Question
What type of lighting do skylights provide for houseplants?  

If you can picture this, we have a tri-level home, but it is all open, from the great-room up to the kitchen & dining room!  (Dining room has double patio doors, always with blinds open.  Kitchen only has the small window over the sink.)  Since this whole area of the house is so open, it all gets decent light from outdoors.

I have 2 skylights in my great-room, front of the house, which face south, along with 6 large windows in the front that together make a large picture type window.  (They have a peak-a-boo type curtain (covered at the top like a valence,) a small space to let in light, then wooden shutter blinds at the bottom, which are always open to let light in.  There is a lot of light in this room.  Also, it has cathederal type ceiling, which spans 2 levels.
I have 1 skylight each in bathroom 1 & 2, that are on the west side.

I've yet to read how skylights apply to indoor lighting for houseplants!  I'm hoping you can shed some light on this topic!  (Pun intended!)

I have lots of houseplants, & have been researching to make sure they are in the best place they can be!  But, the skylights are most puzzling to me!  Thank you so much, in advance, for your help!!!

Answer
Hi Rose,

The light from skylights is very difficult to assess because every configuration is different. Here are the factors that can affect the light that comes through a skylight:

Distance above the plants
Direction the skylights face
Size of the skylight
Angle of the skylight
Composition of the transparent material
Large trees casting shadows

So that is the reason you are having a hard time getting definitive information about the light that comes through a skylight.

In general, light from a skylight is less intense than light from ordinary windows. This is mostly because the light comes only from the top, so side and lower branches do not get much light. In addition, most skylights are many feet above all but the tallest of plants. Light intensity drops off dramatically with each foot of distance from the light source.

If your skylights are more than 5 or 6 feet above the tops of the plants below, then they are providing low light, at best. So low light plants are probably in order in most cases. The exception would be if there is a nearby regular window.

I hope this is helpful. If there are specific locations or plants that you are considering and you can tell me more about the skylight involved (see my list above), then I may be able to provide more specific information. If you live in NYC, then I can visit your home and give you a very accurate assessment. Otherwise, you will have to pay my transportation expenses!

Please let me know if any of this is unclear or if you have any additional questions. If you would like to e-mail me some photos, I may be able to provide some additional insights.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

You can E-mail me directly at: [email protected]