Composting Events and news

18. Jan, 2021

Winter  weather  can make it difficult to get on to, and dig, the garden making it difficult to bury the precompost produced using a Bokashi system. The answer may be a Soil Factory where the pre-compost is mixed with compost or soil in a small lidded bin with drainage holes.  I   harvest compost from one of my compost  bins  in advance (when weather permits) and store it in the shed for a week to dry a little so that  It mixes with the Bokashi  pre-compost better if it is not to moist. 

The lower 4 inches of the container are filled with the  compost. The pre-compost is then added directly from the Bokashi fermenter. This is then covered by a 2-3-inch  layer of fresh soil or compost  and mixed well.This layering can be repeated until the container is full. The  top layer should be about 4 inches of soil. Once full I leave it for a few days and then mix it again covering with a final layer of compost (or soil) The loose-fitting  lid is then  be put in place. 

The waste will take between  three and twelve weeks to completely break down, depending on the temperature and type of waste. It is worth checking progress  after 2-4 weeks (when I usually find mine is ready). At this stage    the proportion of material recognizable as waste food will have decreased and that of “soil” will have increased.  Mixing the soil factory contents weekly will speed the process. The waste breaks down more quickly  when  warm but not too hot (under 40C). Decomposition slows at lower temperatures so during the winter it is best kept indoors or well insulated if left on a balcony the temperature should  not fall below 6C

The is more information at 


15. Jan, 2021

Calculating the green: brown ratio of composting ingredients tends to be something that is reduced to a guess that we have about equal amounts being added to the bin. With concern about the balance only coming to the fore when something goes wrong.  I have an Aerobin 400 on my Demonstration site and was revisiting the Aerobin website when I found an easy-to-use calculator which provides a good way of checking that the different items being added to the bin end up producing a mix of the right ratio.

  This    "Simulating composting in your Aerobin" software enables users to enter the weights the different materials being added to their bin and will calculate  Carbon & Nitrogen ratio , Moisture levels and the Biomass Density.  I have used it with my Aerobin and found it a very quick and simple means of checking the G:B ratio of the materials I have added (

It would also provide an interesting lockdown competition for allotment sites etc getting plot holders to give the weights of the differing items being added to their bins and seeing who is the best “Mixer.”

12. Jan, 2021

I use pallet bins for most of the communal composting on our Demonstration site  but must admit that they are not necessarily  the most attractive garden feature. However,  there are commercially available wooded bins that give the garden a smarter professional appearance such as the Forest Garden ( ) large capacity slot-down bins, giving easy access to the contents . When buying wooden compost bins,  I would recommend choosing those where the wood has been pressure treated, so that they should last for at least 15 years, and that  can be extended so that they expand  into a two or three bin system.

Bins of this type are ideal for hot compost systems where the bin can be layered when it is first filled and then turned weekly  for a month. It may seem a lot of work, but it is quite rewarding particularly if the temperature is monitored.  Of course, if only one bin is used the material can still be layered even if it takes a while to fill the bin.

10. Jan, 2021

 We are about to add a Subpod to the Stokes Wood Allotment exhibits. Subpod   a relatively new wormery composting system  that is ideal for use in raised beds on the allotment and  community gardens, (where several composters can be in  used to form a bank of units). When installed  in the home garden the unit is designed so that it can be used as a  seat,  enabling gardeners to sit on their worms.  

  It is designed so that the part that houses the worms is  underground, so that the worms have access to the soil enabling them  to breed as rapidly as they like because there is always room for their population to grow. As important for the point of view of an allotment or community garden where the wormery may not be as closely monitored as at home the soil in the raised bed acts as an insulator in both hot and cold weather. While converting kitchen and vegetable waste to compost this twin chambered wormery also  increases the worm population in the raised bed.

Covid-19 restrictions mean that at present I cannot get to the Demonstration site to install  the Subpod but the idea of the demonstration is to the divide a raised bed into two and allow children visiting the site  to compare the  worm numbers in Subpod half  of the bed with the over half.

6. Jan, 2021

Old tyres can be used to make a compost bin and there was a time when they were appearing on allotments all over the country. Using tyres in this way had the   advantage providing a bin at no-cost and of saving the cost of disposal  while the plot was occupied by the person who built the bin. However, when that individual left the site the Society, landlord or next tenant  was faced with the cost of disposing of the tyres. As a result, tyres have rightly been  banned from many allotment sites. However, people may choose to use them at home,  and I have updated this information at the request of some of these readers.

  The bin was usually used in a   stack of 5 car tyres (larger tyres while making a larger bin too heavy for many people to handle safely). The bin is best built on a paving slab or weldmesh  base  to restrict the entry of rats through the bottom of the bin. The sides are rat proof as radial tyres contain steel wire . The rims of the tyres can be packed with old plastic compost bags or damp browns such as autumn leaves,  straw or hay this provides an area of additional bedding for the composting worms. A modified method which makes the tyres lighter to handle is to cut off  the tyre sidewalls using an  electric saber saw. If the bin  is to  be mounted on a slab once the bottom trye is in position can be filled with worm rich compost from an existing bin to act as a starter. Normally the stack will consist of five tyres to give a convenient working height. Unless the tyres are large and heavy in is best to wire them together in case, they are knocked  over, but this is unlikely as once filled the construction is quite stable. A piece of plywood cut to size or an old compost bin lid can be used as a cover held in position by a bungee cord.

  There are reports of chemicals leaching from the tyres. One of the other disadvantages of using tyres is that the compost at the bottom of the bin can only be harvested by removing the other tyres, so once full the bin needs to be left until all the compost is  ready and it is then best left for a year or two before use.