Harnessing the sun in Irish gardens

Hendrik Lepel’s clever Sun Harness Garden, sponsored by Peppermint Farm Glasshouses, at Bord Bia Bloom 2024 demonstrated how to harness the sun’s energy in Irish gardens. Here Hendrik offers some tips on how to create a warm microclimate that will support local ecosystems.

What inspired your show garden at this year’s Bloom?

My inspiration for the Sun Harness Garden came from my studies in permaculture at the Kinsale College of Further Education, where I learned about harnessing solar energy. The primary concept of this garden was to demonstrate a system that captures and utilises solar energy, creating a microclimate that benefits both plants and people. This idea is especially relevant in Ireland, where the summers are short and sunlight can often be scarce.

I designed the Sun Harness Garden to inspire visitors by addressing a common theme in Irish life – the desire for more sunlight and warmth. My hope is to encourage people to rethink their own gardens and consider incorporating sun-harnessing elements to enhance their outdoor spaces.

How do you harness the natural heat from the sun?

To harness natural heat, you have to look at the north-south aspect of your garden: if you have the space you can incorporate multiple sun traps, such as a horseshoe-shaped planting scheme, with taller plant layers (trees) on the north side, opening to the south, and sloping toward the east and west orientations. Within this south-facing area you can therefore create a beneficial microclimate. Garden elements such as south-facing dry stone walls can act as heat stores, providing a warm microhabitat that supports local ecosystems.

A greenhouse is particularly effective for creating a microclimate where you can really feel the solar gain even without the sun present. It also extends the growing season by allowing plants to be cultivated earlier and harvested throughout the seasons.

Is there a growing trend for outdoor rooms in Ireland?

Absolutely. Personally, I believe the garden is the next most important “room” or “come-together-space” after the kitchen. It’s an outdoor space for relaxation and sensory enjoyment, a place to unwind.

Since the pandemic, with people spending more time at home, there’s been a noticeable shift toward enhancing outdoor spaces. Across Ireland, I see a variety of outdoor structures being used as hang-out spaces, offices, sheds, garden rooms and outdoor kitchens. People are increasingly recognising the importance and value of having a private, green retreat within their own homes.

What benefits do greenhouses offer?

A greenhouse offers significant advantages, especially for small gardens. It can retain warmth without requiring direct sunlight, extending the growing season and providing potential benefits for food security. With a greenhouse, even a modest garden can be made more productive, maximising output in limited spaces.

The key engagement space or element in my show garden was a round glass structure called Rondo which was supplied by my sponsor, Peppermint Farm Glasshouses. It is a 360 degree rotatable glass pavilion, where you can experience first-hand the power of harnessing the sun. Inside you can feel the warmth of the sun, or, in its absence, the heat retained in the patio below. The pavilion can be opened by 180 degrees, with glass panels that rotate to adjust to the wind direction, offering both ventilation and shelter – ideal for Ireland’s variable weather. It’s an outdoor room that integrates seamlessly into garden spaces and enhances the overall experience.

How was your experience designing a Bloom show garden?

Bloom was an incredible experience, especially as it was my first time entering a show garden competition. Creating a show garden involves presenting a mature look that, under natural conditions, takes years to establish, so it was a challenging and rewarding process.

One difficulty was the limited three-week timeframe to build the garden. I lost a week to illness which meant a lot of catching up. Being based in County Cork also added logistical challenges with frequent travel back and forth. However, the camaraderie among designers, who were always ready to lend a hand, made a big difference. Winning a silver medal was a true highlight and made all the hard work worthwhile.

You can find more information and images of the Sun Harness Garden here .