The Window Farm

The simplest possible indoor food-growing system. One plant per jar on a windowsill or suction-cup shelf, using passive Kratky hydroponics. No pumps, no electricity for water movement, no plumbing. Exists to prove to yourself that you can grow food indoors before committing to anything larger — what you learn here transfers directly to The Shelf Stack.

Footprint Window-mountedWindowsill or suction-cup shelves, 3–6 jars across a standard window Yield 3–8 plant sitesHerbs and small leafy greens Cycle 25–45 daysSeed to first harvest, herbs continuous after

Cost tier entryDifficulty weekendLand noneRisk lowMonthly savings ~$25First benefit ~21 days

① Choose your build

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

First JarENTRY$5–15

One mason jar, one plant, one window. The lowest possible barrier to entry. You probably already own half of this.

Container

Quart mason jar (32 oz) with standard lid~$2

Wide-mouth preferred. You probably have one. Must be wrapped in tape, foil, or a sock to block light — algae grows in clear glass.

if you prefer… (2)

Opaque 32 oz food container~$3No light-blocking step needed.

Recycled dark glass jar$0Already opaque. Free from kitchen.

Net pot + medium

2" net pot + hydroton clay pebbles (small bag)~$3

Drill or cut a hole in the mason jar lid to fit the net pot. Template provided in Sequence.

if you prefer… (2)

Yogurt or cottage-cheese cup with holes + rinsed gravel/perlite you already have$0Punch drainage holes. Functional for herbs at jar scale. Rinse medium between grows.

Rockwool cube in DIY foam collar (pool noodle)~$2No net pot needed.

Nutrients

MaxiGro dry nutrient (single-part)~$8 / 1 lb

One scoop per gallon. One pound lasts hundreds of jars. Simplest possible nutrient for beginners — one product, one measurement.

if you prefer… (2)

Dilute liquid houseplant food already on hand (¼ strength) — or plain water for the first cutting while roots form$0Cuttings live on stored energy for 7–14 days. Buy nutrients only after you decide to keep the system.

Masterblend 4-18-38 + calcium nitrate + Epsom salt~$303-part, cheaper per gallon, more to measure. Same nutrients used in the Shelf Stack — buy this if you plan to graduate.

Seeds or cuttings

Basil seeds (packet) or a fresh basil cutting from the grocery store~$2

Grocery store basil: cut a 4" stem below a node, strip lower leaves, place directly in net pot. Roots in 7–10 days. Fastest start.

if you prefer… (3)

Grocery-store herb cuttings (basil, mint, or similar)$0–few dollars for the bunchCut a 4″ stem below a node, strip lower leaves, set in the net pot. Roots in 7–10 days. Fastest low-cost start.

Any herb seed packet — cilantro, parsley, mint, chives~$3Same setup, slower start than cuttings.

Lettuce seed~$3Butterhead or leaf varieties, not head lettuce.

pH (optional at this scale)

None — tap water left out 24 hrs to off-gas chlorine$0

At mason jar scale with herbs, pH management is optional. Tap water works. If you see problems, get pH drops later.

if you prefer… (1)

pH test drops + pH Down~$8Worth it if your tap water is very hard (above pH 8.0).

Mounting

Existing windowsill$0

Place jar on the sill. Done.

Window GardenRECOMMENDED$25–45

4–6 jars on suction-cup acrylic shelves, with a clip-on grow light for non-south-facing windows. A real herb garden that produces daily.

Containers

4–6 quart mason jars, light-blocked (foil tape or fabric sleeves)~$8–12

Wide-mouth. Light-blocking is non-negotiable — exposed nutrient water grows algae within days.

if you prefer… (1)

4-pack Kiicii Kratky planter cups~$15Opaque, purpose-built, includes sponge medium.

Net pots + medium

2" net pots (6-pack) + hydroton (1 lb bag)~$6

One net pot per jar. Hydroton is reusable — rinse between grows.

if you prefer… (2)

Yogurt or cottage-cheese cup with holes + rinsed gravel/perlite you already have$0Punch drainage holes. Functional for herbs at jar scale. Rinse medium between grows.

Rockwool cubes (50-pack)~$5Disposable, easier for beginners.

Nutrients

MaxiGro dry nutrient (single-part), 1 lb~$8

One level teaspoon per quart jar. Dissolve fully before placing net pot.

if you prefer… (1)

Masterblend 3-part~$30Cheaper per gallon, same nutrients as the Shelf Stack. See Path A note.

Seeds / cuttings

3–4 herb seed packets or grocery store herb bunches for cuttings~$6–10

Recommended starter mix: basil, mint, cilantro, parsley. Each jar gets one variety.

if you prefer… (1)

Grocery-store herb cuttings (basil, mint, or similar)$0–few dollars for the bunchCut a 4″ stem below a node, strip lower leaves, set in the net pot. Roots in 7–10 days. Fastest low-cost start.

Mounting

Acrylic suction-cup window shelves (2-pack, 15" wide)~$12–18

Holds 2–3 jars per shelf. Weight limit ~7–10 lbs per shelf. Clean glass with alcohol before mounting for strongest hold. No drilling, no damage, renter-friendly.

if you prefer… (2)

Existing windowsill$0If wide enough for multiple jars.

Tension rod across window frame + S-hooks + hanging jars~$10DIY alternative.

Light (if needed)

10W clip-on LED grow light with timer (gooseneck, clamp-mount)~$12–18

Required if your window is north- or east-facing with less than 4 hrs direct sun. South-facing with 6+ hrs of direct sun = no supplemental light needed. Position 10–14" above the jars. Timer: 14–16 hrs on / 8–10 hrs off.

if you prefer… (2)

Any desk or clamp lamp with a daylight-spectrum bulb you already own (temporary)$0Confirms whether the window is enough before buying a grow light.

LED light strip adhesive-mounted to window frame~$10Covers more jars but less focused.

pH management

pH test drops + pH Down solution~$8

At 4+ jars, pH starts to matter. Test each jar at setup. Target 5.5–6.5. Most tap water is 7.0–8.0 — add a few drops of pH Down per jar.

if you prefer… (1)

Digital pH pen~$15Faster testing, needs calibration.

⑤ The Echo

The First Grow10 min

Most people never build the bigger rig because they need a win first. The Window Farm exists to prove to yourself that you can grow food indoors with almost nothing. The psychology of starting matters here: a single jar of basil on a windowsill changes your relationship with food production in a way that no amount of reading does. What you learn here transfers directly to The Shelf Stack — nutrient mixing, pH awareness, light requirements, and the Kratky air gap principle. Common first-timer mistakes to avoid: overcomplicating nutrients (one product, one teaspoon — that is enough), underestimating light needs (most failures are light failures, not nutrient or water failures), and refilling the jar too often (the air gap is supposed to form, let it). Grocery store herb cuttings are the fastest start — you skip the germination wait entirely and have a rooted plant in a week. This is the gateway rig. Treat it like one. Build it small, build it cheap, and let the win you get from it carry you into the next rig.

Light Is the Limiting Factor8 min

The honest conversation about windows and light. A south-facing window in summer is a different world from a north-facing window in winter — the difference can be six hours of direct sun versus almost none. Most windowsill herb failures are actually light failures, not nutrient or water problems. How to assess your window: the noon shadow test (stand at the sill at noon — is sunlight on the surface or just nearby?) and the phone light meter app (free, gives you a foot-candle reading). Below 1,000 fc and your herbs will be leggy and slow regardless of how good your nutrients are. When to add a clip-on grow light: any time the answer to 'does this window get 4+ hours of direct sun?' is no. A $12 LED clip light on a timer is the single highest-leverage addition to this rig — more impact than any nutrient upgrade. Light hours and intensity interact: 14 hours of weak supplemental light can outperform 6 hours of strong direct sun for herbs. This is why the timer matters as much as the light itself. Plants integrate light over the day; you are buying duration, not just intensity. Carry this lesson into every Grow rig you build after this one.

The Jar That Makes the Next Rig Possible6 min

Basil browning in a jam jar is a better teacher than another book about vertical farms. The Window Farm exists so the household can fail cheap and fast: wrong light, overwatered roots, a plant that never took. Cost is a few dollars. Stakes are low enough that you try again. When the first jar actually yields a handful of leaves for dinner, something larger unlocks. Permission. The Shelf Stack stops looking like a fantasy because the same Kratky logic already lived on the sill. You already know how roots smell when they are happy, how fast a jar can tip if the shelf is shallow, how a north window lies about winter light. Skip this rig and the bigger Grow builds absorb every beginner mistake at once. Run it and the mistakes stay small. The Sequence is short on purpose. The real output is confidence you can point at — one living plant, grown indoors, without a pump or a lecture.

⑥ Feeds

How this rig connects to the rest of the Ark.

→ information The Shelf Stack The Window Farm is the gateway rig for The Shelf Stack — Kratky method, nutrient mixing, pH management, and light assessment all transfer directly when a builder graduates from 6 jars on a window to a full vertical hydroponic rack
→ material The Worm Bank Spent nutrient water (diluted, at end of a Kratky cycle) is poured into worm bedding as moisture; root balls and dead plant material go into the worm bin as feedstock
← material The Sky Well Rainwater (or filtered water) from The Sky Well is the preferred jar fill source — naturally lower pH and chlorine-free compared to municipal tap water, reducing the need for pH Down at this scale
→ material The Living Pantry Fresh herbs harvested from the Window Farm integrate directly into daily cooking — the jar-to-kitchen pipeline is the shortest Feed in the entire Ark
→ information The Rack 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 Porch Garden Herb cuttings and seedlings can be started on the Window Farm and transplanted to Porch Garden beds when weather warms — the Window Farm becomes the seed-starting facility for the Porch Garden
← material The Porch Garden Reverse direction: porch-grown herbs can be brought indoors during deep winter for continued harvest in the Window Farm
→ material The Guild Ring Companion plants (herb seedlings, comfrey starts from root cuttings) propagated indoors and transplanted to the guild during establishment — the Window Farm becomes a seed-starting facility for the perennial Grow rigs
→ material The Walipini Seedling starts move from indoor windowsills to the Walipini in late winter (when outdoor seedling production is impossible). The Walipini becomes the propagation hub for the entire outdoor Grow domain in early spring.
← material The Seed Bank Saved seed stocks the Window Farm for next season without packet purchases.
→ material The Seed Bank Best Window Farm plants selected mid-season become Seed Bank candidates.

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.