Wheatgrass is the young grass of the common wheat plant, harvested at about a week old when it is sweet, tender, and at its nutritional peak for juicing. Growing it at home is far cheaper than buying juice shots, and it is a genuinely satisfying indoor crop: from dry seed to a dense, knee-high carpet of green in 7–10 days, on a windowsill, with one shallow tray of soil. The process is simple — soak, sprout, sow, water, harvest — but wheatgrass is notorious for mold if you crowd the seed or overwater, so technique matters. This guide gives you the full tray method with soaking times, watering routine, harvest height, the cut-and-come-again trick for a second crop, and exactly how to keep mold out.
Key Takeaways
- Wheatgrass grows from hard winter or spring wheat berries to a 7-inch harvest in about 7–10 days.
- Soak the berries 8–12 hours, pre-sprout 1–2 days until tails appear, then sow densely on 1–2 inches of soil.
- Use a shallow tray with drainage; bottom-water when possible to keep the canopy dry and mold-free.
- Harvest with scissors just above the soil when the grass is 6–7 inches tall and the blades start to split.
- Mold is the main problem — caused by overcrowding, poor airflow, and a wet canopy; not the harmless white root hairs.
What You Need
- Hard wheat berries (hard red winter wheat or hard white wheat, sold as wheatgrass seed) — about 1 to 1½ cups per standard 10×20-inch tray
- Two shallow trays — a standard 10×20-inch seed tray with drainage holes, nested inside a solid tray to catch water and allow bottom-watering
- Potting/seed-starting mix or quality compost — enough for a 1–2-inch layer
- A spray bottle and a watering can
- A second tray or sheet of newspaper to cover the seed during germination
- Sharp scissors for harvesting
You can grow wheatgrass hydroponically without soil, but the soil-tray method is more forgiving, yields a thicker crop, and gives you a stronger second cutting. Wheatgrass fits right into a soil-free or small-space indoor growing routine — explore more methods on our urban gardening hub.
Step-by-Step: The Soil Tray Method
Step 1 — Soak the wheat berries
Rinse the berries, then soak them in a jar of cool water for 8–12 hours (overnight is easy). They will swell to nearly double their size. Drain off the soak water — you can keep this rinse for plants if you like — and you are ready to pre-sprout.
Step 2 — Pre-sprout for 1–2 days
This optional but recommended step gives wheatgrass a head start and reduces mold. Keep the drained, soaked berries in the jar (use a mesh lid like you would for sprouting) and rinse and drain them twice a day for one to two days, until you see little white root tails about 1/8–1/4 inch long emerging from most of the seeds. Pre-sprouted seed germinates fast and evenly once sown.
Step 3 — Prepare the tray
Fill the draining tray with 1–2 inches of moist potting or seed-starting mix and level it gently — do not compact it. Water it so it is damp throughout but not waterlogged. Set this tray inside a solid catch tray.
Step 4 — Sow the seed
Spread the pre-sprouted berries across the soil in a single, dense layer — they should touch but not pile up two-deep. A 10×20 tray takes roughly 1 to 1½ cups of dry seed. Do not press them in or bury them; resting on the surface is correct. Mist the seed lightly.
Step 5 — Cover for germination
Cover the tray loosely with an inverted second tray or a sheet of damp newspaper for the first 2–3 days. This dark, humid blanket encourages the roots to grip the soil and the shoots to push up. Mist once or twice a day to keep the seed moist, and lift the cover briefly each day for airflow so it does not get stuffy and moldy underneath.
Step 6 — Uncover and green up
By day 3–4 the shoots will be 1–2 inches of pale yellow grass lifting the cover. Remove the cover and move the tray to bright, indirect light — a windowsill out of harsh direct midday sun is ideal. Within a day the blades turn vivid green as chlorophyll develops. Keep growing in good light and airflow.
Step 7 — Water from the bottom
Once uncovered, switch to bottom-watering whenever you can: pour water into the outer catch tray so the soil wicks it up, then drain off any excess after 10–15 minutes so the roots are never sitting in standing water. Bottom-watering keeps the grass canopy dry, which is the single best defense against mold. Water roughly once a day, or whenever the soil surface feels dry; the grass is thirsty but hates soggy roots.
Step 8 — Harvest at 6–7 inches
Around day 7–10 the grass reaches 6–7 inches tall and the blades begin to split, sending up a second leaf — that split is the signal that nutritional content peaks and it is time to cut. Using sharp scissors, harvest by cutting the blades just above the soil line. Juice or use it right away for best flavor and nutrition; cut wheatgrass keeps a few days refrigerated in a sealed bag.
A Second Harvest
After the first cut, keep watering the tray and it will regrow for a second harvest in another 5–7 days. The second cutting is usually a bit thinner and less sweet than the first, and a third cut is rarely worth it — the mat of roots exhausts the shallow soil. Once the tray is spent, the whole root mat and soil makes excellent compost. If you compost indoors, our bokashi composting guide covers an apartment-friendly way to recycle spent trays.
Beating Mold: The Real Skill
Mold is the only thing that reliably defeats home wheatgrass growers, and it comes down to four controllable factors: crowding, moisture, airflow, and seed quality. Sow a single dense layer, not a pile; keep the canopy dry by bottom-watering; give the tray good air movement (a small fan on low nearby works wonders in a humid kitchen); and start with clean, viable seed and a clean tray. A common point of panic is the fuzzy white growth around the base of the grass — this is almost always the plant’s fine root hairs, which are harmless and disappear when misted. True mold is gray, blue, or black, smells musty, and forms web-like patches on the stems and soil. If you see real mold, improve airflow and reduce watering immediately; a lightly affected tray can sometimes be saved by harvesting above the mold line, but a heavily moldy tray should be composted and restarted.
Troubleshooting
Moldy soil or stems: too crowded, too wet, too still — sow thinner, bottom-water, add airflow. Yellow, leggy grass: not enough light after uncovering; move to a brighter spot. Grass falling over or rotting at the base: overwatering and standing water — drain the catch tray and water less. Patchy, uneven germination: old or low-quality seed, or the tray dried out during germination — keep seed moist under the cover and buy fresh berries. Bitter or sour grass: harvested too late (past the split-blade stage) or stressed by heat — cut at 6–7 inches and keep the room around 60–75°F. White fuzz on roots: harmless root hairs, not mold — mist them and they settle down.
Wheatgrass is one of the most rewarding indoor crops precisely because it is so fast and visual. If you like growing food this way, pair it with a jar of homegrown sprouts on the same counter — between the two you will have fresh living greens year-round with no garden at all. For more indoor and small-space growing projects, browse the urban gardening hub.
Frequently Asked Questions
How long does wheatgrass take to grow?
About 7–10 days from sowing to harvest. Add 1–2 days for soaking and another 1–2 days for pre-sprouting, so the full cycle from dry seed is roughly 9–13 days. Harvest when the grass is 6–7 inches tall and the blades begin to split.
How do I stop wheatgrass from getting moldy?
Sow a single dense layer rather than a pile, water from the bottom to keep the canopy dry, give the tray good airflow (a small fan helps), and use clean seed and a clean tray. The harmless white fuzz at the base is usually root hairs, not mold — true mold is gray or black and musty.
Do I need to pre-sprout the seed?
It is optional but recommended. Pre-sprouting for 1–2 days after soaking — until tiny root tails appear — speeds germination, evens out the crop, and reduces mold. You can sow straight after soaking, but expect slightly slower, less uniform results.
Can I grow wheatgrass without soil?
Yes, hydroponically on a tray or in a jar, but the soil method is more forgiving, yields a thicker mat, and produces a better second cutting. Beginners almost always have more success starting with the soil tray method.
How many times can I harvest one tray?
Usually twice. After the first cut, keep watering and the grass regrows in 5–7 days for a second, thinner harvest. A third cutting is rarely worthwhile because the shallow soil is exhausted — compost the root mat and start a fresh tray.