Cold Storage for Seed Potato vs Table Potato: Two Jobs, Two Temperatures

Two lots of potatoes can look identical in the crate and need opposite things from a cold store. One is table potato, headed for a kitchen, and you want it to stay asleep — no sprouts, no greening, no sugar build-up. The other is seed potato, headed back into a field next season, and a dormant tuber that will not wake up on time is worthless. Same vegetable, two storage jobs, and getting the temperature wrong ruins one to save the other.

This extends our guides to cold storage for potatoes and vegetables and storing planting seed between seasons.

The dormancy clock every tuber runs

A freshly harvested potato is naturally dormant — it will not sprout for a period of weeks to a few months depending on variety and growing conditions. After that natural rest ends, the eyes begin to grow whenever temperature allows. Cold slows that growth; warmth speeds it. Every storage decision below is really about where you want the tuber to be on that clock when you take it out.

Table potato: hold it deep asleep

For eating potatoes the goal is maximum suppression of sprouting and minimum weight loss over a long hold:

• Cure first: 10–15 days at warmer temperature and high humidity so cuts and skinning heal and the skin sets. Skipping the cure lets rot in.
• Then pull the temperature down slowly to a cold holding range — commonly around 3–4 °C for long storage of processing and table stock — with relative humidity kept high, around 90–95%, and gentle air movement.
• Keep it dark. Light turns the skin green and drives production of solanine, which is bitter and, in quantity, not safe to eat.
• Accept the trade-off: very cold storage below about 4 °C causes “low-temperature sweetening” — starch converts to sugar, and the potato fries dark and tastes sweet. For crisping and chip stock, storage is often held slightly warmer with a sprout suppressant instead.

Seed potato: cold, but with a plan to wake it

Seed potato storage protects the tuber and the buds inside it, and the temperature is genuinely colder because you are not worried about frying colour:

• Cure the same way first — wound healing matters just as much for seed.
• Hold cold, typically around 2–4 °C, with high humidity (90–95%) to stop the tuber shrivelling and losing the reserves the new plant will draw on.
• The cold keeps the tuber dormant and stops sprouts elongating into the fragile white shoots that snap off during handling and grading.
• Never use a chemical sprout suppressant on seed potato. The suppressants used on table stock also suppress the sprouts you need in the field — a treated tuber may never emerge.

Waking seed potato before planting

Here is the step most people miss. A seed tuber taken straight from a 3 °C store and dropped into a field emerges slowly and unevenly, because it is still physiologically “young.” Two to four weeks before planting you deliberately warm it: move it to roughly 12–18 °C in diffuse light so it “green-sprouts” or chits — short, sturdy, dark green sprouts a centimetre or so long. Chitted seed emerges faster, more evenly, and yields earlier. That warming stage is part of seed storage planning, not an afterthought, and it means your cold room schedule has to allow for pulling seed lots out ahead of the planting window.

Why you should not store both in one room on one setting

If you run a single mini cold store at 3–4 °C and put seed and table stock in together, the table potato is fine but the seed potato is only half-served — it holds, but you still need a separate warmer space to chit it before planting. If you set the room colder for seed, say 2 °C, any table or processing stock in there starts sweetening. The clean answer for an operation handling both is either two rooms, or one room plus a small warm chamber, or a strict calendar where seed lots leave for warming while table stock stays. Our note on onion and garlic curing shows the same principle — one crop, several storage jobs.

Humidity, air, and stacking

Both jobs share the same physical needs. Relative humidity high enough (90–95%) that tubers do not lose water and go rubbery, but not so wet that free moisture sits on the skin and invites rot — which means humidity control and gentle, even airflow through the stack, not just a cold box. Store in ventilated crates or boxes, not sealed bags. Do not stack so deep that the bottom layers are crushed and the centre of the pile cannot breathe. Keep a walk space so you can inspect and pull out any lot that starts to break down before it spreads.

Planning a store for a potato operation

Before sizing a room, be clear about the mix: how much table or processing stock, how much seed, and whether you need a warming stage on site. That decides room count, target temperatures, and whether you specify a suppressant-application setup for the table side. Refrigerant choice, insulation thickness, backup power for load-shedding, and humidity equipment all follow from that brief — our guides on refrigerant choices and backup power cover those. Tell us the crop split and the planting calendar and we will size the store around it.

Reading the store: what a problem lot looks like

Train whoever inspects the room to spot the early signs before a lot is lost. Long white or pale sprouts mean the tuber has broken dormancy and the store is too warm or the lot has been in too long. Green patches on the skin mean light is getting in — find the leak. A sweet smell and any free liquid at the bottom of a crate means soft rot, and that lot comes out now before it spreads through the stack. Shrivelled, rubbery tubers mean the humidity is too low. Condensation beading on the tubers means warm air is hitting cold stock — check door discipline and airflow. Catching any of these in a weekly walk is the difference between pulling one crate and losing a bay.

Ware potato and processing potato: a further split

Even within “table” stock there are two sub-jobs. Ware potato for the fresh market is judged on appearance and can tolerate the colder end of the holding range because nobody fries it. Processing potato for crisps and chips is judged on fry colour, and that is destroyed by low-temperature sweetening, so it is held warmer — often several degrees above ware stock — and relies on a sprout suppressant to stay dormant at that temperature. If you supply a processor, ask them for their required storage temperature and reconditioning window, because delivering sweet stock means rejection at the factory gate regardless of how good it looks.

A storage calendar for a mixed operation

For an operation holding seed and table stock, the room schedule is a calendar, not a setting. Cure both at harvest. Hold everything cold through the storage season. Then, counting back from the planting window, pull each seed lot into the warming or chitting space two to four weeks ahead so it emerges evenly in the field. Table and processing stock stays in cold holding and is drawn down against orders. If a single room has to serve both, run it at the table-stock temperature and accept that the seed side needs that separate warm stage — do not drop the whole room to seed temperature with processing stock still inside.

DE International helps Bangladeshi businesses source from China, move goods door to door by air and sea, clear customs, and set up storage — including cold rooms and warehousing. To talk through a project, contact our team, see the full service list, or start with our China sourcing and buying agent service. Stock lines are in our shop. Prices, capacities, temperatures, and timelines in this article depend on your product and site — ask us for figures built around your case.