Sustainability in the Botanic Gardens

The Utrecht University Botanic Gardens are a place where everyone can learn about plants, with an eye to the future. We maintain our exclusive plant collection in a natural and sustainable way. This is how we show our visitors that an attractive garden with lots of variety and a resilient ecosystem go well together. Head gardener Gerard van Buiten tells us about the sustainable choices in our garden management.

Gerard was raised on sustainability. He grew up on a farm with a balanced ecological cycle. About sustainability in the Gardens, he says: "We are all very conscious about making our work more sustainable. But the choices we make in this must really yield sustainability gains. And often a choice is not that black and white. We want to make our eco-footprint as small as possible, but we also have to be able to work efficiently and well ánd it has to fit within the budget."

Back battery

Back in 2013, the Gardens switched to electric tools. Until then, other power sources were common. It was quite a challenge: "At that time there was only one brand with a seriously good battery. Nevertheless, since then we have been working with an electric hedge trimmer, leaf blowers and a brush cutter. These all have a back battery, which greatly improves their usability. They are also low-noise and don't bring a smell. This is very pleasant for us and the whole environment. We charge the devices via the light grid, thus saving about 400 liters of fossil fuel per year."

Every year about 200 m3 of leaves are collected in the Utrecht Science Park and brought here.

Appropriate

Another example of sustainability is the choice for  the new central walkway made of concrete. Gerard: "That maybe doesn't seem so sustainable at first sight, yet it is. We chose a mix of concrete with recycled concrete and cement with a low carbon footprint. Such a specific concrete path is virtually maintenance-free for 40 years. We don't have to burn away weeds ten times a year now. That saves a lot of emission. Thus, we are always looking for ways of sustainability that really suit us well."

Organic fertilisation

"We're on river clay here. Our lawns, once they are well rooted, we don't really need to fertilise. We leave the grass cuttings and that has enough organic nutrient value for a nice lawn. Outside, we use only organic fertilisation. Every year about 200 m3 of leaves are collected in the Utrecht Science Park and brought here. We grind that into mulch for the garden. That reduces dehydration, reduces weeds and stimulates organisms in the soil naturally."

Dream for the future

There is a lot of peat in potting soil because it has special properties. But less and less of it remains in nature. Gerard: "We have therefore been trying for years to make our potting soil peat-free. At the same time we have to keep our special plant collection healthy. So it is sometimes quite a quest. I am proud that we now only work with completely peat-free potting soil: about 16 m3 per year. People who know our Rock garden are aware that it contains a number of peat walls in which we grow all kinds of special plants. Unfortunately, no good alternative has been found for that yet, but by reinforcing the peat walls with stone walls, that peat will last 10 to 20 years here."

Farmers' sense

So sustainability is also challenging for the Botanic Gardens. The garden team is always open to improvements, sometimes these are not (yet) feasible or they turn out disappointing. Gerard summarises the approach as: common farmers’ sense. With a childhood on a circular farm and a father as garden manager, he's got that down well.