HOTBIN COMPOSTING IN AUTUMN
Autumn is Coming –
Here are a few tips for managing your HOTBIN after your garden clear up!
Time for the big autumn tidy up which means lots of waste. Unlike a traditional heap the HOTBIN will not freeze and continues to work over the winter providing you with a nice batch of spring compost.
To get HOTBIN composting in autumn here are a few tips to help you manage the tidy up.
Tip One: Shred waste where possible. A pile of hedge trimmings that fill a barrow will be a few cm high when well shredded. If you do not have a shredder, careful use of your hedge trimmer or lawn mower can suffice:
- Hedge Trimmer – pile up the waste on soft grass, cross cut repeatedly.
- Lawn Mower – pile waste on the lawn and run over it repeatedly with the mower.
We do not recommend either technique if the twigs are more than 5 mm thick.
Tip Two: If you have lots of brown fallen leaves and the grass is not too damp for one last cut, it is worth spreading the leaves on the lawn and cutting and shredding both in one go. The grass/leaf mix will compost super-fast in the HOTBIN.
Tip Three: Where you have too much, ensure your stock pile is protected from the rain. A large bag of wet cold leaves will be significantly harder to get hot than a dry cold bag of leaves. You will be amazed how quickly a mound of waste can be composted if you maintain 60C using the “little and often” technique.
Tip Four: Do not be tempted to add or squash everything in. Fast composting requires heat and heat requires airflow. If you compress it too much airflow will be restricted. Adding bulking agent (particialy composted woodchip) helps maintain airflow throughout the waste. If you add a lot of cold waste it will take longer to reheat. You are better off adding a 20-30cm (one foot) layer every 2 days over one 50 cm layer in one go.
Tip Five: If your HOTBIN is already full, then check your base layer to see if it is worth removing now. Even if the base does not look like perfect compost, it might be better to remove and use it as winter mulch or for digging in. This is not always easy to assess – if you need help view how does HOTBIN compost look and feel.
Can I add Autumn LEAVES to compost in my HOTBIN
Leaves can go in the HOTBIN and they make great humus.
If you have a lot of leaves (>10 litres, a bucket load), you need to tweak the recipe to ensure they HOT compost.
If you only add thick layers of leaves into the HOTBIN, it is unlikely they will rise above 20-30C as the woody nature means they are hard for bacteria to digest and hence heat is released slowly.
To HOT compost autumn leaves, see the recipe below:
How to HOT Compost Autumn Leaves
There are two parts to successful composting of autumn leaves.
1) Adding a nitrogen source to balance the high carbon in leaves
2) Ensuring that there is enough ‘easy to digest’ waste (e.g. greens, food waste, shredded office paper’ (which creates heat quickly) to keep things hot whilst the hard to digest woody material (in which heat is released slowly) are also digested. In some cases solving (1) & usually solves (2).
Here’s what you need to do to ensure you get the best out of your HOTBIN
Step 1: Shred leaves
Leaves tend to form a dense matted layer that restricts air and oxygen flow within the HOTBIN. We advise shredding the leaves (e.g. using mower or a hedge trimmer).
Step 2: Mix leaves with easier to digest materials like food waste
Many people simply will not have enough food waste to mix with high volume autumn leaf fall. You can cheat a little by adding another easy to digest waste to go with the leaves such as chicken poo, chicken pellets, or a sprinkling of blood bone meal.
The ideal waste to mix with autumn leaves is grass lawn mowing – unfortunately, it is rare in UK to be able to get the mower out in Autumn as it is too wet and compacts the lawn soil. If you have room storing leaves in a wire frame box ready for spring and first grass cut can work really well . (Avoid sealing in black bags – the leaves will go anaerobic (see below for anaerobic method).
Step 3 – Do not add too many each time – little and often is best
More than 10cm (20 litres) of cold wet leaves in one go will “stall” the HOTBIN. The cold leaves will lower the temperature of the HOTBIN below 20°C and the heat production falls below that needed to re-heat. So store the leaves in a pop up bag, protected from rain and add over a couple of weeks – you’ll be amazed how fast they compost.
If you have a large garden with lots of trees and mounds of leaves then possibly doing a little bit each week in the HOTBIN is impractical. Try the following – shred the leaves (e.g. using lawn mower), store in a wire frame or cold compost heap until spring. Mix with first grass cuttings in large volume piles. Turn occasionally.
Leaf Mould Versus Composting
If you are collecting leaves into a wire frame then you might go down the route of just leaving them in the box and waiting 1-2 years for leaf mould.
Leaf mould versus ‘bagging’ i.e. anaerobic digestion
Many compost sites note that ‘bagging’ leaves in black plastic and tying off will create a black slime that can be used as compost. What this really means is you are anaerobically digesting the leaves down to compost. To an extent this is ok, our point would be AD creates methane and you are releasing a GHG that is 24 times more harmful than CO2. And we hope you would agree that every little bit avoided helps.
Aerobic composing is carbon neutral. Also to be honest – the black bags absolutely stink when you open then!
You can now successfully compost large amounts of Autumn leaves in your HOTBIN.