Plastic-Free Ways To Start Seeds Sustainably

Ready to make your green fingers even greener? Try these clever zero-waste and plastic-free ways to start seeds so that you can ditch unnecessary plastic from your garden.

I recently read The Plastic-Free Gardener by Louise Boland – a really helpful book to help you green your garden. In it, Louise writes: “Plastics work their way into every aspect of gardening: the pots that plants are sold in; the handles of tools; the packaging our orders arrive in… Plastic seems to be irredeemably threaded through the gardening process.”

It made me think about my own garden, and how, even though I use the garden to help nature, there are elements of gardening that are decidedly un-environmentally-friendly.

Take the act of buying plants or growing seeds. Most Local Authorities don’t recycle plant pots and seed trays – particularly black ones. This is because the machines that sort plastics can’t detect the black pots, so, unless you have a garden centre near you that operates a plant pot takeback scheme, then they need to be placed in your general waste bin.

However, if you are growing plants from seed, then it’s really easy to start them the plastic-free way. Over the years I’ve tried lots of zero-waste ways to start seeds. Here are six of my favourites, with my top tips to help you achieve the best results.

Zero-Waste & Plastic-Free Ways To Start Seeds

If you’re looking to ditch the flimsy plastic seed trays and plant pots then try these sustainable and plastic-free ways to start seeds. Use the quick links to jump to a specific section, or keep scrolling for the full post:

• Egg Boxes
• Egg Shells
• Toilet Roll Tubes
• Newspaper Pots
• Wooden Or Metal Seed Trays
• Terracotta Pots

Egg Boxes

Cardboard egg boxes are a great zero-waste way to start your seeds off.

There are just two pointers to bear in mind. First, avoid planting anything with long roots, such as tomatoes, corn, squashes, sunflowers, peas or beans. These will outgrow the boxes far too quickly. Instead, I find herbs or small flowers the best for starting off in egg boxes.

Secondly, it’s important to place the egg box on a solid tray. An old baking tray is ideal. This is because over time the moisture can cause the egg box to break down, and it can be tricky to handle. Using the baking tray means you can move your seedlings about, and transport them into the garden, with ease.

To get started:

• Turn the egg box upside down, and with a sharp knife carefully make two slits in the bottom of each cup, to make an x-shape slit. This allows the roots to pop through easily when you plant them out, and help avoid excess water pooling at the bottom.
• Place your empty egg boxes on your old baking trays, or similar, and fill with potting compost.
• Plant your seeds, following the instructions on your seed packet.
• Place the tray in a warm and sunny south-facing window.
• Mist with water when necessary. Avoid over-watering as it will cause the roots to rot.

When you’re ready to plant your seeds, simply tear each cup apart. Because of the moisture, it shouldn’t take much effort. Each cup should easily pull apart by hand. But if not, use some garden snips to create that separation. You can then plant the whole cup directly into the soil. The roots will grow through the slit in the cardboard, and the cardboard will quickly decompose in the soil.

Egg Shells

If you’d like to try an even more zero-waste option, then try using the egg shells to start your seeds in. You’ll need to keep hold of the egg box as well, to keep your eggshells upright, but it’s using two items that would otherwise go to waste in one!

Like egg boxes, this method is best for herbs and small flowers.

If you’re ‘egg-scited’ to get started, then the good news is that this method is really easy. Here’s all you need to know:

• The next time you are cooking or baking, then rather than cracking your eggs in half, try cracking them near the top so you have more growing space. I’ve found tapping them with a spoon is the easiest way to break them. If you can’t do this, don’t worry. As long as the egg is at least cracked in half, it will give your seeds a decent amount of space to get started.
• Carefully wash the egg shells, to prevent bacteria and mould from growing, or any bad smells.
• Pop each eggshell upright in the egg box, and fill each one with potting soil.
• Pop a couple of seeds in each eggshell, referring to the instructions on your seed packet, before popping it by a sunny south-facing window.
• Lightly moisten the soil with a plant mister every few days, taking care not to over-saturate the soil.

Once your seedlings are ready to be planted, there’s no need to remove the eggshell. You can simply gently crush the shell, and remove a few shards from the bottom to allow the roots to emerge. The eggshells with compost in the soil, and provide your seedling with extra nutrients.

Toilet Roll Tubes

For seeds with long roots, skip the eggshells and start them in toilet roll tubes. Easy to make, and completely compostable, these will break down without a trace in your garden once you’re done.

All you need are some empty toilet roll tubes, scissors, potting soil, and, optionally, some biodegradable paper tape. Here’s how to get started:

• Cut four equal slits, roughly just over a centimetre in length, on one end of the toilet roll tube to make four flaps.
• Fold each flap over each other to make a solid base. If it doesn’t feel particularly secure, add a piece of biodegradable paper tape to secure the ends. 
• Place your tubes on a tray or container, packing the tray and container tightly, before filling the tubes with soil, and planting your seeds.
• Once your seedlings are ready to plant outside, you can transplant them straight into the ground – there’s no need to remove them from the tubes. 

Through trial and error, I’ve found it’s really important to pack your tray or container as tightly as you can with toilet roll tubes. It helps keep your tubes upright. Plus the tubes weaken with the moisture from the soil and regular watering. This means they can unravel. Tightly packing them helps to prevent this.

Newspaper Pots

Another good zero-waste option to start your seeds is to make newspaper pots from used newspapers.

It’s really easy to make them. You can buy what’s known as a “Paper Potter“, like this one from Ethical Superstore, to help mould the shape. Or, for a no-spend approach, you can make your own pots using a jar.

Like the toilet roll tube method, you need to place your paper pots on a tray, as they do get quite delicate over time. Plus you need to pack them in tightly to keep them from falling over.

Wooden Or Metal Seed Trays

If you’re looking for a plastic-free alternative that can be reused year after year then try a metal or wooden seed tray. You can buy your own – try this metal compartmentalised seed tray from Crocus (pictured above) is designed to last and last, and works like its plastic counterparts.

Alternatively, this wooden seed tray (also from Crocus) is another sustainable choice. You can even make your own seed starting tray from scrap wood. Not sure how to get started with a wooden tray? Here’s a handy video on how to grow seeds in wooden trays.

Terracotta Pots

Another reusable and plastic-free option is to use terracotta pots – like this set of 10 pots from Crocus that comes with a galvanised metal tray. It looks expensive, but the whole set is less than £20.

Plants have been grown in terracotta for thousands of years, and for good reason. This porous clay allows plants and seedlings to breathe easily. This helps to maintain a good flow of air to the roots. Meanwhile, these pores help water to escape through the walls of the pot, so you shouldn’t get waterlogged roots.

Take good care of these pots, and keep them in a shed or garage over winter, and they should last a long time.

Tips For Successful Growing

If you opt to plant in any of the biodegradable options, such as the paper pots, toilet roll tubes, or egg cartons, then I’ve found your seedlings will need to be watered a little more. I think this is because the paper or cardboard wicks moisture away from the plant. This doesn’t mean you need to go heavy on the watering – a light misting, when needed, is enough to help your seeds grow, without getting waterlogged.

If you’re planting the seedling out directly in its pot, I’ve also found that it’s important to make sure the pot is fully planted in the soil. Otherwise, the paper or cardboard can wick moisture away from your plant. If any paper or cardboard does stick out above the soil, water your plant and then tear off anything that sticks out. As it’s wet, it should come away easily.

More Sustainable Gardening Tips

Looking for more green gardening inspiration? Try digging into some of my top eco-friendly gardening tips:

• How to make a bee watering station
• Vegetables you can re-grow from kitchen waste
• Homemade non-toxic weedkiller recipe
• Surprising things you can compost