Exhibition Quality Potatoes in Polythene Pots
11th Mar 1998
I don't think I've ever had so much correspondence regarding any item that I have written about than the one last year on Allister Gray's success with growing exhibition quality potatoes in a polythene pot. The people who wrote to me were over the moon with the results that they attained, results that seem to be very consistent throughout the country.
The main reason for this of course is the fact that the method of growing them doesn"t depend on the use of soil. Indeed the use of soil is completely unnecessary in the bags as the potatoes are grown in nothing but Moss peat and added fertiliser. This consistency is therefore one reason why most exhibitors are now turning to this method of growing.
Undoubtedly, as in a number of other growing methods in the exhibition game, it is going to cost you some time and money as 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.
Type of Pots
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. I have never tried to grow them in a larger polypot, but if you were to purchase the next size up which is 15" across when filled and 12" deep it will certainly cost you considerably more as it will actually contain 30 litres of compost, nearly double the other size.
I recently phoned Allister to enquire how successful he had been with the system this last Summer, and again he had the best results ever; in fact he had told so many other growers in his locality about his method that the standard of potatoes at the Brechin show were about the best ever. Allister uses a 300 litre bale of peat to which he adds 4 lbs of Vitax Q4 and 4 lbs of Seagold or Calcified seaweed, and that's all that's in the mixture.
A number of readers queried the quantity of fertiliser wondering if there had been a mistake, well there wasn't, the potato is a hungry feeder and requires this level of nutrients for sustained growth. For those of you who want to grow them on a smaller scale then to 1 polypot full of moss peat you need to add 4 ounces of each element.
If you work with a bushel box, then, if my arithmetic is anywhere near right, 1 bushel = 8 gallons or 36.40 litres which means that you can fill just a little more that two polypots from one bushel, one bushel of course would then need 8 ounces of Vitax Q4 and 8 ounces of calcified seaweed. Last year I have to admit the system worked exceptionally well for me and I had some marvellous specimens of good size, shape and condition. As I had no Vitax Q4 to hand I used Chempak BTD (base top dressing) which gave me excellent results.
Once the pots are filled they are then placed side by side into a furrow or trench the width of the pot and about a spit deep, the soil from the row is piled up on either side of the trench to be eventually pushed back around the pots to anchor them in position. Prior to positioning the pots, the bottom of the trench is forked over and 4 ounces per metre length of potato fertiliser is incorporated into the top few inches an a good scattering of slug pellets. If you have no potato fertiliser then any balanced dressing such as Vitax Q4 or Chempak BTD will suffice. A stout cane is then placed behind each pot to which the haulms are regular tied to.
I already have all my potatoes chitted and the varieties for the coming season will be as follows Kestrel, Winston, Nadine, Purple Eyed Seedling and Harmony (both of which I had from Bill Hughes Swansea and formed part of his winning British Championship collection). In addition to the above I shall be growing the new variety called Osprey, bred by the same renowned breeder as kestrel and promises to be every bit as good, this one has a pink eye and I had it from Castlemill seed potatoes.
Another very promising one that I have had gien to me on trial is Merlin. a round white with a nice splash of pink which I'm sure will make it's mark on the showbench in the future. If you haven't already ordered your seed potatoes then a list or catalogues can be had from the following seed potato specialists, but you must order immediately if you are to have a chance of getting them chitted in time;
Castlemill seed Potatoes, Stormont, Lower Borland park, Auchterarder, Perthshire PH 3 1JR. Tel 01764 662 088
G. M. & E.A. Innes, Oldtown, Newmachar, Aberdeen AB21 7PR Tel 01651 862 333
Websters Seed Potatoes, Unit 16, Ogilvy Place, Arbroath, Tayside DD11 4DE 01241 434 833
Suttons, Dobbies, Marshalls, and Thompson and Morgan also have an extensive list of seed potatoes.
Further cultural inforamtion on the growing of these potatoes will be given as the season progresses.