Your office plants looked great in March. Now it's June and something is off — leaves are yellowing, curling at the edges, or going translucent in a way they weren't two months ago. Before you assume the plants need water or a new pot, check the light. In Toronto, summer changes everything.
From late May through August, the sun sits higher in the sky and shines for up to 15 hours a day. South- and west-facing windows that were gentle in winter become intense. Skylights that were welcome in February can scorch plants by noon. And if your building's HVAC runs hard near the windows — which is common in Toronto office towers — you may have plants trapped between blasting cold air and direct summer sun simultaneously. That's a recipe for distress, and it looks different depending on the plant.
Here's how to read what your office plants are telling you.
Signs Your Plants Are Getting Too Much Light
Direct summer sun is the more dramatic of the two problems. It shows up fast and looks alarming, but it's diagnosable once you know what to look for.
Leaf scorch is the most obvious sign. You'll see dry, brown or tan patches — often crispy — on the parts of the leaf that face the window. Unlike fungal browning, which spreads from the edges in, scorch tends to appear as irregular bleached patches mid-leaf or on the surface facing the glass. Bird of Paradise (Strelitzia reginae) is particularly prone to this. So is the Peace Lily (Spathiphyllum), which is popular in Toronto offices because it tolerates low light in winter but can burn badly if it's been left near an unshaded south window come June.
Fading or washed-out colour is a subtler sign. If a plant that had rich green leaves now looks pale or yellowish-green, it may be bleaching from too much sun intensity. This is common with Pothos (Epipremnum aureum) varieties — especially the golden and marble queen cultivars — which do best in bright indirect light but fade and develop dry patches in direct summer exposure.
Curling leaves — particularly when the curl rolls inward toward the stem — can indicate heat stress from direct sun, especially in combination with dry soil. Check whether the curling leaves are on the side facing the window. If so, light is likely the culprit.
Accelerated soil drying is a secondary indicator. If you're watering a plant significantly more often than you were in spring and it still looks thirsty, high light intensity (and the heat that comes with it) may be evaporating moisture faster than the plant can uptake it.
Signs Your Plants Are Getting Too Little Light
Low-light symptoms are slower and subtler. They're easy to confuse with overwatering, underwatering, or pest damage — which is part of why they go undiagnosed.
Leggy, stretched growth is the clearest sign. When a plant reaches toward the light source, producing long internodes (the stems between leaves) with leaves that are smaller than normal, it's etiolating — straining toward more light than it's getting. This is common with Sansevieria (Dracaena trifasciata) placed too far from windows, and especially with ZZ plants (Zamioculcas zamiifolia) in interior conference rooms or reception areas that get very little natural light.
Yellowing lower leaves that drop off is often a sign of insufficient light, particularly when the plant isn't overwatered. The plant is essentially shedding leaves it can no longer sustain photosynthetically. Pothos and Philodendron (Philodendron hederaceum) both display this clearly.
No new growth after the spring growth season is a warning sign, especially in June and July when plants should be in an active phase. If a plant that was putting out new leaves in March through May has completely stalled, it may not be getting enough light to power growth even during peak season.
Dark green, smaller leaves can also indicate low light. The plant is producing more chlorophyll (which reads as darker colour) to capture what little light it has — but the leaves themselves are smaller because the plant has less energy to spend.
Why Summer in Toronto Creates This Problem
The issue isn't just that there's more sun — it's that the angle and intensity shift dramatically between seasons. In winter, Toronto sits at a solar angle of roughly 22 degrees at noon. By the summer solstice, that's closer to 69 degrees. The same window that gave plants gentle, low-angle morning or afternoon light in January now delivers direct overhead-intensity sun for hours.
Meanwhile, buildings respond by running air conditioning hard, which creates a secondary problem: plants near windows often sit in a cold, dry microclimate with air movement that accelerates moisture loss, while simultaneously receiving more intense light. This is the combination that most commonly causes plants to look ill in summer in Toronto offices — they're being pushed and pulled in two directions at once.
Learn how heating and cooling systems affect your office plants year-round
The Diagnostic Walk-Through: What to Check Right Now
If you suspect light problems, here's a quick office walk-through you can do in under 10 minutes:
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Track where direct sun hits. Walk the floor at 11 a.m. and again at 2 p.m. and note which plants are in direct beam. Any sensitive plant — Peace Lily, Pothos, ferns, Calathea (Goeppertia spp.) — that sits in that zone from late May onward may be at risk.
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Check the distance from windows. A plant more than 8–10 feet from a window in a Toronto office building, with no supplemental lighting, is likely in low-light conditions regardless of season.
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Look at new growth vs. old growth. New leaves that are small and pale, or no new growth at all, point to a light deficiency. New leaves that are scorching or fading point to excess.
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Feel the soil at the correct time. Check soil moisture 3–4 days after watering. If it's bone dry in a plant that's near a window, high light and heat are likely accelerating evaporation.
The hardest part of this diagnosis is that symptoms can overlap. A ZZ plant with yellowing lower leaves might be underlit, overwatered, or root-bound. Context and the full picture of your office environment matter.
When It's Time to Bring in Professional Eyes
Most office managers are excellent at keeping their space running — they're not plant diagnosticians, and they shouldn't have to be. If you're seeing multiple plants showing stress symptoms this summer, it usually means something has shifted in the environment that needs a systematic look, not just plant-by-plant troubleshooting.
At Benji's Plant Care, we do summer health assessments for Toronto offices specifically because June is when light-related problems peak. Our assessments cover light mapping by zone, an evaluation of each plant's current condition, and a recalibrated maintenance plan that accounts for summer conditions — sun angles, AC exposure, and watering frequency adjustments. We look at the whole environment, not just individual plants.
The goal isn't just to save struggling plants. It's to set up your office so that your greenery looks genuinely good through summer and into fall, without you having to monitor it week to week.
If your plants are looking off right now, that's useful information. It means something in their environment has changed and needs attention — and the sooner it gets addressed, the less recovery time is needed.
Ready to get a clear picture of what your Toronto office plants need this summer? Book a plant health assessment with Benji's and we'll sort out exactly what's going on.