Grow Light for Hibiscus Indoors for Winter Blooms
A grow light for hibiscus indoors gives tropical hibiscus the bright days it needs to bloom in winter. University of Minnesota Extension notes hibiscus require very bright light to bloom well indoors plus at least 4 to 5 hours of bright direct light. A lamp fills in when winter sun runs short.
The short answer
Tropical hibiscus needs very bright light plus warmth to bloom indoors. University of Minnesota Extension advises 4 to 5 hours of bright direct light plus daytime temperatures of 65 to 75 degrees F. University of Missouri Extension advises holding plant tips 6 to 12 inches from the lamp plus 12 to 14 hours of light with some window light.
How much light does hibiscus need indoors?
University of Minnesota Extension advises a sunny west or south window with 4 to 5 hours of bright direct light. More light, it notes, means more blooms. NC State Extension notes Chinese hibiscus indoors needs a spot with bright light.
| Factor | Target | Tip |
|---|---|---|
| Light | 4 to 5 hours of bright direct light | Add a lamp on dim days |
| Distance | 6 to 12 inches from plant tips | Raise it if leaves bleach |
| Hours | 12 to 14 with some window light | 16 to 18 with none |
| Temperature | 65 to 75 degrees F by day | Avoid cold drafts |
Source: University of Minnesota Extension plus University of Missouri Extension.
Which grow light suits hibiscus?
University of Missouri Extension notes LED plant lights are energy efficient plus long lived. It notes fixtures with three to four fluorescent tubes are needed for plants that require high light. Choose a fixture that covers the whole plant.
How warm should a hibiscus stay for buds?
University of Minnesota Extension notes the plant needs warm temperatures for flower buds to develop. It advises daytime temperatures no lower than 55 degrees F plus 65 to 75 degrees F as ideal. In a cold room, buds may drop or never form.
How to: step by step
- Place the hibiscus in a west or south window.
- Add an LED fixture that covers the whole plant.
- Hang it 6 to 12 inches above the tips.
- Run it on a timer for 12 to 14 hours.
- Hold daytime warmth at 65 to 75 degrees F.
- Watch for bud drop plus adjust light or warmth.
Troubleshooting
Buds drop before opening: cold or drafts. Shift the plant out of cold air.
Few flowers: too little light. Add hours or lower the lamp.
Leggy growth: low light. Add light plus prune in late winter.
For more on lighting see grow lights for cannabis, led light distance cannabis, grow light timers plus cannabis seeds. Kind Seed Co also stocks seeds for indoor growers.
Sources
- Hibiscus, UMN Extension
- Hibiscus, UF/IFAS Gardening Solutions
- Hibiscus rosa-sinensis (Chinese hibiscus), NC State Extension Gardener Plant Toolbox
- Lighting indoor houseplants (G6515), University of Missouri Extension
FAQ
Can hibiscus bloom indoors in winter?
Yes, with enough light plus warmth. University of Minnesota Extension notes hibiscus require very bright light to bloom well indoors. It advises 4 to 5 hours of bright direct light plus warm days. A grow light on a timer can supply the hours a winter window misses.
Why do hibiscus buds fall off indoors?
University of Minnesota Extension notes buds may drop off or fail to form when the plant is too cold. It notes hibiscus cannot withstand extreme changes in temperature or humidity. NC State Extension notes moving the plant can cause leaf plus bud drops, so pick one spot.
How often should I water hibiscus under lights?
University of Minnesota Extension advises soil that stays relatively moist but not saturated. Water until it runs out the drainage holes, then drain the excess. In winter it advises letting the soil dry a little more between waterings, since growth slows.
Should I prune hibiscus indoors?
University of Minnesota Extension advises pruning in late winter to encourage a bushier plant plus trimming back any leggy growth. NC State Extension notes flowers bloom on new growth. Prune before the spring push so the new shoots can carry buds under the lamp.
When can hibiscus move outdoors?
University of Minnesota Extension notes hibiscus can go outside after the danger of frost passes. It advises moving the plant to a porch or shady spot first, then easing it into brighter light. Bring it back inside before the first fall frost.
