Courtesy : horticulture.co.uk
Composting in u.k
For a compost bin the ideal C:N ratio is from 25:1 to 35:1.
The C:N ratio is colloquially but incorrectly also called the ‘Brown-Green Mix.’
Be mindful that C:N and Brown-Green do not have a direct correspondence:
- ‘Green’ compost content has a fairly narrow range of C:N ratios hovering around 30:1
- ‘Brown’ content’s C:N ratio and, therefore, carbon content, varies widely. It ranges from 40:1 to 600:1!
Also, where composting is concerned, ‘Green’ content includes that which is green in colour; however, material like tea leaves, coffee grounds, and manure are considered ‘Greens’ because of their C:N ratios.
Two Simple Rules
You can hit the desired C:N ratio by following two simple rules:
- Strive for a Green/Brown materials 70/30 mix: that is just over two parts Green to every one Brown.
- Be careful with woody and wood-derived materials; use these in very low quantities because they have an extremely high proportion of Carbon to Nitrogen.
Turning and Aeration
Turning and Aeration are crucial to making high-quality compost.
The reason to turn and aerate a compost pile is that if it just sits then the material near the top will decompose at a faster rate while the material that is at the bottom, and which is being compressed by the pile’s weight, will decompose at a slower rate.
Organic materials need air to decompose but materials that are in the middle of the pile or compressed at the bottom would be starved of air.
Turning the compost pile means that there is no bottom layer and no top layer, and this agitation ‘fluffs up’ compressed materials and opens up air channels in them.
Vigorous turning will also bring another benefit; it will tear and break up scraps and pieces.
Use A Handheld Aerator
You will need to turn and mix up, and thus aerate, your compost pile by using a handheld aerator.
Try to choose one that is right for you and also for your compost bin.
If you want to be frugal and go low-tech, do as your grandpa did and use a pitchfork.
Aerate the pile twice or thrice per week.
Also, do so when you add a fair quantity of material to your As-You-Go pile in the bin.
You can insert your aerator through the built-in holes at the top and/or the sides of your bin.
However, you probably will be more comfortable and will be able to do a better job of turning and mixing the compost if you open the lid and use the aerator through this (much) larger opening.
Wetness
The moisture content of the compost pile is another key to effective decomposition.
The pile should remain damp and should never be allowed to dry out because if it does, ‘cooking’ will slow down and the pile will also decompose (more) unevenly.
If, when turning the pile, you observe that it is dry, conservatively water it all over as you turn it such that it is well moistened and damp but not wet.
What Can You Put In A Compost Bin?
The short answer: anything organic, because it will decompose.
The best things to put in a bin are old compost, garden soil, garden clippings and cuttings, vegetable and fruit waste, grass clippings, fresh leaves, dry leaves, mulch, kelp and other seaweed, hay, and straw.
Try to chop up or dice big cuttings otherwise they will not decompose as rapidly as you would like.
Household Waste
In addition, you can put carefully-selected leftover food scraps, twigs, newspapers, rough (not coated or shiny) cardboard, manure, sawdust, wood chips, tea leaves, coffee grounds, old cotton cloth, eggshells, and peat moss.
Do not add rice or grains, cooked or uncooked, or meat or dairy products.
Rice and grains will bring rodents to your compost bin while meat and dairy will attract flies and may well putrefy instead of aerobically decomposing.
Newspapers and cotton cloth should be torn into small pieces and soaked or wetted before being added to the bin to promote decomposition.
All wood-based and wood-derived materials have a very high C:N ratio – 400:1 and higher – so be conservative when including such materials.
Err on the side of too little of these than too much, otherwise the compost pile will remain dry, won’t heat up, and will decompose very slowly and very unevenly.
Layering Materials
How you arrange or layer these materials initially is of some importance.
Put a layer of commercial ‘starting soil’ aka compost starter, plain compost, or even plain garden soil at the bottom, and put a layer of one of these same components right at the top.
Of course, when you turn and churn the pile after a few days everything will get mixed but ‘layering’ is the way to start off on the right foot.
If you anticipate that you may not turn the compost pile for more than three days, put a layer of starting soil (or substitute) on the top.
Weeds
Weeds are organic plant-based material but if you are new to composting or simply don’t have time for fussing, do not put any weeds in your compost bin.
Weeds enjoy warm and rich composting materials so much that they will take root and grow in your compost pile!
On top of that, if weeds go to seed as your compost ‘cooks,’ you could end up with weed seeds in your compost – which means that your nice new compost would sprout weeds.
The way to make sure that weeds do not germinate and turn into compost is to ‘pre-bake’ them, or to use the Batch Composting method, turn the pile very frequently, and even monitor the temperature at its centre to be sure it does not drop below 65°C.
And for all that, you should not put pernicious weeds, like Bishop’s weed and crabgrass, in your compost pile at all.
Manure
If you add manure to your compost bin, do not include horse manure at all.
Other types of manure may be added but these should not be fresh but old or ‘aged.’ Fresh manure is simply too hot to add to a compost pile.
What to put in a compost bin when starting
A very good mix to start off a compost bin would comprise of vegetable and fruit refuse, grass clippings, tea leaves and coffee grounds, chopped or torn-up dried leaves, wetted old cotton cloth or some shredded and wetted newspapers – not to forget some commercial ‘starting soil’ aka compost starter, regular compost, or even plain garden soil.
While these limited materials in the right proportions make for a very good Brown-Green mix, they are also very readily accessible.
