I planted Kerrs Pinks in April with farm yard manure. Now in the 2nd week of October there is only 1 medium size potato and about 4 very marble size potatoes? Do I wait longer or what is wrong? I live on the East Coast of Ireland. I have an allotment bed in my garden. I have grown salad vegetables the first year successfully. This is the first time potatoes have been planted here. I used good quality top soil in my bed. I also sprayed the stalks for blight at the right time. What has gone wrong? The potatoes that I dug were delicious.
Potatoes are ready to harvest when the plants have died down completely.
You mention that you used manure. If the manure is not composted well enough, you could have issues with the Nitrogen levels to high.
You may want to do a soil test to see exactly what your working with.
To much Nitrogen will cause lush greens and not vegetable production.
There are many ways to grow potatoes from soil to straw and containers.
The great thing about gardening is that we are always learning!
Here are some links with more information.