By the Countertop Harvest team · Last updated
Before you start: what you need
- Containers with drainage holes. Illinois Extension suggests a container about 4 inches deep.
- A soilless, peat- or coir-based seed-starting mix.
- Seeds and plant labels.
- A clear cover (a dome or plastic bag).
- A sunny window, or a light on a timer.
If you'd rather skip seed starting, a smart garden with pre-seeded pods handles light and water for you. See best smart gardens for small kitchens.
Day-by-day plan
Day 1: Gather pots and mix
Use containers with drainage holes and a soilless, peat- or coir-based seed-starting mix, pre-moistened to the feel of a wrung-out sponge.
Day 2: Sow and label
Sow a pinch of seeds (at least five) per container, about twice as deep as the seed is thick, and label each pot with the herb and date.
Day 3: Keep it moist
Cover with a clear dome or bag to hold moisture and warmth; a potting mix around 65–75°F suits germination.
Day 4: Line up the light
Plan for bright light: about six hours of sun from a south or west window to start, or a light on a timer for 12–16 hours.
Day 5: Check every day
Keep the mix evenly moist but not soggy; mist the surface and drain any water left standing in the tray.
Day 6: Watch for mold
If mold appears, open or remove the cover for airflow. Remove the cover as soon as sprouts appear.
Day 7: Review and plan
Many herb seeds take 10–14 days or more to sprout, so week one is about steady moisture and warmth. Once true leaves form, thin to the strongest seedling by snipping extras at soil level.
Common first-week mistakes
- Overwatering: constant wetness can lead to damping-off, a fungal disease that kills seedlings, and it attracts fungus gnats (Illinois Extension).
- Letting the mix dry out: once germination starts, a dry spell can kill the seed (University of Maryland Extension).
- Leaving the cover on: remove it as soon as sprouts appear.
- Weak light later: leggy seedlings usually mean not enough light. UMN Extension keeps lights no more than 4 inches above seedlings, and 2 inches is ideal.
What comes next?
Once sprouts appear, light becomes the priority. Read how much light indoor herbs need, and follow weeks 2–4 in our free 30-Day Indoor Herb Planner. Not sure what to plant? Start with the best herbs to grow indoors.
Sources
- Illinois Extension: start herb seeds indoors
- UMN Extension: starting seeds indoors
- University of Maryland Extension: starting seeds indoors
- Penn State Extension: growing herbs indoors
Frequently asked questions
How long do herb seeds take to sprout indoors?
Illinois Extension says many herb seeds germinate in about 10 to 14 days. A heat mat can speed this up.
Should I cover herb seeds after planting?
Yes. A clear plastic cover holds in moisture and warmth. Remove it once seeds sprout, or sooner if mold appears.
How deep do I plant herb seeds?
A common rule is about twice as deep as the seed is thick. Tiny seeds are only lightly covered.
Do herb seedlings need fertilizer in the first week?
No. UMN Extension notes seedlings use nutrients stored in the seed and don't need fertilizer until they have several sets of true leaves.