Scarifying seed

Subject: Scarifying seed Tue Sep 23, 2008 2:54 am

As youse prolly know, scarification is frequently used to improve the germination rate of lotsa spp. eg some Acacia. Seeds get treated with such means as sandpapering, boiling and my favourite: dropping them in sulphuric acid (enough to scarify anyone I reckon).

Yet I haven't noticed (which is typical) anything in this regard re. cactus seed. I suppose someone must have tried it. I'm guessing that if many cactus seeds require a period of soaking in order to initiate germination that they must have relatively tough seed coats.

Which is where, perhaps, scarification could come in. Boiling in battery acid might be a little extreme for cacti, but maybe some chem or physical means could help with some of the more reluctant species.

Subject: Re: Scarifying seed Tue Sep 23, 2008 4:22 am

not usually needed for most cacti, soaking generally isnt either, but may help some sp....if you were to try it i would suggest trying some Opuntia sp...they are usually large, and slow to sprout...perhaps they could benefit form this.

Joined : 12 Jun 2008 Posts : 56 Location : Tas

Some cacti have germination inhibitors on board that need to be soaked out to enhance the chances of growing. These inhibitors are a clever way of not sprouting when a light rain wets the seeds - they only grow when enough of a drench soaks out the inhibitor.

Frustratingly I can't remember the exact reference that I read that listed taxa known to have such inhibitors, but my method has always been to soak overnight in a mugful of water that is initially hot enough for a pleasant cuppa. This way I get upwards of three quarters germinating, and I don't quibble about the ones that don't come up.

I don't think that sandpaper would be a good alternative unless you were exceedingly carfull! It works well for things like rock-hard carob, although these buggers need a good soak in hot water overnight afterward at least, and sometimes up to a week of soaking. But trying sandpaper would probably give cactus seed meal if you werre heavy-handed. Wink

Acid might be a bit much for small seeds with relatively thin coats, unless you played around with dilution ratios and soaking times.

Subject: Re: Scarifying seed Tue Sep 23, 2008 8:44 pm

Yes I guess that some methods are a little too dire for some cactus seed. And as Kada said maybe in a lot of cases these things aren't really necessary.

It sounds as though the germination inhibitors are worth looking at. Leaching them out with hot water i suppose would get close to what happens in the 'wild'. Simulating their natural habitat usually seems to be a good starting point for cultivation etc..

thanks

Subject: Re: Scarifying seed Tue Sep 23, 2008 9:08 pm

I have recently had some frustrating Lophophora seeds - frustrating in that they had crappy germ rates (probably10%)
I tried two things

1: soaking in boiled water for 24 hours
And
2: soaking in boiled water for 24 hours & 100ppm Gibberellic acid

Results were - 1: 19% - 2: 30%

Not really significant results – but it might help to soak in water for a while and GA3 might help too? I will be doing more tests with GA3 and see what happens. Smile

Subject: Re: Scarifying seed Tue Sep 23, 2008 9:12 pm

- Note - sample size was quite small/ ~ 35

Subject: Re: Scarifying seed Wed Sep 24, 2008 6:20 am

i have read about germ. inhibitors as well, but i think that standard cacti sowing methods take care of that well. Moist substrate in humidity tent tends to keep things moist enough for the seeds not to think its a brief rain. soaking can help many species, but i dont think it is required at all. using high humidity in a plastic cover and moist (not dry and not wet) substrate should yield very good results.

i think most people failures, including mine, are more the error of the gardener.

over the years i have found these general guidelines have helped with almost any cacti seed i have sowed.

never bury seeds
top dress with *washed* sand, to prevent any mold and helps with bugs
never use mixes with organic chunks (wood, fibers etc)
keep in a semi sealed container using a clear plastic
keep 20-30 C
make sure there is always a big of condensation, but not huge drops

my %'s went up a LOT after i followed these, and i dont pre treat, sterilise or use chemicals (H2O2, fungicide etc) or anything. after i sow i dont touch them (other than a peak) for a few months, no dampingoff no bugs no problems Smile

watertrade you probably killed them. Lophophora seeds need no treatment, just some moisture and they should be up within the week.

Subject: Re: Scarifying seed Wed Sep 24, 2008 10:27 am

Subject: Re: Scarifying seed Thu Sep 25, 2008 12:26 am

that sucks Sad

even old seeds sprout well...loph seeds last for 10's of years...just need to store them ok....one thing i notice wastes seeds are not dried fully or stored humid, and they may germinate and die while in the bag...this happened to some dragon fruit i had a while ago, i found all tehse half assed germ'd seeds in the bag lol.

Subject: Re: Scarifying seed Thu Sep 25, 2008 10:44 pm

Cactus-seed sprouts eh? ... maybe they're good for you!

Subject: Re: Scarifying seed Fri Sep 26, 2008 4:34 am

an ozzy making a crack at my English....argggggg this will never do! its all good M8.

Subject: Re: Scarifying seed Fri Sep 26, 2008 7:06 pm

Nah its more about my bizarre dietary preferences!