Winston and Kestrel Show Potatoes
28th Apr 1999
I shall be getting on with planting my show potatoes this week if the weather settles down for a few days as it's a job that I can not complete in just one day. The potatoes have been grown in my friend Jim"s back garden for the past five or six years and the spent peat from the trenches and polythene pots have all been worked back into the soil which has by now turned what was a rather hungry soil into a lovely friable dark composty medium.
Even though the soil is now in a really good condition I still won't plant directly into it as the resulting potatoes, though probably excellent in every way for the kitchen, they would inevitably have the odd scab on them which would ruin my chances on the show bench.
The potatoes have chitted well this year and as I am concentrating my efforts on only two banker varieties I should have a large selection to chose from. The varieties are Winston and Kestrel, both well proven on the show bench and both are varieties that have silky skins that clean up well.
The above varieties are more than capable of producing really large specimens if well grown and any that are over 8 ounces in weight should be utilised in the kitchen as they would be considered to be too large according to the NVS and RHS judging rules.
Keeping Down the Weight
One way of ensuring that the potatoes are kept down in weight is not to remove too many shoots from each potato. The more shoots you leave on a potato then the number of potatoes under each haulm should increase but the average weight or size of the potatoes will be smaller. Conversely if you reduce the shoots or sprouts on each one, down to say one, then the number of potatoes under each haulm would be reduced and the weight or size increased.
Try the above therefore by increasing or decreasing the number of sprouts per potato if you are having problems with size. The variety Bishop or Purple Eyed Seedling is often shy of producing large specimens and every seed potato should therefore be reduced to one or two sprouts. With Kestrel and Winston, I intend to leave 3 to 4 shoots on each one as I normally have some very large specimens. It is really up to each individual to reduce the number of sprouts based on previous years results as this can vary geographically as well as according to the strength of the mixture that you are using to grow them in.
Growing them in polythene pots has undoubtedly been a success and I intend to carry on using that system this year whilst at the same time trying out a row or two in a different way. The pots that I used last year were more than adequate for the function and measure 12" across when filled and 11" deep and each pot will take in the region of 17 litres of compost. You will need large quantities of peat in order to fill the polythene pots which are usually referred to as Polypots. However, as your chances of attaining top quality potatoes is vastly improved, the extra money spent should make it all worth while. First thing though is to understand the method; the potato is placed near the bottom third of the bag after it has been filled with the compost where it will grow throughout. Although there is a liberal amount of fertiliser in the bag for the development of the actual potato, the theory is that the feeding roots of the potato can work their way through the relatively small holes in the bottom of the bag to the fertile soil below where they can further sustain the plants growth.
Last year I used a 300 litre bale of peat to which I incorporated 4lbs of Vitax Q4 and 4lbs of Seagold or Calcified seaweed, and that is all that is in the mixture. However, for those who need smaller mixes, then the ratio is 4 ounces of each of the above elements to fill up one polypot. As the plants are growing, do make sure that the haulms are supported and I use a six foot cane pushed into the soil at the back of each pot to which the haulms are tied using a soft strong twine.
The trial this year will be carried out by opening a trench two spades wide and a spit deep. This trench will be lined using thin black polythene, (120 gauge); this material is usually used to cover capillary matting on greenhouse benches and has micro perforations in it which will allow water to drain through. The whole trench will then be filled up level with the above mixture. This should make it much easier to water the plants and allow the roots to have a free run.