Welcome to my WTF Gardening series, where I take common gardening terms and explain them for those who are new to the world of plants. Find the entire WTF Gardening series here.
Whether you’re growing an abundance of delicious vegetables, or you want to give your soil a boost before planting your annuals, compost is your best friend! It’s full of nutrients that will supercharge your plants, making them grow harder, better, faster and stronger!
Here’s the ‘What? When? Why? Where? And how?’ of composting…
Compost is something you can make yourself – you don’t need to buy it from a shop! And actually, it’s even better when you make it yourself, because you can control exactly what goes into it.
There are several ways that you can make compost:
Making a heap
This is possibly the easiest way to make compost, so it’s great for beginners. It doesn’t have to be a messy pile if you don’t like the look – you could always use an open bin to neaten it up and keep everything from spilling out into the rest of your garden. This wooden compost bin is a great option.
Use a digester
This innovative food waste digester takes recycled food and garden waste, and puts it straight into the soil for a super easy composting experience. All you have to do is place it in a sunny spot, and top it up with kitchen and garden waste every now and then.
The power of worms
They say that worms are a gardener’s BFF – and that’s especially true for composting! When worms eat organic matter, they produce a fertiliser known as worm castings, which can be used to fertilise your garden. You can keep worms in a vented, environmentally stable unit where they eat food waste and produce these castings.
A compost pile needs heat to work, and that’s where a hot bin excels! Temperatures in hot bins soar to around 60 degrees Celsius, in order to create compost out of organic waste quickly. The Aerobin works to create compost in less than 90 days! It’s so good that it won RHS Chelsea Product of the Year 2019.
Why compost? Home composting is one of the best ways to get rid of kitchen and garden waste that would otherwise end up in landfill. It’s estimated that food waste is associated with 25 million tonnes of greenhouse gas emissions per year, and over 85% (by weight) of this wasted food arises in households and food manufacture.
Plus, composting produces a fantastic soil improver to help you achieve a thriving garden! So it’s a win-win!
You don’t need to wait until a certain time of year to start a compost heap – you can start right now! Composting can be carried out all year, as and when suitable materials are generated in the garden or home.
However, if you want to hit the ground running with composting, late summer to early winter is the peak time for making compost. If you start within this time, it won’t be long before you have a fantastic soil improver ready to go.
Whether you decide to create a compost heap or use a bin, it is best to make you compost in a location in your garden where the conditions are constant. An area with partial shade is best – too much sun and the compost can dry out, too little and it will get too wet.
If you are using a bin, it must be rain tight. This is to ensure that excess moisture doesn’t get in, as it’ll have no place to go and your compost will (again) get too wet! It also needs to be able to retain warmth, so a well fitting lid is a must.
If you are making a heap, choose an accessible area with level ground and good drainage. You’ll want an area in which you can create a pile between 1 and 1.5 cubic metres (any larger or smaller and it won’t be able to heat up enough to do the composting). Don’t place your heap on a man-made surface such as concrete; an earth base is best. This allows for better drainage, and provides access for organisms such as worms to help break down the compost for you.
Have a very small plot? Consider worm composting instead. This allows you to create enough compost for your small outdoor area, while keeping your composting space to a minimum too.
Microorganisms are what make composting work – even though we can’t see them, we have them to thank for our bountiful gardens!
By composting, we are creating the perfect conditions for these microorganisms to thrive. This includes warm temperatures, the right nutrients, a little bit of moisture and lots of oxygen. When these conditions are met, the microorganisms begin breaking down the waste and producing heat as a byproduct to speed up the process.
It’s important to monitor your compost so that it doesn’t heat up too much (as this can actually kill all the helpful microorganisms), and ‘turn’ it around once a month to aerate the compost. This can be done by using a pitchfork or shovel to carefully toss the compost like you would a salad.
HELPFUL TIP: Be careful when turning open compost heaps, as hedgehogs sometimes like to hang out in them!
What Can You Compost?
You can compost three main types of material: green, brown and accelerators and activators.
Aim for between 25% and 50% soft green materials to feed the micro-organisms. Green materials include:
- Grass clippings
- Annual weeds
- Uncooked kitchen waste such as vegetables
- Certain types of pet bedding, such as hamster hay
Brown materials should make up the remainder of your compost. Brown materials include:
- Wood chippings
- Paper and cardboard (torn or shredded)
- Dead leaves
- Plant stems
HELPFUL TIP: Mix kitchen waste and grass clippings with brown materials such as wood chippings prior to adding to your compost, as these materials can often be too wet and get easily compacted.
Accelerators and activators
If you have a small garden and don’t do much pruning, or perhaps you don’t go through much paper or cardboard boxes, you can sometimes use accelerators and activators to help you out.
Products such as envii’s Compost Accelerator are sometimes added where green waste is in short supply. These contain high levels of nitrogen (a nutrient found in green waste), but should not be necessary if green waste is plentiful.
It is also possible to purchase activators containing carbon (a nutrient found in brown woody waste). These products are aimed at composting grass clippings or other green waste where there is insufficient brown waste.
When is it ready?
Your compost will take between six months and two years to reach maturity (again, using a hot bin will help to speed this up!). Mature compost will be dark brown, with a crumbly, soil-like texture and a smell resembling damp woodland.
It is unlikely that all the material in the heap will be like this, but any remaining un-rotted material can be added to the next batch of composting materials.
What can go wrong?
Wet, slimy compost: Too little air and too much water. Cover to protect against rain and add more brown waste, such as chopped woody material, shredded woodchip, straw or paper.
Dry and fibrous with no rotting: There’s too little moisture and too much brown material. Add more green waste, or try a commercial activator or accelerator.
Flies: Well-run compost bins don’t produce swarms of flies, but if you do see these, then make sure you cover kitchen waste with garden waste after adding it to the heap. Also, check that moisture levels are not too high, as this causes insufficient air in the heap.
What would you like to learn about next in the WTF Gardening series? Let me know in the comments below!
Michael has been involved with gardening and plants since he was just five years old. He is a self-professed Plant Geek, and was listed in the Sunday Times top 20 most influential people in the gardening world, thanks to his plant hunter role at Thompson & Morgan.
Michael was responsible for new plant introductions such as the Egg and Chips plant and the FuchsiaBerry and keeps busy travelling the world in search of new plants as well as lecturing worldwide, including stints in Japan. He is very active on social media – so why not give him a follow at @mr_plantgeek or Facebook. You can also listen to The Plant Based Podcast with Michael and co-host Ellen-Mary on iTunes, Spotify and Google.