Windowsill Herb Garden
A practical guide to growing herbs on a windowsill - light, temperature, pots and watering, feeding, the best herbs to start with, harvesting for more growth and fixing common problems, following Penn State Extension and the RHS.
A windowsill herb garden is a few pots within arm’s reach of the stove, ready to snip into whatever you’re cooking. Penn State Extension notes that herbs can be grown indoors as year-round houseplants, or just in winter to protect tender herbs such as basil. The biggest factor is light.
This guide follows Penn State Extension’s “Growing Herbs Indoors” and the Royal Horticultural Society’s herb guides.
Light: the make-or-break factor
- Most herbs need 6 hours of direct sun (Penn State). Put them in a sunny spot such as a south-facing window (north-facing in the southern hemisphere).
- Some need full sun more than others. Penn State lists bay, rosemary and thyme among the herbs that do best in direct sunlight, and lemon balm, chives and cilantro among those that tolerate low light and need only 2 to 6 hours of direct sun.
- Signs of too little light: Penn State says herbs without enough light become thin and spindly, produce smaller leaves and have less aroma.
- Turn the pots often so each side gets enough light for even growth (Penn State).
- Add light if the window isn’t enough. Penn State suggests placing herbs 6 to 12 inches (15-30cm) from two 40-watt cool white fluorescent tubes for 14 to 16 hours a day.
Temperature and humidity
Penn State suggests rooms of at least 65-70°F (18-21°C) by day and 55-60°F (13-16°C) at night. Most herbs survive the low to mid 40s °F, but basil cannot survive below 50°F (10°C) and should not be kept on a windowsill in winter.
Centrally heated homes have the driest winter air; Penn State suggests grouping containers, standing them on a tray of moist pebbles or near a humidifier, and using a fan if a space is too humid.
Pots and drainage
- Every pot needs a drainage hole and a potting mix that drains well (Penn State). If you love a decorative pot with no hole, grow the herb in a plain nursery pot inside it.
- Give spreading herbs their own pot. The RHS notes that many mints are vigorous, spreading plants best grown in pots to keep them contained.
- Deep pots for taprooted herbs. Penn State says herbs with a taproot, such as borage and dill, need deep pots, and that herbs with large root systems, such as horseradish, fennel and lovage, are poor choices indoors.
Watering
- Water when the mix starts to dry out (Penn State).
- Let woody, Mediterranean herbs dry slightly between waterings: Penn State names bay, marjoram, oregano, sage, thyme and rosemary.
- Never let basil dry out completely (Penn State). The RHS adds: water basil in the morning if possible, because it hates having wet roots overnight, and avoid splashing the leaves.
- Never leave a pot standing in water. Our guide on how to water houseplants covers the checks in detail.
Feeding
Penn State suggests a low dose of water-soluble fertiliser every two weeks, and warns that feeding more often can spoil the herbs’ aroma and taste. Some organic fertilisers smell fishy or of manure, which you may not want indoors.
The best herbs for a windowsill
Penn State names chives, basil and cilantro as great options for an indoor herb garden. Others to consider, matched to your light:
- Basil - the RHS says it needs warm conditions and grows well on an indoor windowsill; keep it warm and moist.
- Chives - tolerate lower light (Penn State); the RHS says to snip them regularly to keep fresh leaves coming.
- Cilantro - tolerates lower light (Penn State).
- Mint - the RHS says it is happy in sun or partial shade; give it its own pot.
- Thyme, rosemary and bay - want direct sun and should dry slightly between waterings (Penn State); oregano likes the same watering.
Penn State adds a caution for pet owners: tarragon is toxic to dogs and cats, so avoid it in homes with pets.
Harvesting to encourage growth
- Pick basil tips regularly. The RHS says picking the shoot tips keeps basil bushy and productive, and that basil may flower sooner in dry conditions; flowering affects the flavour of the leaves.
- Snip chives regularly to keep fresh leaves coming (RHS).
- Trim regularly. Harvesting little and often keeps plants compact.
Common problems and quick fixes
- Thin, spindly growth, small leaves, weak aroma - not enough light (Penn State). Move to a brighter window or add lights, and turn the pots.
- Basil collapsing in winter - too cold; basil cannot survive below 50°F (Penn State). Move it off the cold sill.
- Fungus gnats - Penn State suggests yellow sticky traps near the plants and careful watering.
- Aphids - trim off and bin infested shoots. Penn State notes that soft insecticides such as neem oil or a Bt product can be used in extreme cases, following the label, but are not usually recommended on herbs you eat fresh; always wash leaves before cooking.
- Dry leaves in winter - air too dry; group the pots or use a pebble tray (Penn State).
Repotting
Penn State suggests repotting when roots grow through the drainage hole, ideally in early spring. If you move herbs outside for late spring and summer, acclimatise them slowly to the stronger light and wind.
The short version
Give your herbs the brightest window you have - six hours of direct sun for most - pots with drainage holes, and water when the mix starts to dry. Keep basil warm and moist, let the woody Mediterranean herbs dry slightly between waterings, feed lightly, and pick little and often.
Sources
- Penn State Extension, Growing Herbs Indoors. Read 28 October 2026.
- Royal Horticultural Society, How to grow basil, How to grow mint, How to grow chives. Read 28 October 2026.
Recommended Gear on Amazon
- Windowsill planter - browse current options and reviews on Amazon.
- LED grow light - browse current options and reviews on Amazon.
- Yellow sticky traps - browse current options and reviews on Amazon.
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