F1 Hybrid Exhibition Onions
17th Mar 1999
This coming week I shall be busy at it planting my large exhibition onions in three raised beds each of which is approximately 20 ft long and I should finish up with around 60 plants. Most of the onions that I intend to grow are from seed that were sown a week before Christmas and are from the single onion that Mel Ednie kindly gave me a few years ago. This onion is therefore not only capable of growing to an immense size, it also has all the meritorious qualities that's required in order to have a winning quality set at the highest level.
The remainder, a dozen or so, will be plants that were sown from what is probably the first F1 hybrid exhibition onion seed developed by one of Europe's top onion hybridizer. This is a cross between Ailsa Craig and Balstora and in field trials, where the onions were simply sown directly and thinned to a few inches between each plant, the bulbs grew to over a pound in weight. Given the much earlier sowing date, the benefit of increased vigour that comes with a hybrid, warmth, artificial lights and finally being grown under polythene covers in raised beds should increase the yield considerably.
Another meritorious quality that I'm hoping for in the new hybrid is a much darker skin colour, nearly all the large exhibition varieties posses a very light straw colour, so this deeper shade, if it transpires, should be very pleasing to the eye. The breeder has also taken three of my largest onions last year for further hybridising work and this coming September I should have some F1 hybrid seed for trial from six different lines. Some of the above hybrid plants are also being grown on in pots to see how they will fare as possible candidates for the under eight ounces class, or 227grms or under if staging under RHS rules and 250 grams or less if staging at shows being judged under NVS rules.
I must make it quite clear that the only reason that I"m planting my onion plants so early in the year is because the soil in each raised bed has already been warmed up using soil warming cables, the soil temperature is now at just under 60°F. Please don't even think about planting your onions this early unless you can warm your soil up sufficiently, it would be a disaster, there is a grave risk that they could all probably go to seed or split in two, so wait until the soil warms up naturally to around the 60°F mark. In the meantime pot the plants on into larger pots and think about planting them during April.
Before planting, the temperature and the lights will have been reduced in the greenhouse in order to slowly acclimatise them to their growing environment and each pot will be fully charged with water the evening prior to planting. The beds required very little in the way of base fertiliser dressing as the soil analysis stipulated only an ounce of nitrogen per square metre was required. However, over the last two years, I have noticed that my onions seem to run out of steam towards the end of June to early July and are ready for lifting towards the middle of July. This makes it difficult to have quality onions with good skin condition during September when, over the past few years, the Nationals have been held.
Because of this I intend, as a trial, to deal with one of the three beds in a different manner this year, by forking into the base of the planting hole some Levington slow release nutrients called Ficote 70 which has a ratio of 14:14:14. The release of the balanced plant nutrients from Ficote 70 is temperature dependant with the nutrient release under warm conditions accelerating in line with the plants growth rate. The nutrients are available for at least 3 to 4 month under covers. I am hoping that this element of slow release will keep the plants ticking over for a longer period.
This is a gamble in a way as once the fertiliser has been incorporated into the soil, it's like a ticking time bomb slowly releasing nutrients in line with growing temperatures; should the growing pattern be greater than my needs, then I shall have to put up with it; I shall certainly keep you informed on it's developments. Ficote 70 is a commercial product but Phostrogen also sell a similar product in small quantities called 'Season long' which is also an excellent product should you feel the need for a slower release of nutrients over a longer growing period.
The two canes and plastic support clips that are now supporting the plants in the pots will be retained and re positioned after the onions are planted. The soil thermometer that I have in one of the outer beds will be checked regularly to make sure that the soil temperature doesn't drop too low, also the air temperature will be monitored using a maximum minimum thermometer. Whilst I have no intention of heating the polytunnel should temperatures drop, it will be interesting to note how low they will drop during the next month or so and to see what effects, if any, that low temperature will ultimately have on the plants development. Should the temperature drop below freezing I shall cover the plants over with some fleece that I already have on stand by.