Hotbin composting

I want to produce more fertility for my garden close to home, so I am exploring ways of increasing the amount of compost I can produce. 

I’d been looking for ways to produce more compost faster and reduce food waste, so decided to research hotbin composting. I’m not sure how I first heard about the Hotbin composter, most likely via Permaculture Magazine. The Hotbin is rather expensive, so I wanted to be certain that it would provide me with the solution I needed before buying one.

I needed something that would be practical in my back garden, would not attract vermin, could compost food scraps including meat/fish/dairy and would increase compost production. Living in the countryside with chickens in many neighboring gardens I know there will be plenty of rats around. I don’t mind them so long as we don’t encounter each other (!) and they keep out of my house. Being keen not to set up a rat restaurant in my back garden, vermin-proof was a high priority in my decision making.

Of course we try not to have food waste and use up leftovers as much as we can, making soups and stocks, etc but I live with teenagers – which means there’s often a houseful of them in the kitchen eating pizza – and sometimes there’s mouldy cheese lurking at the back of the fridge, brick-hard forgotten bread or a dish of fungus-covered unidentifiable something …  The local council will collect and compost foodwaste, but it seems a waste of resources to send it off when I could compost it at home.

The Hotbin aerobically composts waste and according to the website produces compost in just 90 days. Made from thick expanded polypropylene (EPP) the manufacturers claim that there is no smell or leaking to attract vermin. I have no idea really what EPP is, but apparently it is highly insulating, holds heat well, is used for making car bumpers (s0 one would assume if therefore durable) and is 100% recyclable. The composter is the size of a wheelie bin, compact enough for use in a domestic garden. Seemed perfect, so I ordered one, which arrived at the start of February 2015.

The Hotbin, light and easy to move when empty, came with easy to follow instructions and accessories including two thermometers – one for inside, one for the lid – a stirring/raking stick, a sack of bulking agent, straps to hold the hatch in place and a plastic bottle which can be used as a hot water bottle if needed, to get things started. The Hotbin works best at 40-60 C.

Brand new, clean Hotbin

Worms loving some not quite composted matter I put in a ‘dalek’composter

As it was early February I chose to put it in the polytunnel. This seemed a good idea at the time but wasn’t! When temperatures warmed in the spring, the Hotbin reached extremely high temperatures – one might almost cooker dinner in it! – so in May I emptied any uncomposted contents into a Dalek composter to finish off and moved the bin outside. Worms loved this, the composter was wriggling with them.

The composted-compost was lovely, rich and ready to put on the garden.

On 16th February 2016  I decided to move it again, this time to a position outside the shed, where it has some protection from the elements thanks to a porch. The Hotbin is very robust and I have noticed no weathering, but I thought some shelter could only be an advantage.

One problem with the design is removing the compost. The hatch is very easy to remove and replace but even with great care, the top layers collapse down. It is a bit unpleasant having that landing on your arm!

March 2016, beautiful rich compost

Not everything had composted, so this was placed in a regular compost bin to finish off

I put the Hotbin on a sheet of old metal, on top of bricks, to really make sure it is vermin proof. The ingredients to start it off again were all ready – animal bedding (full of poo), shredded card, green garden waste including some comfrey leaves, kitchen waste, bulking agent.

First I had to clear the area

Ready for the composter

Composting ingredients all ready

The empty bin

Shredded animal bedding – the gerbils are especially good at turning card into composting material

bulking agent

comfrey

I filled the composter in layers

Giving the mix a good stir as I filled it up

Using the ‘hot water bottle’ to help it start off

Ready to compost

Thermometer and valve

Despite the cold temperatures, the compost quickly reached temperatures over over 40C – steam on a cold day looks lovely.

On 22 March I added more composting ingredients, by 28 March, the contents had dropped by over 12 inches.

Composter full on March 22 2016

After 6 days

Steam when I opened the lid, 23 February

Mostly I love my Hotbin because I can compost food waste and it does produce compost more quickly than my regular composting bins. The main disadvantage – apart from the price – is getting the compost out without all of the uncomposted material falling down too soon. Ideally, I’d have two Hotbins with one finishing off as the other is being filled, but the cost makes this not economically viable for me.

Now that the weather is warmer and it is more abundant, I am adding more layers of  nettles and comfrey which may speed things up further.

Hotbin on April 25th, we took the front panel off to have a look, contents here just over 2 months old: