From time to time someone quotes the Gardeners World potato chitting trial that they did a few years ago, which concluded that chitting potatoes was not worthwhile. Full stop!!
I get quite annoyed about this because in my opinion they did a great disservice to gardeners.
The trial was quite unscientific and ignored the important reasons why chitting can be an advantage. Mainly that chitted potatoes bulk up earlier.
From what I can recall, in their trial they simply planted chitted and unchitted side by side, ealies, second earlies and maincrop. At the end of the Summer they dug them up and weighed them. Yields from chitted and unchitted were the same.
What they did not take into account were the reasons why potatoes are chitted by both gardeners and farmers.
1. Early potatoes bulk earlier and can be dug as immature earlies a week or so earlier. To a farmer that can mean a higher price. To the gardener there are early potatoes on the plate sooner.
2. If the weather is bad at the planned time of planting the chitted potatoes have already broken their dormancy and they can wait until conditions improve without losing yield. Unchitted potatoes will not break their dormancy until they are planted and therefore may have a shorter growing season.
3. If there is blight and tops need to be cut off to prevent infection chitted crops which have bulked up earlier will have a greater yield. That is especially important to organic growers and gardeners growing main crop varieties.