Pistachio shells can be composted but there is a little trick that will make the process so much faster. Collect your pistachio shells in a bowl throughout the week and when the bowl is half full, fill the rest of the space with water and soak the shells for 24 hours. This will soften the shells and help them to break down faster.
This article will explore the easy steps to compost pistachio shells at home. Keep them out of landfill and find out how to turn them into compost at home.
5 Steps to Compost Pistachio Shells
Here are my easy steps to compost pistachio shells at home. These steps will help the pistachios to break down as fast as possible and turn them into rich compost for your garden.
1. Collect your pistachio shells
The first step is to collect your pistachio shells after eating the nut. Most pistachios are sold unshelled so you will end up with lots of shells leftover. You can collect these in a bowl throughout the week as you eat through your pistachios. Set aside a small bowl in your kitchen to collect the shells.
Note: you can add pistachio shells straight to your compost. You can sprinkle a handful of shells into your bin at any time. The reason to collect them in a bowl is so you can easily soak them, described in step 2.
2. Soak them overnight
Soak pistachio shells in a bowl of water for 24 hours before putting them in your compost bin. The shells will absorb some of the water which will help to soften them and allow them to be broken down quicker by soil bacteria.
You can add the shells and the water to your compost bin after this time.
Note: Soaking pistachio shells is not essential but will mean that they will break down quicker, in a few months instead of 2-3 years for dry shells.
3. Sprinkle pistachio shells on top of your compost
The next step is to take the soaked pistachio shells to your compost and sprinkle them over the top. Layer them evenly across the compost pile to give lots of surface area for soil bacteria and worms to digest them.
Try to avoid leaving your soaked pistachio shells in a big lump in your compost. They can end up rotting and smelling and will take a long time to break down.
4. Cover with brown material
Cover pistachio shells with brown material like straw, hay or fall leaves. This help to prevent any pests such as mice or rats from visiting and trying to eat the shells.
5. Mix pistachio shells through with a garden fork
The final step is to mix the pistachio shells through the compost bin or pile. This will help to mix the shells in with other ingredients such as the older compost, food scraps and soil bacteria. Mixing the ingredients together will help all of them to break down faster.
You do not need to mix the shells through each time but it is a good idea if you are adding a whole bowl full. You will bury the shells which helps to hide them from rodents.
Can you compost pistachios shells?
Pistachio shells can be composted in a compost bin, pile or even in a worm farm. Soak the shells overnight to help them to break down faster and help the worms to eat them.
Pistachio shells can be naturally composted on the ground or in your garden beds but prepare to see them for 2-3 years or more before they break down fully. To break down pistachio shells as fast as possible soak them first and then put them in a worm farm or compost bin.
How long does it take to compost pistachio shells?
Pistachio shells can take 2-3 years or more to break down fully. In a compost bin or worm farm they will be broken down into humus or worm castings that can be used in the garden. The nutrients and carbon left in the shells will be digested by soil bacteria and worms and released in a form that allows the plants to absorb the nutrients.
Putting pistachio shells in a compost helps to trap the carbon and avoids the shells rotting in landfill where they can produce methane. Pistachio shells will take many years to break down in landfill so put them in compost bin instead.
Can pistachio shells go in a worm farm?
Pistachio shells can absolutely go in a worm farm and they will break down far quicker if they are soaked first. Put the shells in a bowl and soak them in cool water overnight. You can them tip the shells and water into the worm farm and gently spread the shells out.
Sprinkle over some hay or fall leaves and then cover the whole lot with your worm blanket. You can then let the worms and soil bacteria to go to work to break them down. Soil bacteria will usually move in first to break down the shells and worms will dig their way up to eat the bacteria.
Pistachio shells can still take a year or more to fully break down in your worm farm. I find that worm farms are the fastest way to break down the shells compared putting them in a compost bin. Don’t worry if small amounts of shells are not fully broken down when you add them to the soil. They will continue to break down over time and won’t harm your plants.
How to Compost Pistachio Shells | Summary
Pistachio shells are an organic material so can be broken down in compost. They are particularly hardy so it is best to soak them in water before adding them to your compost. Soil bacteria will move in to break down the shells and they will eventually turn into mature compost. Remember that pistachio shells do take longer to break down than other food scraps because they are so hard.
Don’t worry if there are small pieces of pistachio shells left in your compost. This will continue to break down when you dig them into the soil.
Happy composting.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.