Scored at 22 °C and 50% humidity in light airflow, a prayer plant comes back 91 out of 100 on a west sill, at one metre and at two, and 90 at three metres. At three and a half metres the light runs short and the score drops to 65. Add a summer date, though, and the sill becomes the one spot in that run flagged as a bit bright.
Read on 14 October 2026, the top results can’t agree on whether a west window is allowed. Proven Winners and Indoor Plants HQ list east or west as suitable, and Planterhoma calls both perfect. Spider Farmer, Healthy Houseplants and Plantsopedia want the plant a few feet back from west glass or behind a sheer curtain, and Pistils Nursery sends it to a north or east window instead. None of them ties the west-window warning to a time of year.
The two camps are describing the same window in different months. For this plant the sill is a bit too bright for about three of them, and a metre back is fine in all twelve.
Great fit
This plant should be happy in this spot.
Just the right amount of light
Comfortable temperature
A little dry, but workable
Airflow suits it
The card falls short of the top for the same reason it does at an east window: the air is drier than this plant likes. The east window page is built around that one flag and what actually raises humidity, so this page sticks to the light.
How far from a west window should a prayer plant sit?
Anywhere from the glass to three metres, if you set the calendar aside for a moment. First, what others publish for this plant, as each source prints it:
| Who publishes it | What it says a prayer plant needs | What the figure is |
|---|---|---|
| houseplantjournal.com | 100 FC (20 µmol) foot-candles | minimum indirect light level |
| houseplantjournal.com | 200 FC (40 µmol) foot-candles | good indirect light level |
| houseplantsnook.com | 100–200 foot-candles | chart fc level |
They answer how much light is enough. Not one is framed as a maximum, and a maximum is the half of the question a west window makes people nervous about. At the dim end they agree with us: converted to lux, the 200 foot-candle “good” level falls between the 3 m and 3.5 m rows below, where the score steps down.
| Distance from the glass | Estimated light | What the light is doing | Verdict |
|---|---|---|---|
| 0.3 m, against the glass | 7,800 lux | Just the right amount of light | Great fit, 91/100 |
| 1 m back | 6,000 lux | Just the right amount of light | Great fit, 91/100 |
| 2 m back | 3,780 lux | Just the right amount of light | Great fit, 91/100 |
| 3 m back | 2,381 lux | Just the right amount of light | Great fit, 90/100 |
| 3.5 m back | 1,890 lux | A little dim, but workable | Worth a try, 65/100 |
| 5 m back | 945 lux | A little dim, but workable | Worth a try, 61/100 |
The first three metres barely move: 91, 91, 91, then 90. Between 3 and 3.5 m the estimate falls from 2,381 to 1,890 lux, the light picks up a dim flag and the score drops to 65. At five metres and 945 lux it’s 61. That’s a lot more room than a north window gives, where the same plant runs out of light between one and a half and two metres from the glass.
So “a few feet back” costs nothing. A few feet is about a metre, well inside the flat part of the table, and with no date attached it doesn’t buy anything either. The case for it appears once you tell the engine what month it is.
The lux column is a clear-day estimate built from the compass direction and the distance. Nobody put a meter on anyone’s sill, and a real room with its own glass and neighbours will read differently.
When is a west sill too bright for a prayer plant?
From May to July, at latitude 40. Given a latitude and a date, the engine scales the window’s light by how high the noon sun climbs that day against the equinox. Here is the sill from the first table through a year, at about the latitude of New York:
| The 21st of | Estimated light | What the light is doing | Verdict |
|---|---|---|---|
| February | 6,377 lux | Just the right amount of light | Great fit, 91/100 |
| April | 8,955 lux | Just the right amount of light | Great fit, 90/100 |
| May | 9,360 lux | A bit bright, but workable | Worth a try, 65/100 |
| June | 9,360 lux | A bit bright, but workable | Worth a try, 65/100 |
| July | 9,360 lux | A bit bright, but workable | Worth a try, 65/100 |
| August | 8,970 lux | Just the right amount of light | Great fit, 90/100 |
| October | 6,303 lux | Just the right amount of light | Great fit, 91/100 |
| December | 4,551 lux | Just the right amount of light | Great fit, 91/100 |
April and August sit on the edge, at 8,955 and 8,970 lux, still reading as the right amount of light and scoring 90. From May to July the estimate reaches 9,360, the light is flagged as a bit bright, and the score falls to 65. That’s the burn worry, and for this plant the engine backs it, on the sill and the first half metre, for three months a year.
Pull the pot back a metre and the flag is gone: at one metre and at two the engine reads a great fit in every month at this latitude. A monstera has no summer problem here at all, since on the same June sill it stays a great fit; its comfortable band reaches higher.
Humidity won’t rescue a June sill. We ran it again at 65%, inside the 60 to 80% this plant is comfortable in, and it stayed worth a try. The flag there is light, and only distance or shade moves it.
The calendar works on the back of the room too, in the other direction. Three metres in drops to worth a try from October to February, the same winter squeeze the north window page finds a metre from its glass. So the good strip slides, back from the glass in summer and toward it in winter, and one to two metres back is the part that never moves.
The west window guide makes the general case that a sill which is brutal in July can be mild by November. For this plant the engine puts dates on it: off the sill by May, back on it in August.
Does afternoon heat hurt a prayer plant on a west sill?
Yes, and at a lower temperature than you might expect. Keep the sill at its undated light and change only the air: at 27 °C the engine still calls it a great fit, at 28 °C it drops to worth a try, and from 31 °C it’s not the best fit. That edge sits where several of the guides above put their warm limit, 27 °C or 80 °F, and Planterhoma ties heat above 29 °C to scorched leaves.
West sills pass 27 more easily than the rest of the house, because the sun gets there after the rooms have already warmed up. In June that means a pot on the sill can carry the light flag and the heat flag on the same afternoon. Moving it a metre back clears the light flag for certain. It clears the heat only if the air a metre in really is cooler, which the score can’t know.
If leaves near the glass crisp in July, check the sill’s temperature before you blame the beam. For this plant, one degree past 27 already costs the great fit.
Does a sheer curtain do the same job as moving it back?
Probably something like it, but the engine has no input for a curtain or a blind, so every number here is for bare glass. What it can say is how much distance does the same job: in June half a metre back is still flagged, and a metre clears it. To test a curtain, read the sill with it drawn and the spot a metre back with it open, at the same hour on a sunny afternoon. If the two come out close, the curtain is doing the metre’s job.
The numbers also assume an open west window on a clear day. A tree or the building across the road takes light off every row and pulls the dim step at the back toward the glass. The free spot checker scores the spot you actually have, with the weather where you live.
Published October 14, 2026
