Lighting the Greenhouse

Lighting plays a subtle, but critical, role in the quality of life within and around a home. I’ve lived in places where there was so little natural light that I had to use electric lights even during the day. Or where there was inadequate light, like in the kitchen, for the task at hand. Having built a few homes before this, I was familiar with design criteria to light a home’s interior and had drafted the house lighting plan months earlier.

A good lighting plan should include general, task, and accent lights. However, lighting the greenhouse would be different than lighting the house. I wasn’t able to visualize the greenhouse space until it was erected when I could see the volume of space in the 4 areas to be lit – the seating area, the passage by the livingroom, the food garden area, and the pool. The clear glazing and metal post and beam structure presented a few issues that were not relevant with the house, such as:

  • how to attach fixtures to a metal structure
  • where to place the fixtures for general illumination given the roof height and potential for shadow from the house
  • where to place the fixtures to reduce ‘leakage’ into the night sky
  • without the benefit of reflection from opaque walls and/or ceiling, how many fixtures (and what lumen) would be needed to get the desired level of illumination
  • would I be restricted to exterior fixtures or could I use interior fixtures

I’ve never had a greenhouse before so I did not have direct experience of what task and accent lighting would be needed, where to place the lights, or how to attach them. Even if I had had a residential garden greenhouse it would have been so much smaller and basic than this 35′ wide by 60′ long by 24′ high behemoth that it would not have served as a prototype to figure out lighting requirements. So I looked at similarly sized greenhouses at my local garden nursery. That too, did not help because the lighting reflected their needs which does not include comfortable human residence. Everywhere I went I looked for aspects of the building and site that might be similar to mine and for how the space was lit. I looked at photos and videos of luxury home’s outdoor living spaces. I reviewed photos and videos of other greenhouse-enclosed homes around the world but they didn’t cover this topic. Ordering lead times are ridiculous on so many items that I needed to stop analysis paralysis and make decisions on fixtures to be sure they arrived before the electrician. Ultimately it came down to making the best design I could with the information I had available while being adaptable to new ideas.

Accent Lighting

Accent lighting highlights a specific feature; inside a home this might be something like artwork , or in a landscape this might be something like a specimen tree. To make the short list for possible accent lighting on my project, I thought not only about what features I find aesthetically pleasing but also evoke an emotional response that I want to highlight. To me, the gable roof style is the archetype for shelter and home and the clear greenhouse gable evokes light, life, and growth. Therefore, I wanted to accent the peak of the greenhouse roof.

When the ridge vents are closed, the roof stays dry. When the ridge vents are open, however, rain may blow in. To be rain resistent I selected two exterior LED spot lights. They are plugged into a smart outlet in the eaves and have multiple color settings. The fixtures come with a stand so they are sitting directly on the roof, not affixed to anything, and can be moved as needed to get the best lighting on the peak, or to clean the roof.

General Lighting

General (or ambient) lighting was the challenge. The first idea was a combination of lights on the house, similar to exterior lighting of a standard house, and lights hung from the greenhouse trusses. Both b.o.r.i.n.g.

Then Matt, my builder, asked why not put rope lights on the purlin? What a great idea! I ordered one exterior-grade 60′ rope as a trial that I strung at the 9′ purlin around both sides of the southeast corner where the sitting area is. I L.O.V.E it. Someone driving by literally passed, stopped, and backed up to look for a few minutes.

The rope lights provide a soft indirect light inside and accent the greenhouse shape from the outside. I ordered two more ropes so there are three separate zones, each on a smart switch – the sitting area, the food garden along the west side, and the pool area along the north side.

The roof lights also provide general illumination. During the months where it is dark when I wake up, I turn on the roof lights that give the effect, from inside the house, that the sun is rising.

Task Lighting

Task lighting is just that, providing light for a particular task. There will be task lighting over the potting bench. Other than that, I wasn’t sure where I would need task lighting so I made sure to have enough outlets spaced around the greenhouse perimeter that I can place a lamp just about anywhere. For now I’ve placed a stand lamp to light whatever I feel like doing while sitting in the rocker, like knitting.

Leave a Reply