Starting Your HOTBIN Composter
Give your HOTBIN the best start by building a strong base layer (critical mass) and feeding it the right mix of chopped “easy to digest” waste, shredded paper, and woodchip for moisture control and airflow. Follow the steps below to get hot composting off to a flying start.
Quick Start Checklist (the 60-second version)
✅ Build a 40 cm base layer (roughly to the height of the hatch)
✅ Use chopped, easy-to-digest waste + shredded paper + woodchip
✅ Keep feeding 1–2 times per week (don’t open/close constantly)
✅ Don’t “lasagne layer” - HOTBIN works best when materials aren't isolated in layers
✅ Aim for 40-60°C on the internal thermometer before adding certain waste types
✅ Only use the hot water bottle if the internal temp is below 15°C
✅ Collect liquid fertiliser every 2 weeks (the amount will vary throughout the year).
Step 1: How Much Waste Do You Have to Compost?
To start heating up, HOTBIN needs a minimum amount of material (what we call the critical mass).
The base layer you’re aiming for
Depth: 40 cm (roughly to the hatch height)
Add: Chopped easy-to-digest waste + shredded paper + woodchip as you go.
There are two ways to build it depending on how much compostable waste you have available.
Option A: Patient Start (build the base layer gradually)
Best if: “I don’t have much waste!”
- Feed HOTBIN like a normal compost bin: add waste as you have it.
- Each time you feed, (as per the user guide) add some woodchip + shredded paper to support aeration and moisture control.
- Try to feed 2-3 times per week (using a kitchen caddy helps), so you’re not constantly opening the lid.
Why this works: frequent opening can cool the active zone. Fewer, more purposeful caddy feeds are better.
Option B: Fast Start (build the base layer in one go)
Best if: “I have LOTS of waste!”
- Add a full base layer (40 cm) of chopped fresh waste in one go.
- Mix in woodchip + shredded paper as you build to keep the structure open and balanced.
Tip: using old compost
A handful or two of old compost can help introduce microbes, but old compost has less “food energy” left for the bacteria to digest. For heat, you still need plenty of fresh waste.
Step 2: What Makes a Good Starting Base Layer?
You want plenty of easy-to-digest material to give bacteria a quick energy boost (fast heat), balanced with other materials to keep the mix airy.
Think of it like:
- Sugary snack = quick energy boost (fast heat)
- Banana = steadier energy (sustained activity)
Examples of easy (fast) to compost waste
- Vegetables and peelings
- Fruit and peelings
- Nettles and comfrey
- Chicken pellets
- Blood and bone meal
- Grass clippings*
*Grass breaks down quickly, but add little and often to avoid a soggy, matted layer.
See “How to compost grass in HOTBIN”
Watch our short video on starting your HOTBIN below.
Step 3: What Makes a Poor Base Layer? (what to avoid)
A base layer that’s too “hard to digest” or too dry/woody can stall heating. Avoid these common mistakes:
Woodchip
Woodchip helps airflow, but it has low nutritional value for bacteria.
✅ Use it with fresh waste - don’t tip a whole bag in as the starter.
Old compost
✅ Small handfuls are fine
❌ Large amounts can clog the bin and block airflow
(It won’t help the heat because the “food energy” has already been used up).
Twigs/prunings
✅ A light sprinkling at the base is recommend helps aeration from the get go!
❌ Don’t use twigs as the whole base layer.
Leaves
Leaves can be slow to break down due to a waxy coating.
✅ Where possible shred them and mix with plenty of easy-to-digest waste.
Shredded paper / cardboard
Paper helps moisture balance, but it’s not “food” on its own.
✅ Add only in the recommended mix with fresh waste.
Chop, Chop, Chop your waste
✅ Cut up large items to help the bacteria efficiently digest your waste
(This exposes fleshier parts of waste to ease breakdown)
❌ Don't add whole fruits and veg with skins and peels intact
(Spoilt items of this nature should be cut or quartered to help speedy composting)
Can I compost caddy bags?
Most caddy bags are compostable, but they create an additional protective layer for the bacteria to breakdown before they can digest the waste. They can also block airflow.
✅ Rip open caddy bags and empty waste into the HOTBIN and dispose of elsewhere
Step 4: After You’ve Built the Base Layer (how to keep it working)
Keep adding woodchip and paper
Continue adding woodchip + paper with every feed to keep oxygen flowing and moisture balanced.
Don’t layer (“lasagne”) — disperse instead
Traditional composting often uses neat layers. HOTBIN prefers a bolognaise approach: materials dispersed through the mix. Layering can cause poor aeration and soggy mats.
Don’t turn the whole HOTBIN
HOTBIN doesn’t require turning. Mixing everything can pull cold material into the active hot zone and cool the process down.
Avoid a single-material diet
A varied mix (different “digestibility”) works best for stable hot composting.
Every HOTBIN is different
What you feed it changes how it behaves. Learn your unit’s signals:
-
Looks too wet and smells a bit?
-Add a bit more paper/woodchip
-
Things not heating up?
-Most likely - Airflow restricted, heap too dense, so:
-Add more structure (woodchip) and chop waste smaller
-Stir things up to a depth of 12 inches
Step 5: Is It Hot Enough Yet?
Some waste types should only be added once HOTBIN is consistently 40–60°C. If you’re not sure check the user guide inside the HOTBIN. Use easy-to-digest chopped waste first to build up the heat, then expand the menu once temperatures are stable.
Step 6: Should I Use the Hot Water Bottle?
Use the hot water bottle only when: there is plenty of easy-to-digest waste already in the HOTBIN, and the internal temperature is below 15°C If the unit is warmer than that, the bottle won’t make much difference. Always follow the label instructions.
Helpful HOTBIN Next Reads
What can I put in a HOTBIN? (waste list)
Keeping your HOTBIN Happy (quick troubleshooting guide
Woodchip and paper: how much should I add?