In this guide
Quick answer
On a bright south- or west-facing windowsill, chives, parsley, cilantro, chervil, arugula, bunching onions, mint and oregano all grow from seed in winter. Basil is the one most people try, and it struggles: it wants more light and warmth than a winter window gives. If you want winter basil, add an inexpensive grow light.
Winter light is the problem, not the season itself. A south window in December gets far less light than the same window in June, and the days are short. Herbs that tolerate lower light and cool rooms do fine. Sun-loving, heat-loving herbs stretch, flop and taste weak.
Windowsill herbs ranked for winter
| Herb | Windowsill only? | Days to first harvest (approx.) | Notes |
|---|---|---|---|
| Chives | Yes | 60 | Cut-and-come-again for months |
| Bunching onions | Yes | 50-60 for thin green onions | Sow thickly, snip like chives |
| Parsley | Yes | 70-90 | Slow to sprout; soak seed overnight |
| Cilantro | Yes | 30-45 for leaves | Likes the cool; sow a pot every 3 weeks |
| Chervil | Yes | 40-50 | Prefers lower light; delicate anise flavor |
| Arugula | Yes | 25-35 | Fastest; cut as baby greens |
| Mint (peppermint) | Yes | 70-90 | Grows slowly from seed; keep moist |
| Oregano | Bright south window | 60-80 | Surface sow; let soil dry a bit between waterings |
| Thyme | Bright south window | 80-90 | Tiny seedlings; patience |
| Basil | Needs a grow light | 40-60 | Wants 70°F+ and strong light |
| Rosemary | Needs a grow light | Many months | Very slow from seed; better started in late winter for outdoors |
How to set up a winter windowsill
- Pick the brightest window you have, usually south-facing. Put pots as close to the glass as you can without leaves touching the cold pane.
- Use pots with drainage holes and a light potting mix, not garden soil. 4-6 inch pots are plenty for most herbs.
- Sow more than you need. Indoor germination can be patchy. Thin later.
- Turn pots a quarter turn every few days so plants don't lean toward the glass.
- Watch the temperature. Most herbs are happy at 60-70°F. A window can drop to the 40s at night; move basil away from the glass on cold nights.
- Water when the top inch is dry. Overwatering in low light is the number one way indoor herbs die. Mediterranean herbs (oregano, thyme, rosemary) like to dry out more than parsley, chives and mint.
Stop leggy seedlings
Pale, stretched seedlings that fall over mean "not enough light." Fixes, cheapest first:
- Move them to a brighter window.
- Put a sheet of white card or foil behind the pots to bounce light back.
- Sow herbs that don't mind low light (chives, parsley, chervil, cilantro, mint).
- Add a small LED grow light or shop light 4-6 inches above the plants for 12-14 hours a day. This is the single biggest upgrade for winter herbs, and it's what makes winter basil possible.
Harvest small and often
Indoor herbs grow slowly in winter, so take a little at a time. Cut chives and onions an inch above the soil, snip outer parsley and cilantro stems, and never take more than a third of any plant. Cilantro and arugula are short-lived; sow a new pot every 3 weeks and toss the old one.
Moving them outside in spring
Parsley, chives, thyme, oregano and mint started indoors over winter can go outside in spring. Harden them off for a week (a few hours outside in shade, building up to full sun) and plant them after your last frost.
When spring comes, these plants can move outdoors into a kitchen herb garden or an herbal tea garden.
Frequently asked questions
Can I grow basil on a windowsill in winter? Sometimes, in a very bright, warm south window, but it's usually leggy and weak-flavored. With a grow light it grows well.
Do I need a grow light for indoor herbs? Not for chives, parsley, cilantro, chervil, arugula, onions or mint. You do for good winter basil, rosemary from seed, or a north-facing window.
Why are my indoor herb seedlings dying at the soil line? That's damping off, a fungus that thrives in cool, wet mix. Use fresh seed-starting mix, water from the bottom, and let the surface dry slightly between waterings.
