[ian]

Hi All,
I dug up the last of my main potatoes yesterday , Maris Piper, they had died back the last week of August and have been left in the ground since. I dug up about 6 stone of fair to good size spuds. To my dismay i found tht a third of them had a dry sponge like cavity inside a honycomb of dryness with the outside looking perfectly innocent. Sorry I have no photos. There was no evidence of slug or worm, i am thinking the soil is pest laden or worn out but i do muck heavily the whole area, at least every second year and the potatoes every year and rotate them but still this happens. I think I should give spuds a rest for two years - any thoughts?
Regards,
Ian.

[michael brenock]

if there is no hole on the skin of the potato then it is not slugs or wireworm. If there is a hole on the skin then slugs probably caused it but other pests like earwigs or woodlice may be present. Common scab is the only problem that would fit the description you give. If it occurred in most stalks then it may be a soil problem or nutrition problem and it may have been transmitted from the seed. A picture would be great as it can be hard to describe diseases and pests in vegetables accurately. Keep on growing potatoes in new plot each year and feed with compost and balanced manure, high Potassium and low Nitrogen.
michael brenock horticultural advisor (retired)

[Sive]

I think the damage simply may be due to wet weather after a very dry period. It's been a strange summer....very dry at times, and potatoes need regular watering.

[Gautama]

I'm guessing watering too.
I'd a great crop of earlies but my mains were very small. It only dawned on me the other day where I went wrong: I rarely watered my mains. It was a very dry summer in Dublin but because the weather was fairly cold I didn't think about the need to water.

[Sive]

OOOps Michael....your reply wasn't yet posted when I put my twopence worth in !
I would hesitate to offer advice after Michael has done so !
However I use the Dr D.G.Hessayon Vegetable and Herb Expert book all the time whenever we have potato issues, as it has good illustrations and that book describes something called "hollow heart" which seemed to fit Ian's description.

[Lius]

I'm glad to see other member have had the same problem as me with their main crop of spuds this year. I was afraid my attempt at "Square Foot Gardening" this year didn't suit main crop spuds even though everything else did well even the early spuds. It was also my first year planting a main crop of spuds as previous I did not want to grow spuds that I had to spray, so this I tried blight resistance Sarpo Mira which gave a large number of smaller (tasty-tasty) tubers; I also suspected that I hadn't watered them enough, now I know. Live and learn.