Kew Gardens

Compost and Waste Management

I have been to Kew several times – but this time I was given the chance to see a bit of the behind the scene of the running and management. As part of our theoretical module on the course we met David Barnes, the Manager of Horticultural Support at Kew.

Kew Garden has a responsibility to protect and take care of its collections of plants and seeds. With this comes a responsibility to its surroundings and setting as well. Kew is located on flat, dry and free draining gravely and sandy soil. The soil gets very dry in the summer – with nutrients draining away. Kew is also located on the Heathrow fly path and the emissions and pollution also affects the garden and its species.

Irrigation is a must for Kew. The irrigation system has recently been updated.  The water comes from the mains and fills up a 70 000 litre storage tank – from there it leads to water ring circulating the whole site and from there feeding directly to the plants. This reduces the leaks and makes it easier to control which areas you water. 

Rainwater is collected from the main buildings and fills up tanks. The rainwater collecting system is not as developed as they would like – but is something they are looking on improving for the future.

The composting system is well developed at Kew. All the plant material from the maintenance on site is broken down to compost on site. It is all a natural and organic process with only stable manoeuvre added to the other ingredients of water and CO2.  The manoeuvre comes from the stables at St John’s Wood.

The compost yard has been there for 10 years and is built on concrete with a moat surrounding and collecting the runoff water from the compost heaps. This is to protect the Thames from runoff water which has very high levels of nutrients. The runoff water is instead collected and lead into a tank where it is filtered and then used to water the compost heaps. 

The materials are sorted on the yard by heaps of: herbaceous, manoeuvre and woody materials.  The woody materials are shredded and screened. Whilst the herbaceous materials only need shredding.  The wood chips are mixed 4:1 with the manoeuvre. Water is added and the heap is turned once to further speed up the process. It takes about 8 weeks before it is ready to go back out in the gardens to be used as surface mulch.

Close up look at the wood chips mixed with manoeuvre and to the right the wood chips are completely broken down into surface mulch.

The herbaceous materials are mixed on a 1:1 with manoeuvre. No water is added to this process as the herbaceous materials already have a high level of water.  The compost is ready after 6 weeks and is used as soil conditioner which is dug down to mix with the soil on a deeper level.

Herbaceous material starting to break down into compost.

The gardens are saving half million pounds every year by producing their own compost and it is obviously the most sustainable alternative as well.

An interesting fact about the compost heaps are the high levels of energy that they generate.  David Barnes mentioned that pipes could be lead underneath the heaps to help with possible water heating for an example. This is something I am surprised that Kew has not investigated further yet.

The talk also reached a point of discussion the waste generated by the public and if this is recycled. At the moment there is no recycling in place for this. David Barnes said that most of the waste from the public is high level of low weight plastics. Which is costly and complicated to recycle and there is issues with storing that amount of waste on site. But he said that he would like to put some systems in place.

I think the clue for this may lay in the management of the visitors. Waste is something that is hard to control – cause even if the food and products sold on site are being controlled  and more sustainable – you can’t keep people from bringing in their own food and waste to the site. 

The issue of carbon footprint was also discussed and I think that David Barnes answered the questions very well. He said how do measure the carbon footprint for a site for Kew. There is obviously the energy the site uses and the carbon that it emits. There is also certain inherited carbon in the buildings and also all the people visiting Kew.

The later can be put done to trying to manage your visitors and the way you can encourage them to think about the way the travel to the site for an example. Like the Eden Project gives discounts to everyone that arrives by cycle or foot.  This could be tried at Kew by maybe give discounts to everyone that produce a travel card or people showing that they live locally and can show that they walked to the site.

The visit was interesting and it was good to see the composting process which is surprisingly simple and organic. I think I site like Kew still has a long way to go in sustainable management processes – but by listening to David Barnes you realise that the interest is there and it comes downs to costs and procedures.

Kew Garden

Went to Kew Gardens on a great autumns day. Never been during the autumn before and it was quite different. Also the opportunity to go up the tree top walkway. It was very cool, but actually when you were there my first impression was that it was quite short. I thought that it would have been a lot longer (even though I realise that it would have been quite impractical, expensive and too disturbing for surrounding trees roots).

It is still very successful. The different feeling you get when you are up there and I like the fact that the walkway is not very wide - which makes you feel apart of the surroundings a lot more. The material use is great as well. It is very rustic and I love the soft mesh on the railings. The rusty colour compliments the autumn colours on the trees great.

Marks Barfield Architects are the architects behind it. The design is based on the Fibonacci sequence- which is simple mathematical sequence that lies at the heart of the growth of many plant structures. The ratio provides a perfectly proportioned growth pattern. This sequence is used for the spacing of the connection points for the diagonals of the walkway trusses. The legs are based on a simple historical tree. I think as a designer it is fun to read and see where other designs that you see come from. Sometimes the idea is good and it is looks good - but like in this case I think that the idea doesn't really come across in the design.

When reading on Kew Gardens website it says that the walkway: "gives visitors the opportunity to journey from the fascinating root system, learning about a tree's life underground, to the top of the tree canopy to explore biodiversity from above." I think a lot more could have been done to let us investigate the roots of the trees.

When walking round the gardens I realise the importance of trees and deciduous plants and a more naturalistic landscape. It is great to see so many different colours and bare trees as well.  A lot of urban and designed landscaped have a lot of evergreen low maintenance planting. In the introduction of the 'Dynamic Landscape' by James Hitchmough and Nigel Dunnett they talk about ' blocks of evergreen shrubs, mechanically cut on a regular basis to maintain an artificial geometric shape'.

I usually go for a lot of evergreen species when I incorporate planting in my designs and I think I can be a bit more brave and get more interesting and good designs. Using a more a ecological process for plants to grow together and let the site be developed by the process.

Vasa parken - Stockholm

When I went home to Sweden for an early Christmas, I took the opportunity to visit a park in central Stockholm. The park is called Vasa parken and has had some updating over the past years and there is still some work going on. What I knew before I went was that they have these very cool trampolines for kids to play on. I thought they looked great when I saw photos of them and I wasn't disappointed. They were great and we had to try them of course.

I thought maybe they would stand out to much and break up the traditional park too much. But I actually think they were great and the colour looked perfect on a very cold winters day. There some kids in quite different ages playing on them when we were there. The rest of the park is very traditional and very Swedish. It is surrounded by old beautiful houses. You could see that some parts have been done up, but there are also a lot of elements kept in the park, which retains the character of a very old park with a history.

I like the ice rink, with the seating platforms on one end. Which probably is used for football during the summer and spring. There were kids skating on it. It is all free and the kids just bring their own skates. That is something I used to do when I was growing up and I love the fact that you can still go out and do that. And in central Stockholm all for free. It really encourages kids to play outside, even if it is cold and dark outside. It is still safe as well.


I really like the fact that the park is so Swedish and that the character of the park has been kept through regeneration. If the park looked great on a cold winters day, I think it will look beautiful on a summers day.

Kew Garden