Tough harvest, how to proceed in storage?

Harvesting conditions are not easy this season on both clay and sandy soils. Potatoes are coming in covered with mud and storage is quite a challenge and with some lots storage is not an option at all. "Even lots that came in under reasonable conditions earlier this season require a lot of extra attention," notes Jasper van de Braak, storage advisor at Tolsma-Grisnich. In his working area in eastern North Brabant and the province of Limburg, the Netherlands, he sees many challenges with drying potatoes and that is not always without losses.  

"With the harvesting conditions since mid-October, potatoes often arrive wet and/or with a lot of soil. This means that it is very difficult to find the drying conditions for the right balance between wound healing and preventing wetness and bacteria from affecting healthy potatoes," Van de Braak sees in his working area. As a result, many lots have been behind the shelves for some time but are still fully in the drying phase. "A customer of mine had harvested a batch that was still in reasonable conditions compared to now, before the heaviest rain. This batch had arrived at around 14°C with little rot at first glance. That seemed to go well in the beginning, but from experience in the field it was known that there were places on the plot that could cause problems during storage. Just two weeks later that happened and rot and leaking tubers emerged."

We are talking about a batch on a slatted floor with AC fans, with a Vision Control storage computer and heater automation. "To get the batch under control, we have tried to keep the batch at a constant temperature of 14°C. The higher the temperature, the faster the wound healing. You want the wound healing to be completed as quickly as possible to prevent further spread of diseases to the healthy tubers. For example, wound healing at 12°C takes an average of 28 days, at 15°C it takes twenty days and at 18°C about fourteen days. But if your storage temperature is above 15°C, bacteria and rot will spread more quickly. The correct temperature is therefore crucial to prevent further spread. Fortunately, the weather was reasonably suitable for this and maximum external ventilation was then maintained and this was maintained for two weeks. After that, external ventilation was reduced somewhat and a switch was made to regular internal ventilation, with the fans running for 45 minutes every three hours."