Light Requirements for Plants
I'm just writing all this advice out so I can show off my plant collection 🪴
Lighting is probably the hardest thing to figure out for a new plant parent. Our eyes adjust to darkness, so they are pretty awful at detecting if a spot has adequate light for a plant. Remember, no plants are really "indoor" plants. All plants grow naturally outdoors. We are bringing them into our homes because we want them there. The tropical plants which we tend to keep in our homes tend to be canopy plants, growing underneath larger plants which provide them shade from the sun.
When buying a plant, consider where the plant lives in nature. If it normally grows in the shade of larger plants, it will probably be a decent houseplant. However, with grow lights being so readily available nowadays, you can have almost any plant indoors if you are willing to invest some time and effort into setting up lights.
Often people come to me for advice on a plant struggling in their home, only to show me a plant that requires full sun (Rose bushes, Cactus, Basil, Potatoes) on their living room table. To ask a full-sun requiring plant to live in the shade is almost akin to babysitting your friend's child, but only feeding them one small meal a day. Yes, they might survive for a bit, but it isn't what they need to grow or thrive.
Our houses have a lot less natural lighting than we think. The most accurate way to measure the light your house has is to invest in a lux meter, we sell them for $20 at Casita Verde and it measures the footcandles(FC) of light in a given spot. In general, most plants need at least 200FC to grow. 50-200 FC is "low light", 200-1000 FC is "medium light" and 1000+ is "high light". Although most of our plants require indirect sun, they still require a minimum amount of foot-candles on their foliage. Place the lux meter on the foliage, with the probe facing toward the light source. A lux meter is also very helpful in deciding how close to place a grow light to your foliage.
If you are unable to get your hands on a luxmeter, think about where the foliage is in relation to the light source. Not just the sky, but the actual sun. If you put your head at foliage-height, is there a part of the day where the sun is visible to the plant? If you place your hand out in front of the plant during the day with no other lights on, does it cast a shadow?
It's a tricky thing to explain to someone, which is why I like the concrete numbers a luxmeter gives me.
The direction of your windows matter. In the US, in general, light intensity for the directions is as follows:
- North- this is "low light" and will not get enough FC for high light plants. This is an ideal spot for plants such as: Snake Plants, Prayer Plants,ZZ Plants, Peace Lillies, Pothos, Syngonium, and Philodendron
- South- This is the best light for most houseplants. It is bright, but not too direct. Most all medium to high light requiring plants will thrive in the lighting of a south facing window. This spot is ideal for plants such as: Hoya, Philodendron, Dracaena, Peperomia, Syngonium, Ferns, Begonia, Alocasia, Aralia, Ficus.
- East- Put your high light requiring plants over here. I keep some of my Hoya right on my eastern windowsill, and they love it. This is a great spot for Peperomia, Ficus, and Hoya. East windows get the cool morning sun, which is ideal to not scorch your foliage.
- West- This is extremely high light! I keep my cactus and succulents in my western window, it gets about 6 hours of direct sunlight a day. This is a great spot for Aloe, Agave, Echeveria, Haworthia, and Desert Roses. I put a sheer curtain up in my west window, and most plants thrive right in front of it. The curtain diffuses the light and prevents foliage from scorching. However, low-light plants will burn even with a sheer curtain. I've scorched Begonia and Prayer Plants in this window. I have Hoya, Philodendron, Syngonium, Lipstick Plants, Bromeliads, and lots more in front of the West window. (It's a crowded area of my house lol)
Artificial and Grow Lights
Most of my plants are under some sort of artificial light. Speaking from personal experience, those red and blue colored lights are ineffective and I found I had better results using a simple daylight bright LED bulb in a normal lamp. The red/blue lights left my plants etiolated and overall in poor health.
An example of daylight bright LEDs.
For Hoya, cactus, succulents, or anything that loves sun, I use full spectrum LED grow lights. I swear by them, I'm not sponsored or affiliated with them in any way. They can be purchased here. I've been using these lights for about 2 years now, and love the results. They are able to sun-stress Hoya, and don't etiolate cactus as long as it's placed right in above it.
I find running my lights for 14 hours on per day has gotten me the best results.
If you run artificial lights, I highly recommend getting an outlet timer. If you're like me, you'll eventually forget to turn them off or on, condemning your plants to an eternal night/day...or week.