Herbs on a winter windowsill need light you can measure by how they grow, not by how purple the lamp looks in a photograph.
We ran compact LED panels over basil and small greens, noting heat, noise, and whether the plants stayed compact or stretched toward a dim corner.
Light the plant can use
A full spectrum that still looks fairly white is easier to live with in a kitchen. The plants care about intensity at the leaf, not the marketing wheel on the box. A lamp that runs hot in a small tent is a lamp that dries the pots out.
- Enough intensity that basil does not get leggy.
- A quiet driver if the lamp lives in the room with you.
- Heat you can hold a hand under for a few seconds.
- A timer, because you will forget.
If the stems are long and the leaves are small, the lamp is too far or too weak.
A winter of leaves
Keep the lamp close and raise it as the plant grows. Water a little less than you did in summer. Indoor herbs fail from wet soil and weak light more often than from the wrong shade of diode.
Buy the lamp you can leave on a timer above the pots you already have.
