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Medwyn Williams

Hello. I'm Medwyn Williams – eleven times Gold medal winner at the Chelsea Flower Show, Past Chairman of the Royal Horticultural Society Fruit Vegetable and Herb Committee and President of the National Vegetable Society.

Crunch Time for the Exhibition Potatoes


My potatoes have now been planted for 12 weeks and will more than likely be ready for harvesting. It’s very important to know when to start harvesting the different varieties as you really want them when they are approaching optimum growth.

We are now getting very close to crunch time as regards the exhibition potatoes that were planted on the 8th May. They were planted strictly in accordance with the way Trevor Last grows them which I fully explained in my Garden News articles on the 18th and 25th April this year. The articles certainly generated a lot of response and it seems to me that a number of growers have decided to follow Trevor’s method. Some of you may well have sown a bit earlier than I have, in such cases you will probably harvest earlier than myself as well.

Planting Regime

It suits my growing regime perfectly to plant the potatoes during early May, first the temperatures are rising so they will reap the benefits of warmer evenings to come. Secondly once they are planted and covered over with polythene I can forget about them until after my return from the Chelsea Flower show. Mine were planted on two very sandy raised beds which I used to grow my short carrots in and I managed to get 3 rows of polypots, 9 per row in each bed which gives me a total of 54 bags. I have no specific show or classes in mind until I actually see the quality of what I have grown, but looking at the haulms, I would say that they are already starting to talk to me!! With no particular aim in mind rather than proving how well Trevor”s system works, I eventually planted the following varieties – 10 Maxine, 12 Winston, 14 Kestrel, 15 Amour. 2 Martine and 1 Jersey Royal.

A few of you will certainly frown at the inclusion of the last variety, but I just had to have a go at it after a customer of mine, Graeme Le Marquand from Jersey sent me some really top quality seed potatoes from one of the better growers in Jersey. Graeme reckons that the variety could well have show potential so I shall certainly be looking forward to see what sort of shape and skin condition it possesses. I have really spent time looking after the haulms this Summer, behind every pot I have pushed in a 4 ft cane and the haulms have been tied to the cane on three occasions.

This may or may not mean a thing as regards the ultimate quality of what I shall harvest, however, it certainly made it a lot easier to spray the plants against Blight on the one occasion that I have done. Usually I can get away here in Anglesey without spraying as the crop is lifted very early and usually before any potential spores have had time to do any damage. The other benefit of tying up was that it minimised the risk of snapping off the tender haulms when I was passing between the rows. Some of the top growers don’t bother tying the haulms at all, they leave them to their own devices to settle down naturally on top of the pots.

I am certainly not going to question that theory, but as I prefer to water my pots individually with a hand lance, I discovered a few years ago that if the haulms are left to collapse totally around the pots I found it extremely hard to get the water directed to where it should go, right into the pot. The way over this of course is to set up a watering system, either seeping hoses on top of the pots or a sprinkler type system over head. It is very crucial during the tubers development that they have plenty of water, they must never go without, it can seriously affect the quality of the skin finish that you end up with.


My potatoes have now been planted for 12 weeks and will more than likely be ready for harvesting. It’s very important to know when to start harvesting the different varieties as you really want them when they are approaching optimum growth. In order to make sure that I was going to lift them at the right condition, I sacrificed one bag from the middle of the pile a week ago. The skin condition was perfect on most of them but a few were lacking a little on overall size, so I have left them until this weekend. The skin condition is very important on potatoes, it should be as smooth as silk if they have been looked after properly.

The skins on the newly harvested potato varieties are very tender so you must make sure that it has set firm, this will enable you to wash off the compost and give the potato a shine with a soft sponge and water with no fear of the skin peeling off. In order to get the skin into this washable condition you have to remove the haulms completely from the potatoes leaving about 4 inches of stalk. It’s very important after this to make sure that the bags don’t get wet again and you can guard against this in two ways. Either throw over the whole bed a sheet of polythene or remove the pots and take then into a garage or polytunnel. They can then be covered over with black and white polythene, white side up if in a polytunnel to keep them cool and dark.


The potatoes can be removed from the bags after a minimum of 7 days when they can then be graded into various sets and different shows that you intend to compete at. Spend plenty of time to closely examine each tuber to make sure that there are no blemishes on them such as slug holes or scratches. They can then be stored back in the same peat that they came out of, use boxes or buckets that are clearly labelled with the variety and the quantity and which show or class they are intended for. Keep them cool and in the dark and wash them as near to judging as you can so that they look fresh and sparkling. Who knows, with a little bit of luck I might even get a Red card this year, if I do, it will certainly be down to the advice given by Trevor Last.


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25th July 2007 I am often asked what is the best method of growing both long carrots and parsnips for the show

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