The Rack Farm

Indoor microgreen and sprout production system on standard shelving. Produces harvestable food in 7–14 days — the fastest seed-to-harvest rig in the Grow domain. Introduces staggered planting (one tray planted, one harvested daily), the same mental model used in The Shelf Stack. High nutritional density per square foot — microgreens contain 4–40× the nutrient concentration of their mature counterparts.

Footprint 2ft × 4ft × 6ft4-tier wire shelving, 8 tray positions Yield 1–2 lbs per tray per cycleContinuous daily harvest of 2–4 oz when staggered Cycle 7–14 days2–3 day blackout, then under light

Cost tier starterDifficulty weekendLand noneRisk lowMonthly savings ~$60First benefit ~10 days

① Choose your build

Every build below is complete on its own. Pick the one that fits your space and budget.

First TrayENTRY$15–30

Two trays, a bag of seeds, and a window or a single light. Proves the concept in 10 days — you can eat what you grew before your next grocery run.

Trays

2-pack standard 10×20 nursery trays — one solid bottom, one with drain holes~$4

The solid tray is the water reservoir (bottom-watering). The drain-hole tray holds medium and seeds and nests inside the solid tray. You need at least two sets to stagger: one growing, one freshly planted.

if you prefer… (1)

Repurposed baking sheet + aluminum roasting pan$0Roughly same dimensions, free if you have them.

Growing medium

Coco coir brick (compressed, expands to fill 3 trays)~$5

Rehydrate in warm water. Spread ½–1" thick in the tray. Best balance of moisture retention, aeration, and cost. Naturally sterile — resists mold better than soil.

if you prefer… (2)

Hemp grow mat (pre-cut 10×20)~$2 / matZero mess, no rehydration. Slightly lower yield but much cleaner.

Thin layer of potting soil (~1" deep)~$3Works fine but messiest option.

Seeds

Radish microgreen seeds, 4 oz bag~$6

Best first-time species: germinates in 24–36 hrs, harvest in 7–10 days, 1–2 lbs per tray, hard to kill. Spicy. Needs ~30–35g per 10×20 tray; 4 oz bag = 3–4 trays.

if you prefer… (2)

Sunflower seeds, 8 oz bag~$6Larger, nuttier, more substantial. Pre-soak 6–12 hrs. 10–14 day cycle.

Pea shoots, 8 oz bag~$6Sweet, crunchy, kid-friendly. Pre-soak 6–12 hrs. 10–14 days.

Light

Sunny window (south-facing, 4+ hrs direct sun)$0

Works for personal use. Greens may lean toward the light — rotate tray daily.

if you prefer… (1)

4ft LED shop light, 5000–6500K, 40W~$15Hang 6–12" above tray. Timer 12–16 hrs. Eliminates window dependency.

Watering

Spray bottle (misting) for top-watering~$2

Mist seeds 1–2× daily during germination. After germination, switch to bottom-watering: pour water into the solid bottom tray and let the root mat wick it up.

if you prefer… (1)

Small watering can with narrow spout~$5Easier for bottom-watering once roots are established.

Cover

Second tray (inverted) or damp towel~$0–2

During the 2–3 day blackout phase, cover the planted tray to block light and hold humidity. An inverted 10×20 tray is ideal. Remove cover when sprouts are 1–2" tall.

Daily HarvestRECOMMENDED$60–100

8–10 tray positions on a wire shelving rack with LED shop lights. Plant one tray per day, harvest one per day. Continuous daily supply of fresh microgreens for a household.

Structure

4-tier wire shelving unit (48"×18"×72")~$45

Same shelving as the Shelf Stack — if you build both, you're buying one type of rack for your whole Grow domain. NSF-rated, adjustable shelf height. Each shelf fits two 10×20 trays side by side.

if you prefer… (2)

2-tier bakers rack~$30Smaller footprint, fewer tray positions.

DIY 2×4 lumber frame~$20Plans provided. Cheapest option.

Trays

10-pack 10×20 trays — mix of solid bottom and drain-hole (5 of each)~$15

Each growing station needs one of each (nested). 5 stations = 5 trays in various stages at any time. Buy extra — you'll break a few and want to expand.

if you prefer… (1)

Bootstrap Farmer heavy-duty 1020 trays~$3 / trayThicker plastic, lasts years. Worth the upgrade if you're committed.

Growing medium

Coco coir bricks, 5-pack (expands to fill 15+ trays)~$12

One brick per 3 trays. A 5-pack lasts months.

if you prefer… (1)

Hemp grow mats, 10-pack pre-cut to 10×20~$18Cleaner, faster setup, slightly lower yield.

Lights

4ft LED shop lights, 5000–6500K, 40W (×2)~$20

One light per two-tray shelf. Mount under the shelf above. Timer 12–16 hrs on / 8–12 hrs off. Same lights used in the Shelf Stack.

if you prefer… (1)

LED grow light strip, adhesive mount~$15Lower profile, easier to mount in tight spaces.

Light timer

Mechanical 24hr outlet timer~$5

Plug lights into timer. Set once. Never think about it again.

if you prefer… (1)

Smart plug with schedule~$8WiFi optional — built-in timer works without internet.

Seeds

Starter variety pack: radish (8 oz) + sunflower (8 oz) + pea shoots (8 oz) + broccoli (4 oz)~$20–25

The 'big four' for beginners. Radish for speed, sunflower for substance, peas for sweetness, broccoli for nutrition. Buy from a bulk microgreen seed supplier — garden packet seeds work but cost 5–10× more per ounce.

if you prefer… (1)

Single-species bulk bag~$15 / lb1 lb of radish seed = ~12 trays. Buy in bulk once you settle on favorites.

Watering

Spray bottle + small watering can~$5

Spray bottle for misting during blackout. Watering can for bottom-watering after germination. Pour into solid bottom tray, let root mat wick it up. Never water from the top once roots are established — mold risk.

Labels / markers

Masking tape + marker~$2

Label each tray: species + planting date. When you have 8 trays in rotation, you will lose track without labels. Single most important non-obvious step for staggered production.

Hydrogen peroxide (3%)

Standard drugstore bottle~$2

Light misting on seeds at planting prevents mold — the most common microgreen failure. One spray per tray at sowing. Optional but strongly recommended, especially for sunflower and wheatgrass which are mold-prone.

Sprouting Add-OnADD-ON$5–12

Mason jar sprouting for grains and beans — wheatgrass, mung beans, lentils, alfalfa. Different from tray microgreens: sprouts grow in the jar, no soil or medium needed, harvested in 3–5 days. Uses different counter space than the rack.

Container

Quart mason jar + stainless mesh sprouting lid~$5

Soak seeds in jar overnight. Drain through mesh lid. Rinse and drain 2× daily. Sprouts in 3–5 days. Invert jar at an angle in a bowl to drain between rinses.

if you prefer… (1)

Multi-tier sprouting tray~$12Grows 3 varieties simultaneously. More organized, takes up more counter space.

Seeds

Mung bean, lentil, or alfalfa sprouting seeds (1 lb bag)~$5–8

Use seeds labeled 'for sprouting' — these are tested for pathogen safety. Do not use garden seeds or microgreen seeds for jar sprouting; different treatment standards.

③ The Sequence

01Prep medium10 min Coco coir: break off a section of the compressed brick, place in a bowl, add warm water, let expand for 10 minutes, fluff with fingers. Hemp mat: lay the pre-cut mat in the drain-hole tray, no prep needed. Soil: spread a 1" layer of moistened potting soil in the tray.
02Pre-soak seeds (if needed)5 min + wait Radish and broccoli: no soak needed. Sunflower: soak in room-temperature water for 6–12 hrs, drain. Pea shoots: soak 6–12 hrs, drain. Soaking softens the seed coat and speeds germination.
03Sow seeds5 min Spread seeds evenly across the surface of the medium. Dense but not piled — one layer deep, seeds touching but not stacked. Per 10×20 tray: radish ~30g, sunflower ~140–250g, peas ~250–280g, broccoli ~13g. Mist with spray bottle until moist. Optional: one spray of 3% hydrogen peroxide to prevent mold.
04Blackout phase2–4 days Cover the tray with an inverted tray, a damp towel, or a piece of cardboard. Place in a warm spot (65–75°F). Check once daily — mist if the surface looks dry. Do not uncover for light. This phase lasts 2–4 days depending on species. Roots will push into the medium and sprouts will be 1–2" tall, pale yellow/white.
05Uncover and light1 min When sprouts are 1–2" tall, remove the cover. Place under the LED shop light (6–12" above the tray) or in the sunny window. Within 24–48 hrs, the pale sprouts will green up dramatically — chlorophyll production kicking in. Start bottom-watering: pour water into the solid bottom tray so the root mat wicks it up. Stop misting from above — wet leaves invite mold.
06Grow outdaily check Maintain light cycle (12–16 hrs on, 8–12 hrs off). Bottom-water daily — check that the solid tray has ¼–½" of water. The root mat will drink it. Do not let it sit in standing water for more than 30 minutes — drain excess. Watch for mold (white fuzzy patches, distinct from white root hairs which are normal). If mold appears, increase airflow (small fan nearby) and reduce moisture.
07Harvest5 min When the first set of true leaves appears (the second pair, after the initial seed leaves), the microgreens are ready. Typically day 7–14 depending on species. Using sharp scissors or a clean knife, cut the greens just above the medium line. Harvest the entire tray at once — microgreens don't regrow like herbs. Rinse gently, pat dry, eat or store sealed in the fridge (5–7 days).
08Reset tray10 min Remove the spent root mat and medium. If using coco coir: the root mat + coir goes straight to the Worm Bank as feedstock (this is a Feed to Loop). Rinse the trays with water and a splash of white vinegar or hydrogen peroxide. Air dry. Refill with fresh medium and replant. The cycle restarts.
09Stagger for daily harvestongoing To produce microgreens every day, plant one new tray daily (or every other day for a smaller household). With a 10-day average cycle, you'll have 10 trays in various stages at any time — some in blackout, some greening up, some ready to cut. Label each tray with species and plant date. Harvest the oldest tray each morning. Same staggered production concept used in The Shelf Stack — learn it here, apply it there.

④ Reference Tables

Yield Reference

Per-species at-a-glance — seed rate, soak, blackout, harvest

Species	Seed per 10×20 tray	Pre-soak	Blackout days	Total days	Yield per tray	Flavor	Difficulty
Radish	30–35g	No	2–3	7–10	1–2 lbs	Spicy, peppery	Easy — best first crop
Sunflower	140–250g	Yes, 6–12 hrs	2–3	10–14	1–2 lbs	Nutty, crunchy	Easy, watch for mold
Pea shoots	250–280g	Yes, 6–12 hrs	2–3	10–14	1–2 lbs	Sweet, tender	Easy
Broccoli	13g	No	2–3	10–12	~11 oz	Mild, fresh	Easy
Wheatgrass	450g	Yes, 4–8 hrs	2	8–10	1–2 lbs (juice only)	Earthy, sweet	Moderate — mold prone
Basil	10–15g	No	3–5	16–24	6–8 oz	Herbal, aromatic	Moderate — slow germination

⑤ The Echo

Ten Days to Food12 min

The Rack Farm is the fastest proof-of-concept in the entire Grow domain. You plant seeds today and eat food you grew in your own home in ten days — faster than a grocery delivery subscription, and infinitely more resilient. The psychology of seeing food grow from nothing on your kitchen rack changes how you think about food in a way that no Costco haul does. Why microgreens specifically: 4–40× the nutrient density of mature plants. A single tray of broccoli microgreens contains more sulforaphane than a full head of mature broccoli. The 'big four' species earn their spots for distinct reasons: radish for speed and ease (the best first crop), sunflower for substance and flavor, pea shoots for sweetness and kid appeal, broccoli for nutritional density. Together they cover speed, substance, flavor, and nutrition. A single 10×20 tray costing about $2 in seed and medium produces $15–20 worth of microgreens at grocery store prices. This is the rig that pays for itself the fastest, and the one that builds the most belief in the rest of the Grow domain. Ten days is the gap between deciding to grow food and eating food you grew.

The Stagger10 min

Staggered planting is the single most important production idea you will carry from the Rack Farm to every other Grow rig. Instead of planting everything at once and harvesting one overwhelming batch, you plant a little every day and harvest a little every day. Continuous flow, not boom-and-bust. How to calculate your stagger: if a species takes 10 days and you want to harvest daily, you need 10 trays in rotation. If you only want to harvest every other day, you need 5. Scale up or down based on household size. Three things make the system work in practice: (1) labeling every tray with species and plant date — without labels you will lose track within a week, (2) harvesting the oldest tray each morning so the rotation enforces itself, and (3) replanting the empty tray immediately so the queue never breaks. This same logic applies to The Shelf Stack (lettuce plantings staggered across shelves) and to The Living Pantry (FIFO rotation of stored food). One concept, used everywhere. Learning it on a 10-day cycle with cheap seed is the right place to learn it — the cost of a missed stagger is a few ounces of greens, not a season's worth of food.

Mold Is the Only Enemy8 min

The single most common microgreen failure is mold, and it is almost always a moisture management problem, not a contamination problem. Learn to tell white root hairs (normal, healthy, fuzzy at the base of sprouts where they meet the medium) from actual mold (fuzzy patches on the surface or up the stems, often with a musty smell). Confusing the two leads to throwing away healthy trays. Three causes, three fixes: (1) too much moisture on the leaf surface — stop misting from above after germination, switch to bottom-watering exclusively. (2) Poor airflow — small fan on low, or simply space trays apart so air can move between them. (3) Contaminated medium — use naturally sterile coco coir, or mist seeds with 3% hydrogen peroxide at sowing. Sunflower and wheatgrass are the most mold-prone species; if you're losing trays of those specifically, the H2O2-at-sowing step is non-optional. Panic-spraying everything with fungicide is the wrong response — hydrogen peroxide at planting plus proper moisture management solves 95% of mold issues without any chemistry beyond what's already in your medicine cabinet.

⑥ Feeds

How this rig connects to the rest of the Ark.

→ material The Market Stand Microgreens and specialty crops → direct sales
→ material The Batch Line Surplus herbs → craft production (tinctures, etc.)
→ material The Living Pantry Daily microgreens and sprouts feed directly into tier-one fresh pantry rotation
← information The Window Farm For builders who want faster, higher-density results than the Window Farm but are not ready for The Shelf Stack, microgreens on The Rack Farm are the next step — parallel path, not a replacement
→ material The Worm Bank Spent root mats and growing medium go directly into the worm bin as carbon-rich feedstock — every 7–14 days, every tray produces a root mat ready for composting; one of the most reliable Feeds in the entire Ark
← material The Sky Well Water source for misting and bottom-watering — microgreens use very little water, just a few cups per tray per day; rainwater or filtered preferred
← information The Vault Seed-variety reference, planting-schedule templates, and yield-tracking logs stored offline — as the stagger system grows, a printed reference card showing species, soak times, seed density, and expected harvest dates becomes essential
→ information The Shelf Stack Graduation path — same shelving, same lights, same stagger concept; everything learned about light, timing, and rotation here transfers directly when scaling up to full-size leafy greens
← information The Shelf Stack Parallel and complementary — Rack Farm produces microgreens daily, Shelf Stack produces full-size greens weekly; both share shelving, lights, and growing-medium suppliers, so build them together

⑧ Go Deeper

ManyArks endorses no single source — these are starting points that fit the Ark philosophy. In a Vault bundle, these external links require the clearnet.