Potatoes and Leeks
28th Feb 2001
We have had the hardest frost here in Anglesey for many years, indeed over the past few seasons I have been able to leave my geraniums outside in their Summer containers giving me an even better colour display the following Summer. It's not be this year though, they have all been killed off and it's not too late to still get some frosts.
Particularly vulnerable to frost at this time are the young sprouting shoots on your exhibition potatoes, do make sure that they are well protected.
The problem with potatoes is that they can not be covered over with anything dark for too long as you want the emerging shoots to be green, strong and sturdy and this can only be achieved through allowing plenty of light to get at the shoots. Mine are currently in the garage which is frost free, but if you have them in a shed, then do cover them over with one or even two layers of fleece that will give the shoots some 5 degrees or so of protection.
As we are now nearly into March, hopefully the weather will soon warm up, this will be a sure sign that the aphids will start to look for some nice young shoots to have a bite at. Potato shoots can very quickly be covered with these sap sucking insects and these are also responsible for transmitting viruses so do keep your eyes open on your potato stock. If you suspect that some aphids are beginning to colonise then a spray of a suitable insecticide should keep them clean. For even sturdier shoots, add some Maxicrop to the sprayer which I find quickly darkens up the young shoots.
My leeks are progressing along nicely and will soon be ready to be moved on into 6 inch pots as the roots are already well wrapped around the 4 inch pot.
Leeks are undoubtedly hungry plants when actively growing so the mixture this time will contain more soil than previous and is as follows - 4 parts of Levington M3, 3 parts of soil sieved from last years leek beds. Do not make the mistake of sieving your soil too fine, the roots on both leeks and onions prefer to have plenty of rough, coarse material in the mix which not only resembles what their growing environment is going to be like, it also allows for plenty of air to get at the roots in the pots as well as sufficient free drainage. Finally add 1 part of medium grade Vermiculite, I find that both the leeks and the onions love this light airy moisture retentive material and really helps towards promoting a vigorous and strong root system.
The leeks will now be placed back in my growing cabinet for ten days or so, just enough time for the roots to get set into the new compost. After this point I intend to remove them and place them on the open bench in the greenhouse without any added lights on to them. The reason for taking them off the lights, even though they have only been subjected to a regular 16 hour lighting period throughout, is that they appear to me to be very advanced and I certainly do not want to push them along any more than is necessary.
The air temperature in the greenhouse will be maintained at a minimum of 55°F so hopefully the growth rate will slow down, the plant will become a darker coloured green and generally look sturdier.
At this point as well I intend this year to give them their first collar which will be made from a piece of builders damp course material measuring 9 inches by 12 inches. This will be rolled around the barrel or stem of the leek, initially to give a height of 9 inches. As the plant grows on and extends upwards in search of light, so the collars will be extended. The next collar, depending on how the plants are growing, will probably be given when in their growing beds and will be the same piece of material only rolled around the barrel the opposite way around so as to give a length of 12 inches.
Further collars will be given as they grow on by cutting another piece of damp course material measuring 15 inches by 18 inches. This means that you only really need two pieces of material to give you three lifts on the blanch. As the leeks are usually planted with the root plate 3 inches below soil surface the 18minch collar should be the last one.
Always bear in mind when applying collars to your leeks that it's very important that the length of collar applied at any given time is in proportion to the plants size and weight. It"s no use at all for instance applying a 9 inch collar to leeks that are only 10 twelve inches tall and pencil thick, in such cases you must wait until the plant is much larger all round. As a rule of thumb I always like to see my button a few inches down inside the collar with enough flags or leaves above the top of the collar hanging down and nearly touching the compost in the pot. Later on the flags will be growing so well that they will actually be lying on the bench itself and care must be taken not to damage them.