Short answer: Convert an NFT lettuce target into greenhouse area by defining usable channel length, holes per channel, hole spacing, aisle and service area, nursery capacity, crop cycle and simultaneous plant stages. Plant positions are a layout result, not a fixed number per square meter.
A plant position is one growing hole. Annual harvest volume also depends on crop cycle, nursery time, variety, climate, losses, cleaning and market scheduling. Ask suppliers to state whether their capacity number describes main NFT channels only, nursery seedlings, total holes or saleable heads. Do not compare offers until the same definition is used.
| Input | Why it changes capacity |
|---|---|
| Channel length | Determines holes per channel after end clearance and fittings. |
| Plant spacing | Variety and target head size affect the distance between holes. |
| Channel spacing | Influences light, airflow, crop access and the number of rows. |
| Aisles and service zones | Workers need safe access for planting, inspection, cleaning and harvest. |
| Nursery and utility area | Seedlings, tanks, filters, dosing and packing cannot occupy production channels. |
Begin with the clear internal greenhouse dimensions. Reserve perimeter access, main aisles, cross aisles, tanks, fertigation, electrical space, nursery and packing as required. Divide the remaining growing width by the channel module and the growing length by usable channel length. Multiply channels by holes per channel, then check whether workers can actually operate the layout.
This method should be shown on a drawing. A spreadsheet number without row dimensions, clearances and channel supports is not enough.
The nursery should match the transplant schedule, germination period, losses and buffer stock. Define seedling trays, benches, irrigation, hygiene, lighting or shading and movement into the NFT area. A system with many channels but an undersized nursery cannot maintain the planned weekly planting rhythm.
Long channels and large zones can increase differences in flow, oxygen, nutrient concentration and root temperature. The designer should state channel slope, flow assumptions, supply and return arrangement, pump duty, pipe sizes and maximum zone size. Confirm whether zones can be isolated for cleaning without stopping the entire farm.
Test source water before finalizing filtration and dosing. Define tank volume, A/B dosing, pH and EC control, filtration, disinfection, drain return and nutrient correction. NFT roots depend on continuous flow, so identify critical pumps, backup power, low-flow alarms and emergency response. Duplicate pumps should have a tested changeover method.
In hot or humid locations, evaluate roof and side ventilation, insect net, shading, fan-pad or fog cooling and water availability. Cooling performance should be based on outside temperature and humidity, crop-zone targets and airflow. Root-zone temperature and warm nights may become limiting even when daytime air temperature is reduced.
Ask for steel member sizes and coating, covering datasheet, NFT channel material and thickness, supports, pump curves, filter sizes, dosing accuracy, sensor specifications and spare parts. A lower-cost option can be useful when its limits are transparent. Avoid removing safety, backup or water-treatment items without understanding crop risk.
Target plant positions and weekly harvest schedule
Lettuce type, hole spacing and channel spacing
Dimensioned greenhouse, channel, aisle and nursery layout
Channel material, thickness, length, slope and supports
Hydraulic zones, pumps, pipes, filters and return system
Water laboratory report, tanks, dosing and sanitation
Ventilation, shade, cooling and root-zone strategy
Power, backup pumps, alarms and emergency operation
EXW, FOB and CIF scope, packing, containers and spare parts
It depends on spacing, channel layout, aisles, nursery and service areas; require a dimensioned plan.
No. Germination, crop losses, cleaning, nursery timing and market grade affect saleable output.
Yes, if the quotation is for a complete production system rather than channels only.
Prioritize water flow, critical pumps, power, alarms and a tested emergency procedure.
Use the tropical NFT lettuce guide, water-quality checklist and backup-power checklist.
Send the plant target, site climate, water report and available area through the contact page for a capacity-input checklist.