The storage manager’s data playbook: Turning sensors, CO₂, and trendlines into decisions

By Lukie Pieterse, Editor/Publisher Potato News Today

A practical mid-winter storage playbook – using trendlines, zone comparisons, and simple routines to cut shrink and prevent late-season surprises

Modern potato storages generate more data than ever – temperature probes, RH sensors, CO₂ monitors, fan logs, refrigeration run-time, and dashboard alerts. The challenge for most managers isn’t getting data; it’s turning data into clear decisions that protect quality, reduce shrink, and prevent late-season surprises.

This playbook focuses on decision-grade monitoring – using trendlines, zone comparisons, and simple routines to catch problems early, before they become expensive.

Start with a mindset shift: single numbers lie; patterns tell the truth

A single temperature reading can look “fine” while one corner of the pile quietly warms. CO₂ can be “acceptable” today while rising steadily week after week. RH can appear stable while condensation risk builds because temperature spread is widening.

Three practical principles help cut through the noise:

• Trends beat snapshots: direction, rate of change, and persistence matter.
• Spread beats average: the gap between warmest and coolest zones is often your best early warning.
• Context beats theory: interpret numbers alongside outside weather, ventilation strategy, refrigeration activity, and recent handling/removal events.

The “Big Four” signals worth mastering

If you focus on only a few indicators, make it these:

1. Temperature spread across the pile (warmest minus coolest zones)
2. Return-air vs supply-air behaviour (pile response versus what you are pushing into it)
3. Relative humidity stability (consistency over time, not chasing a single number)
4. CO₂ trendlines (baseline plus direction)

These signals connect directly to what matters: shrink, rot risk, sprout pressure, sugar management, and shipping quality.

Sensor placement: data is only as good as what it represents

Many monitoring failures are not “software problems” – they are placement problems. A sensor can be accurate and still be unhelpful if it represents an easy, stable area rather than a true risk zone.

A practical baseline includes:

• Multiple sensors per zone (avoid a single “token” probe)
• Coverage of known risk areas: corners, doors, plenum edges, and historically warm/wet pockets
• A consistent logic for depth (near-surface and deeper pile readings where possible)
• A clear map: every sensor ID must correspond to a real-world location a manager can visualize instantly

A good test: If a sensor alarms, do you know where to go and what you’re likely to do? If not, the system isn’t yet decision-grade.

Temperature: focus on spread, drift, and stubborn zones

Setpoints matter, but pile behaviour matters more. The most useful temperature questions are: Is the pile uniform? Is it responding predictably? Is any zone refusing to behave?

Key indicators:

• Rising temperature spread can signal airflow distribution problems, developing hotspots, or uneven pile density.
• Slow drift upward in one zone often shows up well before quality breaks down.
• A stubborn warm pocket that resists cooling is a red flag – treat it as an airflow or distribution issue until proven otherwise.

Decision triggers managers can use:

• If warm zones persist despite adequate fan time, investigate distribution, short-circuiting, or plenum issues rather than simply increasing runtime.
• If spread increases during outside weather swings, assess whether ventilation strategy is creating uneven pile response.
• If warming follows removal/handling activity, consider the role of stress, damage, or localized moisture changes affecting respiration.

Relative humidity: stability matters as much as the number

RH is often over-simplified. Chasing a perfect RH number can distract from the bigger risk: instability that creates repeated condensation cycles.

Good RH monitoring looks like:

• Stability over time (avoid large oscillations)
• Consistency across zones (uneven RH can point to uneven airflow, temperature gradients, or moisture migration)
• Condensation awareness (warm air meeting cooler surfaces, or warm and cool zones interacting within the pile)

A practical rule: when temperature spread increases, condensation risk often increases – even if the RH number looks “fine.” RH should rarely be interpreted in isolation.

CO₂: the underused early-warning signal

CO₂ monitoring can be one of the most useful “pile stress” indicators, especially in the mid-to-late season. CO₂ trends help managers see rising respiration or restricted gas exchange before visible problems appear.

What CO₂ can signal:

• Increasing respiration (temperature-, variety-, or stress-related)
• Restricted airflow or gas exchange in pockets of the pile
• Early biological activity that may precede visible quality decline

How to use CO₂ practically:

• Establish a baseline for your facility each season (normal ranges vary).
• Watch direction and slope – a steady rise is often more meaningful than a single high day.
• Compare zones if possible: if one area is rising faster, it can point to where the pile is struggling.

CO₂ becomes particularly valuable when dormancy begins to shift and respiration dynamics change.

Alarms vs analytics: don’t let notifications run your storage

Many systems are built around alarms. Alarms are useful, but by the time they trigger you may already be in the early stages of a quality event.

Think of it this way:

• Alarms: “Something is already wrong.”
• Trends: “Something is starting to shift – fix it while it’s still cheap.”

The goal is to learn the “pre-alarm” patterns: rising spread, persistent warm zones, and climbing CO₂ trendlines.

A simple weekly routine that prevents most surprises

A playbook only pays off if it becomes routine. Here is a realistic rhythm:

• Daily (10 minutes): check temperature spread, CO₂ direction, and any zones drifting off pattern
• Weekly (30 minutes): review the last 7 days of trendlines, not just today’s values
• After major events (weather shift, removal, maintenance): do a “reset review” to confirm the pile response remains normal

What to record weekly (short and useful):

• Warmest and coolest zones (and the spread)
• CO₂ trend direction (flat, rising, falling)
• Any zones behaving “stubbornly”
• One decision or action taken based on the data

This builds a lightweight decision trail without creating paperwork.

Turning patterns into action: practical “if-then” thinking

Common examples:

• Spread widening + one warm zone persisting: suspect airflow distribution; inspect risk areas rather than simply extending fan time.
• CO₂ rising steadily + no obvious temperature jump: suspect restricted airflow pockets or increasing respiration; check known risk zones and ventilation effectiveness.
• RH oscillating + outside weather swinging: reassess outside-air strategy and avoid condensation cycles.
• Return-air trends do not match supply changes: the pile is not responding uniformly – treat it as a distribution problem before changing targets.

What to watch in Jan/Feb: the “quiet shift” period

January and February often feel stable – and that can create complacency. It’s also when subtle trend changes begin:

• Dormancy shifts can alter respiration dynamics
• Small airflow non-uniformities can show up as persistent spread
• Moisture migration can quietly set conditions for later problems
• Sensor drift or weak placement becomes costly when managers rely on those readings

A disciplined data routine during the calm period is what prevents late-season scrambling.

The takeaway: make data boring – and it starts paying you

Well-run storages make data boring – not because nothing happens, but because trends are checked routinely, decisions are consistent, and surprises are rare.

When monitoring becomes decision-grade, the benefits are tangible:

• Reduced shrink and fewer localized losses
• Earlier detection of pile stress and developing hotspots
• Better quality at shipping and fewer “mystery” claims
• More confidence during volatile outside weather
• Less firefighting late season, when the cost of mistakes is highest

In tight-margin years, competitive advantage is not always a new piece of equipment. Sometimes it’s simply learning to read the story your pile is already telling you – early enough to act.

Author: Lukie Pieterse, Editor/Publisher Potato News Today