June: Carbon in the Garden

Do we get credit for carbon sequestering in our garden? That was our big question for June. We have a large inner city yard with a small house, a big garage, and lots of extra city land under our care because we’re on a corner.

We have six trees, hedges and a whole lot of bushes. We grow a dozen kinds of fruit. We also grow some herbs and veges. We take good care of the soil, are organic gardeners, and prefer hand tools to power tools, including a push mower.

(For anyone wondering about what fruit grows in Calgary, we have apple, pear, strawberry, raspberry, rhubarb, gooseberry, kiwi, grape, black currant, Nanking cherry, Saskatoon berry, cherry. We pick more apples and pears than we can use each fall; the volume of the rest varies from small to none.)

The research:

A tree value study in California breaks down the significant value of trees, for carbon sequestering, help with heating and cooling, cleaning the air and beauty. California ‘Street Tree’ benefits valued at $1 Billion

But it’s hard to convert that data into anything relevant for one garden.

Our six trees calculated out to roughly 1.5 kg of carbon stored each year. We read that we can save about 2 lbs of carbon for every lb of fruits or vegetables we grow ourselves (yes, we noticed the change in units of measure to lbs. It came from a US website).

We came across some really interesting recommendations for garden carbon sequestering:

“For deep carbon sequestration, the basic requirements are as follows: Help plants maximize photosynthesis and tend the soil biology. Minimize plowing or tilling and digging, grow multi-species polycultures, don’t leave soil bare for extended periods, don’t use pesticides or synthetic fertilizer.”  Ecological Gardening: Backyard Carbon Sequestration: What Does Synthetic Fertilizer Have to Do with It?

“To store lots of carbon in your garden and keep it there, grow big trees and lots of biomass with woody stems, make sure these plants live a long time, and compost all your yard waste. Wood is the key, whether it’s in canopy trees, understory trees or shrubs.  …compost all your garden wastes on site or in your community to lock most of that carbon up in the soil for long-term storage.” The Carbon Footprint in Your Garden

Other recommendations include growing food, avoiding synthetic fertilizers, using less water/collecting rain water, and using planters and containers from upcycled materials. Oh, and let lawn clippings fall.

A garden with lots of trees is a wonderful place – we have dappled shade in the summer; light in the winter; snow on branches and places to hang bird feeders and hammocks; fresh organic food; a cooler house in the summer; an endless supply of compost; beauty and nature for the neighbourhood; a sanctuary for birds, bunnies and squirrels; and endless entertainment for passing dogs because the garden smells so interesting.

Do we get any credit?

That’s the hardest answer of anything we’ve researched. It’s brutally difficult to calculate. We’ve chosen to not claim credit, to know we’re doing well, and to look for ways we can do better.

Carbon in our garden plays out in several ways:

1. carbon sequestered – in soil, plants, most especially in trees
2. carbon saved because we grow some food for ourselves
3. carbon used in inputs to the garden – plants in pots on trays, seeds in paper envelopes in a box for delivery, city water, soil additives.
4. carbon used in what we dispose of, like plant pots and trays. We do compost everything but woody stuff (no chipper), and diseased material. Once the city sets up green bin collection that material will go to city composting.
5. energy use in the garden – power tools, and propane for the flame weeder we use on our gravel driveway (which is permeable to water, a good choice, and we avoid chemical weed control, a good choice, but uses bad choice propane to save Maureen’s wrists from digging weeds out of gravel, which Maureen has decided is a good choice.)

What can we change:

• we can be aware of inputs, and try to reduce them
• we can lean even more to hand tools instead of power tools
• we can work harder to use all the food we grow, and to share any extra
• we can continue sharing extra plants with neighbours
• we can work harder to remember to use rain water instead of city water

And we can enjoy our beautiful garden every day, knowing many people don’t have this opportunity to be stewards of a little bit of land.