The farm that grew slower the day you fixed it
You built the sprinkler. You hooked the pump to the river, wired a solar panel, put the sprinkler over the planter and turned it on.
And your hemp got slower.
That is not bad luck, and it is not a bug. Soil saturation in Rust peaks for plant happiness at around 75%, not 100%. A sprinkler running flat out over one large planter pushes saturation past 90% — and an over-watered plant is stressed in exactly the way a real one rots in pooled water.
The conditions display still reads “good” at 100%, which is why almost nobody notices.
The four conditions, and the one that governs everything
Every plant shows four conditions. The lowest one decides how fast it grows.
| Condition | How to keep it high |
|---|---|
| Light | Open sky outside. Indoors: ceiling lights at 2 rW each, on solar panels or batteries |
| Water | Keep the planter topped up — but not drowned. Salt water hurts |
| Temperature | Mild biomes are easiest. In snow or on cold desert nights, an electric heater or a fire nearby |
| Ground | Starts reasonable in a planter and drops as plants feed. Fertilizer pushes it back up |
The consequence is the thing most farms get wrong: a planter with perfect water still crawls if the room is dark. Whichever of the four is worst sets the speed for all of them, so a perfect irrigation rig inside an unlit box buys you nothing.
Getting the water
Manual — the wipe-day method
Fill a water jug or bucket at a lake and pour it straight into the planter.
Fine for two or three boxes. It gets old immediately at scale, and it means a daily chore you cannot skip.
The automated chain
Water Pump / Water Catcher → Water Barrel → Sprinkler → Planters
Solar Panel → Battery → Sprinkler (power)| Component | Detail |
|---|---|
| Sprinkler | 75 metal fragments at Workbench Level 1. Needs power and a water feed |
| Water Pump | 5 rW, must sit in a river, lake or ocean |
| Water Catcher | Small holds 10,000 ml, large holds 50,000 ml |
| Ceiling Light | 2 rW each |
| Water Purifier | Required if your source is sea water |
Throughput — pick a source that keeps up
| Source | Rate |
|---|---|
| Small Water Catcher | ~3 L/min in moderate rain, ~0 in dry weather |
| Large Water Catcher | ~6 L/min in moderate rain, ~12 in heavy rain |
| Water Pump (powered) | ~30 L/min, needs power and water nearby |
Rain-dependent catchers are a reserve, not a supply. If your only source is catchers and the wipe rolls into a dry stretch, saturation craters.
Hitting 75% instead of 100%
| Setup | Result |
|---|---|
| One sprinkler per large planter at full input | Too much — pushes past 90% |
| One sprinkler centred between two planters | The sweet spot for most setups |
| Sprinkler with an Electrical Branch upstream, set to low passthrough | Throttled input, works well |
| Smart Switch + timer cycling sprinklers on and off | Averages ~75% across the cycle, no hand-tuning |
If you do not want to tune by hand, the timer approach is the one that holds through the night.
How many planters per sprinkler
Groups of three or six. Not more. Put a sprinkler over more boxes than that and none of them stay topped off.
The official Facepunch Farming Basics page warns that a three-group sprinkler can fail to keep its own plants topped off if it also has line of sight to neighbouring planters — so the goal is controlled overlap, not maximum coverage.
A ~3 m spray radius is a rough placement heuristic only. Walls, planter spacing, height and what else the sprinkler can see all change it. Measure the actual build in game.
Sprinklers mount on a wall, floor or ceiling — mount it so the spray lands on soil, not on the back of a wall.
The W gene doubles the problem
Every seed carries six genes. Three are good, two are bad:
| Gene | Effect | Want it? |
|---|---|---|
| G | Growth rate | Yes |
| Y | Yield | Yes |
| H | Hardiness in poor conditions | Situational |
| W | Water intake — drinks more | No |
| X | Empty filler | No |
A clone with two W genes drinks roughly 50% more water than one with zero. That pulls saturation down faster for it and for everything sharing its planter.
If you are stuck with a W-heavy clone, either give that planter its own water line at low throttle, or accept that the box will run drier than the rest.
The target strain is GGGYYY.
The rest of the farm, briefly
- Fertilizer comes from a Composter (crops, clippings, food scraps, horse dung). It raises soil quality toward 100%. About 1 fertilizer per plant per cycle.
- Fertilizer goes in the planter, not on the plant.
- Eight stages: seed, seedling, sapling, crossbreed, mature, fruiting, ripe, dying.
- Clone at crossbreed or mature — clones copy the parent’s genes exactly. Harvest everything else at ripe.
- With good G genes and proper irrigation, hemp ripens in roughly 40-60 minutes.
- Spare or spoiled crops go into the Composter, and excess produce sells for scrap at the Bandit Camp produce exchange.
Six mistakes
- Maxing the sprinkler. The single biggest one. More is not better past 75%.
- Ignoring rain cycles. Catcher-only farms die in a dry stretch.
- Mixing W-heavy and W-free clones in one planter. Their needs differ and the average suits neither.
- Stacking too many planters on one pump. Eight on one line is fine; sixteen starves.
- Building indoors without lights. You would be better off outside — the worst of the four conditions governs growth.
- Using sea water raw. Run it through a powered purifier first.
Related guides
- Rust Farming Guide — crops, planters and the full genetics system
- Rust Electricity Guide — powering pumps, lights and sprinklers
- Rust Base Building Guide — where the grow room goes
- How to Get Low Grade Fuel Fast in Rust — hemp’s real purpose
- Rust Crafting Guide — what the harvest becomes
- How to Get Scrap Fast in Rust — selling spare produce
- Rust Tips and Tricks — the small things