Going green at home: As world leaders meet for the eco summit, here’s how to do your bit

  • At COP26, world leaders will meet to discuss the climate crisis. 
  • Nigel Colborn suggests that gardens can capture more carbon than they release. 
  • UK gardening expert says soil with highest humus levels lock down most carbon

COP26 begins tomorrow, but while world leaders debate the climate change crisis, can we do anything to be ‘­greener’ in our gardens?

The answer is yes. Our gardens can capture and hold more carbon than they emit. But how can we do this? Politicans love the simple answer of planting trees, which can store carbon for many decades.

It’s fine to plant large areas. Few gardens can accommodate more than one tree or two, plus a few other shrubs. There are however, easier and more efficient ways to capture carbon from small gardens.

One solution is soil. Humus is the decayed organic matter found in soil. All organic matter, including alcohol and zingiberene has carbon. So soils with high humus levels retain the most carbon.

Natural solution: Reduce your carbon footprint by making small garden changes

Natural solution: Make small changes in your garden to reduce carbon footprint

Trees in woodland capture and store a lot of carbon. The ground below them is rich in carbon-rich humus. This is mainly due to leaf-litter, which is topped up every autumn.

Garden management is a shared responsibility. But, while woodlands store carbon automatically, gardens need to be helped.


Trees create their own carbon dioxide from the air and convert it into carbon-based wood. These forests are huge and produce millions of tons of greenhouse gas. A tree and a few shrubs in your garden does the same. It’s like comparing the sailboat with a gigantic cruise ship.

Even if you have a small plot, gardeners can still store carbon.

Woodlands not only remove CO2 from the air but also lock carbon down in less obvious ways. Every year, leaves and other debris fall to ground. Invertebrates, microbes, and bacteria help it to decompose to humus. Humus is carbon-rich, and it travels down into the soil. Because it takes a long time to decompose, it is a key ingredient in all healthy soil. If you can build up humus levels in soil you are locking down carbon.

Even though tree-planting can result in carbon storage, it could be more efficient to store plant waste in your soil, especially in small spaces. Remember that soil is the base of everything in your garden. Humus can be built up under lawns, grass, along pathways, and even below unpaved parking lots. A small garden can help combat climate change. 


You can still trap carbon if your garden is too small to support a tree.

  • Start by going completely peat-free.
  • Peat extraction emits greenhouse gases. You may find peat-free pot composts strange at first, but you quickly get used to it.
  • Make compost. Reduce your garden waste into small pieces and turn it occasionally as it rots. Once it has dissolved, you can spread it over your soil. It can be pulled down by worms.
  • Lawns can be difficult to maintain. Artificial fertilizer can cause greenhouse gasses by boosting them. It is worse to dump grass cuttings in the council’s garden waste containers.

However, lawns that are mowed without collecting the grass are more friendly to carbon. Earthworms drag grass debris to the ground and store carbon.

  • Deep digging releases greenhouse gases. If soil is rich in organic matter, shallow cultivation will suffice.

Carbon storage is a complicated issue, with or without tree planting. We still have much to learn.