Mould attack on slow-sprouting cactus seeds.

I have some containers of sterilized cactus mix on top of a cloth mat that wicks up any excess moisture --- but it's taking so long for the cactus seeds to germinate that the mat was becoming mouldy. I replaced the mat. It's been five weeks since I started the seeds. I didn't think it was going to take this long.


-How can I kill the mould without killing the cactus seeds?

-The longer the seeds take to sprout, the more problematic the mould will become, so should I start over and pre-treat the germination containers somehow?

 

You can look for damping off solution. It is an antifungal commonly used to prevent fungus on seedlings. I have no idea if it will work on your mould problem though.

I have had success with cactus seedlings without resorting to using a cloth to remove moisture.
I place a small disposable cream cheese container or such with soil (humid, not wet) into a ziplock sandwich bag. Seal, keep at about 70-75 Deg F, under lighting. I have had success with a cactus soil sold at IGA under the name of Zantro (I think). I used the soil straight out of the bag, no sterilisation.

Good luck.
Waz

 

How long did it take your cactus seeds to sprout?
Did you bury them? Or were they right on the surface?
I have my conatiners like yours (semi-sealed to prevent drying) --- it's just that 5' 6 weeks have gone by now that's creating the mould issues. Yes, someone else mentioned that brand of soill, I'll remember that, thanks. But I think the problem is the seeds.

 

Seeds can take anywhere from a few days to a few months to germinate.

Can't say much more than that right now.

Waz

 

"..few months..." ?
Well, given the practical reality of starting seeds, don't you think that if a seed hasn't made a move within a month and a half, it's somewhat of a waste of time keeping on keeping on with it when even most cactus seeds pop (if they're going to pop at all) within two weeks? Have you ever kept a seed in a germination mode for " a few months "?
I got all excited when I saw some green -- turned out to be a green coating of mould on one of the white-colored rocks in the sand-coir mix.
:)
Hey, if six weeks have gone by and it's been perfect humidity, diurnaly-varying temperature between 70F and 85F from a timed lamp, etc, and not one seed has popped --- they're probably dud seeds. No?

 

Not necessarily.
The seeds might be fine, just waiting for the proper conditions to germinate.
Depending on the plant (not specifically cactus) , seeds might even require a freezing before they will germinate.
Maybe you are too hot, too dry, too humid. Maybe you have the wrong soil, the pH is off, ...

And yes, I have seen seeds sprout several months after planting them. Generally I expect some action within 4-8 weeks.

Maybe you can try to find out what seeds you have planted. Find out when these cacti flower and what the conditions are in the area that they grow in are like. You might get some clues...

And that green stuff is probably not mould. It is a plant (chlorophyl is green). Maybe some sort of algae or moss / plant scum that is often seen growing on wet rocks.

Waz

 

Good point about mould vs plant --- I think you're right. A different container has developed thin hairy stuff thats different from the green coating on the white rocks --- for sure this other hairy stuff is mold.

This has become like an experiment designed to answer the question: "What starts growing first in microwave-irradiated soil?" Answer: chlorophyl stuff starts within days, closest to the light --- at lower light levels, after a month, mould grows.

Oh, and this particular cactus is native to the western, upwind (hence very wet) side of the Bolivian and Peruvian Andes mountain range at altitudes between 1500 meters and 3500 meters. They have acclimatized to this super-wet environment and are more like normal plants in their watering preferences.
All the literature says in relation to germinating these seeds --- mimic diurnal temperaure variations which I did with a timer and lamp (71F to 85F), keep them very moist which I did with a sprayer, and they'll sprout in under a month. But it's well over a month and nothing's happening.

Maybe a decompression chamber would help --- perhaps it's the reduced atmospheric pressure at 1.5 to 3.5 km altitude that is the critical factor.

How important is pH to cactus seed germination?

 

I have said all I can say on the topic Thomas.

You can always try again eh?

Waz

 

Yes, you have, and I appreciate the input --- now when it all goes south on me at least I can say to myself, "I did everything right according to what I know AND the according to the combined wisdom of those who frequent webforums (like this UBC one)."
;)
The seed dealers have agreed to replace the seeds as soon as I've decided to throw in the towel on them (couple weeks from now).
Several ppl have recommended a certain brand of cactus mix that I will get, and I'll ask for either a different batch of san pedro seeds or some different cactus seeds altogether because I really do have a gut feeling that these seeds are duds.

To reply to your comment about trying again --- I absolutely will try again. In fact, even though the seeds didn't germinate this time, I've learned lot's from the experience. I've learned that even if you nuke the soil, stuff starts re-growing in it after a certain amount of time goes by, despite somewhat sealing it.
Next time I start seeds that might take a long time to pop, I'll use an anti-fungal treatment and see how long I can make the soil continue to be mould-free with the anti-fungal treatment. I didn't "fail to germinate " cactus seeds, as much as I "succeeded in growing chlorphyl-related coatings on white rocks and hairy mould creatures."

 

So much for the cactus seeds. Despite an antifungal application, mold started to grow, so that's the end of that. I tried some other seeds in the same soil and they sprouted just fine, although I know that doesn't really prove anything.