Formalin and HWT

I’ve read many posts where people use Formalin as a fungicide when doing HWT. Many posts say Formalin has been banned. I see it is available for sale on Ebay.

1) Should I purchase some for my HWT?
2) How to safely dispose of the Treated water?
2) What concentration would I use? Both 37% and 10% Formalin are available.

I’ve used bleach in the past but Formalin sounds like a preferred product.

4 comments for “Formalin and HWT

  1. Test your bulbs and soil, first, to see if you have nematodes and fusarium. Your extension service can direct you to a university lab. No need to waste product and create exposure if your bulbs are pest-free.

  2. Hi, Bill,

    I know a teeny-tiny bit about this, enough to tell you to leave it in the same container outside in the sun for 48 hours and then flush it down the toilet if you’re rural, or a toilet or storm grate drain if you’re in a community. (This information came from a West Virginia Environmental Scientist about 2002). Formalin is sensitive to light.

    I’m pretty sure it’s bad stuff, and many people will advise you not to use it, and certainly not to breathe it, but in case people now or in the future, read this message, those are the only two ethical ways to get rid of it.

    Both 10% Bleach and hydrogen peroxide lose a lot of their efficacy with a high organic load, and I assume Formalin is in the same category, so make sure your bulbs and the net bags they are in are absolutely clean of all loose skins and roots, and even give them a rub, before you rebag for HWT, no matter what additive you use.

    Oh, and no matter which additive you use, don’t stand over the top of your cooking vessel and watch the water circulating as you’ll be breathing in the vapors.

    Unlike Bleach, which loses its ooomph after 24 hours, or Hydrogen peroxide, which loses its oooomph in a few hours, Formalin indeed stays pretty potent, so I’m glad you raised the question, Bill.

    Suzy

  3. Hi Bill,
    I had hoped that this issue was resolved many year’s ago. Maybe it would be wise to go back to the ADS Journals, the RHS Year Books and to Daffnet historical postings. Most evidence is anecdotal but strongly supported.
    In my view formalin is very dangerous and no longer necessary. We have determined that sun drying and the careful storage of bulbs will negate fungal problems. Over the years I have become convinced that cold dipping with fungicides is actually counterproductive. The rewetting of bulbs in summer warmth actually encourages fungal development. HWT will control nematode and bulb fly issues and improve the general health and vigour of your bulbs.
    Keeping it simple is the healthiest outcome both for you and your bulbs.

  4. Thanks for everyone’s input. I have always used bleach in my HWT and it seams to work just fine. I’ve always supported Organic gardening and have grown daffodils for years organically. Broke down last year and used some inorganic fertilizer. Did a soil test and found I was really short on Phosphorus. The fertilizer helped increased the size of the bulbs.

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