By Lukie Pieterse, Potato News Today
Why the real yield battle continues in the store, long after harvest ends, and how potato storage managers can stay ahead of risk and disappointment.
From the outside, harvest looks like the grand finale of the season. The last trailers roll in, cameras catch the dust and the sunset, and the focus of most observers moves on. But for potato growers and storage managers across the Northern Hemisphere, the real test is only beginning behind closed doors.
For the next six to ten months, millions of tonnes of potatoes will sit in storages where small shifts in temperature, humidity, airflow, and human attention will decide how much of that hard-won yield actually makes it to market. The field may be quiet, but the stakes in the store are as high as ever.
From field to store – understanding the crop in front of you
Every storage season begins with a deceptively simple question: what exactly are we putting away this year?
That question goes far beyond variety and tonnage. Before anyone touches a control panel, the best storage managers build a detailed mental profile of each lot. They consider the variety and end use, knowing that French fry, chip, table, and seed potatoes all have different temperature targets and defect tolerances. They think back through the season: whether it was hot and dry or cool and wet, whether late rains complicated harvest, and whether machinery was ever pushed in marginal conditions just to get the crop out.
Maturity, dry matter, and skin set all matter, too. Immature skins and low dry matter will behave differently in storage than a fully matured, high-gravity crop. Disease history also travels into the shed: late blight in the canopy, soft rot in low spots, silver scurf on tubers, or blackleg in certain fields all shape risk. Finally, harvest and handling patterns – long queues with full trailers in the sun, rushed grading lines, cold soil days at the end of the season – leave a signature on the crop, no question about that.
Put together, these details shape curing regimes, air patterns, sprout control plans, and how intensely a lot will be monitored. A clean, cool, well matured crop from a gentle season can be handled differently from a warm, stressed, scuffed-up crop taken off muddy fields at the end of a difficult autumn.
The scale may be industrial, but the mindset has to be investigative: what happened to these potatoes before they reached the door – and what does that mean for the next eight months?
The first 72 hours – taking control of heat and moisture
The first days in storage are the most unforgiving. Potatoes arrive with field heat trapped inside them, free moisture on the skin, and fresh wounds from harvesting and handling. Left unchecked, that combination drives high respiration, condensation, disease development, and unnecessary weight loss.
In this window, the job is to bring order to chaos. Managers work to level the loading pattern so that pockets of very warm potatoes are not buried together in one corner. They use ventilation to remove field heat steadily, pulling temperatures down toward curing conditions without shocking the tubers. Cooling too aggressively can make blackspot bruises show up more severely and increase stress; cooling too slowly leaves the pile “breathing hard” for too long.
Moisture management is just as important. Air movement and humidity are adjusted so that free water is removed from tuber surfaces and structural elements, but the crop does not desiccate. The goal is a dry skin, not a dry potato. Condensation patterns on ceilings and walls are watched closely, because they often reveal where warm, moist air is being trapped. Those damp patches usually mark the first places where trouble will appear later.
During this period, small mistakes scale quickly. A blocked duct, a fan left off in one section, or a cold air blast pointed straight at fresh, bruised tubers can have consequences that echo through the entire season. The best managers treat the first 72 hours almost like an emergency response phase – alert, present, and willing to adjust.
Curing and wound healing – letting the crop recover
Once field heat is under control, the focus shifts from firefighting to healing. Harvest, grading, and loading inevitably leave micro-wounds and bruises on tubers. With the right conditions, the potato’s natural suberization process seals these wounds and reduces the risk of rot. Without those conditions, the same wounds become open doors for bacteria and fungi.
Good curing depends on a few core principles. First, temperature should be stable rather than constantly moving up and down. A modestly elevated, steady curing temperature is usually kinder to the crop than a series of quick fluctuations that undo healing and add stress.
Second, humidity needs to be high enough to support wound healing and minimize shrink, but not so extreme that free moisture builds up on structural surfaces and equipment. Long-term wetness on steel and timber is a warning sign, not a target.
Ventilation continues, but the emphasis shifts from rapid cooling to gentle, even air movement that removes respiratory heat and CO₂ without drying the pile excessively. Throughout this phase, managers watch for early signs of soft rot, pink rot, or leak. Sacrificing a small volume of badly affected tubers early is far cheaper than trying to reclaim a large section of the pile once decay spreads.
Curing is also when experienced storage managers start to “read” the season. They note whether the pile cools in a predictable way, whether specific varieties are clearly more fragile, or whether certain fields show more mechanical injury or disease. Those impressions guide where to focus attention in the weeks that follow.
Airflow and pile design – avoiding the quiet corners
Impressive fans and ductwork mean very little if the air is not actually going where it needs to go. Piles that are too high or too wide for the system, or that are loaded in ways that block ducts and returns, inevitably create quiet corners where temperature and gas levels drift away from targets.
After harvest, managers pay close attention to real airflow rather than just design drawings. They may use simple tools – smoke bombs, ribbons, handheld anemometers, or foggers – to see how air moves through and over the pile. What looks good on paper sometimes behaves very differently when potatoes, soil, and timber are involved.
Pile geometry is checked to ensure that height and width do not exceed what the system can handle. Attempts to “squeeze in” extra volume by overfilling often create stagnant cores that never really cool or dry properly. At the same time, managers walk walls and corners, monitoring tuber temperatures and watching for mold growth or localized condensation. These areas sit in slower-moving air and are often the first to show pressure bruising or quality decline.
Obstructions are another frequent enemy. Bulkheads, tarps, pallets, or stray equipment that partially block ducts, returns, or exhaust paths give air an easier path around the pile instead of through it. Experienced managers talk about “walking the air” – physically following the path air actually takes through a storage and checking that measurements support what they see and feel. That habit, established early, saves trouble when outside weather turns extreme later in the season.
Temperature and humidity – doing the simple things well
Different buyers, markets, and regions have different storage recommendations, but potatoes consistently prefer environments that are cool without freezing, stable rather than erratic, and humid without constant dripping.
Once curing is complete, attention shifts to pulling the store down to the long-term holding temperature appropriate for the product and market. Processing potatoes, table stock, and seed all have different optimal ranges, and those targets are shaped further by variety, contract terms, and expected draw-down timing.
The descent to holding temperature is most successful when it is planned. Managers reduce temperatures in measured steps rather than chasing short-term swings in outside weather. They try to avoid creating condensation traps by coordinating temperature changes with ventilation patterns, so that warm, moist air does not suddenly hit cold surfaces and deposit water on ceilings and walls.
Humidity is another balancing act. Running storages at a high relative humidity is essential to limit moisture loss and protect weight, but a permanently soaked ceiling is a red flag. In the long term, constant dripping points to problems with ventilation balance and can encourage mold growth in certain zones.
Finally, all of these environmental decisions need to line up with logistics. There is little sense in perfect long-term holding conditions for a lot that will be shipped early, or in aggressive cooling that triggers sugar accumulation in fries or chip varieties destined for quick processing.
Clean storages and clean habits – hygiene as cheap insurance
Pathogens do not care whether they are on a tuber, the underside of a catwalk, or in a forgotten cull pile behind the building. Once harvest is done, it is tempting to relax on hygiene, but the post-harvest period is exactly when sanitation needs to become a routine rather than a once-a-year wash-down.
Cull removal is a simple but powerful step. Getting rid of diseased or rejected tubers regularly, and keeping cull piles well away from intakes, doors, and traffic routes, reduces the chance that spores or bacteria will be drawn back into fresh air streams. Floors and catwalks deserve similar attention. Mud, juice, and standing water form thin, slimy layers that become reservoirs for bacteria and mold; keeping these areas scraped and dry cuts down background pressure.
Roofs and plumbing are another focus. Even a small leak that drips onto the pile or creates standing water around supports can, over time, turn into a local problem zone. Prolonged damp patches in one place almost always lead to issues.
On top of this, managers think about what – and who – comes into the storage. In multi-farm or multi-site operations, shared equipment, borrowed tools, and frequent visitors can quietly move disease between storages if basic hygiene rules are not followed.
Hygiene work is rarely glamorous, but it is one of the least expensive ways to reduce storage risk, especially in seasons where late blight, pink rot, or other field-borne diseases are already present.
Hotspots and crisis management – finding problems early
Even the best-run storage will occasionally develop trouble spots. A corner warms up, a patch of tubers starts to smell wrong, or CO₂ levels rise in one zone. The difference between a minor incident and a major loss is the speed and clarity of the response.
Post-harvest routines that help here are built around structure and attention. Storage rounds are planned, not left to chance. Every store is walked on a fixed schedule; fans, doors, drains, and sensors are checked systematically rather than glanced at when someone happens to have a spare moment. Notes are taken. When something looks or smells off, the location is marked and revisited after a defined interval so that vague impressions become visible patterns.
All the senses matter. The first hint of soft rot is often a subtle change in odour. A slightly sticky catwalk can indicate juicing below long before a patch becomes visible from above. When indicators suggest a problem, managers must be willing to open the pile, cut inspection windows, and pull out suspect boxes or sections. It is always easier to replace a small void than to reclaim a collapsed, rotting mass inside a bulk store.
In some regions, fogging or other approved treatments are used as part of the response toolbox. Even then, early detection remains the foundation. Once a rot pocket transforms into a full-fledged “compost heap” inside the pile, options become limited, expensive, and messy.
Sprout management in a changing regulatory world
In many countries, the toolbox for sprout control has changed dramatically in recent years. Regulatory shifts, residue concerns, and buyer expectations have forced storage managers to rethink long-established routines. Many are now combining new chemistries, tighter environmental control, and varietal choice to keep sprouts in check.
Planning starts early. Managers assess the dormancy potential of each lot, recognising that variety, seasonal stress, and harvest conditions all influence how long tubers will naturally remain dormant. Heat-stressed crops, or those pulled from the ground in very warm conditions, may break dormancy far earlier than the same variety in a cooler year.
Based on that assessment, they build a timeline that maps expected sprout growth against curing, pull-down, and shipping schedules. Lots that are likely to sprout early are earmarked for earlier movement or more intensive management.
At the same time, managers check which sprout control tools and application methods are acceptable for each buyer and market, particularly when storages feed multiple customers or export destinations.
Crucially, temperature and humidity are treated as active partners in sprout management rather than fixed background conditions. Stable, cooler environments reduce sprout pressure and can extend dormancy, reducing reliance on costly or limited products.
Documentation runs alongside these decisions from the start of the season: what was applied, at what rate, in which store, and when. By the time auditors or buyers ask questions, the record is already there.
People, procedures, and safety – the human side of good storage
Storages do not manage themselves. Behind every quiet, well-behaved pile is a small group of people who show up, notice things, and act. As operations get larger and more complex, the human and safety dimensions of storage management become just as important as temperature curves and humidity charts.
Clear responsibility is the first step. Someone has to be explicitly responsible for each storage each day. When responsibility is vague or shared among “whoever is available”, details fall through the cracks. Simple, written procedures support that responsibility. Checklists for daily rounds, alarm responses, fan changes, and safety checks make sure that essential tasks are done even when the most experienced manager is away.
Safety deserves constant reinforcement. Work around conveyors, catwalks, confined spaces, and electrical panels is never risk-free, and too many serious farm accidents happen in and around storages during the quieter months. Training, signage, and a culture that supports safe behaviour are not luxuries – they are part of professional storage management.
Communication ties it all together. Staff need to feel comfortable reporting unusual smells, noises, or condensation patterns without worrying that they are over-reacting. The worker who raises a false alarm today may be the same person who prevents a major loss tomorrow.
At a broader level, the storage manager is often the bridge between the field team, the agronomist, and the buyer. Open, timely communication up and down that chain means problems are not hidden, surprises are fewer, and everyone understands how storage decisions connect back to field choices and forward to processing or packing.
Digital tools and data – extending, not replacing, experience
Across the potato value chain, storages are quietly becoming more connected. Sensors in ducts and piles, remote monitoring platforms, automated control systems, and even machine-learning tools are now present in many regions. Their value is often most obvious in the immediate post-harvest phase, when conditions change quickly and risk is high.
Digital systems give managers the ability to see inside the pile in real time. Temperature, humidity, and CO₂ readings from multiple points can be graphed and compared, making it easier to spot trends that would otherwise remain invisible until quality problems show up at grading.
Well-configured alerts allow managers to respond quickly when conditions drift outside safe parameters, reducing the time between something going wrong and someone doing something about it.
Over several seasons, stored data becomes a powerful review tool. Managers can compare how different varieties behaved, how particular storages responded to cold snaps or warm spells, and how changes to ventilation strategies played out. Larger operations use digital platforms to coordinate multiple storages, sometimes across different sites, without needing to be physically present in every building every day.
Even so, screens are no substitute for human presence. They cannot hear a bearing about to fail or see a new roof leak. The most successful operations treat digital tools as an extension of human judgement – extra eyes and memory that support, rather than replace, the experience of skilled storage managers.
Turning one season’s lessons into the next season’s advantage
When the last lorry leaves and storages finally start to empty, the temptation is to quickly pivot back to field planning, seed bookings, and machinery maintenance. Yet the weeks immediately after a storage season offer one of the best windows for reflection.
Resilient businesses use that window to document outcomes by lot: shrink levels, defect patterns, and overall quality are recorded against variety, field, and storage conditions. They take note of surprises – varieties that stored better than expected, or technologies that did not live up to their promise. They connect field and storage decisions, asking which agronomic choices clearly influenced storage behaviour, for better or worse.
The key is to convert lessons into specific actions. That might mean adjusting harvest timing on a particular soil type, lowering pile height in a problem store, adding more temperature probes in historically tricky corners, or rewriting a daily checklist. Over time, this habit turns storage from a series of isolated campaigns into a learning system where problems do not just hurt – they teach.
A quiet building, a live crop, and a long responsibility
From the outside, a potato storage can look uneventful for months on end – a closed door, a gentle hum, an occasional truck. Inside, millions of living tubers continue to breathe, lose water, respond to temperature changes, and interact with whatever microbes travelled in with them.
For storage managers across the Northern Hemisphere right now, post-harvest is not an afterthought. It is the moment where they set the tone for the entire season: will this be a year of steady, controlled confidence, or a year of chasing problems from one corner to the next?
Getting storage right begins with a simple mindset shift: harvest is not the end of the job. It is the start of a different, quieter, but equally critical campaign to protect the yield that was so hard won in the field.
Author: Lukie Pieterse, Potato News Today
Cover image: Credit Allan Parker