Grow Light for Basil Indoors for Bushy Winter Plants
A grow light for basil indoors helps plants stay compact plus leafy when winter windows run dim. Penn State Extension notes most herbs need 6 hours of direct sunlight, or a spot 6 to 12 inches from two fluorescent bulbs for 14 to 16 hours. Basil also wants warmth, so place it in a warm room.
The short answer
A grow light for basil indoors fills in when windows are dim. Penn State Extension advises 6 to 12 inches from fluorescent bulbs for 14 to 16 hours. Iowa State University Extension advises 14 hours a day for grow lights plus 18 inches for a plug in LED shop fixture. Pinch tips often for bushy basil.
How much light does indoor basil need?
Iowa State University Extension notes light is usually the most limiting factor for herbs indoors plus most need around eight hours of direct light. Penn State Extension notes most herbs need 6 hours of direct sun.
| Setting | Recommended range | Source |
|---|---|---|
| Fluorescent distance | 6 to 12 inches | Penn State Extension |
| Fluorescent hours | 14 to 16 hours | Penn State Extension |
| LED shop fixture distance | 18 inches | Iowa State University Extension |
| Grow light hours | 14 hours | Iowa State University Extension |
| Day temperature | 65 to 70F | Penn State Extension |
Source: Penn State Extension plus Iowa State University Extension.
How close should the light hang over basil?
Penn State Extension advises 6 to 12 inches from two fluorescent bulbs. Iowa State University Extension advises 9 inches for a T5 fluorescent shop fixture plus 18 inches for a full spectrum LED shop fixture. For a fixture sold as a grow light, use the package directions.
Why does basil stretch on a windowsill?
Penn State Extension notes herbs without their preferred light grow leggy with a reduced aroma. It advises turning windowsill pots often so each side gets light. University of Minnesota Extension notes basil is one of the most popular culinary herbs, plus a lamp fills winter gaps.
How to: step by step
- Set the pot in a warm room away from cold drafts.
- Hang the light at the distance listed for the fixture.
- Run the light 14 to 16 hours a day on a timer.
- Lift the light as plants grow.
- Pinch stem tips to encourage side shoots.
- Water once the top of the mix feels dry.
Troubleshooting
Long, thin stems: the light is too far away. Lower it.
Pale or faded leaves: the light may be too close. Raise it a little.
Slow growth in a cold room: basil is chilled. Shift it somewhere warmer.
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
- Growing herbs indoors, Penn State Extension
- Growing herbs indoors, Iowa State University Extension and Outreach
- Growing basil, University of Minnesota Extension
- How to set up supplemental lights for indoor plants, Iowa State University Extension
FAQ
Can basil grow under a regular LED bulb?
Iowa State University Extension describes a plug in LED shop fixture with full spectrum light placed 18 inches from the foliage. It advises at least 3,000 lumens with lights on for 14 hours a day. A single household bulb gives far less light, so a shop fixture or grow light suits basil better.
Should a grow light run all night?
No. Penn State Extension advises 14 to 16 hours of fluorescent light for herbs, plus Iowa State University Extension advises 14 hours a day for grow lights. Plants also need a dark period. A plug in timer sets the same schedule every day so the lamp turns off at night.
Does basil need a south window as well as a light?
Not always. Penn State Extension notes a sunny south window can supply the 6 hours of direct sun most herbs need. In winter that light often falls short, so a lamp adds the rest. With a grow light on a timer, basil can grow well away from any window.
How warm should indoor basil be?
Penn State Extension advises rooms of at least 65 to 70F during the day plus 55 to 60F at night for herbs. University of Maryland Extension notes basil is not tolerant of chilly temperatures. Set basil away from cold glass plus drafts in winter so growth does not stall.
Should indoor basil pots be rotated?
Yes, when they sit on a windowsill. Penn State Extension advises rotating pots often so each side gets enough light for uniform growth. Under a grow light hung straight above, rotation matters less. A quarter turn every few days evens out growth on plants near a window.
