Writen by
Ed Bollom
Ed Bollom started his career studying sustainable horticulture at Cannington College in Somerset and serving an apprenticeship with the Professional Gardener’s Guild. Since then, he has worked in historic gardens all over Britain, from Osbourne House on the Isle of Wight to Chatsworth House in Derbyshire. His passion has always been for productive gardening, and he spent 5 years as senior gardener in charge of the kitchen garden at Highgrove House, growing fruit, vegetables, herbs and cut flowers for the future King Charles III. On moving to Scotland, Ed spent 10 years building up one of the largest kitchen gardens in Europe at Gordon Castle in Moray, growing a huge array of seasonal produce for the estate, local community and an award-winning café. He now runs a gardening and design business with his wife Anna based in Fochabers.
Gordon Castle Walled Garden
Some tips for making garden compost
• Looking after the soil is the key to successful gardening, and adding organic matter in the form of compost or manure is the best way to keep your soil healthy. Soil with plenty of organic matter in it will provide almost all of the nutrients your plants need as well as retaining moisture during droughts.
• Whilst horse or farmyard manure is great for bulking up your soil, your own home-made compost is the gold standard of organic matter, reducing the risk of introducing harmful chemicals and weeds to your garden and feeding the beneficial micro-organisms essential to all soil and plants.
What can I compost?
• You can safely add almost any plant-based material to your compost heap; whether that’s prunings, cardboard, kitchen waste, wood chip, seaweed or grass clippings, as long you mix it in roughly the right proportions it will rot down to make useful compost.
• If you’re using seaweed, leave it in the rain for a few days to wash out any excess salt.
• The rule of thumb is ‘the more the merrier’, it’s well worth trying to make as much compost as possible.
• Remove any plastic or synthetic material from packaging that you want to compost.
• A hot compost heap (above 55 degrees) should kill off weed seeds and perennial roots but it’s probably best to avoid putting them on the compost heap in the first place.
• Beware of herbicide contamination in manure. Pyrelid weedkillers used as selective herbicides on grass can pass through into horse and cow manure and damage your crops.
• It is useful to divide compostable materials into two categories: green material and brown material.
Green Material
Green materials tend to be high in nitrogen and will rot down quickly. The bacteria that decompose green materials generate a lot of heat that can be useful to kill off plant pathogens and weed seeds.
- Green leaves and soft stems from both ornamental and vegetable plants
- Grass clippings
- Kitchen waste (but avoid meat)
- Coffee grinds
- Horse and farmyard manure
- Chicken manure
- Seaweed
Brown Material
Brown material tends to be tougher and more woody but it still makes fabulous compost. It is mostly decomposed by fungi and rots down slowly generating less heat.
- Woody prunings
- Fresh leaves
- Chopped up paper and cardboard
- Woodchips
- Straw
- Animal bedding
- Thicker herbaceous perennial stems
A good balance for a compost heap is to layer up roughly three parts green material to one part woody material. The greens will add heat, moisture and eventually nitrogen to your compost whilst the browns will add fibre, air and eventually carbon. A heap with just green material can be wet and airless, leading to a smelly heap. Don’t worry if you can’t get exactly the right proportions, you’ll tend to produce more green material in the summer and brown in the winter, just do your best to create a good mix of both.
Heaps, bins and bays
- The simplest method of composting is just to make a heap in a corner of your garden, this can work surprisingly well but can be untidy and won’t heat up as much as a compost in an enclosed container or bay. If your DIY skills aren’t great, this can still be an effective and easy method of composting.
- Cylindrical compost bins can be very effective, they won’t dry out and should retain heat well. The small rectangular hatches at the bottom of the bins are pretty useless, its much better to tip the whole thing out if you want to turn or use your compost.
- Wooden bays measuring 1x1m make a great system for composting in small to medium gardens. You can make them from 3 pallets wired together or from recycled timber. Avoid using treated wood.
- It normally takes 8–10 months to create good garden compost
- Turn your compost every 2 or 3 months to add air and mix in any un-composted material sitting on the top or at the edges
- Whether you use heaps, bins or bays, try to have them in threes. The first to fill with fresh material, the second with material in the process of rotting down and the third to turn the second in and out of.
- It’s better to have small bays that you fill quickly and heat up quickly than larger bays that never warm up.
- Don’t worry if your finished compost is a bit lumpy and uneven, it will carry on rotting down after you’ve put it in on the soil.
- If possible, try to add 2.5cm of compost to your plot every year but as little as 1cm will still make a big difference.
To dig or not to dig?
- Digging is a great way to add air, release compaction and improve the structure of your soil. It is also a good way to incorporate not so well rotted compost into your plot.
- The downsides to digging are that you may disturb dormant weed seeds that will start to germinate, it can disrupt the web of fungal mycelium in the soil and its hard work!
- No-dig methods rely on putting down a thick layer of compost as a mulch in the autumn to protect the soil and possibly prevent surface weed seeds from germinating. It’s important to have narrow beds that you don’t have to walk on to tend and harvest, thus avoiding compaction.
- No-dig is great for soil micro-organisms and is less physically demanding but you do need to add a reasonable amount of compost to your soil every year for it to work properly
