Planting Show Potatoes for Chelsea
18th Jan 2001
Potatoes should have some shoots prior to planting
Before you start make sure that those potatoes you intend planting have some shoots on them which will help the potato get off to a good start. For Chelsea I usually grow around eight varieties for a good colour mix planting about ten of each kind and in the past I have been successful with good sized potatoes from the following varieties : Winston, Kestrel, Salad Blue and Salad Red, Lighthouse, Coco, Pentland javelin, Osprey. This year however I am concentrating on fewer varieties in order to give me an even larger selection to chose from.
As my greenhouses are all full to the hilt at this time of year I always start them off in my friend Jims' greenhouse. He has a ten by eight type and the heater is set at just above freezing which still gives the potatoes a first class start. They are all initially planted up into five inch pots, I use square ones for convenience as they fit better on the bench and the post are first half filled with Levington M2 or some Gro bag compost, the potato is then placed on top with the sprouting eyes upwards and then covered over with more compost and in my case, labelled.
The potatoes grow well in this manner as they take very little room and in a week or two they will soon be pushing through the compost. They are then left on the bench until around the end of February to early March at which point they are taken from Jims" to a large commercial type greenhouse at the Bangor University. By this time they will have had the odd spray of a pesticide to make sure that no sucking aphids get a chance to colonies on the tender succulent shoots. The haulms will now will be anything between six and eight inches in height and ready for moving on.
Deciding on How to Grow On
In your case you now have to decide how you are going to grow them on; you can use either the polythene pots that many use for growing them to exhibition standard or use a large plastic pot. In the past I have used very successfully for eating, some second hand floristry buckets and just after Christmas is often an ideal time to pick these up for next to nothing from some of the major supermarkets. I have now got over a hundred of these and you need to do is to drill a few holes through the bottom to permit adequate drainage. Another way of growing them on is to use old fertiliser or compost bags but do make sure that you cut off the two bottom corners, once again for drainage.
Fill the bags twelve inches high with a peat based medium, some old Gro bags will do but make sure that you add some balanced fertiliser to the mixture. Roll the edges of the bag down leaving just enough of the sides left to retain water. Remove the potato plant from the five inch pot and plant it well down into the compost until the haulms are buried up to half their height, water well and leave them in just a cold greenhouse. In many ways this is the best method as it contains more compost which allows you to plant up to three of these plants in one bag. Another good thing about utilising these bags is that they can save the growing haulms of the potatoes from frost.
Over the past few years, where I live here in Anglesey, we have been very fortunate in not having any real hard frost so a layer of fleece over the haulms would suffice and keep them frost free. With the bags though all you have to do if it is freezing is to roll up the sides of the bag and tie it together above the haulms, this will keep the frost off and during the day it can be rolled down again.
45 Gallon Drums
In my case the potatoes are planted in 45 gallon drums cut in half and laid out in a row on a concrete floor and the drums are filled up with Levington compost. Five plants go to each half drum and planted once again until only half the height of the haulm is exposed The bottom third is given some fresh Levington M3 and the remainder is filled up with Gro bag material. the reason for using Gro bags is because the tomato and the potato plants are related, they are both from the Solanum family so the potatoes should, and do, grow well in this medium. I have only covered them over once with fleece whilst I have been growing them like this at Bangor in the last five years as the weather has been so mild, but I will have some fleece to hand, just in case.