Scottish Rock Garden Club Forum
Cultivation => Cultivation Problems => Topic started by: SusanS on January 24, 2012, 07:47:01 PM
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Hi Everyone,
I am currently writing a college assignment on bulb growing. All of the books I have consulted (and Darren has a LOT of bulb books :) ) say that in order to get Hyacinths in flower for Christmas you should buy prepared bulbs.
(Google wasn't much help.)
There is no indication of how this preparation is done. There is some advice on how to grow the said 'prepared bulbs' once you have bought them. I stress this is not a question about simply forcing them to flower a little earlier than usual but specifically about the pretreatment of those bulbs sold for Christmas flowering.
Can anyone help please?
Cheers
Susan
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I may be wrong, but it is my understanding that prepared bulbs are simply pre-chilled. As you know the prepared bulbs need a cool growing on period to get some roots under them, but this cool growing period is shorter than the total chilling time required to induce flowering. so you buy pre-chilled bulbs that only require a short period off cool growing to induce flower. if you buy non prepared bulbs you can grow them longer in cool temps and then bring them in for forcing, but most places do not have the bulbs early enough for you to chill at home and still get flowers for Christmas. the regular bulbs could be used for early spring forcing but not winter.
hope I am right....
B
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Hi Bryan,
thank you for your reply. Both Darren and I thought it was that the bulbs had been chilled for a set period prior to purchase, thereby bringing the growing season forward.
However thought is not enough when you are studying ??? , as one of my tutors is fond of say "Where is your evidence?"
But now I have had my 'thought' validated by someone else, it has become a fact ;D and I can quite happily include it my assignment.
Cheers
Susan
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Here's something that might be useful: paper on the "Global Flower Bulb Industry: Production, Utilisation and Research.... all 116 pages of it... free!
http://media.wiley.com/product_data/excerpt/06/04705052/0470505206.pdf
I'm wondering if Luit has mentioned these preparation sytems in the Weekly Lisse pages?
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Martyn Rix Growing Bulbs (1983) has a section devoted to forcing bulbs for Christmas but curiously says nothing about how they are 'prepared'.
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Martyn Rix Growing Bulbs (1983) has a section devoted to forcing bulbs for Christmas but curiously says nothing about how they are 'prepared'.
that's one of the books I looked at and curiously exactly the same wording is used in the RHS encyclopedia ;D
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Thanks Maggi,
this looks a really useful site not only for this assignment but also for another one I have yet to start which is one the use of DNA /genetics within the horticultural industry. :)
Susan
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I don't know if it is just a case of one period of chilling that "prepares" the bulbs - I think it may a be a sequence of periods :-\
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http://www.bulb.com/ibc/binaries/pdf-bestanden/hyacinth_forcing-guide.pdf
"Temperature treatment: Introduction
The growth cycle of the hyacinth bulb encompasses distinctive periods - leaf formation,
flower formation and stem elongation. Forcing is achieved by advancing the flower-formation
period and then providing the most effective type of cold period. This is why hyacinth bulbs
grown in Mediterranean countries are used to produce very early flowers. The leaf-formation
period is accelerated by higher temperature during the bulb’s cultivation stage, hereby
starting the flower formation period earlier.
In contrast to other bulbous plants, early flower- formation in the hyacinth is achieved by
providing specific temperatures. One way of achieving this is to increase the temperature of
the soil in which the bulbs are grown (“Herald hyacinths”). Because of its expense, this
method is very rarely used. More commonly, the bulbs are lifted early and then given a
temperature treatment in an air-conditioned chamber to advance flower formation. The
lifting date and temperature treatment are the factors which separate the two methods of
production pot and cut flowers.
Temperature treatment: Prepared hyacinths
Bulbs are lifted around 20 June after which a specific sequence of temperatures is applied to
advance flower formation. Depending on where the bulbs are grown, the cultivar and the
lifting date, the flower is completely formed during the second half of August. In technical
terms, this is described as having reached “Stage G”. Since the hyacinth has a flower
cluster, this stage is not reached until the last floret is differentiated. The stem elongation
period can then proceed. Prepared hyacinth bulbs are used for producing pot plants intended to bloom until late December, and cut blooms until mid-January."
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Maggi you are an absolute star.
I might get to bed before midnight after all. ;D
Susan :-*
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Can I just drop in a say my Hyacinths in the garden have flowers above ground
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It true! Everything is known or can easily be discovered by users of this Forum. ;D 8)
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Susan, the chilling period is required for flower elongation. The evidence they request is everywhere: non treated bulbs will flower half inside the leaves rosette. The proper sequence of temperatures is an industrial secret. No one would expect the Dutch to reveal them.
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Susan, the chilling period is required for flower elongation. The evidence they request is everywhere: non treated bulbs will flower half inside the leaves rosette. The proper sequence of temperatures is an industrial secret. No one would expect the Dutch to reveal them.
and quite rightly so. :) As with any industry it takes time and money, not to mention a lot of hard work, to carryout research and develop good processes. :)
Thanks for your help everyone.
I think I have it clear now and my assignment is almost finished. Just need to compare modern practice / science against the 'rituals' I was shown as a child.
For example planting bulbs on a pile of crushed shell and course grit, (irrespective of soil type), and using a measure to ensure all the bulbs were at exactly the same depth.
Some of them I am sure were introduced to make sure that as a youngest I did the job properly ;D whilst others were very much "I've always done it this way" or "So and so planted his this way and he always got a good show" but without a real understand of why it worked.
Susan
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Susan, did not find this earlier, but here is a link to the site of IBC where you may find PDF’s about preparation of other bulbous plants as well. Don’t know how long this site will stay online because IBC does not exist anymore since Jauary 1st 2012.
http://www.bulb.com/ibc/us_en/professional/collection.jsf/Information/introduction (http://www.bulb.com/ibc/us_en/professional/collection.jsf/Information/introduction)
Maybe useful for your progress at school? ;)
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Hi Luit,
Thank you on behalf of Susan. I'm sure she will reply herself this evening - she is out at her work experience at a nursery today.
Cheers,
Darren.
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Hi Luit,
thank you very much for the link - I've just had a quick peek. I certainly will print out some of the information for future reference as it looks like a very comprehensive and informative site.
As Darren said I have been on work experience at the nursery today. Very aptly todays job was to line out the bulbs ready for the nursery reopening on 01st Feb.
It was lovely to look at the sales tables full of pots, with their healthy little shoots and in a few cases flowers. I spent a lot of time potting up the bulbs in the autumn, so it was great to see them looking so well. I am looking forward to seeing them in flower - there are 26 different narcissus varieties alone, so it should be a colourful display. 8)
Thanks again to everyone for their help. :)
Susan
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"and quite rightly so. :) As with any industry it takes time and money, not to mention a lot of hard work, to carryout research and develop good processes."
Of course, just in case it wasn't clear. Obtaining such precise temperatures involve years of research, expense and losses. It is only fair that they enjoy the benefit of their efforts.