Skip to Content

How To Save Coffee Grounds & Egg Shells For Your Garden – And Store Them Too!

One of the best ways to prepare for a great garden season in advance is to start saving and storing all of the spent coffee grounds and egg shells that come from your kitchen during the fall, winter and early spring months.

Unfortunately, during the garden off-season, many valuable kitchen scraps go unused. Vegetable scraps, fruit peels, rinds and remnants head into the trash instead of heading to the compost pile. As do two of the most soil and plant building remnants of all – coffee grounds and eggs shells!

But although it can be difficult getting to and maintaining your compost pile in the winter for all of your kitchen scraps, when it comes to coffee grounds and egg shells, with a few simple, safe and easy saving methods, you can store these amazing soil and plant building nutrients for when you need them most – garden season!

store egg shells and coffee grounds
Coffee grounds and egg shells are the two most valuable of all “leftovers” coming from the kitchen. By saving them during the garden off-season, you can have plenty on hand for spring planting season!

Both coffee grounds and egg shells have tremendous benefits when it comes to gardening. Not only are they wonderful in the compost pile, they are also great for protecting and powering plants. And in a myriad of incredibly powerful ways!

Why Saving Egg Shells & Coffee Grounds Is So Important…

Coffee grounds contain traces of nitrogen and other key plant-loving minerals and nutrients. In addition, they also help to attract worms, all while adding better structure and water absorbing qualities to the soil.

Egg shells, meanwhile, also contain traces of valuable nutrients that are helpful to plants and the soil. When mixed into the soil, these nutrients easily leach out and are absorbed by the roots of the plant. For all of those beneficial reasons and more, we put both materials down into every single planting hole in the spring.

Whether it’s planting our tomato, pepper and other vegetable transplants plants, or digging in all of our annual flowers around the farm, coffee grounds and egg shell remnants go into ever hole. We also sprinkle both on top of many of our plants for added nutrients and to protect against pests. (See: Why Saving Coffee Grounds & Egg Shells Is A Must For Garden Season)

saving egg shells and coffee grounds
Adding crushed egg shells when planting tomato plants can help prevent blossom end rot. It can also help build strong stem cells to support a bigger harvest!

Because of that, we need and use a lot of both at planting time. And the only way to make sure we have plenty on hand is to save our coffee grounds and egg shells all throughout the off season. But that can often be a bit tricky when it comes to storing them without having them mold or smell.

Storing Egg Shells & Coffee Grounds

Coffee grounds tend to be quite damp and moist coming out of a coffee maker. Storing them at room temperature, especially without first drying them a bit can often make them quick to mold. Unfortunately, even with drying them, they can often absorb moisture and still go moldy.

Egg shells quite often have the same issue. The wet, sticky, slimy interior of egg shells can also have room temperature shells molding fast. Even worse, with egg shells, it can create a nasty odor as well.

For these reasons, most who try to save egg shells and coffee grounds usually throw them out at the first sign of mold. They also abandon the thought of trying to save any in the future.

wet coffee grounds
After brewing, coffee grounds are extremely wet and moist. And if they stay that way for long, mold can quickly form on their surface.

But here’s the good news, with the most basic of prep for each – and using just a bit of space in your freezer – you can safely and easily store them for months on end. All without having to worry about them molding or smelling.

How To Safely Store Coffee Grounds & Egg Shells

The freezer is actually the perfect storing space for both grounds and shells. By keeping the materials frozen, there is zero chance of mold or smell. Even better, you can take them out and use as needed, keeping the rest safe and sound in a deep freeze.

And if you are worrying about taking up too much space (especially with the egg shells), as you will see below, there is a quick and easy solution to that problem as well. With that in mind, here is a look at how to store each in a snap!

Storing Coffee Grounds In The Freezer – How To Store Coffee Grounds & Egg Shells For A Garden

Storing coffee grounds for the long haul is the most simple of all. There is really no reason or need to dry them out first if you will be freezing them, since there will be no chance for mold to form.

For us, we use a resealable plastic freezer bag that can be quickly opened and re-opened. Every morning, after the coffee is done brewing, we just pop the bag out of the freezer and scrape the grounds into the bag.

Even in a frozen state, the grounds are able to easily be crushed down. It makes it easy to keep the bag filled flat, saving tons of storage space in the freezer.

It is important to scrape the coffee grounds off of the filter and not save both. Not only does it save space, the filter will freeze hard to the grounds making them hard to remove later. Most coffee filters are compostable. So if you happen to still have your compost pile going in the winter, by all means throw the filter and the small coffee ground remnants still sticking to it into your pile.

As for storing, we can usually fit about 75 to 100 coffee filter’s worth of grounds into a one gallon freezer bag. Saving a few bags up over winter and early spring certainly gives us plenty of grounds ready to go by planting time!

Storing Egg Shells In The Freezer – How To Store Coffee Grounds & Egg Shells For A Garden

With egg shells, the process is still simple, but it does involve an extra step or two to make the most of your saving efforts. Although you could simply crumble up fresh eggs shells and pop them into a resealable plastic freezer bag, it can take up a lot of room.

freezer bags
With coffee grounds, simply emptying them into a one-gallon resealable plastic bag can keep them safe and mold free.

By first grinding down the egg shells first into a near powder-like substance, you can save substantial space. And it’s super easy and fast to do with a little hand held coffee grinder. Just toss in the shells and grind them down! Affiliate Product Link: Electric Coffee Grinder

Grinding your shells into a powder also has another huge additional benefit. Egg shells can take a long time to break down in larger bits and pieces. But egg shell powder is more easily absorbed into the soil. That means nutrients get to and power plants all the faster!

We actually save a week or so of egg shells at a time and then put them on an old cookie sheet in the oven to dry. To do this we set the oven on 200° (F) for about 20 to 30 minutes before grinding. This dries out the shells and makes grinding them quick, easy and mess-free.

Final Thoughts…

One final note, always wash out your coffee grinder with soap and warm water to keep any bacteria off of the blades. Once ground up, simply pop your egg shell powder into the freezer exactly the same way as your coffee grounds, and you will be more than ready for planting for success next spring.

Here is to saving and safely storing egg shells and coffee grounds this winter! Happy Gardening – Jim and Mary.

As always, feel free to email us at thefarm@owgarden.com with comments, questions, or to simply say hello! You can sign up for our free email list in the subscribe now box in the middle of this article. Follow us on Facebook here : OWG Facebook. This article may contain affiliate links.