.

When painted and placed right, pistachio shells can look like beautiful succulents. You can try making gorgeous hanging succulent flowers, or a bright and cherry-painted floral wreath, a decorative tree, a lovely ombre necklace or make an array of lotus candle holders. You can also create beautiful mosaics with the shells, including mosaic wall art, 3D paintings, to fruit baskets.

4. Deterring pests

Pistachio shells can also be used to deter irksome critters. Simply spread the shells as a thick top dressing around outdoor plants to deter squirrels, chipmunks, and raccoons from digging in the soil. The shells can also be used to deter slugs and snails, but only if the shells are salted.

Create a blockade against slimy gastropods by sprinkling the shells in a line around individual plants or the entire perimeter of the garden. Indoors, pistachio shells can be added to houseplant containers to prevent our furry friends from messing with our beloved greens.

5. Making a potted plant filler

You can lessen the need for copious amounts of soil for your decorative plants by filling the bottom portion of the container with pistachio shells. Allow for enough room at the top for potting soil.

The planting depth should be matched to the mature size of the cultivar. Herbs, lettuce, and other smaller plants need only 12 inches of soil while tomatoes and other larger specimens would be better off with 24 to 36 inches of soil.

6. Drainage for potted plants

As a bonus, pistachio shells can assist with drainage for indoor plants’ root systems. Using pistachio shells to line the bottom of any potted plant will prevent them from becoming waterlogged. The trick is especially useful when the pot lacks a proper hole for drainage.

With an empty container, add an inch or so layer of pistachio shells along the bottom. Top the container up with soil and add plants. Water that is not taken up by the plant will drain into this pistachio shell layer, keeping the root system up and away from excess moisture.

7. Making Christmas ornaments

If you are a fan of handmade ornaments, pistachio shells can help you create beautiful Christmas ornaments. In addition to being an add-on for your tree, it can also be a fun, festive activity for the kids to create their decorations.

8. Making candle holders

This might have been referred to earlier in this list, but here it comes in details. Pistachio shells can be brought together to create beautiful-looking blooming candle holders. You can easily paint them to look more elegant or vibrant. Picture that candle-lit dinner with your spouse or spouse-to-be, with the candles, held up by the beautiful art you did by yourself.

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About Rinkesh

A true environmentalist by heart ❤️. Founded Conserve Energy Future with the sole motto of providing helpful information related to our rapidly depleting environment. Unless you strongly believe in Elon Musk‘s idea of making Mars as another habitable planet, do remember that there really is no 'Planet B' in this whole universe.