Seed floats in water -- is it chaff?

My Dialaelia seed capsule burst open after only three months and when I mixed the seed in the calcium hypochlorite solution it all floated to the top. Question: does this mean necessarily the seed is bad? Isn't seed supposed to sink? (I don't have a microscope to look at it.)

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Cheers,

Alex

This is a message I got on another forum, I decided to post it here too so we have it:

"Not necessarily. If the majority of seed are sterile, you can often tell just by the way they behave. They don't fall individually, they stay clumped. Some seeds sink fairly quickly and some float until they become more saturated. I do a 24 hour pre-soak with sugar water and a bit of dish soap. After 24 hours with frequent agitation, the seeds containing embryos should be on the bottom. Sterilization will be more thorough because air in the seed will have been displaced and the sugar water should help stimulate any contaminants in their cystic stage to become active so they can be killed."

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Cheers,

Alex

Thanks for posting!

amaximia, that's very good info. I was going to say to wait 24 hours to see before you came to any conclusions, but I never knew about the sugar water / dish soap method. Thanks a lot!

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Louis J. Aszod

I think the sugar water is only meant to "draw out" the bacteria. Standing in water with the 2 drops of soap, so called "wetting agent" is what causes the sinking. I'm about ready to desinfect with calcium hypochlorite since it's been 24 hours. I'll try flasking then.

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Cheers,

Alex

What is calcium hypochlorite and what is it sold as? I am new to the flasking part of orchids and one method I read used 30% bleach and sterile water. The other method used Hydrogen peroxide. What method is this and how is it done? I am planning on buying some seeds and they are going to beed to be sterilized. Thanks for the info.

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Josh

So many orchids and so little time!!

Sodium hypochlorite is what they make bleach with; bleach is a weak solution (%1.5 –*%3.5) of sodium hypochlorite. When these techniques call for a %30 or %10 bleach solution, this does not mean a %30 or %10 solution of sodium hypochlorite (which would be very dangerous to work with) but instead a %.6 or %.2 sodium hypochlorite solution.

As far as the use of hydrogen peroxide goes, I seem to remember that these were interchangable in terms of technique. Solutions for both can be used in the same way, for the same purpose. Don't take my word on it though; it's been a little while since I've done research on flasking techniques.

Let us know how it goes!

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I am trying to hurt your dog.

Thanks Sue. So a 30% bleach solution would be 3 parts bleach to 3 parts water? I think I did the clac right. I will check back here to make sure I got the concentrations right before I do it. What would you use sue to do your seeds and how would you go about mixxing? I will let everyone know how it goes. I will be ordering from the seed bank progect in the next few days. Will give a list of what I purchased and what took. Thanks again.

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Josh

So many orchids and so little time!!

%30 bleach solution: 3 parts bleach, 7 parts water. BTW, check your source on this – %30 seems awfully strong to me; usually a %10 solution is plenty for sterilization.

It's been a while since I've tried sowing any seeds, and we never got down a good technique. I don't remember how we mixed the medium, but I do remember that it ended up being a little chunky.

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I am trying to hurt your dog.

Hi

I sterilize with both bleach and H2O2. I have much success with both.
I soak for 24 hours in a sugar solution. This activates bacteria and fungi making them more suseptable to the sterilizing agents. It also makes the seeds sink.

I use a 5% bleach solution. I mix it as follows:

5 ml of 5.25% sodium hypoclorite bleach
95 ml distilled water

for 12-15 mintues

The H2O2 is stratight from the bottle 3%.

for 20 mintues.

I leave seeds in H2O2 for longer becasue I have more contamination when using it. But that could be becasue the seed is more contaminated to begin with.

I put one drop of wetting agent in with all of the above. The wetting agent is one or two drops of dish soap in 50 ml of water. I use the small test tubes the Aaron Hicks advertises on his web site to sterilize my seeds. Work very well. Buy his book, it is excellent.

Kyle