Do you throw away loads of cardboard egg cartons every year? Most of us do, but here’s the crazy thing: they have so many clever uses in the garden! Once you know what you can do with them, you’ll never throw them away again…
1. Chit Potatoes
The neat, spud-sized diameter of each cup in an egg carton makes them ideal for holding potatoes securely upright as they sit on a bright windowsill or greenhouse bench to chit (sprout) ahead of planting.
![Chitting potatoes in an egg carton]()
Egg cartons are perfect for chitting potatoes to get them off to a powerful start
2. Start Seeds
The spacing of egg carton cups makes them a fab free alternative to plug trays. Start by spiking holes into the bottom of each cup to create drainage holes. This allows excess moisture to quickly drain through so the cardboard doesn’t become overly soggy and fall apart. Next, fill your carton with potting mix that you’ve pre-wetted so they’re evenly moist. Dib holes, drop in your seeds, and carefully cover them over by gently combing over potting mix from the sides or sifting it on top. And then to finish, give them a good spray of water to further wet the top.
Cardboard egg trays can be quick to dry out because each plug is relatively small and the cardboard will try to soak up moisture from the potting mix. Check regularly, and water if the potting mix starts to dry out.
![Seedlings in an egg carton]()
Tear apart each cup of the egg carton when it's time to plant seedlings
A great way to slow evaporation – and therefore extend the time between each watering – is to pop your carton into a plastic bag. Old bread bags are a good fit for this, or pop them into a seed tray with a propagator lid on top. This extra layer of protection also creates a cosier environment, helping to speed up germination.
Then when it’s time to plant, simply tear apart each cup and plant your seedling and its cup into damp soil. You’ll find it much easier to do this if you thoroughly wet the cardboard beforehand by standing the trays in a shallow reservoir of water. The roots will quickly push through into the surrounding soil as the cardboard breaks down.
![Planting egg carton carrots]()
Once carrot seedlings are growing, plant the whole egg carton
3. Grow Carrots
An ingenious variation on sowing into egg cartons is to use each cup of an egg carton to help grow carrots. There are two ways to do this:
Option 1: Remove off the very bottom of the egg carton cups by soaking the base of the egg carton in water so it gets nice and soft, and then just pinch the bottom off and widen the hole with your finger. Pop the carton into a seed flat or tray, fill it with potting mix, then sow two or three seeds into each before very lightly covering them over. Water and pop into a bread bag or propagator just as before.
After a few weeks, snip off or pull out excess seedlings to leave just one in each cup. Grow these on to plant the whole thing outside in another few weeks, without separating the cups. The genius of doing this is that these seedlings will suffer none of the slug attacks or hit-and-miss germination of directly-sown carrots, but the best bit is that they are literally perfectly spaced.
Dig a small trench for your carton, gently push back the soil around it, and the little carrots are good to go! The roots will grow through the holes cut into the bottom, and the cardboard surrounding them can serve a bit like a mulch, helping to keep weeds from competing. Carrots hate root disturbance, but this method won’t upset the young roots either. It really is a win-win-win scenario!
![Egg carton in a container]()
An egg carton can be used to perfectly space carrots in a container
Option 2: Cut out the bottom of the egg carton cups as before, then cut the carton to shape to fit a container of your choice (this works well for larger sized cartons). Fill the container most of the way up with potting mix, then push the egg tray into place on top . Make a hole in the bottom of each cup, sow your seeds directly into the potting mix through the hole, then cover them over. Because the seeds are directly in the potting mix so there’s less worry of them drying out, but you still have the automatic spacing benefit provided by the egg carton, and it helps to mulch the soil and keep it nice and moist.
![Planting sets in an egg carton]()
Onion or shallot sets fit perfectly into egg carton cups
4. Start Sets
Egg carton cups are also a convenient size for starting off onion or shallot sets. Fill up your tray to the brim with potting mix, then nestle in your sets. Turn each one like the dial on a radio while lightly pushing them downwards so that they settle right down into position.
After a few weeks, tear each cup apart, make a hole in the soil, and plant the set with its cardboard cup. This is a fab way to get a head start under cover while the ground is still occupied by a previous crop, or to protect the sets from birds that have a habit of pulling them out of the soil thinking the tips are a tasty worm!
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Egg cartons can provide safe storage for ripening tomatoes
5. Store Tomatoes
The cups are also a great size for storing harvested tomatoes. This is particularly good for stubbornly green tomatoes, giving them time to ripen while keeping them physically separated to reduce the risk of in-store diseases spreading.
Pop one harvested tomato into each cell, then store them in a cool, dark place. The egg cartons can be safely stacked too, saving space. How handy is that?!
![Saved seeds in an egg carton]()
Dry out and store saved seeds in your egg carton
6. Store Seeds
The individual cups are also great for drying and storing saved seeds. Place your seeds in their waiting cups, along with a label so you don’t forget what’s what – or just write onto the cardboard itself.
Leave cartons open while the seeds dry off in the gentle warmth and then, once they’re crisp dry and good to store, simply close the lid and move them to a cool, dry place for storing till it’s time to sow – taking care, of course, not to jolt the seeds about or mix them up!
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Egg cartons make safe hidey-holes for slugs, making them easy to pick off
7. Slug Traps
Lay upturned carton lids or bases onto damp soil where slugs can be a problem. The cool and shade that this provides will serve as a magnet for slugs that are keen to get out of the warm, drying sun and into the dank, dark shelter on offer. Then all you need to do is come along every few days, lift it up, and remove any slugs or snails you find.
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Cut up egg carton lids into plant labels that can be composted after use
8. Make Labels
Cut lids into strips to make temporary plant labels. Write on the details using a biro or pencil, then carefully push it down into the soil or hold it in position while filling your pot or tray. The labels will last just long enough to be useful for your seedlings and, when they’re done, you can toss them onto the compost heap.
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Stacked egg cartons in a box offer a safe hideaway for beneficial bugs
9. Build a Bug House
Perhaps you’re a professional baker, or maybe you just really, really love your eggs and have loads of eggs trays piling up. If so, this is a great way to make use of all those trays! Stack cartons up inside a wooden box on its side to offer shelter for beneficial bugs such as beetles and lacewings. Keep them as dry as you can by popping them somewhere relatively sheltered from the rain and by raising them off the ground on small rocks. Now you’ll have a legion of the good guys in residence, right where you need them – lovely job!
![Egg cartons in a compost heap]()
Add egg cartons to your compost when you're done with them to help keep the heap in balance
10. Compost Them!
And remember, you can compost cardboard egg cartons too. Cardboard is an excellent ‘brown’ that’s perfect for balancing out fresher ‘green’ materials. Tear them up into pieces, then just bung them on your compost heap. The soft, almost spongy cardboard that egg trays are made from is fantastic at soaking up excess wet in a compost heap, helping prevent soggy, smelly compost.
Take care to peel off any labels before composting and, if you’re worried about the glue that’s used to stick the label to the cardboard, just peel away the cardboard from around it then throw that bit away as normal. When composting any cardboard, stick to plain cardboard, and avoid any that’s glossy or heavily dyed.
