A standard hoop house built from bolt-together 3 m bays. A heavy ridge rail runs down the centre line; two arms ride it on carriages — each with a yaw joint, a telescoping Z mast, shoulder, elbow and a 3-axis wrist, so it can reach every corner of the bay. Each wrist carries an RGB-NIR camera and a low-power laser, and docks tools from racks in the core bay: soft gripper with pouch, weed extractor, irrigation wand, precision seeder and cradle pads. Fixed dome cameras on the hoops scan every bay. The AI turns detections into a prioritised task queue, assigns them to the arm whose half of the rail they fall in, verifies low-confidence targets with the wrist camera before acting, and calls both arms together for loads over the single-arm payload.
Growth from bare soil. The beds start empty. Once the system is online the arms transplant, sow and plant seed pieces; lettuce goes in one column every few days so heads come in steadily. You can watch seedlings emerge and grow, crops flower before they set fruit, and fruit size up and colour before harvest. Click any plant (or bare spot) to see its stage, development, next harvest, stress and yield so far. Click the battery, solar array, cistern, cold store, dehydrator, compost bins, tiny house, heater, fans, weather mast, AI cabinet, an arm or a bed's frame to see its status now and an hourly history chart (48 h, 30 days, a year or everything).
Site & weather. Pick a site in the System report — Nairobi, Miami, Phoenix, Little Rock, Seattle, Minneapolis or Anchorage. Weather follows that station's 1991–2020 normals with random warm and cold spells, wet and dry runs, rain or snow, wind and the odd storm; the sun follows the real latitude and calendar. Snow piles up on the ground, the arches and the solar panels; heavy roof snow is melted off or slides. Wind above 12 m/s closes the sides. Inside, the AI opens the roll-up sides, then runs exhaust fans; on hot afternoons it pulls air through wet pads and draws a shade cloth. The frost heater (heat pump or propane) only holds what the crops in the beds need — 3 °C above the frost-damage point of the most tender crop in the beds, at most 5 °C (4–5 °C for tomatoes, peppers, beans, pumpkins, basil and sweet potatoes, 0 °C for lettuce, −3 °C for kale alone), nothing when the house is empty. Temperature and daylight drive development: cool or dark days slow growth, heat stresses crops and makes tomato, pepper and pumpkin flowers drop.
Planting calendar. Before the run starts, the greenhouse model is run over a normal year at the chosen site and every crop is "grown on paper" from each possible planting day. Days where frost, cold, winter darkness or summer heat would not cut it far below its best form that crop's window (Crops tab). Crops that can't grow at a site are swapped for one that can, and a bed whose main crop is out of season grows a quick rotation crop in between.
Living off it. The farm is sized before day 1 to feed one person from year 2 on: every bed is grown through two normal years of the site's weather and the harvest is replayed through the store (roots are dried before they go soft, beans keep two years), plus a 10 % margin; a worse year is topped up with bought rice and beans, which is counted. The answer is a number of identical houses of up to 8 grow bays; house 1 is simulated plant by plant and houses 2+ repeat its plan. At the end of year 1 the owner compares the harvest with the plan and adds houses if it fell short. The only food bought in steady state is cooking oil (the crops lack fat) and supplements (B12, vitamin D, and calcium + zinc when the crops fall short); rice and beans bridge the first months while the store is empty. The owner lives in the tiny house beside the greenhouses (Person enters walks them over). Everything is metered: a PV array and LiFePO4 battery — sized against three synthetic years of the site's weather — supply the greenhouses, robots, nursery, storage and the house; roofs drain to a cistern; greywater goes back on the beds; spent plants, weeds, scraps and composting-toilet solids are composted and urine is used as fertilizer. The System report charts needs met, harvest, food in store, energy, battery and water over time, checks the sizing against the simulation, and lists every outside input with its cost and source. Simulate 1 year runs a whole year in a minute or two.
Fish, chickens and switches. A 5 m³ tilapia pool in a small pond house and a five-hen coop sit west of the greenhouses. Fish and eggs go into the diet, the pool water fertilizes the beds and the manure goes to the compost; their feed is bought. Every component in the Components panel — fish pool, chickens, dehydrator, recycling, rain catchment, solar + battery, solar-first scheduling, wind turbines, seed saving, waste to animals, surplus sales — can be switched on or off at any time (also from its card or the report). Each switch is logged and drawn as a dashed line on every history chart, so the effect on diet, purchases, fertilizer, water and energy shows over time; Apply & restart re-sizes the farm with the set that is on.
Money. The balance in the header starts at minus the farm's build cost (DIY parts; the tiny house is the household's home and isn't counted). Every simulated day adds the food sold and the food eaten from the farm at grocery prices, and takes off everything bought plus an upkeep reserve for film, shade cloth, pads, battery, inverter and robot parts. After a full year the report projects the break-even at the last 12 months' rate and charts money out against money in. Market houses (report → Grown for sale) are extra greenhouses planted with tomatoes, peppers, lettuce, kale and basil only for sale; they add build cost, energy, water, seed and fertilizer, and most of the income.
Closing the loop. Seed saving: when a crop's seed bank is short, a few lettuce, kale and basil plants are left to bolt and set seed (an arm brushes the kale and basil flowers, then cuts the dry stalks for the seed tray); seed comes from one ripe tomato truss, pepper and pumpkin a year, and the plumpest beans, small seed potatoes and a few sweet-potato roots are held back at harvest. Waste to animals: the arms sort what they clear — leafy residue, weeds and trimmings go to the hens and the fish pool, scraps and food past its date to a soldier-fly bin whose larvae replace part of the bought feed; manure, pool water and frass carry the nutrients back to the beds. Sell surplus: storage is limited, so food beyond what the plan says the house needs until the next harvests (plus six weeks, and never less than 120 days' worth), or that won't be eaten before it spoils, is bagged by the arms into crates for a weekly farm-stand pickup; the income is netted against the outside inputs.
Battery, scheduling and wind. In sunshine the panels run the farm directly; the battery is there for the dark hours and cloudy spells. With solar-first scheduling on, flexible loads wait for the sun: the dehydrator, nursery lights and water heater run by day, the cold store pre-cools by day and coasts at night, the fish pool is warmed to 28.5 °C by day and allowed to drift to ~24 °C overnight, the central computer sleeps after dark and the circulation fans cycle. That roughly halves what the battery must carry. Everything is sized for the lowest 20-year cost, not to be failsafe: for each share of the load a small backup generator may cover (0–15 %), the sizing finds the cheapest PV + battery over three synthetic years, adds the generator and its fuel, and keeps the cheapest. It also tries a water-tote heat store and 1–6 homebrew wind turbines and keeps them only if they lower the total. The cistern is chosen the same way: tank cost against 20 years of the water still bought. Wind pays only at windy, cloudy sites; you can force a number under Wind turbines in the report.
Export. Export ▾ (top bar) or the buttons in the System report download everything the simulation uses and produces: site climate, crop and animal parameters, nutrition per 100 g, diet targets, prices and sources, the crop table (time to harvest, yield and calories), sizing, monthly results and the full daily log, energy, water, nutrients, compost, costs and the robotics parts list. Print / save as PDF lays it out for paper (the daily log stays in the spreadsheet); Spreadsheet writes an .xlsx with one sheet per table.
Real growing times. Crops grow on the true calendar: lettuce is ready about 40 days after transplant, potatoes at about 100 days, tomatoes give their first truss at about 70 days and keep cropping for months. Every harvest is weighed. At 1× and 30× you watch the robots in real time; above that the sim runs as a time-lapse (up to a day per second, so every night is still shown) and robot work the arms can't show on screen is completed at the pace two arms could really manage. The Diet tab feeds one person from the stores every evening and tracks intake against their Dietary Reference Intakes; the Crops tab lists each crop's timing, yield and sources.
Crop timings, yields and nutrients come from extension-service trials and USDA FoodData Central (sources in the Crops tab); climate normals from NOAA; prices from current US retail listings (sources in the System report). Robot dimensions and payloads, and costs marked EST, are illustrative.