Poor space organisation leads to rapid spread of pests and disease. "I'll put the seedlings wherever there's room, new transplants next to old ones, tools wherever is convenient" — this approach typically ends in a thrips or powdery mildew outbreak within a month.
Definition
Zoning is the division of a production space into functional areas with controlled movement between them. Each zone has defined rules for entry, exit, and servicing.
Flow Logic: Clean and Dirty Never Cross
The core principle: material movement is organised so that contaminated materials (new transplants, waste) never cross paths with clean ones (finished product, sterile substrate).
Inbound flow: seeds → storage → substrate preparation → sowing → growing → harvest → packaging → finished product storage
Outbound flow: spent substrate → waste zone (out of facility)
Five Functional Zones
1. Entry and Sanitation Zone
- First barrier before the production area
- Minimum: footwear change, hand sanitation
- For food production: clothing change or protective coat
2. Quarantine Zone
- Separate space with a physical partition
- New planting material held for 7–14 days
- Daily IPM monitoring: yellow sticky traps, inspection of leaf undersides
- Tools are not transferred to the main zone without sanitation
3. Growing Zone
- The primary zone with the strictest access control
- Dedicated tools for different crops
- Assigned tools do not leave this zone
4. Preparation and Packaging Zone
- Physically separate from the growing zone
- Temperature: +4–8°C to preserve product quality
- Separate HACCP sanitation schedule
5. Materials Storage Zone
- Seeds, substrate, fertilisers — stored separately from the growing area
- Seeds: 10–15°C, dry, no humidity fluctuations
- Fertilisers kept away from seeds (hygroscopic salts draw moisture)
Why Quarantine Breaks Down
"This seedling looks fine, I'll put it straight in with the rest" — this is the primary cause of problem spread. Thrips at an early stage are only visible under a magnifying glass; Fusarium in the roots only becomes apparent once the plant is already sick. A week's hold with daily monitoring is cheaper than treating the entire grow zone with chemicals.
Documenting Your Zones
Zoning that exists only in the operator's head is not zoning. A proper zone map must include:
- Label for each zone and its boundaries
- Access rules
- Material movement diagram
- Location of sanitation barriers
Three Mistakes That Cost the Most
- No quarantine zone — one infected pot contaminates the entire main growing area within a week
- One set of tools used across all zones — a direct vector for disease transmission
- People moving without a flow plan — the shortest route often cuts across clean and dirty zones
How to Check Whether Zoning Is Working
- A zone map exists on paper
- The path from new transplant to the main growing area always runs through quarantine
- Physical barriers prevent disease spread between zones
- New operators understand the system from day one