Size the aisle from the machine outwards, not from the room inwards. In rooms harvested mechanically, the working aisle between two rows of racking should be 1.5 m in a new growing room (1.2 m is the workable minimum for a Newton picking lorry), the main access aisle at the head of the room 2.5 to 3 m, and every motorised unit keeps at least 50 cm of clear buffer from walls and fixed objects. Everything below explains where those figures come from and when you should depart from them.
What width does each aisle need?
| Aisle | Typical width | What has to fit in it |
|---|---|---|
| Working aisle between rows, new growing room | 1.5 m | The machine, plus the picker turning and reaching |
| Clearance for a Newton picking lorry | at least 1.35 m recommended, 1.2 m minimum | Measured between the lower stop profiles of the racks; the extra width is room for the picker on the platform |
| Main access aisle, head of room | 2.5–3 m | Two-way traffic; transport passing a stationary machine |
| Buffer from walls and fixed objects | at least 50 cm | Crush-hazard clearance around any motorised unit |
| Margin over your widest tool | plus 20–30% | Human movement around the machine |
Why is the working aisle the width it is?
For hand picking, aisles are often kept narrow to win growing area. Once a machine runs in the aisle, that logic reverses: the aisle has to hold the machine, the picker and a margin between them.
A Newton picking lorry is stable in motion, but it still needs clearance to move vertically and horizontally without touching the racking. Measured between the lower stop profiles of the racks, a Newton works from 1.2 m, but at least 1.35 m gives the best picking ergonomics and room for the picker on the platform. Too little, and you get two problems at once — mechanical wear on the aluminium shelving, and a picker who works more slowly because part of their attention goes on not hitting the structure. A hydraulic Pascal picking trolley has its own footprint, so confirm the dimensions of the model you are actually buying rather than assuming they are interchangeable.
There is an ergonomic floor to this as well. A picker has to turn, reach out for a container and shift their stance. Cramped movement shows up first as a drop in kilograms per hour and later as strain injuries and turnover.
How wide should the main access aisle be?
The main aisle carries the heaviest traffic on the farm: empty containers in, full containers out, machines going for service. At 2.5 to 3 m, a transport unit can pass a machine that is standing still without either of them having to reverse.
Keep the 50 cm buffer around anything motorised. It is a crush-hazard clearance, not a convenience, and it is the dimension most often lost when a room is filled up to the last centimetre of growing area.
Does the floor decide whether the width works?
Yes — a correct width on a bad floor behaves like a narrow one. If the slab slopes toward the racks or toward the centre, the equipment tilts, the usable width shrinks and you have a safety problem that no drawing shows.
Rails follow the same rule. Precision-made rails define the path the machine takes, so the aisle width has to be planned with enough clearance from building columns, climate ducts and drop pipes. Those are the obstructions that pinch a nominally correct aisle down to an unusable width at exactly one point in the room.
What does aisle width do to airflow and light?
Tight aisles restrict circulation, which lets CO2 and humidity pocket around the beds. Slim rack profiles help, but they do not replace space the air can move through. Light behaves the same way: in a narrow aisle pickers shade the bed they are working on, and there is nowhere safe to hang insect light traps clear of a moving machine.
Do aisles need extra width for evacuation?
Local regulations usually set a minimum clear width for escape routes, and that width has to be clear in an emergency, not on a normal day. Check whether your equipment can be moved without power: a manual override on the drive and manual lowering on the platform mean an aisle can be cleared during an outage.
How do you size an aisle in three steps?
- Measure your widest tool at its widest point in use, not folded.
- Add 20–30% for human movement around it.
- Validate against the racking layout — rails, columns and the services running down the room.
Related reading
- Shelf layout that removes harvest bottlenecks
- Retrofitting aluminium shelving into existing rooms
- The most common shelf design mistakes
- All Knowledge articles
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