These jungle-floor plants grew best at the dimmest settings I tested — and actively shrank when the light got strong.
The experiment: 12 species · 4 intensity levels · ~3 months · Units: PPFD (µmol/m²/s)
Caladiums and alocasias evolved on the shaded floor of tropical forests, under a canopy that filters out most direct sun. Bring that instinct indoors and it means something specific: to these plants, "bright" reads as danger, and the data showed it clearly.
Caladium: a peak in the middle-low
The green caladium did best at 133 PPFD: it was the only group still adding spread at our early-June check. At 82 it actually kept pace for five weeks before dropping most of its leaves at that last reading; at 267 it held on; but at 533 PPFD it collapsed — losing spread and shedding leaves.
Caladium spread through early June. 133 PPFD (green) finishes highest; 82 PPFD (blue) led early, then dropped at the last check; 533 PPFD (red) falls off the bottom.
Leaf count: the 533 PPFD group lost leaves instead of adding them — though the 82 PPFD group also shed leaves at the final check.
And it isn't subtle. Here are two of the three-plant groups at that early-June check, side by side:
Same caladium variety, about six weeks in. 133 PPFD (left): new leaves still unfurling. 533 PPFD (right): stunted, barely hanging on.
Alocasia: even the low end is plenty
The 'Green Velvet' alocasia pushed this further — its best spread came at the lowest level I tested, 82 PPFD, and it stalled or shrank at everything above. The variegated form (trialled only up to 267 PPFD) was the starkest case: by mid-July the plants at 133 and 267 had died back, while the pair at 82 PPFD was still growing.
Alocasia 'Green Velvet' spread through late May. Low light (82 PPFD) leads; higher intensities flatten out. Later in the summer every group declined, but the 533 PPFD plants were the first to die back completely, by mid-June.
Before and after: the green caladium at 133 PPFD (top) and 'Green Velvet' at 82 PPFD (bottom).
The exception: Anthurium
Not every aroid is this fussy. The anthuriums were far more forgiving: one hybrid kept growing at every level from 82 to 267 PPFD, the other did best at 133, and neither collapsed the way the caladiums did — the closest thing to a "put it anywhere" plant in the whole experiment. If you love aroids but have a bright spot, an anthurium is the safe bet.
A note on the calendar. The caladium and alocasia charts stop in late May to early June. Over the following weeks these plants declined at every light level, so later readings no longer separate the levels cleanly. The one pattern that held all summer: the 533 PPFD groups were hit first and hardest.
Foliage aroids, practical settings
- Caladiums: 82–133 PPFD. Keep them below 267.
- Alocasias: 82 PPFD is plenty; variegated forms are the most burn-prone.
- Anthurium: flexible — anywhere from 133 to 267 PPFD works.
More from this experiment
- Part 1 — The setup: 12 houseplants, 4 light levels
- Part 2 — The brightness map: which plant goes where
- Part 3 — Echeveria: compact rosettes and pink color
- Part 5 — Butterwort and staghorn fern
- Part 6 — Five light colors on one dwarf tomato
Lighting we'd recommend
- Barrina T5 5W magnetic grow lights — gentle, even light that suits the 82–133 PPFD these plants prefer; mount them under a shelf rather than right above the leaves.
- Barrina Orbgrow 9W dimmable puck — for a single statement plant; run it toward the low end of its dimming range.
Skip high-output fixtures for these plants — strong light is exactly what they don't want.
