Most standard container farms are transformed from 40-foot containers, with external dimensions of approximately 12.2m (L) × 2.44m (W) × 2.9m (H), resembling an enlarged steel box. The key lies in its interior: the shell is refitted with polyurethane double-sided color steel insulation panels, acting as a thermal jacket to maintain the internal temperature between 15–30℃, regardless of extreme external conditions (–20℃ in winter or 40℃ in summer). Tempered glass observation windows on the container sides facilitate monitoring plant growth and allow natural light entry on sunny days, saving energy.
Upon opening the door, the interior resembles a three-dimensional vegetable garden:
A central passage of 0.9–1m width is reserved for easy access to picking and maintenance;
Multi-layer planting racks line both sides, typically designed with 4 tiers, each about 60cm in height. For instance, Auma Agriculture's planting rack measures 1.3m×0.65m×2.4m, with a 4-tier structure capable of cultivating hundreds of plants. A single container can accommodate 14 such racks, totaling approximately 2,000 vegetable plants—equivalent to the planting area of 2 mu (0.13 hectares) of land, but occupying only 1/20th of the space of traditional farmland.
The tidal shallow flow water bed is most common, resembling a large tray with a shallow layer of nutrient solution at the bottom. After sowing, seedlings are placed in perforated trays that float on the water surface, with roots directly absorbing nutrients. A water pump circulates the nutrient solution periodically to ensure uniform distribution. For example, spinach and pak choi can yield 2.5–4.5kg per square meter, harvested every 25–28 days—twice as fast as open-field cultivation.
Coconut coir, rock wool, or other substrates replace soil for growing strawberries and melons. These substrates retain water and nutrients like sponges, providing a base for root systems. For instance, strawberry planting troughs filled with substrates can accommodate 50–100 plants per square meter, with each plant yielding 100–120 fruits annually (25–30g per fruit). A single container can produce approximately 4,600kg of strawberries per year—equivalent to the output of 10 mu of open-field strawberry farms.
For fodder cultivation, perforated trays are used with roots suspended. Top sprinklers spray nutrient solution 4–5 times daily, resembling rainfall to wet the roots. This method enables extremely rapid growth: harvested every 7–10 days at 15kg per square meter, a container can yield 150–215kg daily. Within 6 days, the yield can reach 7.5–8.5 times the weight of the seeds—ideal for feeding cattle and sheep.
The nutrient solution tank functions as a large stockpot, containing water and fertilizers like nitrogen, phosphorus, and potassium. It is equipped with EC sensors (for concentration), PH sensors (for acidity/alkalinity), and liquid temperature sensors. For example, when growing lettuce, the EC value should be maintained at 1.2–1.8ms/cm, PH at 5.5–6.5, and temperature at 20–25℃. When sensors detect low concentration, solenoid valves automatically release fertilizers from storage tanks; if acidity/alkalinity is off, regulators are added—no manual supervision required.
Air conditioners cool in summer, and heat pumps warm in winter, stabilizing temperatures between 15–30℃. Different plants have specific preferences: leafy vegetables thrive at 26℃, while strawberries prefer around 21℃. In Auma Agriculture's containers, air conditioners and heat pumps work in tandem to maintain 20℃ even when external temperatures drop to –10℃, preventing plants from "catching a cold".
Plants require 60%–80% humidity—too dry causes wilting, too wet fosters mold. Industrial humidifiers function like large sprayers, automatically releasing water mist when humidity sensors detect levels below 60%. For example, maintaining 80% humidity while growing fodder ensures lush, tender growth.
Plants need CO₂ for photosynthesis, similar to humans needing oxygen. CO₂ cylinders in the container are connected to pipes via solenoid valves. When CO₂ sensors detect concentrations below 400ppm (normal air level), the system automatically releases CO₂ to maintain 800–1000ppm, boosting photosynthesis efficiency by 30% and accelerating growth.
Container farms primarily use LED plant growth lights, such as Auma Agriculture's 25W LEDs, which are 70% more energy-efficient than traditional bulbs and generate less heat to avoid damaging plants. Their spectra can be adjusted:
660nm red light: Promotes photosynthesis, strengthening leafy vegetables;
430–440nm blue light: Prevents excessive elongation, sweetening strawberry fruits;
510nm green light: Strong penetrability, reaching lower leaves.
Lights are connected to controllers with timers. For example, lettuce is set to receive 12 hours of light daily (6:00–18:00), turning on and off automatically. Closer proximity to lights increases illumination—20–30cm is ideal. For instance, installing lights 25cm above strawberry planting troughs achieves 3000–5000lux, similar to spring sunlight.
Temperature sensor: Measures –40℃ to 120℃ with ±0.5℃ accuracy, alarming when internal temperatures exceed 30℃ in summer;
Humidity sensor: Detects 0–99% humidity with ±3% accuracy, alerting when conditions are too dry or wet;
CO₂ sensor: Operates within 400–2000ppm with 1ppm resolution, signaling the need for CO₂ supplementation when levels are low.
For substrate-cultivated crops, sensors are inserted into the soil:
Humidity sensor: 0–100% soil moisture, ±2% accuracy within 0–50%;
Electrical conductivity sensor: Measures soil fertilizer concentration, ±3% accuracy within 0–10000us/cm;
PH sensor: 0–9 pH range with 0.1 resolution—strawberries, for example, prefer slightly acidic conditions (pH 5.5–6.0).
Data from all sensors are transmitted to a mobile APP via WiFi. Auma Agriculture's system, for instance, provides real-time monitoring of:
1# air temperature: 25.3℃, humidity: 44.3%;
2# soil electrical conductivity: 105uS/cm, CO₂ concentration: 327ppm.
Devices can be controlled remotely via smartphone: dim or brighten lights, activate humidifiers at low humidity. Historical data charts also help analyze temperature fluctuations and optimize growth conditions.
The utility room houses a 200L liquid tank, similar to a large water bucket, storing prepared nutrient solutions. It is equipped with a UV sterilization lamp to kill waterborne bacteria and prevent root rot. A chiller beside the tank cools nutrient solutions in summer, maintaining 20–25℃ to avoid root "heatstroke".
Resembling an intelligent spice box, the fertilizer blender has separate compartments for different fertilizers. When the EC value in the nutrient solution tank is low, it automatically adds nitrogen, phosphorus, and potassium in proportion—more precise than manual mixing and labor-saving.
The enclosed, humid environment of containers is prone to mold. The ozone generator, like a small fan, operates daily to produce ozone that kills airborne bacteria and mold. For example, using it 2–3 times weekly while growing fodder reduces pests and diseases without pesticides.
The distribution box contains switches controlling all equipment, with a total power of about 14kW (equivalent to four air conditioners running simultaneously). For leafy vegetable cultivation, approximately 150kWh is consumed daily, with 22.78kWh per kg of vegetables—lower costs than open-field farming due to high yields.
Nutrient solutions in hydroponic systems are not discarded but recycled after filtration. Growing 1kg of vegetables uses only 45L of water (equivalent to two barrel water containers), 80% less than open-field cultivation. A container producing 1,890kg of vegetables annually consumes only 8.6 tons of water—sufficient for a person's three-month usage.
LED lights are 60% more energy-efficient than traditional HID lamps, and timers prevent waste. For strawberry cultivation, daily power consumption is about 120kWh, with 10kWh per kg of strawberries. While open-field farming avoids lighting costs, irrigation and fertilization still consume electricity—container farming proves more cost-effective due to higher yields.
The enclosed container prevents insect entry, and ozone disinfection reduces pests and diseases. For leafy vegetables, no pesticides are needed—simply rinse before eating, safer than field-grown produce. Occasional aphids can be manually removed, eliminating chemical use.
Spinach, pak choi, and other leafy vegetables are ideal for hydroponics, harvested every 25–28 days. A container can plant 2,000 seedlings, yielding 7.5kg daily. Each rack layer is equipped with 3×25W LED lights, illuminated for 12 hours daily at 26℃, 80% humidity, and 1.5ms/cm EC—resulting in tender, green leaves.
Strawberries use substrate cultivation in planting troughs, with 2×28W special lights per trough, illuminated for 14 hours daily. Maintain 21℃, 60% humidity, and 800ppm CO₂. Flowers and fruits appear within 45–60 days; although perennial, yields decrease by 30%–40% in the second year. A container produces 4,600kg annually—five times the output of 1 mu (0.067 hectares) of open-field strawberries.
Fodder uses aeroponics, harvested every 7–10 days with 150–215kg daily yield per container. Requiring 3000–3500lux waterproof lights and 4–5 daily nutrient sprays at 25℃ and 80% humidity. Within 6 days, seeds grow into fodder, yielding 7.5–8.5 times their weight—perfect for feeding poultry and livestock.
A container farm, though a simple steel box, embodies the wisdom of modern agriculture: simulating ideal climates with insulated shells, replacing sunlight with LED lights, using sensors and apps as "farmers", and recycling resources to save costs. It liberates farming from dependency on weather, enabling fresh vegetable cultivation in cities, deserts, or even the Arctic—like trapping spring permanently in a box. Perhaps in the future, container farms will dot neighborhoods and office districts, allowing people to pick freshly harvested spinach with nutrient solution droplets on the way home—this is the tangible, magical transformation technology brings to agriculture.
