How to Make Great Compost with a Dalek Composter – The Complete Guide
The short answer: great compost from a dalek composter requires four things – shredded material, the right brown-to-green ratio, adequate moisture and regular aeration. Get all four right and a dalek will produce excellent compost in 3-6 months. Get any one wrong and you’ll end up with a slimy, slow or bone-dry heap that goes nowhere for a year.
I’ve been composting with dalek bins for over twenty years and the tips below are the result of some early failures and gradual refinement. These are the specific changes that transformed my composting results.
What Is a Dalek Composter?
A dalek composter is the informal name for the standard black/green plastic compost bin you see in many UK gardens. The name comes from the resemblance to the Doctor Who robot: tapered body, removable lid, small hatch at the bottom for extracting finished compost.
Dalek composters are sometimes free or heavily subsidised from many UK councils, widely available from garden centres and one of the most practical composting solutions for a standard/small garden. Their compact footprint, closed design and ability to retain heat makes them well suited to UK conditions. The plastic construction keeps the heap warmer than an open pile (which can help in our cooler climate) and the lid retains moisture effectively and keeps the rain out.
The Four Dalek Composting Problems (and How to Fix Them)
Material Is Too Course
Size does matter. If you want to give your compost a big head start then you’ll need to ensure the material you add to your bin is as small as possible. Fruit/vegetable peelings, soft prunings and other ‘wet’ ingredients tend to break down very quickly meaning size is less important. However larger woody ingredients like twigs can take many years to decompose.
The microorganisms that break down your compost waste work on the surface area of each piece. Double the surface area and you roughly double the decomposition speed. A thick branch takes years; the same material shredded into 2-3cm pieces takes months.
What to Do
A garden shredder is the best single investment you can make to improve your dalek composting. I was given an excellent Bosh AXT garden shredder a few years ago and it transformed the speed of my composting almost immediately. All prunings and woody cuttings now go through it before entering the bin. This alone takes months off the composting time. If ever it fails I will replace it in a heart beat.
If you don’t have a shredder, use secateurs or garden shears to cut woody material into pieces no longer than 3-5cm before adding to the bin. Any cardboard should be torn or cut into small pieces. Kitchen scraps should be chopped rather than added whole. Another hack is to lay out your prunings on the lawn then mow it up using your lawn mower with the collection bag on.
Likewise paper and card going into the compost should be shredded first. Either tear them up small or you can do like us and use a standard office shredder to chop them really small. We find that adding shredded material (browns) in the summer helps balance the huge supply of greens our garden produces.
Too Much Green Material
One of the most common problems people have with their compost heaps is the addition of too much ‘green’ material. If your heap is made primarily of green plant cuttings, grass clippings and vegetable scraps then you’ll almost certainly struggle to make good compost.
Browns vs Greens – what counts as what:
| Greens (nitrogen-rich) | Browns (carbon-rich) |
|---|---|
| Grass clippings | Shredded cardboard |
| Vegetable and fruit scraps | Shredded paper |
| Fresh plant cuttings | Dry leaves |
| Coffee grounds | Woody prunings (shredded) |
| Fresh weeds | Straw or hay |
| Tea leaves | Wood chip or sawdust |
What to do
Aim for a rough 50:50 ratio of browns to greens by volume. In practice most home composters end up slightly greener than this which is fine. However if your heap starts smelling or becoming wet and slimy, it needs more browns added immediately.
Our top tip: keep a pile of shredded cardboard, paper or dry leaves next to the bin. Every time you add kitchen scraps or grass clippings, add a roughly equal volume of brown material on top. This becomes an automatic habit after a few weeks.
Lack of Moisture
Another common problem with dalek composters is not enough moisture. The organisms that break down your waste need moisture in order to thrive. While the snugly fitting plastic lids do a great job at keeping the heat in your heap, they tend to not let any rain water into the pile. This can lead to a lack of moisture.
The way I diagnosed the problem was the discovery of a colony of ants living in the middle of one of our daleks. Ants avoid moisture and will only take up residence in a sheltered dry environment. If you reach into the middle of the heap, the compost should be ever so slightly damp to touch. It should not be sopping wet and heavy, but not dry and crumbly.
As a general rule if you think your heap is too dry add a watering can of water. Going forward, whenever you add more material (especially dry matter like shredded paper, dry leaves etc) give the heap a good soak with a watering can. When you take a handful of material from the middle of the heap and squeeze it it should feel moist/wet but no drips of water should come out of it.
When you do get the moisture levels right in a dalek composter, the fact that they are plastic and have airtight lids means they do a great job of keeping the moisture level constant going forward.
Not Enough Oxygen
Aerobic bacteria (the kind that break down compost quickly and without producing unpleasant smells) require oxygen. A dalek’s sealed plastic construction limits airflow compared to an open heap, and without intervention the material inside tends to compact over time, pushing oxygen out.
An oxygen-deprived heap doesn’t stop decomposing, but it switches to slower anaerobic decomposition which produces unpleasant smells and takes significantly longer.
How to Increase Oxygen in a Compost Heap
A compost turner or aerator is the solution — a long-handled tool that works like a corkscrew, pushed down into the centre of the heap and twisted to introduce air without emptying the bin. Compost aerators are inexpensive, simple to use and make a genuine difference to the speed and quality of decomposition.
I use mine once a week on each bin — it takes less than a minute per bin and keeps the material well aerated without the back-breaking work of emptying and reloading. Regular turning also mixes material that has been at the edges (where it’s cooler and decomposes more slowly) with material from the hot centre.
How Long Does a Dalek Composter Take?
With all four problems above addressed (shredded material, correct moisture, balanced browns and greens, and regular aeration) a dalek should produce usable compost in 3-6 months during the warmer months.
In winter, microbial activity slows significantly and composting time increases. The best approach for UK conditions is to keep adding material throughout the cold months, which helps keep the heap active ready for spring when temperatures rise.
Signs the compost is ready:
- Dark brown or black colour throughout
- Crumbly texture that holds together when squeezed
- Earthy smell (similar to forest floor)
- Original materials are no longer identifiable
- Presence of worms throughout
If material in the top half of the bin is still recognisable but the bottom half is finished, simply extract the finished compost from the bottom hatch and leave the unfinished material to continue.
Using Dalek Compost for Chilli Plants
Homemade compost from a dalek is excellent for chilli growing. It is usually rich in nutrients, well structured and free of the peat issues that commercial composts increasingly face.
We use our dalek compost in two ways:
As a soil improver. Worked into beds or borders in the greenhouse where some of our chilli plants grow in the greenhouse. Homemade compost improves drainage in clay soils and water retention in sandy soils while helping to feed the soil so it can support better growth.
As a compost mix ingredient. Mixed with perlite and a small amount of well-rotted manure as the basis of our container potting mix. We don’t use it as the sole growing medium as the nutrient levels and structure vary between batches. Based on our 20 years experience it works best mixed with a commercial compost base. See our complete guide to the best potting medium for chilli plants for our exact recipe.
FAQ
How long does it take to make compost in a dalek?
With shredded material, correct moisture, balanced browns and greens and weekly aeration, expect usable compost in 3-6 months during the growing season.
Why is my dalek compost slimy and smelly?
The classic sign of too much green material and not enough air. Add a significant quantity of shredded cardboard or chopped up dry leaves immediately, then aerate with a compost turner. The smell should reduce noticeably within a week. Going forward, match every bucket of kitchen scraps with a roughly equal volume of dry brown material
Why is nothing happening in my dalek composter?
Three most common causes: the material is too large (shred/chop everything before adding), the heap is too dry (add water/keep moist), or there’s too much brown material without enough nitrogen-rich greens to fuel the bacteria. Check all three.
Can I compost chilli plants in a dalek?
Yes. End-of-season chilli plants compost well, particularly if you shred the stems first. Remove any remaining fruit before composting if you want to avoid random chilli seedlings appearing in your garden the following year from seed. Roots and old potting compost from containers can also go in.
Do dalek composters attract rats?
A dalek with a properly fitted lid and no cooked food or meat scraps very rarely attracts rats. The sealed design is actually better than an open heap for pest resistance. Never add cooked food, meat, fish or dairy to a dalek.
Is dalek compost good for chilli plants?
Yes. Homemade compost is an excellent soil improver and compost mix ingredient for chilli plants. We use it mixed with perlite and commercial compost as part of our potting medium. See our potting medium guide for exact ratios.
Can I use dalek compost in pots?
As a partial ingredient in a potting mix, yes. As the sole growing medium, not recommended. Homemade compost alone tends to compact in pots and nutrient levels vary between batches. Mix with a commercial peat-free compost and perlite for the best results in containers.
Related Guides
Best Potting Medium for Chilli Plants. How we use homemade compost as part of our potting mix for container-grown chillies. The exact recipe including ratios.
Making Compost — A Comprehensive Guide. Our broader guide to composting methods beyond the dalek including open heaps and hot composting.
Feeding Chilli Plants. Once you have great compost, feeding is the next variable that determines your harvest.
Growing Chilli Peppers in the UK: Complete Guide. The complete growing guide covering everything from germination to harvest.
What an interesting article. Thank you for sharing all your experience. I might try a power paint mixer to turn the compost.