Mellow Compost Lab

Lab Environmentals

Here we describe the garden and related (geographical) environmental elements relevant to compost data analysis

The broader context for the Mellow compost lab is important to understand and interpret the data analysis - here we outline elements such as geographical location, climate data, seasonality, bin locations in the garden, garden size, household type and soil type.

Geographical location and hardiness

The Mellow compost lab is located in the north east of Leeds (county of Yorkshire, United Kingdom). Its hardiness zone is 9a (using the USDA scale): … As a general rule, the UK is marked primarily by cool (but not frigid) winters and warm (but not scorching) summers. The UK enjoys a fairly long frost-free season that extends from early spring to late autumn …”. Leeds is in the horizontal north of England corridor; Leeds tends to be windy whereas the western part (Manchester part gets more rain and less wind); due to the Pennine landscape.

Climate data

Below ia a table relating to average monthly conditions in Leeds for temperatures, rainfall and daylight. This data set should be useful to contrast and compare when discussing compost results throughout this site.

Warm & Cool seasons

We define two seasons  to articulate compost input/outputs and cycles/phases in relation to annuals and seasons. In the context of the work in the lab, I refrained from using the four seasons (Spring, Summer, Autumn and Winter) to keep the discussions and results/analysis simple. In reality, given we do not have hot summers (as shown in table above) and autumn leads gently to winter, summarising the seasons into just two parts seems sensible enough.

  • Warm season [Apr-Oct]

  • Cool season [Nov-Mar]

Bin locations in the garden

All the five compost bins are located in the back garden; with bin A-D in a row  and bin E by the side. Bin E is custom made. We built the wooden frame in 2017 with two equal size containers, one is bin E (450L) and the other container is for leaf mould making (called LM#1). Both bins have an upper half-gate that lifts vertically to ease access the lower part of material (compost or leaf mould). All bins have direct sun exposure.

Bins A-D back garden
Bin E and LM#1

Garden size & garden waste

Our garden has a total “soil” area of 96 m2; of which 55m2 is grass area; 28m2 is raised beds (vegetable plots) and 13m2 is rows of roses, plants, fruits and bush plants. The garden generates roughly ¾ of the green (home) waste.

Household type & kitchen waste

For the purpose of generating kitchen waste, we are a couple in their early sixties (at time of writing) and early fifties when we started MCL in 2012. Our diet contains plenty of fruits and vegetables, so plenty of kitchen waste (slightly on the acidic side because of fruit peels & scraps). The kitchen waste makes up roughly 1/4 of the green (home) waste.

Garden soil type

Our garden  soil is really  clayey throughout; The official classification for our area is Soilscape 17: “Slowly permeable seasonally wet acid loamy and clayey soils”. Hence the need for raised beds for our vegetable plots. For our bottomless compost bins, we tend to dig the bottom to aerate it before levelling it again. We have also experimented with a ~15 cm Hügelkultur sublayer underneath the bottomless compost bins to aid worms and microorganisms.