Recommendations, haworthia seeds zero germination

[MatDz]

Your pH might be way too low as well, it's basically an acidic concoction.

If there is lime in the compost, acetic acid will react to form calcium acetate. Calcium acetate is alkaline, not acid, as are all salts of weak acids (weak has nothing to do with concentration/strength - it means low levels of ionisation/dissociation - low Ka). This is why chalk, the calcium salt of carbonic acid, is alkaline.
If there is little or nothing alkaline in the compost, the acetic acid will evaporate and have no effect.

All assuming that the compost is not "drowned" with vinegar (which is usually around 6% acetic acid).

Every day is a school day, thank you!

[iann]

Calcium acetate is hardly alkaline. It is a salt, of a weak acid (the acetic acid) and a weak base (calcium hydrogen carbonate, the soluble base formed in the presence of limestone). All other things being equal, a solution of calcium acetate does have a pH slightly above 7, for example a 0.2M solution (far stronger than the vinegar solution could produce) has a pH of 7.6, but hardly something that is going to frighten seeds. It is commonly used to buffer solutions to a pH near 7, in combination with other salts, because of its tendency to dissociate into the weak acid and weak base depending on the presence of stronger acids or alkalis.

I don't know how to germinate Haworthia seed, though. Producing the seed in the first place is tricky enough!

[Astro]

The few times I've tried Haworthia from seed I've treated them similar to Lithops seed (in a baggie with night-day variations between 5-10C at night and maybe 20-25C during the day). I got some decent results with that approach.

[Davey246]

Calcium acetate is hardly alkaline. It is a salt, of a weak acid (the acetic acid) and a weak base (calcium hydrogen carbonate, the soluble base formed in the presence of limestone). All other things being equal, a solution of calcium acetate does have a pH slightly above 7, for example a 0.2M solution (far stronger than the vinegar solution could produce) has a pH of 7.6, but hardly something that is going to frighten seeds. It is commonly used to buffer solutions to a pH near 7, in combination with other salts, because of its tendency to dissociate into the weak acid and weak base depending on the presence of stronger acids or alkalis.

I don't know how to germinate Haworthia seed, though. Producing the seed in the first place is tricky enough!

pH above 7 - that is alkaline. I said precisely nothing about how alkaline. You might like to give us the figures for calcium carbonate solution? (Calcium carbonate has very low solubility (low Ksp)).
I was correcting the assumption that vinegar would acidify the compost, other than that, you just repeated what I posted - calcium acetate is alkaline, and why.
Buffering is only ever achieved by using two (or more) salts.

[iann]

Calcium acetate is hardly alkaline. It is a salt, of a weak acid (the acetic acid) and a weak base (calcium hydrogen carbonate, the soluble base formed in the presence of limestone). All other things being equal, a solution of calcium acetate does have a pH slightly above 7, for example a 0.2M solution (far stronger than the vinegar solution could produce) has a pH of 7.6, but hardly something that is going to frighten seeds. It is commonly used to buffer solutions to a pH near 7, in combination with other salts, because of its tendency to dissociate into the weak acid and weak base depending on the presence of stronger acids or alkalis.

I don't know how to germinate Haworthia seed, though. Producing the seed in the first place is tricky enough!

pH above 7 - that is alkaline. I said precisely nothing about how alkaline. You might like to give us the figures for calcium carbonate solution? (Calcium carbonate has very low solubility (low Ksp)).
I was correcting the assumption that vinegar would acidify the compost, other than that, you just repeated what I posted - calcium acetate is alkaline, and why.
Buffering is only ever achieved by using two (or more) salts.

*sigh*

[Tony R]

*sigh*

I agree with you, iann.

[yonnoy]

Many thanks for your comments. My soil is composed by 80% pumice and 20% compost. I added that solution of water and apple vinegar to create an alkaline environment in order to prevent fungus. I have zero mold and fungus, and zero germination of course.

Yesterday I put the containers bagged in a multilevel shelft, no direct sunlight. At 1 p.m. (when sunlight hits) I put a transparent plastic blanket to reduce heat and a 50% shade cloth. At 4 p.m. I retire both.

[LHMBB]

There was a recent report in Haworthiad of germinating in just water, which may give better results

[MatDz]

There was a recent report in Haworthiad of germinating in just water, which may give better results

I did a "wet kitchen paper" thingy with truncata seeds and got about 90% of them to germinate, some within the first week, and some a good month later, so there are benefits of it. The annoying part is the need to move every germinated seed to a pot within the first few days after germination.

[Aiko]

There was a recent report in Haworthiad of germinating in just water, which may give better results

Do the seeds of Haworthia float?

For Habranthus and Zephyranthus (and probably other papery like seeds) you can get them to germinate buy just floating them on the surface of water. They float on the top, maybe a few sink fully or halfway down, which I don't think is a problem.

I do this kind of 'sowing' in my greenhouse in spring, so the water gets nice and warm due to the sun. You can easily replace the water with some fresh water if it starts to turn green a bit after one or two weeks (I just use rain water).