How to use eggshells in your garden and compost 

Written by Ollie Wilkinson

Cracking the case on what to do with your eggshells 

We don’t beat around the bush when it comes to gardening and sustainability, and are shell-bent on making full use of your eggs. Turn over a new leaf and nip waste in the bud with our guide on how to use eggshells in your garden. 

From the cupboard to your plate and beyond, we dig up the dirt on how to make your green space blooming beautiful in one shell swoop.  

What is composting? 

Bringing new meaning to rotten and degrading, composting is a groundbreaking (literally) way to nurture your garden, recycling natural and organic matter into fertiliser for your plants. 

Hardcore composters guard their proud piles and boast-worthy bins closely. And for good reason. Once you’ve made your compost bin and learned what compost is used for, there are unwritten rules you need to adhere to when building your lasagne-like collection of waste, with one accidental drip of cooking oil or sneaky weed enough to ruin a perfectly nutritious feast for your soil. 

Eggshells are a cause of great discussion in the gardening and composting world. Forget “what came first, the chicken or the egg?” This is the where the real, fiery, egg-based debate is at. 

Is it okay to put eggshells in the compost? 

Almost 13 billion eggs are eaten in the UK every year, with tons of shells ending up in landfill. But composting eggshells doesn’t just crack the problem of excess food waste in your kitchen. It also provides a fantastic wealth of nourishment for your garden. 

Your compost is like a big, chunky, healthy smoothie for your garden, and eggshells are a sure-fire way of ensuring it remains filthy, rotten rich in nutrients.  

The calcium from eggshells strengthens the cell walls of your plants, the magnesium aids the process of photosynthesis, and the potassium reduces water loss and wilting. This means, the next time you enjoy an omelette, your compost can benefit from the same wholesome dose of nourishment by gobbling up the shells. 

We know what you’re thinking. This all sounds great, so why all the debate? Well, there are some concerns about using eggshells in compost, largely revolving around the dreaded S-word. No, not that one. We’re talking about salmonella. 

Not to be confused with a silver-coloured, edible fish called Ella, salmonella is the bacterium that causes food poisoning. Clinging to raw eggs like a Werther’s Original on your grandma’s teeth, this invisible devil can be a danger to your compost’s hygiene, particularly if you’re using it to fertilise homegrown produce. However, this risk can be alleviated with careful preparation. 

How do you prepare eggshells for compost? 

As we all know, cooking eggs will remove any traces of the dreaded S-word. No, not that S-word – we’re still talking about salmonella. The same applies to eggshells.  

A hot compost is made to warm itself in the sun, breaking down quicker and destroying any bacteria through heat. This makes hot composts the best home for uncooked eggshells, as it reduces the risk of any food poisoning in your fertilised fruit and veg. If you don’t have a hot compost, we recommend giving the eggshells a quick wash before they plunge into your pile. 

Many composters will tell you they’ve composted eggshells in the past, only to find them still intact years later. This is because eggshells are tough to crack (pun well and truly intended).  

To avoid chunky pieces, the best bet is to crush your shells first. Think of it as giving the compost a head-start on breaking down your food waste. There are many ways to do this, but we find using a food processor or good ol’ fashioned pestle and mortar the most efficient and easiest. 

Wondering if your eggs are still within their shell-by date or ready to be crushed into the compost bin? Check out our blog to discover “how to test your eggs for freshness”. 

How long does it take for eggshells to compost? 

Eggshells can decompose within a few months if you grind them into a fine dust. Once your shells crumble enough to become just another indistinguishable ingredient in your wonderful pile, they’ll release a truckload of growth-spurt-inducing calcium into your soil. 

If you split your eggshells into small fragments, it can take roughly one year for them to break down into the soil. Thrown in almost whole, and you could be looking at several years before they decompose. This slows down the whole composting process, depriving your garden of that sweet, nutritious, earthy goodness.  

Can you put too many eggshells in your compost? 

“How many eggshells is too many?” A phrase you probably never envisioned yourself asking. But here we are. 

Much like squash, tea and mathematics, composting is all about getting the right ratio. Too many apple trimmings and tea bags can cause it to overheat and smell, whereas excessive cardboard or straw can mean there’s not enough nitrogen for rapid decomposition. 

Eggshells take a lot longer to break down compared to many other compostable goods, and too many of them can increase the acidity of your compost. This shouldn’t be a problem, unless you plan on using it to grow plants that prefer low soil pH.  

The average family spends £470 a year on food that ends up uneaten in the bin. If you’d like to join us in the fight against waste, explore our sustainable produce before checking out our blog on how to cut down food waste

Do eggshells in compost attract rats? 

Any food scraps can attract local pests, including eggshells. But shells do not give off a strong scent, so there’s little risk of these bringing in rodents on their own. 

We deliver our farm-fresh eggs within an absolute minimum of seven days before the use-by date. But if you do find an out-of-date egg hiding at the back of your fridge, we advise against throwing it in your compost, unless you have an enclosed bin. 

The smell of rotten eggs attracts rats, and the stench can be pretty darn awful. Think, farting wet skunk feasting on sewer-soaked brussels sprouts and you’re about halfway there. 

When composting food scraps, you should: 

  1. 1. Use an enclosed compost bin (if you can) 
  1. 2. Bury them deep into your compost 
  1. 3. Regularly turn your compost 
  1. 4. Plant mint nearby 

Follow these steps, and you can say rata-toodle-oo-e to any sneaky, squeaky rodents trying to make their way into your compost. 

Do eggshells keep bugs away? 

If something’s been nibbling away at your garden, it’s usually a case of whoever did the slime did the crime, with snails and slugs both common garden pests.  

If you’re plants are beginning to look a little sluggish, it’s worth stopping to shell the roses. 

Saved by the shell: how do eggshells prevent slugs and bugs? 

Laying crushed eggshells on the top of your soil and flower beds will prevent these munching menaces from ruining the hard work you’ve put into your garden. 

The sharp edges of your eggshell barrier will deter slugs and other crawling pests, leaving them too shell-shocked to brave the journey to your delicious strawbs.  

Are eggshells good for plants? 

There are many benefits of eggshells in the garden. Including them in your compost, fertiliser and soil can be a great source of calcium for your plants, providing they’re given enough time for all shell to break loose. 

The plants that love eggshells the most are tomatoes, cucumbers and many others that are prone to blossom-end rot, a problem that eggshells are very good at preventing. 

How do you use them for potted plants? 

Eggshells are just as much of a treat for your garden as they are for your houseplants. Here are a few ways you can use them indoors: 

  1. 1. All-natural fertiliser – if you let crushed eggshells sit in boiling water overnight, it creates a homemade, organic plant fertiliser crammed full of nutrients. You can then use this to water your plants. 
  1. 2. Eggshells for plant pots – eggshells make great seed starters and propagation pots. Clean them out, add the soil and seeds, and before you know it, you’ll have a sprouting plant that you can later place in a bigger pot. 

Are they bad for any plants? 

Eggshells shouldn’t be used around plants that thrive in acidic soil. This includes azaleas, rhododendrons and blueberry bushes. 

All’s shell that ends well 

Using eggshells in your garden is a great way of sowing the seed of reducing waste, as well as ensuring your compost is the cream of the crop. 

If you’ve got more ways of reducing waste in your home, we’d love to hear them. Drop us a tweet or message on Facebook to share the love! 

Puns that didn’t make it past the editor: 

  • • When composting, we believe whoever shelled it propelled it. 
  • • Cause to shell-ebrate 
  • • Come out of your shell and compost. 
  • • The best flowers don shell suits 
  • • Composting? I’ll be there with shells on 
  • • Okay bloomer. 
  • • Keep your garden rosy 
  • • Shells like green spirit and are a great way to achieving composting nirvana. 
  • • Plants need shell or high water 
  • • There’ll be shell to pay 
  • • Brought down to earth. 
  • • Composting eggshells is as easy to say as it is to do – unlike selling seashells on the seashore. 
  • • Little yolks shell great oaks. 
  • • What fresh shell is this? 
  • • I’ll stop composting when shell freezes over 
  • • No need to drop bombshells when you can drop eggshells. 
  • • Sweet shell of success. 
  • • The way they bond with compost is eggshellent. At least, that’s what Sean Connery thinks. 

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