Scratching before sowing?

[Shane]

Has anyone tried scratching cacti seeds before planting? I've heard for some plants it increases the germination rate. It works by scraping off some of the protective coating that keeps seeds from germinating

I have a bunch of F. wislizeni seeds and I'm thinking of doing some experiments. I think putting seeds in a jar of sand and shaking it would scratch them up. Maybe an acid soak for another batch. Would be interested in hearing people's thoughts on this

[miguel2112]

In a quick search of Ferocactus wislizeni there was no mention of the need for scarification of the seed. You could sow a few and see how well they germinate to see if there's any need for further action on your part. There are plenty of articles here and elsewhere for advice on how to sow seed. Let us know how they do.

[Aloinopsis]

Ferocactus don't need scarification in my experience.

Some cryptocarpic Mammillarias like Mammillaria luethyi definitely do though.

[Shane]

Thanks for the feedback miguel and Aloinopsis. What got me interested in the first place was a brief reference to scarification on the Ferocactus wikipedia page. I did not realize there were cacti seeds that are known to need scarification (particularly opuntia, which incidentally explains why my opuntia hasn't sprouted yet). Reading about scarification of other cacti seeds makes me wonder if shaking in a jar of sand would be aggressive enough to have any effect whatsoever

My prior sowing of five F. wislizeni seeds yielded two successful germinations and one abortive germination all about two weeks after sowing. Five is a very small sample size (it was all I had at the time), but that rate leaves room for improvement

[Aloinopsis]

With some of the Mammillarias that need scarifcation, they want to be positioned on sharp sand and then rained on heavily for days or weeks. That's the kind of scarification they get in the wild. The seeds themselves may not even move, they just get slowly pushed onto sharp sand or rocks repeatedly by rain until they gently open. This also ensures that once they do sprout, it is wet enough.

[Steve Johnson]

Does anyone know if Frailea castanea seeds need to be scarified for better germination? Reason I ask is that I do pretty well when I pot-sow seeds around the base of the parent plant, and I'd like to try it with a highly self-fertile F. castanea.

[Steve Johnson]

Does anyone know if Frailea castanea seeds need to be scarified for better germination?

I was able to answer my own question, and it is -- no!

[dwood5513]

Larger seeds like opuntias or baobobs definitely need some scarring. A metal file helps tremendously.

[Shane]

I finally was able to test this. I sowed a test batch to determine background germination rate on 7/3. It's currently 70-80% and rising. I'm guessing I'll see 80-90% ultimately

With only 10-20% non-germination I don't think I can reasonably expect statistically valid results from any experiment that I could do. So I'll call this case closed. Thanks for the input everyone

On a side note, one of my non-scarified did finally germinate (much to my surprise)