Scored for a wax plant at 22 °C and 50% humidity, a west sill at 7,800 lux comes back 99 out of 100, and one metre in it still reads 98 at 6,000 lux. At 1.2 m the light turns a little dim and the score drops to 68. From there it drifts down to 63 at three metres.
Read on 14 October 2026, the answer box at the top of Google’s results says a west window suits a hoya, then offers two placements: tough, acclimated types such as carnosa right against the glass, sensitive ones a few feet back. Below it, nobody calls west a bad window. Hoya Treasures, a specialist seller, is the cautious one. It warns that summer sun and heat near the glass get intense, and that the leaves facing the light can bleach. None of the pages puts a number on the distance.
That missing number decides it. For a carnosa, the part of a west room that scores a great fit is about a metre deep, and from November to January even the sill falls short.
Great fit
This plant should be happy in this spot.
Just the right amount of light
Comfortable temperature
Humidity suits it
Airflow suits it
Is a west window too much sun for a hoya?
Everything here is scored for Hoya carnosa, the common wax plant. The hoyas the answer box calls sensitive aren’t in these tables, so take its few-feet advice for them on its own terms.
Start with what other people publish for a hoya’s light, each figure in the unit its source chose:
| Who publishes it | What it says a hoya needs | What the figure is |
|---|---|---|
| getgrowli.app | 4,000–8,000 lux | Hoya page, 'bright, indirect' tier; the site prints the same band for several other plants |
| getgrowli.app | 400–800 fc | The same tier, given in foot-candles |
| foliage-factory.com | approx. 10,000–20,000 lux | Product page for Hoya carnosa 'Compacta', 'care at a glance', lux at leaf level |
| foliage-factory.com | approx. 10,000–20,000 lux | Product page for Hoya carnosa 'Tricolor', same figure |
| extension.illinois.edu | 300 foot candles | Tier figure: the wax plant is listed under high or bright light, and that tier is set at 300 foot candles |
| mrec.ifas.ufl.edu (archived) | 125 foot-candles | UF/IFAS interior minimum, for about 10 hours a day; read from a web.archive.org copy of 13 August 2025, the live page now returns 404 |
| mrec.ifas.ufl.edu (archived) | 1500-2000 foot-candles | UF/IFAS commercial production light, from the same archived copy |
| bloomingexpert.com | 1,500–2,000 foot-candles | Second-hand: attributed to The Sill, whose hoya page now returns 404, so it could not be checked there |
For light, no. The card reads the sill’s 7,800 lux as ideal, and June, the brightest month in the season table below, scores 100 there. The figures above stretch from a living-room minimum to commercial production light, and the Foliage Factory band for two carnosa cultivars starts above anything this window reaches even in June.
Heat can flag the sill. Hold the light where the card has it and raise only the air temperature: the verdict stays a great fit up to 28 °C, turns worth a try at 29 °C and reaches not the best fit right now at 33 °C. A monstera on the same sill holds on a degree longer, and its page prints the whole temperature run; a pilea gives up two degrees sooner.
Bleaching is the warning no score can check. A plant’s history isn’t an input, so a hoya that spent spring on a bookcase and meets the July beam all at once can pale on its window side while the card still reads 99. Bring it forward over a couple of weeks.
How far back from a west window can a hoya go?
About a metre. One hoya, walked back from the glass:
| 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, 99/100 |
| 1 m back | 6,000 lux | Just the right amount of light | Great fit, 98/100 |
| 1.2 m back | 5,470 lux | A little dim, but workable | Worth a try, 68/100 |
| 2 m back | 3,780 lux | A little dim, but workable | Worth a try, 65/100 |
| 3 m back | 2,381 lux | A little dim, but workable | Worth a try, 63/100 |
| 3.5 m back | 1,890 lux | Too dim here | Not the best fit right now, 47/100 |
The step falls between 1 m and 1.2 m. On one side sit 6,000 lux and 98; on the other, 5,470 lux and 68, with the light column moving from just right to a little dim. Past it the score sinks slowly to 63 at three metres, then 47 at three and a half.
Lay the answer box’s two placements over that table. The glass is the top row. A few feet back is the slippery one: three feet is a little under a metre and still a great fit, while four feet is about the 1.2 m row and isn’t. For a carnosa, a few should mean three.
A jade plant runs out of light at the same metre of a west room, though for a jade the step drops it from worth a try to not the best fit. A string of hearts loses its great fit at the same metre. At south glass the hoya itself keeps a great fit out to about two metres.
Does a hoya need to move closer to a west window in winter?
Yes, right up to the glass, and from November to January even that isn’t enough. Here’s the card’s sill on the 21st of six months, at latitude 40, roughly New York’s:
| The month | Estimated light | What the light is doing | Verdict |
|---|---|---|---|
| January | 5,070 lux | A little dim, but workable | Worth a try, 67/100 |
| February | 6,377 lux | Just the right amount of light | Great fit, 98/100 |
| June | 9,360 lux | Just the right amount of light | Great fit, 100/100 |
| October | 6,303 lux | Just the right amount of light | Great fit, 98/100 |
| November | 5,023 lux | A little dim, but workable | Worth a try, 67/100 |
| December | 4,551 lux | A little dim, but workable | Worth a try, 66/100 |
June reads 9,360 lux and 100. That same light flags a moth orchid on this sill as a bit bright. October still clears the line at 6,303 lux and 98. November falls under it at 5,023 lux and 67, and December bottoms out at 4,551 lux and 66. Scored day by day, the sill leaves the band around 28 October and returns around 14 February.
The great-fit strip grows and shrinks with the calendar. From May to July it reaches about 1.35 m into the room, at the equinoxes a little under a metre, and by late October half a metre. Pulling a hoya back for summer, as Unsolicited Plant Talks suggests, costs nothing on light if back means a metre. Coming forward again is the catch: by 21 September a pot at one metre has already slipped to worth a try.
Latitude moves the dates. At 30 degrees the sill holds into mid-November; at 50 degrees it drops out in mid-October. Either way, the sill stays the brightest place in a west room, so that’s where the pot spends winter.
How do you find the line in your own room?
With a light meter.
The lux figures in our tables are estimates built from the window’s direction, the distance and a clear day, not meter readings, so your own numbers will differ. The line is what to look for: 6,000 lux sits inside the band for a carnosa and 5,470 doesn’t.
Hold the meter where the leaves would be, on a bright day in October or February, when the strip is thinnest but still there. A reading taken in the direct beam late on a summer afternoon shows the window at its peak, which is more than the plant gets across the day.
What else moves the line at a west window?
Shade, and in autumn it doesn’t take much. The October sill clears the line by only a few hundred lux, so a balcony overhead or a neighbour’s tree can put a hoya under it weeks before the dates above. Neither is an input here. The west window guide covers what else does well in the afternoon beam, and the free spot checker scores your own sill with the weather where you live.
Published October 14, 2026
