How to Grow Microgreens on a Windowsill in 7 Days

Direct Answer

You can grow microgreens on a sunny windowsill in about 7 days by filling a shallow tray with 1-2 inches of seed-starting mix or coconut coir, scattering fast-growing seeds such as radish or mustard densely over the surface, misting until evenly moist, covering the tray for 2-4 days, then moving it to the brightest window you have. Radish microgreens can be ready in 5-7 days; broccoli, arugula, mustard, and kale often take 8-12 days; pea shoots and sunflower usually need 10-14 days. For best results in an apartment window, use a small tray that fits your sill, keep the medium moist but not soggy, add airflow if humidity is high, and harvest with clean scissors just above the soil line when the seed leaves open.

Windowsill Microgreens: Quick Setup Checklist

• Best tray size: Use a 5"x5", 5"x10", or 10"x10" tray for narrow apartment windowsills; use a 10"x20" tray only if you have a deep sill, shelf, or plant stand.
• Best window: South-facing is strongest, west-facing is usually workable, east-facing can work for fast crops, and north-facing often needs a small LED grow light.
• Best beginner seeds: Radish, mustard, broccoli, arugula, pea shoots, and sunflower are more forgiving than basil, cilantro, beet, or carrot.
• Best medium: Seed-starting mix or coconut coir holds moisture evenly; hemp mats reduce mess but can dry faster at the edges.
• Best watering method: Mist during germination, then bottom-water once roots form so stems stay drier and mold risk drops.
• Realistic harvest: A small windowsill tray gives garnish-to-salad-topper quantities; exact yield depends on tray size, seed type, density, light, and harvest height.

What Microgreens Are and When to Harvest Them

Microgreens are young vegetable, herb, or grain seedlings harvested after the seed leaves, called cotyledons, open and before the plant becomes a baby green. They are older than sprouts, which are grown mostly in water and eaten root-and-all, but younger than lettuce mixes or baby kale.

For a 7-day windowsill harvest, choose radish, mustard, arugula, or some broccoli varieties. Pea shoots and sunflower shoots are excellent indoor crops, but they usually need closer to 10-14 days. Slower herbs such as basil and cilantro can take 14-21 days and are better after you have grown a few easy trays.

Microgreens are valued because they deliver bright flavor in a small amount of space. Published research has found that some microgreen varieties can contain higher concentrations of certain vitamins and phytonutrients than mature leaves, but the numbers vary widely by crop, growing conditions, and nutrient measured. Treat microgreens as a fresh, flavorful addition to meals rather than a miracle food.^[1]

Best Windowsill Conditions for Apartments and Small Kitchens

Light by Window Direction

• South-facing window: Usually the best choice, especially in winter. Watch for hot glass on sunny afternoons and rotate the tray daily.
• West-facing window: Good for radish, mustard, broccoli, and pea shoots. Afternoon sun can dry the tray quickly, so check moisture twice a day.
• East-facing window: Gentle morning light works for fast crops, but growth may be slower and stems may stretch.
• North-facing window: Often too dim for compact growth, especially in winter. Use a small LED grow light for 12-16 hours a day if stems look pale or leggy.
• Low-light winter window: Move trays as close to the glass as temperature allows, clean the window, use reflective white cardboard behind the tray, or supplement with a grow light.

Temperature and Humidity

• Ideal room temperature: 60-75°F works for most microgreens; peas and brassicas tolerate cooler rooms better than basil.
• Cold windowsills: If the sill feels icy at night, move the tray back from the glass after sunset or place it on a cork mat or folded towel.
• High household humidity: Open the cover once daily during blackout, avoid overwatering, and run a small fan nearby on low if condensation builds up.
• Dry heated apartments: Mist more often during the first few days, but do not leave standing water in the bottom tray.

Materials Needed

• Shallow tray with drainage holes, sized to your sill or shelf
• Second solid tray or plate to catch drainage
• Seed-starting mix, coconut coir, or a compostable growing mat
• Microgreen seeds from a food-safe supplier
• Spray bottle for misting
• Cover, second tray, or clean cardboard for the blackout period
• Clean scissors or a sharp knife for harvesting
• Optional: small LED grow light for north-facing or winter windows

How to Grow Microgreens on a Windowsill: Day-by-Day

Day 1: Plant the Tray

1. Moisten the medium: Add water before planting so the mix feels like a wrung-out sponge, not mud.
2. Fill the tray: Add 1-2 inches of medium and level it gently without compacting it hard.
3. Sow densely: Scatter seeds evenly so they sit close together but do not form thick piles. Large seeds such as peas and sunflower need more room than radish or broccoli.
4. Press for contact: Gently press seeds into the surface so they stay moist and root evenly.
5. Mist well: Spray until the top is evenly damp.
6. Cover for blackout: Place a second tray, lid, or clean cardboard over the seeds to create darkness and humidity.

Days 2-4: Germinate in Blackout

1. Check once or twice daily: Lift the cover briefly and mist if the surface looks dry.
2. Look for roots: White root hairs are normal and often appear fuzzy; they are not the same as mold.
3. Keep covered until lift-off: Remove the cover when seedlings are roughly 1-2 inches tall or pushing against it.
4. Pre-soak large seeds next time: If peas, sunflower, or beets germinate unevenly, soak them 8-12 hours before planting your next tray.

Days 4-7: Move to the Window

1. Expose to light: Move the tray to your brightest window once the seedlings are upright.
2. Rotate daily: Turn the tray 180 degrees each day so stems do not lean toward the glass.
3. Switch to bottom-watering: Pour a little water into the bottom tray, let the medium absorb it for 10-20 minutes, then pour off excess.
4. Watch color: Yellow seedlings should turn green within 24-48 hours of good light.
5. Harvest fast crops: Radish and mustard may be ready as soon as the seed leaves are open and the stems are crisp.

Days 8-14: Finish Slower Varieties

1. Keep light strong: If seedlings stretch, move the tray closer to the window or add a grow light.
2. Keep watering: Bottom-water every 1-2 days and adjust for your apartment's humidity.
3. Harvest when ready: Cut just above the soil line once cotyledons are open and before true leaves dominate.
4. Plan your next tray: Start a new tray every 7-10 days for a continuous windowsill harvest.

Frequently Asked Questions

Can I grow microgreens without any special equipment?

Yes. A shallow tray, seed-starting mix, seeds, and a sunny windowsill are enough to get started. A small LED grow light helps if your window is north-facing or you are growing in winter.

Do microgreens regrow after cutting?

Most microgreens do not regrow reliably after harvest. It is usually better to compost the tray and start fresh for the next batch.

Are microgreens safe to eat raw?

Microgreens are generally eaten raw, but always use food-safe seeds and a clean growing medium, wash before eating, and avoid any batch that smells off or shows fuzzy mold.

Why are my microgreens leggy or pale?

Leggy or pale microgreens usually need more light. Move the tray closer to the window, rotate daily, or add a small LED grow light for 12-16 hours a day.

What is the easiest microgreen for beginners?

Radish and mustard are the easiest and fastest for beginners. They germinate quickly, tolerate a range of conditions, and are often ready to harvest in 5-7 days.

Sources

1. Nutrients and bioactive compounds in microgreens: a review – PMC/NIH