Reading your windows: which way do they face
Okay. So we've done bright versus dim, we've done what "bright" even means to a plant instead of to you. New topic, and it's the one that actually lets you use all that. Which way your windows face.
This is the thing nobody measures and everybody guesses wrong, and I mean that literally — I've had people in this class stand up, walk to the window, and admit they've lived in the house four years and don't know which direction it faces. That's normal. Don't let it embarrass you. I didn't know either until I got stubborn about the plant thing.
Here's why it matters more than "is it bright in here."
The four directions, roughly
South-facing windows get the most light, all day, and it's strong. If you're in the northern hemisphere — which, yes, we are — south is your sun. Plants that want a lot of light, direct sun, that kind of thing, go here. This is also where a fiddle-leaf fig would go if you were going to get one, which, you know how I feel about that.
North-facing windows are the gentlest. Soft, indirect light most of the day, no direct sun really ever. Good for things that like it dim-ish. Snake plants do fine here. So does Steve, actually, though Steve would probably do fine in a closet, that plant does not care about anything.
East-facing windows get morning sun. Gentle, not too hot, for a few hours, then it tapers off for the rest of the day. This is a really forgiving direction. A lot of houseplants like east light because it's bright but not blasting.
West-facing windows get afternoon sun, and afternoon sun in Utah is no joke. It's later, it's hotter, and by summer it can actually scorch leaves that touch the glass. If you've got a west window, you want to watch it a little more, maybe pull sensitive plants back a foot or two in July.
How to actually figure out which way your window faces
You don't need a compass app, though you can use one, phones have them built in now. Simpler way: think about where the sun rises and sets relative to your house. Sun comes up in the east, goes down in the west. If you know your street, you probably know this already, you just haven't applied it to your windows before.
Or do it the lazy way, which is what I actually do — walk to a window in the morning. If the sun's coming in hard, that's an east-ish window. Check the same window in the late afternoon. Hard sun then, it's west-ish. No sun either time but it's still fairly bright all day, you're probably north or you've got some shade situation going on outside, a tree or a neighbor's roofline.
Watch the actual light, not just the compass
Direction gets you close, but it's not the whole story. A south window with a big shade tree outside it might act more like an east window. A north window in a room with white walls and no curtains can bounce around more light than you'd think. So once you know the direction, spend a day actually watching the room. Where does the sun land on the floor. Does it reach the plant or stop three feet short. That's the real answer, the compass is just a shortcut to get you close.
Where I learned this the hard way
I've told you I'm not great with ferns, and here's the specific way I found that out. I had this idea in my head — plants like humidity, ferns especially, ferns are jungle plants, so ferns must want it warm and damp. Fine so far. Then I looked around my house for warm and damp and landed on the worst possible spot: right next to a heater vent, in a corner that barely got any window light at all. In my head I was thinking "cozy jungle corner." In reality it was the driest air in the entire house, blasting hot dry air directly onto a plant that wanted the opposite of that. Nine days. It went crunchy in nine days. I didn't even get a chance to feel good about my plan before it was over.
The lesson wasn't really about ferns. It was that I was reasoning from a feeling — "this corner feels cozy" — instead of actually checking what the light and air were doing there. Same mistake people make with windows. You assume a room is bright because it feels bright to you, standing in it with your very capable human eyes. Your plant is not using your eyes.
What to do with this
Walk your house room by room. Note which windows are north, south, east, west, roughly. Then match up what's already living there — is your pothos in a north window struggling to hang on, is something delicate baking in a west window every afternoon. A lot of "I don't know why this is dying" mysteries solve themselves right here.
Before next time
Figure out which direction at least one of your windows faces, using the sunrise/sunset trick or your phone's compass, and just sit with that information a minute before you do anything else with it.