Selecting Onion Bulbs for Seed Production
17th Dec 1997
Apart from having the dreaded white rot disease on about five onions out of 65 in my polytunnel this Summer, I was more than pleased with the remainder. The seed that I sowed came from the one single onion that was given to me by Mel Ednie, the current world record holder for growing the heaviest onion. The onion that I had however didn't come from his heavy onion bed but from another tunnel full of very large quality onions. Whether or not they were from the same strain as the heavy ones I"m not sure but the one given to me was perfectly shaped.
I now have a number of excellent onions that have stored perfectly and most of these will be re potted for seed production this coming week. The exception will be about a dozen that I placed in the cold store unit at Bangor University so that I can hopefully, take them with me as part of my proposed vegetable display at Cincinnati in Ohio during the last week in April next year.
There is no doubt that if you are to improve on the quality and consistent shape of your onions for exhibition, then the selection of bulbs for seed production is very important, so why don't you have a go yourself. You may well have complained that the onions you have grown this last season were very much a mixed bunch making it very difficult to get a matching set. The first thing therefore is to select a healthy bulb of good shape with high shoulders and a rounded bottom as against a flat one.
One thing that I have discovered over the years to my amazement is that you don't of necessity need artificial heat to produce the seed, it is certainly advantageous but not absolutely essential. A cold greenhouse will do fine in a large area of the country, after all if the onion rots because the frost gets at it, why worry; if it hadn't been planted it would have been eaten anyway. My father has a small 12 by 8 aluminium greenhouse and every year he puts down for seed a couple of nice shaped specimens in a ten inch pot using Levington M3 as the potting medium.
We are of course lucky living in Anglesey that we don't normally have too much extensive frost, but by covering them over with some layers of newspaper when there is a frost warning and placing some peat up around the pots, it's amazing how hardy the onion plant is and with a bit of luck it should survive to produce flower heads the following Summer and eventually your own seed.
Fortunately I have some heat and sufficient space currently for the onions to get established in the pots. Planting the bulb is easy, just make a slight indentation in the compost and sit the onion on top, do make sure though that wherever you are going to position the onion for it's initial growth, ideally it must not be moved about. Moving the pots around from place to place while the onion is trying to establish a root system can be a disaster, as the onions are so heavy, any movement early on will merely snap away any developing roots and the plant has to start growing new roots from the beginning once more.
As I said earlier it's important that you only plant the healthiest of bulbs, cut away any of the dried up neck as close to the shoulder as you can without cutting into the flesh. By doing this it will give you an idea of the condition of the onion around the neck as well as leaving the are free for the green leaves that will eventually push themselves out of the bulb. Another area to be vigilant of is right underneath the bulb, around the root plate, this can often go bad and any disease present will most certainly prevent the onion from rooting properly.
I have on many occasions, when my back has been against the wall and not enough onions to put down for seed, used the odd suspect bulb by completely removing a few layers of outer skins, even the heavy fleshy ones until the disease has been completely removed. When doing this you will very often find that you will expose a number of roots that have grown from the root plate inside the layers of skin, these of course are fine and care should be taken not to damage them. Removing the outer layers also has an advantage that in so doing you are exposing an are around and above the root plate where new roots will grow from.
If therefore you have a really nice shaped onion that you think you would like to see more of in two years time, then please have a go, there's nothing more rewarding than winning with a set of onions at a show that were grown from your own seed.