Ted Snazelle, Mississippi

Update on Using Bleach as a Post-Lifting Daffodil Bulb Dip

June 10, 2013
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Categories: Basal Rot, Diseases and Pests, Fungus

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In The Daffodil Journal, Volume 48, Issue 3 (March 2012), pages 214 – 216, you will find my article on using bleach (sodium hypochlorite) as a post-lifting daffodil bulb dip.  In the article, I mentioned that plain bleach (no additives) contains 6% sodium hypochlorite (NaClO [NaOCl]).  Although I have worked with formaldehyde from my undergraduate days all the way through my 43 years as a professor, I finally came to the conclusion that formaldehyde is just too dangerous to work with, not only because it is a known cause of cancer (carcinogen),  but also because it’s volatility makes it potentially quite dangerous to the eyes.  So, my standard practice now is to dip my lifted and washed daffodil bulbs in 0.5% NaClO for 15 minutes.

It seems that generic  6% NaClO bleach is no longer available (at least not in the Kroger store where I shop).  Instead, a generic bleach, often labeled 33% stronger (because it contains 8.25% NaClO instead of 6.0% NaClO) is available.  According to the label, generic 8.25% NaClO generates 7.86% chlorine, and it is the chlorine that actually kills spores of fungi, including spores of the basal rot fungus, Fusarium oxysporum f.sp. narcissi.  So, in order to make a gallon of 0.5% NaClO, you need to put one cup (237 mL) of 8.25 % NaClO bleach (slightly more than the actual 229 mL required) in an empty, washed gallon milk jug and then fill the one gallon milk jug to the top with water giving you a gallon of 0.5% NaClO.

How do I dip my bulbs?  First, I take mesh bags of freshly lifted daffodil bulbs and hose them off thoroughly, removing as much soil, etc. as possible.  Then, I take two five gallon buckets and put approximately 2.5 gallons of 0.5% NaCLO in each bucket.  Next, I tie one end of a rope around several bags of bulbs and the other end of the rope around several other bags of bulbs.  Noting the time, I then simultaneously, and vigorously, dip both strings of bulbs in and out of the 0.5% NaClO of the two buckets, and then let them stand for the remainder of the 15 minutes.  After 15 minutes, the bags of bulbs are removed from the 0.5% NaClO and allowed to drain and dry until the next morning.  Last, the bags are hung from the rafters of my carport storage building to complete drying and too cure the bulbs for about eight or more weeks.   The dirty (muddy) 0.5% NaClO is then disposed of by pouring it over my gravel driveway or onto my daffodil beds where I had previously dug the bulbs.  Sometimes, I will pour the used 0.5% NaClO over large fire ant hills.  I doubt that this kills the fire ants; however, it might encourage them to move over to my neighbor’s yard!  I feel that one use of the 0.5% NaClO makes it too dirty, and perhaps less potent, than the fresh 0.5% NaClO.  So, as generic bleach is so cheap to buy, I make a fresh batch of 0.5% NaClO for each time I dip daffodil bulbs.

Safety measures to be followed:  1) wear protective eye ware, 2) vinyl or rubber gloves, and 3) immediately wash off with running water any NaClO that may have splashed or spilled onto exposed skin.

So, for 5 bonus points to be added to your narcissus basal rot control exam:  1) How do you spell correctly the scientific or species name of the basal rot fungus? 2) How do you make a gallon of 0.5 % NaClO? 3) For what does the f.sp. of  Fusarium oxysporum f.sp. narcissi  stand? 4) How many milliliters (mL) are there to a cup? and 5) What is the name of the active ingredient of bleach?

Answers to basal rot control questions:

1) Fusarium oxysporum f.sp. narcissi

2) Add 1 cup of 8.25% NaClO to a gallon milk jug and fill it the rest of the way to the top with water.

3) form of species OR forma specialis

4) 237 mL

5) sodium hypochorite or NaClO

7 responses to “Update on Using Bleach as a Post-Lifting Daffodil Bulb Dip”

  1. David Adams, New Zealand says:

    Ted,

    Why dip in any chemical, or waste water washing bulbs when sun drying both sterilises and cleans bulbs in one harmless procedure?

    Dave

  2. Bob Spotts, California Bob Spotts, California says:

    For me, sun drying here in Oakley, California has not been harmless. It cooks the bulbs.

  3. Don Caton, Pennsylvania says:

    I have been digging one of the beds this past 2 weeks.  The weather has not been great – about 3 non-consecutive  days of sun,  6 inches of rain in two weeks, humidity above 70%.  They are bagged and sort of drying on my porch, but due to the high humidity, they are still damp.  Ted’s article sparked an interest. Is the bleach treatment still effective if the bulbs have been out of the ground for more than 72 hours?  If I do use this method, is it still okay or necessary to HWT later this summer?

     

  4. Kathleen Simpson, West Virginia says:

    Don,

    I have had problems before with deformed bloom the year after planting, when doing a prolonged soak (20 minutes) in a 10% chlorox/90% water solution right after digging.  However, there was no storage loss, the plants seemed to be especially vigorous, and the bloom was normal the 2nd year down.  As you say, the weather this year is really bad for digging and the bulbs I dug Friday were still damp this evening and maybe showing some signs of rot – they just spent 15 minutes in a 10% bleach solution and will be dried inside.  To heck with next years blooms – I want these particular div 5 bulbs to make it through the summer!  Taking them out of their bags, spreading them on newspapers, changing the paper frequently, and using fans speeds up the drying.

    Good luck.

  5. Ted Snazelle, Mississippi Ted Snazelle, Mississippi says:

    Friends,

    I have read with interest the comments about my use of bleach (sodium hypochlorite [NaClO]) as a disinfectant on lifted, washed daffodil bulbs. Usually, I dip the bulbs the same day they are lifted and washed.  I don’t leave my bulbs out in the sun to dry because as Bob Spotts said: ” For me, sun drying here in Oakley, California has not been harmless. It cooks the bulbs.”  Ditto Mississippi!

    Don Caton, asked: ” Is the bleach treatment still effective if the bulbs have been out of the ground for more than 72 hours?”  I believe that the bleach treatment would still be effective as its disinfectant properties ought to kill fungi, etc. that are on the outside of the bulbs.  I assume there would be no reason why HWT could not be performed on the bulbs later in the summer.  HWT late in summer would be effective in killing bulb and stem nematodes, bulb scale mites, and fly larvae.

    Kathleen’s comment caught my attention: “I have had problems before with deformed bloom the year after planting, when doing a prolonged soak (20 minutes) in a 10% chlorox/90% water solution right after digging.  However, there was no storage loss, the plants seemed to be especially vigorous, and the bloom was normal the 2nd year down.”

    In the one controlled experiment that I ran, The Daffodil Journal, Volume 48, Issue 3 (March 2012), pages 214 – 216, all the bulbs were ‘Ice Follies’ and were planted fall 2010 at the entrance to our subdivision.  They were dug after blooming and dying down in spring 2011.   The lifted bulbs were washed and given a 15 minute soak in O.5% NaCLO.  Then they were hung to dry and cure over the summer with very little or no storage loss. Fall 2011, they were planted again at the entrance to our subdivision.  In spring 2012, I  did not notice any deformity in bloom.  That being said, the only differences in my NaClO dip and Kathleen’s was that I used 0.5% NaClO for 15 minutes, and she used 0.6% NaClO for 20 minutes.  Could Kathleen’s higher concentration of NaClO and longer time of dip caused the deformation of the bloom as it developed in the bulb?  I don’t know.  However, it has occurred to me that if the roots of the bulbs were still fresh and white, and not dried up at the time of the NaClO dip, the NaClO could have been absorbed by the roots, and once inside the bulb could have damaged the bloom meristem enough to cause bloom deformation that was seen the following spring but not    in the spring a year later.  So, if the NaClO damaged the embryonic bloom, and the deformed flower was seen the next spring but not in the spring a year later, then one would could conclude that the NaClO in the bulb had dissipated. Does the condition of the roots of the lifted bulb, determine whether NaClO is absorbed or not?  Absorbed . . . embryonic bloom damage?  Not Absorbed . . . no embryonic bloom damage?   More food for thought.

     

  6. David Adams, New Zealand says:

    Ted and Bob,

    This is a true but facetious comment not made to add to the scientific reasons for dipping bulbs. I too have cooked bulbs during sun drying, it gets very hot here in Canterbury. I think the key is more to make sure the bulbs are completely dry before storage. But I would add that I and others, have cooked more bulbs with HWT than we have with sun drying.

    Dave

  7. Don Caton, Pennsylvania says:

    Thanks for the discussion. It seems that there are varieties of concentrations of NaOCl on the market.  The one I am using is made by CLOROX.  It states 6% NaOCl, yields 5.7% chlorine. With this in mind,  what is the proper amount of CLOROX should I use to get the 0.5% recommended by Ted?  I know it to be a ratio  but I flunk math and  chemistry is ancient history.
    Also, for my pool, I use Spectrum chlorinating granules – sodium dichlor-s-triazinetrione dihydrate 99% –    available chlorine is 55%.  could this be used and at what rate?

    Don