Cutting up seed potatoes
Two days ago I was given two brand new potatoes to grow, one a very white oval variety with very smooth skin and shallow eyes called Libertie whilst the other is a brilliant red colour but the eyes may be a little deeper called Red Cheftain. I really wanted these for my display at Tatton in July as well as a small dish on my stand at Malvern during the last weekend in September. So how can I possibly get enough potatoes from single sets of each variety? Well it can be done by cutting the potato up and making sure that every piece of it has a shoot developing from an eye.
This is something that many old gardeners used to do years ago when times were hard and they wanted the maximum output from a given potato. Some cut them as they were planting others cut them before hand allowing the cut surface to dry out a little preventing grubs from eating it or from rotting away. By cutting it in half, usually through the rose end where there is normally a strong cluster of shoots they were doubling their amount of sets. In my case though I wanted the maximum amount of seed potatoes to plant so I first cut through the main cluster and then sub dived them wherever there was a chit or shoot emerging from the eyes.
Cutting them does not reduce the yield if a sufficient size piece is used and this can improve the size of the potatoes which is not a bad thing of course when you want them for exhibiting. The reason for that is that each eye develops its own plant, too many sprouts amounts to crowding giving you more potatoes but smaller in size. The whole seed potato itself only provides food for the early stage of growth, once planted up in my own potato compost, roots will develop from the base of the shoots. After this point the young plant will then grow on getting all the nutrients it requires from the fertilisers in the growing medium.
The two white varieties produced 13 pieces with a shoot on each whilst the two red ones produced 16 pieces. From four potatoes therefore I now have the potential to plant 29 that in theory should produce me sufficient crop to make two good baskets. The white variety would appear to have a real opportunity of winning on the show bench as well. However the shoots on the cut pieces are all at a different stage of development with the ones on the Rose end being more advanced than the others. One precaution I took when cutting through them was to make sure that I wiped the knife clean after each cut just in case I passed on a virus form one variety to the next.
I cut the potatoes last Saturday morning and each piece was carefully dried with absorbent tissue and then left on a tray for the cut surfaces to dry out prior to planting them on Monday.
However I won’t be planting them directly in to the 20 litre pots as there’s always a possibility that one or two might not develop and possibly rot away. So what I’ll do is plant each individual piece into a 5 inch pot using my own potato compost. This way I can re plant them into the 20 litre pots at varying stages as the haulms slowly develops on them. I will have to be very careful when handling the cut pieces as the shoots are often right on the edge and can easily be knocked off. This is the way I used to start all my potatoes
when I was growing them for the Chelsea displays in May and it worked perfectly.