Grow wheatgrass indoors by soaking the seeds overnight, sowing them densely on moist soil, and harvesting the blades in about 7–14 days.
You soak the seed, spread it on a shallow tray of moist potting mix, keep it dark and damp for a few days, then move it into bright light. In roughly a week and a half, you’re cutting fresh blades with scissors.
This guide walks through the full cycle, the common mistakes that turn a tray fuzzy with mold, and what to do about them. If you’re ready to buy seed, a tested roundup of the best wheatgrass seeds for home trays can help you start with the right variety.
Soak The Seeds First
Begin with food-grade wheat berries meant for sprouting, not seed treated for field planting. Measure out enough to cover your tray bottom in a dense layer — roughly 3–4 seeds per square centimeter. Rinse them, then soak in clean water for 8–12 hours, or overnight.
Oregon State University Extension’s wheatgrass handout recommends a slightly longer soak of at least 12 hours, then keeping the seed moist and rinsing and draining it every 8–12 hours until tiny roots appear. A warm spot around 70–75°F, away from direct sunlight, coaxes the fastest sprouting. After the soak, give the seed one final rinse and drain it well before sowing.
Sow Densely On Moist Soil
Fill a shallow tray — about ⅔ inches deep with drainage holes works well — with 1/2 to 1 inch of moist potting mix or seed-starting mix. Spread the soaked seed evenly across the surface and press it down lightly for good seed-to-soil contact. Do not bury it; most growing guides say wheatgrass stays surface-sown or only barely covered.
Cover the tray with a damp paper towel, newspaper, or a loose lid to hold humidity, and keep it in a warm, dark place for the first 1–3 days. Mist daily to keep the surface moist but never waterlogged. KidsGardening’s wheatgrass guide uses the same approach: moist mix, seed on top, a paper towel cover, and room temperature out of direct sun.
Move To Light And Harvest
Once sprouts reach about 1/2 inch tall, remove the cover and shift the tray to bright indirect light. Direct sun at this stage can stress the tender shoots. Keep the soil evenly moist and watch for the blades to grow straight and green — a sign the grass is healthy.
Harvest when the blades stand 6–8 inches tall, usually 7–14 days after sowing depending on warmth and light. Cut them with scissors at the base, rinse, and juice them right away. Leaving the tray in indirect light and keeping it moist sometimes yields a second, smaller cutting, though flavor and nutrition drop the second time around.
| Stage | What To Do | Timing |
|---|---|---|
| Soak | Rinse seed, soak in clean water | 8–12 hours |
| Drain | Rinse and drain every 8–12 hours until roots appear | 1–3 days |
| Sow | Press densely onto 1/2–1 inch moist soil | Once |
| Germinate | Keep dark, warm (70–75°F), and misted | 3–5 days |
| Grow | Move to bright indirect light, water daily | 5–10 days |
| Harvest | Cut blades at 6–8 inches | 7–14 days total |
Mistakes That Ruin A Tray
Most indoor wheatgrass failures trace back to moisture. Overwatering until water puddles rots the seed and invites mold; underwatering during those first dark days dries out the seed bed and stops germination cold. Use a tray with drainage holes, and mist lightly rather than pouring.
Mold deserves a special note. In humid climates it’s common even with careful watering. Burying seed too deeply and hitting sprouts with direct sun too early round out the usual list of mistakes; both are easy to avoid with the simple steps above.
One honest caution: wheatgrass comes from wheat, and wheat contains gluten. If gluten sensitivity or celiac disease is a concern, check with a healthcare provider before adding wheatgrass juice to your routine.
References & Sources
- Oregon State University Extension. “Wheatgrass Pet Pal” Details the overnight soak, rinsing schedule, and 70–75°F sprouting range.
- KidsGardening. “Wheatgrass Growing Guide” Covers moist seed-starting mix, the no-bury rule, and removing the cover at 1/2 inch.
FAQs
How long does wheatgrass take to grow from seed?
Wheatgrass is usually ready to harvest about 7–14 days after sowing. The exact timing depends on temperature and light: warmer rooms around 70–75°F speed sprouting, while cooler spots slow it down. Harvest when the blades reach 6–8 inches tall, not on a strict calendar date.
Can I grow wheatgrass without soil?
Yes. Wheatgrass grows well on a bare tray of damp compost or a soilless medium like coconut coir. The key requirements are consistent moisture, good drainage, and a dense sowing of seed. Without soil you may need to mist more often to keep the seed bed from drying out.
Why is my wheatgrass turning yellow?
Yellow blades usually mean too much direct sun, uneven watering, or a tray that’s overdue for harvest. Move the tray to bright indirect light and keep the soil evenly moist. If blades are already yellow and limp, harvest what’s still green and start a fresh tray for the next crop.