BY KATIE - MYGREENPOD, 13th Mar '14

HOW TO GROW YOUR OWN IN AN URBAN ENVIRONMENT

As the global population becomes increasingly urbanised, and the planet’s soils become degraded through intensive cultivation, a horticultural product known as biochar offers a unique solution to sustainable growing.

Because of its moisture retaining qualities, biochar is an essential ingredient in urban container growing. It’s ideal for window boxes and pots, which are often the only potential growing space in cramped cities where vertical gardening is becoming an increasingly common sight.

Biochar has been referred to by US biochar expert, Wae Nelson, as ‘the oldest new thing you’ve never heard of’, and it’s certainly no new invention. Studies of soil at sites throughout the Amazon Basin suggest that ancient Amazonian civilisations made a primitive type of biochar and added it to their land to grow food in inhospitable soils.

The result was a rich and fertile black earth – or ‘terra preta’ – with a high carbon content, which is still evident today.

Using biochar is a simple form of carbon sequestration.

Biochar is a highly porous, high carbon form of charcoal that naturally helps improve soil structure, enhances soil fertility and boosts soil health whilst locking away atmospheric carbon dioxide for hundreds of years.

Using biochar is a simple form of carbon sequestration. It is made from any waste woody biomass that has been charred at a low temperature with a restricted supply of oxygen, a process called pyrolysis. This process results in a stable form of carbon that is removed from the atmospheric carbon cycle when added as a soil amendment.

One tonne of carbon locked away in biochar represents the equivalent of three tonnes of carbon dioxide being removed from the atmosphere – an essential step towards cutting the carbon footprint of food production.

By blending biochar with microorganisms and natural nutrients, Carbon Gold’s unique biochar replenishes the diverse soil biology that is often missing from lifeless, urban soils.

Because biochar creates a natural refuge for good bacteria to flourish and improves soil structure, it also supports a ‘no dig’ approach, which reduces the greenhouse gases released by digging (and saves you some back-breaking work!).

Plus, as all the benefits of Carbon Gold’s products result in higher yields, it means you can grow your five-a-day in less space.


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UK engineering supporting global biochar production

British biochar business Carbon Gold was founded in 2007 by Craig Sams, co-founder of Green & Black’s and former Chairman of the UK’s leading organic charity, the Soil Association. Carbon Gold’s ambition is to help people mitigate climate change and support sustainable food production through the development of biochar-based products and projects, simultaneously removing carbon dioxide from the atmosphere and improving soil fertility.

Not only does Carbon Gold sell a unique range of biochar products for UK gardeners and growers, it also supplies British engineered biochar kilns to rural development projects throughout the world. The company often works in partnership with Pro-Natura, an international NGO that creates ‘Super Vegetable Gardens’ in areas of severe desertification.

Using biochar to enhance lifeless, arid soils, these remarkable gardens produce a sustainable supply of fruit and vegetables for local communities in five-week cycles throughout the year. Carbon Gold’s biochar kilns are currently helping cacao farmers in Belize to increase their crop yields sustainably, and a French engineering base in Ashgabat, Turkmenistan, now produces its own supply of biochar to grow fresh fruit and vegetables for workers and their families.

Carbon Gold is also developing a kiln for a project funded by the Department of Energy and Climate Change and coordinated by the RSPB, where natural habitats for birds are being restored in Scottish wetlands.

Bringing biochar to Britain

On the back of biochar’s international success, Carbon Gold was inspired to introduce horticultural products to the UK ­— not only to help gardeners, growers and farmers sequester carbon and improve soil health, but also to enable more people to grow their own food in urban and rural settings.

To do so, it has developed a range of biochar-based products, now popular with home and professional growers. Carbon Gold’s GroChar range is Soil Association approved for use in organic production, and is designed to enhance soil for growing high cropping fruit and vegetables – whether that’s in a small, city window box, a suburban garden or on a commercial farm.

The 100% peat-free composts are key to the fight against the desecration of natural peatlands. Formulated from coir, the fibrous husk of a coconut, GroChar composts are enriched with biochar, mycorrhizal fungi, seaweed and wormcasts, which provide the perfect growing medium for propagating and potting. The magic ingredient, biochar, keeps nutrients in the top level of soil and helps make them readily available to plants, while also retaining water and adding structure to the soil.

The GroChar Soil Improver is Carbon Gold’s flagship product. It looks like charcoal, but actually contains a mix of biochar, microorganisms and trace elements, which are added straight to the soil, mixed with potting compost or dusted onto the roots of seedlings before planting out to increase nutrient uptake and and the soil’s water retention. Used by celebrity growers James Wong and Alys Fowler (see below), it’s become a firm favourite with both amateur and professional growers.

The vital relationship between soil and carbon

Soil is a major store of carbon and its role in reducing CO2 emissions is substantial – it locks away carbon dioxide, preventing it from being released into the atmosphere. Peatland soils hold the highest density of carbon; their destruction not only removes irreplaceable organic matter from the land (peat is currently used for the large-scale production of most mainstream composts and as a fuel for non-renewable power stations), it also releases significant volumes of carbon dioxide into the atmosphere.

While the Earth’s soils are an important sink that keep greenhouse gases out of the atmosphere, plants thrive on carbon. Carbon is the building block of life – the essential ‘black gold’ for all living and growing things. It’s the organic matter in soil that gives plants the carbon they need to be healthy and resilient to disease.

Saving the planet, one garden at a time

Does biochar hold the key to saving our planet’s rapidly degrading soils? Does it help lock away carbon for a planet facing climate change? Can it help the world grow more of its own food? Carbon Gold certainly thinks so.

It believes that biochar can play a significant role in the fight against climate change, as part of a wider effort to cut energy consumption, reduce greenhouse gas emissions and resist intensive farming practices which can lead to deforestation and the destruction of natural ecosystems.

Great global claims that can, it says, be put into practice by growers across the country – however much space you have to play with.

Grow your own urban fruit and veg with biochar

It’s surprisingly easy to grow your own food, even if your outside space is more rooftop than allotment.

Vertical gardening

Gaining popularity with urbanites, vertical gardening makes the most of the space available. By creating a ‘green wall’ or fixing pots to your exterior walls or fences, you can grow a whole array of plants – from strawberries to nasturtiums. By planting in a peat-free, biochar-based compost, your soil’s water retention will improve significantly – meaning plants will grow healthily in a restricted environment. Plus it won’t matter if you forget to water them once in a while!

Patio pots

A common sight in most suburban gardens, but why limit them to flowers? Edible gardening is fast on the rise, with growers replacing tulips for tomatoes and lilacs for lettuce. Using a biochar blended fertiliser will encourage large, healthy root systems and improve nutrient uptake for abundantly fruiting plants.

Window boxes & windowsill herbs

Don’t have a garden? Don’t worry! The good old window box not only gives your home a stylish touch, it can also grow your favourite ingredients. Perfect for cut-and-come-again salad leaves. Alternatively, set up your own mini herb garden in small pots, cans or even cups on a sunny windowsill for easy-to-reach cuttings. By adding a teaspoonful of Carbon Gold Soil Improver, plants growing in small spaces can access all the moisture and nutrients they need.

Carbon Gold has put together a special bundle of all the products you need for your very own urban farm. The Urban bundle consists of 1x20l GroChar All Purpose Compost and 2x1kg GroChar Soil Improver, and costs £22.97. Use the promo code ‘GP-02’ at the check-out for free delivery.

What the experts say

James Wong, ethnobotanist, television presenter and garden designer, uses this biochar blend to bring on the exotics and tropicals he’s famed for growing in the UK. ‘I love the soil improver’, he said. ‘It performed exceptionally well at (paradoxically) improving the drainage and water retention of my London clay, which normally bakes rock-hard in the summer so water just runs off the surface. Water now soaks in instantly and is retained for significantly longer, so I need to water half as much. The subsequent effect on plant growth is also impressive, meaning I could plant far more densely than I would have done in previous years. More crops in the same space with less watering, excellent!’

Alys Fowler, gardening expert, writer and TV presenter, is also a fan. ‘I’ve found that, by using Carbon Gold Soil Improver in my garden, I’ve seen improved soil structure and fertility, which has resulted in stronger, healthier plants’, she said.

Biochar benefits soil health and plant growth in several ways. It holds onto nutrients, preventing them from leaching away and making them available to plants. Its microscopic honeycomb-like structure provides a home in which mycorrhizal fungi and beneficial microbes can grow and flourish, which leads to strong root development and increases disease resistance. The porosity of biochar also improves soil structure and reduces the need for watering. The outcome is stronger, fast-growing plants and a higher yield.

Working with Royal Warrant-holding tree surgeons, Bartlett Tree Experts, Carbon Gold has also explored the benefits of biochar for keeping carbon capturing trees stronger for longer. Biochar has been found to promote quicker establishment of transplanted trees and significantly reduces losses, encouraging better root growth and healthy soil biology. As it retains moisture, biochar minimises drought stress, increases photosynthetic efficiency and boosts trees’ natural immunity to pests and disease.

Carbon Gold sells biochar-based composts, soil improver and fertiliser. For more information,   VISIT THE WEBSITE