Spud Special: Potato harvest crawls on north of the border

Better harvesting weather recently (light rain rather than torrential) has enabled better progress to be made with the potato harvest north of the border.

Overall there is estimated to be about 25% of the crop still in the ground. Most growers have left heaviest land till last and 5 acres a day per harvester has been the norm. But conditions have meant bruising has not been a problem, unlike English crops. 

Slow store filling means getting the cold store doors shut and temperature pulled down are the priority for quality. Tuber temperatures going into store have not fallen below 10C, which means curing should have been completed within 7-10 days of lifting.

While boxes are drying on the surface, most have varying degrees of rotting tubers inside so temperature should be reduced by 0.25-0.5C per day as bacterial rotting will not be significantly slowed until temperatures are below 6C. Fridges will also pull condensation and heat out of boxes caused by the tuber breakdown.

Monitor stores carefully – the temperature differential between the box surface and 6-8in below should not exceed 0.6C, otherwise this will result in a condensation layer and more air circulation though the boxes is required.

Box stacking patterns in stores are going to be critical this season. Make sure that there are no gaps where air can shortcut back to the fridge without going though the boxes – gaps can be blocked up with plastic. If there are any hot spots, consider putting extra fans in the roof to provide additional benefits.

There is no evidence yet of the early dormancy break and sprouting seen in England. Although some crops were planted early in Scotland, they did not have the period of heat and drought stress that is probably the major reason for the early dormancy break further south.

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