Over the past season I have been doing an informal study on solar lighting for gardens and landscapes. The idea of having a sustainable light source that uses no exterior energy source sounds good, but according to my findings solar lights are just not ready yet as a viable outdoor lighting source.
In the spring I had purchased a number of different types of solar lights made by different companies, some cheap and some expensive, to test out myself so that I could recommend them in my landscape designs and consulting to my friends and clients equally to or instead of low voltage electric lighting.
I already had a low-voltage lighting system that I had designed, built, and installed to great effect, but I wanted to see if the promise of an off-the-grid system was feasible for both decorative and functional purposes.
The function of a solar light is to gather energy from the sun, temporarily store that energy, and then use that energy to power a light bulb that night. A solar light has a solar panel that gathers the sunlight during the day that is turned into energy and stored in batteries and then that stored energy is used as the energy source by the light bulb that same night.
The advantage of landscape low-voltage lighting is that you can put it anywhere, as long as you can bury the wires, and have them on a timer to turn off and on at will; you can even have different zones lighted up at different times on the property.
The premise of solar lighting is a bit different. Theoretically, you can put it anywhere in the landscape and you don’t have to worry about the wiring; you have to consider that it will only work in areas that receive sunlight.
Currently, solar lights turn themselves on as soon as it is dark enough and will last as long as the battery has a charge in it, which typically are only a few hours. They must have direct sunlight during most of the day in order for them to work that night. They can’t be placed in shady areas; on cloudy days, and especially on rainy days, they will not work that night at all, limiting their functionality.
Additionally, the amount or brightness of the light solar lights put out is far too low to be considered functional in most applications. Typically, you can only see the light itself instead of what it is lighting. It’s like the difference between a 6-watt nightlight compared to a 75-watt reading light.
This is a real problem if you need a light or lights to see your driveway or your walkways, which can make it an unsafe area, especially in a high-traffic area, or on the properties of senior citizens. As a result of the shortness, brightness, and amount of needed sunlight, I would not recommend them at all for functional lighting in which the need for light is a requirement especially in a safety situation.
However as a decorative light, they can be charming. If all you need is a bit of detail or color in your darkened landscape for a few hours after dark, they are decent. I would say that the only real use for solar lighting at this point is for decorative purposes.
A number of attractive lights are available in a number of different colors from most large hardware stores or garden centers. They can be added to a large planter for some color or in a “black hole” in the nightscape. Or they can be grouped together ornamentally in the garden for an interesting effect. The imagination is the limit – also so is the amount of sunlight it gets during the day.
I still would recommend low-voltage lighting for this purpose at this point in time. The solar light technology is just not ready for usage in the different applications. There might be some company that is making a better product, but I have yet to see or hear about it. If that does happen and the technology makes a useful advancement, then I will post that information.
One possibility is that for those who have a solar panel system on their roofs in order to get them off the power grid somewhat then you could tie the outdoor landscape lights into that source but you would still have to use a low-voltage lighting system to make use of the stored energy.
Now that I have used the solar lights for a full season and have personally seen their shortcomings and issues, I am planning on converting all of my favorite solar lights into low-voltage lighting for next year.
So in conclusion, I would not recommend solar lighting at all for safety or functional purposes and still would not use them for decorative lighting myself – too limiting.
For other landscape design, wildlife habitat, native plant, or gardening tips and ideas take a look at my website for Ferret Hollow Gardens, a certified wildlife habitat, www.ferrethollowgardens.com or take a look at my Garden Blog.
I’m Stephen Coan, I exclusively provide landscape design, garden design, plant lists, consulting, and project management services for public, residential, commercial, and wildlife habitat projects using sustainable green practices with a combination of native and ornamental plant species that are site appropriate for the conditions.