In summer, a bright window can be “good enough” for many indoor plants. In winter, that same spot may quietly become low light—leading to slow growth, smaller leaves, leaning, and even leggy growth.
So, is window light in winter enough?
For some plants in some homes: yes.
For many common houseplants: often not—especially if you’re far from the glass, the days are short, or the sun angle is low.
This guide helps you decide quickly (no meters needed), and tells you what to do next—whether that’s moving the plant, improving the setup, or adding a grow light for indoor plants.
Why winter window light is often weaker than you think
Even if your room “looks bright,” plants care about usable light intensity and how long they get it.
In winter you typically get:
• shorter days (fewer total daylight hours)
• lower sun angle (light enters more sideways, less direct)
• more cloudy weather (lower intensity)
• more indoor shading (buildings, curtains, screens, deeper rooms)
That’s why indoor plants winter light is one of the most common causes of slow growth and stretching during colder months.
The fastest test: 5 signs your winter window light is NOT enough
If you see 2–3 of these, your plant likely needs more light than the window is providing.
1. Leaning toward the window (strong directional growth)
2. Longer gaps between leaves (leggy growth / etiolation)
3. New leaves are smaller than usual
4. Slower growth for weeks (with normal temperature)
5. Leaf drop or the plant “thins out” over time
If your plant looks stable, keeps normal leaf size, and stays compact—your winter window light might be enough.
The “distance rule”: how far from the window are you?
This alone predicts a lot.
• Right next to the window (0–30 cm / 0–12 in): window light may be enough for many foliage indoor plants
• Near the window (30–90 cm / 12–36 in): often borderline in winter
• More than ~1 meter / 3+ feet away: commonly not enough in winter unless the window is very bright and unobstructed
• Corner / deep room: usually not enough without support
If you can’t move the plant closer, adding a LED grow light is usually the most reliable fix.
The “shadow check” (a simple way to judge winter light)
On a clear day around midday, place your hand near the plant and look at the shadow:
• Sharp, clear shadow: stronger light (better chance window light is enough)
• Soft, blurry shadow: weak light (often not enough in winter)
• Barely any shadow: very low light (support is recommended)
This isn’t perfect science, but it’s a fast, practical indicator for winter sunlight for plants.
If window light isn’t enough: 3 easy upgrades (from simplest to strongest)
1) Move the plant closer (and remove obstacles)
• Get it nearer to the glass
• Avoid heavy curtains, dark screens, or furniture blocking light
• Clean the window if it’s dusty (small improvement, but real)
2) Make window light more usable
• Rotate plants weekly to avoid leaning
• Use a light-colored wall or reflective surface nearby to bounce light
3) Add a grow light for indoor plants (the most reliable winter fix)
If your plant is beyond the “bright window zone,” a LED grow light gives you consistent daily light—without relying on weather.
A simple starting point for a winter grow light schedule:
• bright window boost: 6–8 grow light hours
• weak window light: 8–12 grow light hours
• low-light rooms: 12–14 grow light hours
The easiest way to avoid guessing: use the app
Winter light changes week to week. Consistency is hard when you’re manually switching lights on/off.
If you’re using Glowrium G4/G5/G6/G7/G8, the updated grow light app can help you keep things stable. In the app’s Plant Assistant, you’ll find plant profiles, light requirements, and watering timing suggestions. After you bind a plant to a compatible light, the app can recommend a target grow light duration—and you can choose from multiple timer styles, including options that follow local sunrise/sunset and add extra light before sunrise or after sunset.
That means you can treat window light as the “base,” and let the app handle the “boost” automatically.
