How to Grow Microgreens: Complete Beginner’s Guide

Growing microgreens is genuinely one of the easiest food projects you can do at home. I am not saying that as marketing copy. The actual process — once you know the steps — takes about 5-10 minutes of active work spread over 10 days. The rest is waiting.

But the information online is scattered and contradictory, especially on the questions that actually determine whether your first tray succeeds: exactly how many seeds per tray, how much water at each stage, when to uncover, when to harvest. I have been growing microgreens for 18 months and failed enough early trays to know exactly where beginners go wrong.

This guide covers everything from tray setup to plate. Start with radish — it is the most forgiving variety, grows in 6-8 days, and will teach you the process without wasting expensive seeds on mistakes.

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What You Need Before You Start

Equipment

1020 growing trays (two per variety: one with drainage holes, one solid bottom) — Check price on Amazon
Spray bottle (for misting during germination) — Check price on Amazon
Kitchen scale (for accurate seed density — this is the most important tool on this list) — Check price on Amazon
Kitchen scissors or sharp knife (for harvest) — Check price on Amazon
Grow light or sunny south-facing window (see the lighting section below)
Humidity dome (optional but helpful for maintaining moisture during blackout) — Check price on Amazon

Growing Medium (choose one)

Coco coir brick (my recommendation — $15 for enough to fill 20+ trays) — Check price on Amazon
Potting soil (Fox Farm or Happy Frog work well — $15-20 per bag)
Hemp growing mats (cleaner, lower yield — good for beginners who want minimal mess) — Check price on Amazon

Seeds (for your first grow)

Radish seeds, 1 lb (red arrow variety is the most reliable beginner variety) — Check price on Amazon

The Complete Process Step by Step

Step 1: Prepare Your Growing Medium

If using coco coir: Drop a compressed brick into a large bucket. Add 4 cups of water and wait 10 minutes. The brick will expand and absorb the water. Break up any remaining compressed chunks with your hands until you have a uniform, crumbly consistency. Properly hydrated coco coir should hold its shape when squeezed but not release water. If water drips out, let it dry slightly before filling your tray. If it falls apart without holding shape, add a small amount of additional water.

Fill your drainage-hole tray with coco coir to about 1 inch depth. Do not pack it down — loose and airy is better than compressed. Smooth the surface with your hand so you have an even planting bed.

If using potting soil: Scoop soil directly into the drainage tray to 1 inch depth. Lightly moisten the surface with your spray bottle — you want it damp through the top 1/2 inch, not soaking wet. Let it sit for 5 minutes before seeding.

If using hemp mats: Place one mat in the solid bottom tray (no drainage needed with mats — bottom water management instead). Add 1/4 inch of water to the tray and let the mat absorb it for 2 minutes. Drain any standing water. The mat should be uniformly damp, not sitting in water.

Step 2: Pre-Soak Your Seeds (Variety-Dependent)

Pre-soaking softens the seed coat and jump-starts germination. Not all microgreen seeds need it — small seeds like radish, broccoli, kale, and mustard germinate fine without soaking. Large seeds benefit significantly.

Pre-soak these seeds for 4-8 hours before planting:

Sunflower seeds (hulled or un-hulled): 4-8 hours in room-temperature water
Pea shoots: 8-12 hours in room-temperature water
Corn shoots: 8-12 hours in room-temperature water
Beet and chard: 4-6 hours

Skip pre-soaking for:

Radish (all varieties)
Broccoli
Kale
Mustard
Arugula
Cilantro
Basil
Amaranth

To pre-soak: place seeds in a bowl with 2-3x their volume in room-temperature water. Let sit for the specified time, then drain and rinse in a fine mesh strainer. Plant immediately after rinsing — do not let soaked seeds dry out.

Step 3: Seed Your Tray (Density Is Everything)

This is where most beginners fail. Too many seeds causes overcrowding, which leads to mold, weak stems, and low yield. Too few seeds wastes tray space and produces a sparse, patchy result. Use your kitchen scale.

Seeding density by variety (per 1020 standard tray, 10x20 inches):

Variety	Seed Weight per Tray	Notes
Radish (all varieties)	1.0-1.5 oz	Start at 1 oz; increase slightly if tray feels thin
Broccoli	0.5 oz	Small seeds, dense when spread — go light
Kale	0.5 oz	Similar to broccoli
Mustard	0.5 oz	Small seeds — easy to overseed
Arugula	0.5 oz	Tiny seeds; a light hand is critical
Sunflower (hulled)	2.0-2.5 oz	Large seeds need more weight for coverage
Sunflower (un-hulled)	3.0-4.0 oz	Hull takes up space; adjust by coverage not weight
Pea shoots	2.0-2.5 oz	Large seeds; spread in a single layer
Beet/chard	1.0-1.5 oz	Cluster seeds — separate by hand before spreading
Cilantro	1.0 oz	Pre-crush seeds lightly to separate the paired seeds
Wheatgrass	1.5-2.0 oz	Spread in a single layer

Spreading technique: Pour measured seeds into the tray and spread with your hand, using a pushing and rotating motion to distribute evenly across the entire surface. Every square inch of the tray should have seeds — no bare patches, but also no deep piles. For tiny seeds (broccoli, arugula), pinch and release over the surface rather than pouring.

After spreading, press seeds gently into the growing medium with a spare tray or a flat surface. This improves seed-to-medium contact for better germination. Not required with hemp mats, where light pressure from your hand is enough.

Step 4: Mist Thoroughly and Cover

After seeding, mist the entire tray surface with your spray bottle until seeds are visibly wet — not drenched, but uniformly moist. For coco coir or soil, this means the top layer is damp and seeds are slightly darker from moisture. For hemp mats, a thorough spray is enough since the mat already holds moisture from pre-wetting.

Cover the tray for the blackout period. Stack your second solid-bottom tray directly on top of the seeded tray, upside down. If you have a humidity dome, use it instead — it maintains moisture better and gives you a quick visual check through the lid.

The cover serves two purposes:

Darkness: Germinating seeds do not need light. Covering prevents light from reaching the seedlings for the first few days, which forces them to stretch upward looking for a light source — this produces taller, more harvestable stems.
Weight and moisture: The weight of the cover tray helps seeds stay in contact with the growing medium (especially important for large seeds like sunflower). The enclosed environment reduces moisture evaporation so you do not need to water during germination.

Place the covered tray in a warm location: 65-75°F is ideal. Room temperature in most homes is fine. Do not put trays in the refrigerator, in direct sunlight, or near a heating vent.

Step 5: The Blackout Period (Days 1-3 or 1-4)

Leave the tray covered and largely undisturbed for 3-4 days. Check once per day by lifting a corner of the cover:

Seeds should be germinating and sending up white or pale green shoots
Growing medium should still be damp but not waterlogged
No standing water in the tray

If the surface looks dry: Remove the cover, mist once, replace the cover. If you see pooled water: Pour off the excess drainage water from the solid bottom tray below. You want damp, not wet.

By day 3, most fast-germinating varieties (radish, mustard, broccoli) will be pushing the cover tray upward. This is normal and expected — the seedlings are reaching for light. When the seedlings are clearly pressing up against the cover, it is time to uncover regardless of the day count.

Signs the blackout period is working: Pale yellow-green shoots with slightly elongated stems. This is etiolation (light-deprivation stretch) and is exactly what you want. When you give these pale seedlings light, they green up rapidly within 24-48 hours.

Slow germinators: Sunflower, peas, beet, and chard may need 4-5 days of blackout. Do not rush it — undercooked sunflowers do not recover well once they hit light.

Step 6: Uncover and Give Light

Move the tray to your grow light or window and begin the light schedule: 16 hours on, 8 hours off. Use a plug-in outlet timer so you do not have to think about it — consistency matters more than precision.

The seedlings will be pale from the blackout. Within 12-24 hours of light exposure, chlorophyll production kicks in and the greens develop color. Radish turns from pale yellow to vibrant green in about 12-16 hours. Sunflower takes closer to 24-36 hours.

Light height: Position grow lights 6-10 inches above the canopy. Closer means more intense light, more compact growth, and faster greening. Too close (under 4 inches with a T5 strip) can cause light stress on delicate seedlings. Adjust based on how your greens look — compact, upright stems mean your light is at the right height. Floppy, stretching-toward-the-light stems mean you need to lower the light.

Step 7: Watering Method — Bottom Watering vs Top Misting

Bottom watering is the preferred method from day 4 onward. Pour water into the solid bottom tray below the drainage tray — the coco coir or soil wicks moisture upward through the drainage holes. This keeps the root zone moist while keeping the canopy dry, which dramatically reduces surface mold.

To bottom water: pour 1-2 cups of room-temperature water into the solid bottom tray. Let it absorb for 15 minutes, then tip out any remaining water that has not been absorbed. You want the growing medium damp, not sitting in water.

How often to water: Every 1-2 days, depending on your environment. In a dry environment (under 40% humidity), water daily. In humid conditions, every 2 days is enough. Check by pressing a finger into the growing medium — it should feel damp, not dusty or soaking.

When to top-mist: Use your spray bottle for the first 24-48 hours after uncovering if the top of the canopy looks dry. After that, bottom watering alone is sufficient. Top misting when the canopy is dense increases mold risk — wet leaves in a dense tray do not dry out easily.

pH of your water: Ideally 5.8-6.5 for microgreens. Most tap water in the US is in this range. If you notice yellowing despite adequate light and water, pH may be the issue — a pH meter ($15-20) and a bottle of pH down ($10) are worth having. Check price on Amazon

Step 8: Days 5-9 — Daily Check-In

During the light phase, check your trays once daily. The routine takes 2-3 minutes:

Bottom water if medium feels dry
Check for any mold (white fuzzy patches on the soil surface — different from white root hairs on the stems, which are normal)
Check that your light schedule is running

If you see mold: Do not throw the tray out immediately. Surface mold on the growing medium that has not spread to stems is common and manageable. Point a small fan at the tray and reduce watering frequency. The mold typically recedes as the canopy closes over the surface and the growing medium dries slightly.

If stems are falling over: Two causes — insufficient light or overseeding. Increase light intensity (lower the light 1-2 inches) or check that you did not seed too thickly. Fallen stems can be propped up slightly by misting the canopy — the surface tension of water on dense foliage helps greens stand upright temporarily.

Step 9: Harvest Timing — When to Cut

Harvest timing affects both yield and flavor. The two standard harvest stages:

Cotyledon stage (first seed leaves only): Days 6-10 for most varieties, before the first true leaf appears. This produces the most delicate, intense flavor — the cotyledons are packed with the seed’s stored nutrients and concentrated flavor compounds. This is the stage most commercial microgreens are harvested at.

First true leaf stage (one set of true leaves emerging): 2-4 days after cotyledon stage. Slightly more mature flavor, marginally higher yield by weight. Texture is slightly less delicate. The first true leaf looks different from the cotyledons — rougher, more lobed, variety-specific in shape.

Harvest timing by variety:

Radish: 6-8 days (cotyledon stage)
Mustard: 7-9 days
Broccoli: 8-10 days
Kale: 9-11 days
Sunflower: 9-12 days
Pea shoots: 12-16 days (harvest at 2-3 inches of growth, before tendrils coil)
Arugula: 8-10 days

How to harvest: Use sharp kitchen scissors or a sharp knife. Cut horizontally just above the growing medium — you want to cut above the root mat, below the seed hulls that may still be attached to the stems. A clean cut produces a better harvest than pulling or tearing.

Harvest the entire tray in one session. Microgreens do not regenerate after cutting (with the exception of pea shoots, which sometimes produce a second flush). Do not try to harvest half a tray and save the rest for later — once cut, the greens decline faster.

Step 10: Storage — Up to 10 Days Refrigerated

Do not wash microgreens before storing. Washing introduces moisture that dramatically accelerates spoilage. Store unwashed and wash right before eating.

Storage method:

Harvest dry greens directly into a container or zip-lock bag
Line the container with a dry paper towel (absorbs any condensation moisture)
Place harvested greens on top of the paper towel, loosely — do not compress
Cover with another dry paper towel, then close the container
Refrigerate at 34-40°F

Shelf life: 7-10 days for most varieties, stored properly. Sunflower microgreens are more delicate and peak at 5-7 days. Radish keeps well for 8-10 days. Pea shoots can last 10+ days if harvested dry and stored carefully.

Signs of decline: Yellowing, sliminess at the base of stems, off smell. Once any of these appear, the batch is past its peak — use immediately in cooked dishes or compost.

Yield expectations by variety (per 1020 tray):

Radish: 2.5-4 oz finished greens
Broccoli: 2-3 oz
Sunflower: 4-6 oz
Pea shoots: 3-5 oz
Kale: 2-3 oz
Mustard: 2-2.5 oz

Common Beginner Mistakes

Overwatering. The most common cause of mold and failed trays. Microgreens need consistent moisture, not constant saturation. If in doubt, water less and water from the bottom.

Skipping the kitchen scale. Eyeballing seed density produces patchy, inconsistent trays every time. Weigh your seeds. Radish at 1 oz per tray, sunflower at 2 oz, broccoli at 0.5 oz — measure it.

Too much light too soon. Uncovering before 72 hours and immediately blasting with full grow-light intensity can shock delicate pale seedlings. Uncover when they are pushing against the cover, not on a rigid schedule.

No air circulation. A still, humid environment above a dense tray is a mold incubation chamber. A small $15 USB desk fan pointed in the direction of your trays (not directly at them — indirect airflow is enough) prevents surface mold. The people on r/microgreens who report chronic mold problems consistently do not have air circulation. The people who report clean trays consistently do.

Harvesting too late. After the first true leaf appears, flavor often becomes more bitter (especially kale and arugula) and stem texture becomes tougher. Harvest at cotyledon stage for the best eating quality.

Your Complete Shopping List

Everything you need to grow your first 10 trays:

Bootstrap Farmer 1020 trays (5-pack with drainage trays) — Check price on Amazon
Coco coir brick (fills 20+ trays) — Check price on Amazon
Radish seeds, 1 lb (red arrow variety) — Check price on Amazon
Kitchen scale (essential for seed density) — Check price on Amazon
Spray bottle (for misting during germination) — Check price on Amazon
Barrina T5 grow lights (4-pack, 2 strips per tray) — Check price on Amazon
Outlet timer (for 16/8 light schedule) — Check price on Amazon
Small clip fan (air circulation, mold prevention) — Check price on Amazon
Kitchen scissors (for harvest) — Check price on Amazon
Humidity dome (optional, for blackout period moisture retention) — Check price on Amazon

Total setup cost: approximately $80-100, including seeds for 15+ trays. Cost per tray after setup: roughly $1-1.50.

Where to Learn More

r/microgreens — Post photos of your trays, troubleshoot mold, ask about timing. The community is active and genuinely helpful. Search before posting — most beginner questions have been answered in detail.
True Leaf Market blog — Variety-specific growing guides with exact timing and density recommendations. More detailed than most YouTube content.
Epic Gardening (YouTube + blog) — Comprehensive microgreen content covering seed selection, growing media, and troubleshooting common problems.
On The Grow (YouTube) — Step-by-step tray walkthroughs from germination through harvest. Good for visual learners who want to see the process in real time.
Bootstrap Farmer blog — Commercial-scale growing advice that scales down well. Their seed density charts and moisture management guides are reliable.

Last updated March 2026.