Surface 'sterilisation' of seeds.

[Giles]

I was interested to see in the Trillium thread, mention of the use of Hydrogen Peroxide to reduce surface contamination of seeds, prior to incubation.
Any advice as to concentration and length of time of exposure?
(I've only used bleach before on tough seeds: Domestos diluted 1 in 10 for 30 mins).

[Rodger Whitlock]

The 3% solution widely sold in pharmacies will do the job.

A friend was once driven to despair by his inability to grow Linum flavum compactum from seed. The seeds would germinate well but then keel over. I suggested using peroxide for surface sterilization, based on something I'd read somewhere — don't ask; I don't know where — and it worked. Simply put, though we think of seeds as being free of diseases, their coats can carry some.

I'm thinking about maybe following Susan Band's practice and routinely peroxiding all seeds from now on.

[Susan Band]

Giles, I just order it online as I never get round to remembering when I am near the shops. It comes at 33% with instructions for diluting to 3%. It is sold in alternative health shops apparently you can use it for some skin complaints. Mind you don't order it along with your fertilizer. Thats what is used for bombs 
Susan

[Giles]

Thankyou Rodger and Susan.
I've got 3% (Sainsbury's sell it).
How long do you leave it on the seeds, please?

[Susan Band]

For the Trillium seed I leave it for about a couple of hours as there is usually a lot of gunk to get through.It heats up if you put too many seed in too little solution.
Susan

[Giles]

 

[Maggi Young]

It heats up if you put too many seeds in too little solution.

Now that is an interesting observation....... a chemical reaction of some kind taking place.....

[Sinchets]

Did you not do the chopped liver in hydrogen peroxide experiment at school? Smells hellish but is lots of fun 

[Hans J]

Hi all,

I use this method with sterilisation with H2O2 since many years -please look in older advices from me :

http://www.srgc.org.uk/smf/index.php?topic=4142.msg108951#msg108951

http://www.srgc.org.uk/smf/index.php?topic=727.msg22277#msg22277

http://www.srgc.org.uk/smf/index.php?topic=1457.msg35110#msg35110

For other seeds I use Aatiram :

http://www.srgc.org.uk/smf/index.php?topic=727.msg21506#msg21506


Hans

[jomowi]

In the lab we used to use (2-5% if I remember right)  sodium hypochlorite (bleach).  It can also be used when getting samples of tissue ready for tissue culture.  If it is not left in contact too long it will not damage even soft tissues.

Brian Wilson

[Rodger Whitlock]

[Hydrogen peroxide] comes at 33% with instructions for diluting to 3%.

Speaking ex cathedra as a chemist, I would discourage anyone from buying 33% H₂O₂. At that concentration it is a strong oxidizer, and poses a hazard. It's also strong enough to raise blisters on your skin if you are not careful. The 3% concentration is widely available available and much, much safer.

Historical note: Most attempts to prepare pure H₂O₂ have ended up with an explosion.

[Diane Whitehead]

I sometimes use hydrogen peroxide, but in one experiment it was
lethal to the seeds.

The experiment was this:  hellebore seeds need to be sown when
ripe, receive at least two months of warmth, and then germinate
a couple of months after the temperature drops (usually in November
or December).  Books and seed catalogues do say however, that
older seeds will germinate "later".

I collected 204 seeds in the summer and kept them at ambient
temperature until the next April when I divided them into two lots.
One lot was soaked in diluted hydrogen peroxide (the 3% kind
sold in our drugstores) for three days.  I did nothing to the others.
They were sown in April 2003, and none has germinated in all that
time.  Every January I tip them out and count how many seeds are
still there.

The most interesting part for this current discussion, though, is that
by January 2004, 24 unsterilized seeds were still OK, but only 1
sterilized one.

[Darren]

Have to echo Rodgers remarks. In my own career in chemistry I've had burns from numerous unpleasant substances and strong peroxide is among the worst. And mopping spillage up with tissues then putting them straight in the bin is a good way to start a fire. If you get it on you it will bleach the skin (albeit temporarily) , can blister, and the initial pain is soon replaced by a maddening itch.

When I used to sow orchid seed I was recommended to use Milton sterilising tablets as sold for sterilising baby paraphernalia. These worked well, store easily and are controllable. I have no idea if they are still available or if the active ingredient is the same.

[gote]

I have some views on the topic under "washing of seeds" in this forum.
Göte