Continuing the  posts on food waste in the lead up to Food Waste week in March I would like to briefly summarise the position in respect to composting and the role we can play in reducing the:

• waste sent to landfill and the
• road miles associated with kerbside food collection.

 In addition, food composting at home reduces the   need for  bonfires  on allotments and in gardens and the smoke nuisance they can cause.

 Home composting has long been promoted as a way of dealing with uncooked food, but much has been made of the  “problem” dealing with meat and fish, dairy products and leftover cooked food with many sources incorrectly  saying that these cannot be composted as the compost would  smell and attracts  flies and  rats.

 As discussed in recent posts cooked food can be composted at home quite easily.

The simplest method if you already have a compost bin such as a Dalek  is to Bokashi the food waste and then add it to the compost bin or if you do not have sufficient  garden add it to a soil factory. http://www.carryoncomposting.com/416920212

However, the are several home  compost bins designed to treat cooked food waste  available at relatively low prices. http://www.carryoncomposting.com/142941463    

The Green Johanna is a compost bin which includes a base unit will take two parts food waste mixed with one part garden waste. The bin will take  the kitchen waste produced by a family of  five.  

The Hotbin is available with a 100 litre or  200 litre capacity bin and will operate at between 40⁰ to 60⁰C C if  feed at least 5 kg of waste per week producing compost  in 90 days.

The Jorraform 125 is a metal tumbler dual chambered bin designed for the fast composting of food waste from larger families or small cafes etc.

Biolan Quick Composter and the  Biolan Biowaste Composters are more expensive and are designed for year-round composting of domestic kitchen biowaste.

The Green Cone is frequently mentioned in articles on food composting, but it is not a compost bin but a food digester which needs to be partially buried in well-drained soil. The food waste is housed in a basket below ground level and the cone acts as a solar panel to help heat the contents. It is not suitable for clay soils and does not take garden waste. It can  work well and deal with the waste from  a waste conscious family but that many people confuse it with a compost bin  and  fill it above ground level, or  add garden waste,  and experience problems.

Wormeries
A large   wormery will compost most types of leftover food but it is necessary to bury the food waste with about 2-5cm of bedding otherwise it will smell and attract flies.  This makes it impractical to use a normal sized stacking wormery to dispose of significant amounts of cooked food waste on a regular basis. The  is a new wormery which is buried in the garden and could be used to deal with regular small amounts of  cooked food waste without attracting flies of creating unpleasant odours. http://www.carryoncomposting.com/142941459

 The pie chart shows the ration of different compostable household waste 

A CarryonComposting Power point and Zoom presentation will be available during the week.

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 http://www.carryoncomposting.com/416920212 

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 (https://www.aerobin400.com/aerobin400-UK/compostsimulator.aspx)

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.”