Growing herbs on a windowsill: light, warmth and the right pot

When it is too cold outside, a bright window can keep some fresh herbs coming. Indoors, light is everything: an herb on a dim windowsill does not die quickly, it just grows thin and spindly, with smaller leaves and less aroma.

Which window

• South is best, then west. Look for a window that gives at least 5 hours of sun a day.
• Sources differ on how much is enough: Maryland Extension says a south window with 5–6 hours suits most kitchen herbs; Iowa State says most herbs need around 8 hours of direct light indoors.
• In winter, when days are short, a window alone is often not enough.

Grow lights, in plain numbers

• Hang the light 6–12 inches above the leaves.
• Run it 12–16 hours a day; a plug-in timer does this for you.

Warmth, pots and feeding

• Kitchen herbs are comfortable at 65–75°F by day and 55–65°F at night.
• Grow each herb in its own pot with drainage holes. A 10-inch pot gives the roots enough space.
• Feeding advice ranges from weekly at half strength to every six months. Plants indoors grow slowly, so start light.

The five herbs indoors

• Basil: a good windowsill herb for fall, winter and early spring. Give it your sunniest window and sow a few seeds every 2 weeks.
• Chives: can spend winter on a bright windowsill; a pot benefits from a light frost outside before it comes in.
• Parsley: wants high light and a cool spot.
• Mint: grows in a south window, but can outgrow an indoor space fast.
• Cilantro: possible in a deep pot with plenty of sun.

Whatever you grow, take no more than a third of a plant at once and let it regrow.

Sources

Every fact in this guide comes from the publications below. None of them reviewed or endorsed Balcony Bounty.

• University of Maryland Extension. Growing Herbs in Containers and Indoors. extension.umd.edu/resource/growing-herbs-containers-and-indoors
• University of Maryland Extension, Frederick County Master Gardeners. Growing Kitchen Herbs Indoors. extension.umd.edu/sites/extension.umd.edu/files/2021-03/FC-MGPub%20Ind…
• Iowa State University Extension. Growing Herbs Indoors. yardandgarden.extension.iastate.edu/how-to/growing-herbs-indoors
• Oregon State University Extension. Growing herbs indoors adds flavor, saves money. extension.oregonstate.edu/news/growing-herbs-indoors-adds-flavor-saves…
• University of Illinois Extension. Herbs: Basil. extension.illinois.edu/herbs/basil
• University of Wisconsin–Madison Extension. Chives, Allium schoenoprasum. hort.extension.wisc.edu/articles/chives-allium-schoenoprasum/
• University of Illinois Extension. Herbs: Parsley. extension.illinois.edu/herbs/parsley
• Utah State University Extension. Cilantro/Coriander in the Garden. extension.usu.edu/yardandgarden/research/cilantro-coriander-in-the-gar…
• University of Illinois Extension. Growing Herbs in Containers. extension.illinois.edu/blogs/good-growing/2015-04-09-growing-herbs-con…