Sooner or later the emergency rations run out. Then survival depends on the greenhouse. Plants in Stationeers are demanding but predictable: every crop has fixed values for light, water, gas, temperature and pressure. Know them and your first bed will bear fruit.
What a plant needs
According to the game data most crops share the same base values. Deviations are listed further down for the individual crops.
| Need | Standard value |
|---|---|
| Light per day | at least 600 s |
| Darkness per day | at least 300 s |
| Water | 0.00006 mol per tick |
| Breathes in | 0.0012 mol Carbon Dioxide per tick |
| Breathes out | 0.0012 mol Oxygen per tick |
| Temperature ideal | 20 to 30 °C |
| Pressure ideal | 50 to 100 kPa |
A tick lasts 0.5 s, so an hour has 7,200 ticks. That turns every value into something tangible: 0.0012 mol per tick is 8.64 mol of carbon dioxide per hour, 0.00006 mol of water is 0.432 mol or just under 8 mL per hour.
Outside the ideal range a plant grows worse. The Greenhouse planner gives 0 to 50 °C and 25 to 200 kPa as the limits within which it survives.
Light and darkness
Plants need both: a minimum time of light and a minimum time of darkness per day. A day lasts 1,200 s on most worlds and about 1,297 s on the Moon (see Planet data sheet).
Artificial light comes from the Grow Light. The greenhouse planner counts it with a factor of 0.8. A worked example for a standard plant:
- Light: 600 s ÷ 0.8 = 750 s of lamp time
- Darkness: 300 s
- together 1,050 s – that fits into a 1,200 s day with 150 s to spare.
Sunlight through a window counts on top, with a different factor on each world. On Mars the planner uses about 0.43.
The exception is the Mushroom: it needs 0 s of light but 1,100 s of darkness, and takes damage after only 120 s of light. Mushrooms therefore belong in a dark room of their own.
Water
Trays and planters get their water from a liquid pipe line; the Hydroponics Tray is itself a pipe piece. Consumption is small:
- Ten standard plants drink 10 × 0.432 = 4.32 mol per hour.
- One litre of water holds about 55.6 mol. So it lasts almost 13 hours.
Small does not mean unimportant. Without water most plants take damage after 1,800 s. Rice drinks twice as much and lasts only 300 s without water.
Air: carbon dioxide in, oxygen out
Plants breathe the other way round from you. According to the game data (value Ratio 0.01) they count on a 1 % share of carbon dioxide in the air. The greenhouse planner assumes full uptake from 1 % and none below 0.1 %.
How fast the CO₂ in a closed room is used up is shown by a worked example with the gas equation n = p · V ÷ (R · T):
- Room of four cells: 4 × 8,000 L = 32,000 L, 101.3 kPa, 25 °C (298 K)
- Gas in the room: 101.325 · 32,000 ÷ (8.3144 · 298) ≈ 1,309 mol
- 1 % of it CO₂: about 13 mol
- ten plants use 86.4 mol per hour – the CO₂ is gone after about 9 minutes.
So a greenhouse needs supply: from a CO₂ tank through an Active Vent, from the crew's exhaled air, or from a mushroom room next door, because mushrooms breathe in oxygen and breathe out CO₂. A Gas Sensor with RatioCarbonDioxide tells you whether the share is enough.
The oxygen the plants release is a welcome side effect. Ten plants deliver 86.4 mol of O₂ per hour. The Soybean also breathes in nitrogen, and the Fern twice as much CO₂ as the others.
Harmful gases
Some gases do not agree with plants. According to the game data these partial pressure limits apply:
| Gas | harmful from |
|---|---|
| Pollutant, Methane (volatiles), Silanol | 1 kPa |
| Hydrochloric Acid, Hydrazine | 0.1 kPa |
After 300 s in bad air they take damage. To give a sense of scale: the outside air on Venus is 28.9 % hydrochloric acid; at about 239 kPa that is almost 69 kPa of partial pressure – 690 times what a plant can stand. Outside air has no business in a greenhouse there.
Damage and patience
Plants do not die at once; they have a grace period for every disturbance:
| Disturbance | Standard | Tomato, Fern |
|---|---|---|
| no water | 1,800 s | 1,200 s |
| too cold or too hot | 300 s | 120 s |
| pressure too low or too high | 600 s | 120 s |
| too little breathing gas | 3,600 s | 1,200 s |
| too little light or darkness | 3,600 s | 3,600 s |
A short power cut or an open airlock door is no disaster. A greenhouse that stays too cold for an hour is.
The crops at a glance
| Plant | ripe after | seeds from | harvest up to | nutrition raw → cooked | light / dark |
|---|---|---|---|---|---|
| Potato | 3,001 s | 4,001 s | 2 | 10 → 40 | 300 / 200 s |
| Wheat | 2,701 s | 3,601 s | 5 | 5 (for flour) | 600 / 300 s |
| Rice | 3,601 s | 4,801 s | 5 | 3 → 10 | 600 / 300 s |
| Soybean | 3,601 s | 4,801 s | 3 | 5 → 10 | 600 / 300 s |
| Mushroom | 3,601 s | 4,801 s | 3 | 10 → 40 | 0 / 1,100 s |
| Fern | 2,401 s | 3,201 s | 2 | – (chemistry) | 480 / 300 s |
| Corn | 7,201 s | 9,001 s | 3 | 10 → 30 | 500 / 200 s |
| Tomato | 11,701 s | 14,401 s | 3 | 15 → 25 | 480 / 300 s |
| Pumpkin | 14,401 s | 16,801 s | 3 | 50 → 80 | 500 / 100 s |
Tomato and pumpkin are perennial: after harvesting they regrow from stage 3. All others you plant again – with seeds or directly with a fruit.
Start with potato and wheat, which deliver after an hour. Plant tomatoes and pumpkins alongside so they are ripe when the stock runs low.
Next steps
- Building with pipes, lamps and chips: Hydroponics and planters: setup and automation
- Getting seeds and using leftovers: Compost, fertiliser and getting seeds
- How many plants your crew needs: Greenhouse planner
- All plants with their values: Plants
- Basics on pressure and gas amounts: Atmosphere and pressure