My lockdown treat

November already (ooh, rather a long time since my last post!), and we’re back in lockdown.  During the spring lockdown, like many people I got myself a treat.  Nothing frivolous like a new dress or lipstick.

It’s a compost bin 😊.

 40C on the lid thermometer

Not just any old compost bin, but a Hotbin; basically a big polystyrene box with a lid at the top for stuff to go in, a hatch at the bottom for stuff to come out and a drain for removing excess liquid.  It also has a thermometer in the lid, to give an idea of the temperature reached by the contents, for the point of the Hotbin is that it is so well insulated that it allows the waste inside to reach temperatures high enough (40-60C, 104-140F) for it to compost much more quickly than a conventional compost bin.  The heat is generated by naturally-occurring bacteria, and allows you to compost material including weed seeds and, within reason, food waste.  The lid thermometer usually registers a slightly lower temperature than the waste actually reaches; to get an accurate reading you have to insert a separate thermometer, which comes with the Bin, directly into the composting waste.

 waste registering 60C

Over the past few months I’ve been getting to know my Hotbin and its needs.  It needs a certain mix of soft kitchen and garden waste, shredded paper (to absorb excess liquid) and woodchip or similar to keep the mix open and prevent it from turning into a messy lump.  It took me a little time to get it up to temperature and keep it there; like some people I know it likes regular feeding (every couple of days or so), and not too much at once.  I’m coming to realise that the paper has to be shredded small for it to mix properly through the softer contents, otherwise it sticks together and doesn’t break down well, so I’ve reestablished my relationship with our little paper shredder instead of just tearing paper up by hand; soft paper like bits of kitchen roll are reserved for the old, conventional, compost bins.  When you get the mix right, the contents of the Bin get really steamy in a most satisfying way.

The Hotbin doesn’t care for newspaper apparently; it doesn’t break down properly in the bin.  This makes sense to me, as I know only too well that mulching my veg beds with newspapers covered with compost can result in the paper drying out and failing to be absorbed into the soil; some of my beds have ended up covered with bits of newsprint, like some sort of rubbish tip.  It’s surprising how long a sheet of newspaper can last out in the garden.

The idea is that the Bin should generate compost good enough for mulching in 30 days, and proper compost in 90.  I take it that this assumes that good temperatures have been maintained, and so I waited for 3 months before taking any compost out, given that temperatures fluctuated a lot until I got the hang of things; in any case the instructions warn that the first batch may not be all that great.  I got two sackfuls of compost from it, and indeed the quality has left something to be desired (though not bad for only 3 months composting): partly the result of not mixing the paper well enough and partly because the mix was probably too wet.  You’re supposed to be able to tap off about an espresso cupful of liquid every week or so, but I’ve been getting a good mugful more frequently than that, and it has leaked out of the overflow vent at times.  I’ve now started to be more careful about wet material, and am ensuring that plenty of paper goes in, which all seems to be working.

Hatch open, ready for the first batch to be taken out ...

 

... emptying in progress

All seems to go well until you stop feeding the Bin.  Just before lockdown we managed a 10-day trip away (one of the reasons for the hiatus in blog posts), and on our return the thermometer was registering a measly 10C (50F).  I’ve been feeding the Bin again and the temperature is slowly rising; if all else fails, the Bin comes with its own hot-water bottle to heat it up!

The conventional compost bins are still in use, as is the council food waste bin.  The latter is only for things that are (probably) beyond the Hotbin’s capabilities (it's not too good with egg shells and avocado skins - neither are other compost bins, to be honest - and it won't digest an avocado stone, I've tried), while the former is still good for waste that isn’t easy to cut up small (most recently, disintegrating and very slimy rhubarb leaves) and for when there isn’t room in the Hotbin – this garden can generate quite a volume of waste and the Bin fills up quite quickly.

A lady came to give us a quote for some decorating work.  She was barely out of her car when she saw the Bin.  “Oh, a Hotbin” she said.  “I can’t get mine hot enough, how do you do it?  And I get too much liquid out of the bottom ….”  We did eventually get around to discussing the decorating; she’s coming to do it in the spring, by which time both of us will have more experience of our bins to discuss!