baggy tips?

[nona]

I suspect it's the high humidity. Never having used gravel only not sure how much moisture is right. For the 2 inch container I have been giving it maybe 3 sprays of a hand pump. Looks and feels wet when mixed up with the smallish gravel. All I can do is keep trying and to watch the moisture levels. Perhaps it requires less than I imagine.

[nona]

Seedlings in a gravel mix should be very resistant to rot i usually leave my seedlings up to 6 months in the baggy with little to no rot knowing that i don't sterilize anything.

Is the coarse gravel in your pic just top mulch? I'm using 1.5 to 2mm gravel. Anything larger and the seed would fall through, no? Some say seeds should be covered to twice depth but I don't see how that's even feasable with gravel.

[nona]

FWIW here is the container/substrate I'm using. It's about 2/3 full (too much?)

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[ElieEstephane]

Seedlings in a gravel mix should be very resistant to rot i usually leave my seedlings up to 6 months in the baggy with little to no rot knowing that i don't sterilize anything.

Is the coarse gravel in your pic just top mulch? I'm using 1.5 to 2mm gravel. Anything larger and the seed would fall through, no? Some say seeds should be covered to twice depth but I don't see how that's even feasable with gravel.

No that's actually my growing mediun...just grit. I wash it down though to remove small and fine particles

[stefan m.]

And you manage to grow seedlings in pure sand? How well does work for you , species wise?

[ElieEstephane]

And you manage to grow seedlings in pure sand? How well does work for you , species wise?

Seedlings can grow in anything the first few months. You just add a few drops of liquid fertilizer. And when the seedlings are of suitable size you either leave them and start fertilizing or repot them into a richer soil. I found that seedlings grow best in coarser particles of around 3-4mm. With fine sand or other fine materials, the medium retains too much water and is more prone to algae formation.

[stefan m.]

How bad is algae/moss? I just put some hydrogen peroxide and it suppress it for a bit. Hasnt bothered me yet(except that one time it died out and my seedlings dried out afterward).

[ElieEstephane]

How bad is algae/moss? I just put some hydrogen peroxide and it suppress it for a bit. Hasnt bothered me yet(except that one time it died out and my seedlings dried out afterward).

Algae in my experiment with fine particles was very rampant. I had a layer almost 1mm thick of alage. Of course, i did not sterilze anything. But hydrogen peroxide is very effective algae control.
With unsterilized coarse materials, i never had algae. And if some appears, you remove the particle algae appear on and then all.is good.
As per expert advice on this forum, it was suggested to use whatever medium you like and then add a 1cm layer of grit. I prefer to use an all grit medium for better development of the taproot looking for more nutrients. I believe a strong initial taproot will lead to much better roots later on.

[stefan m.]

I added like 6mm of fine+not so fine sand. ( kinda had to be stingy at the time)

[ElieEstephane]

I added like 6mm of fine+not so fine sand. ( kinda had to be stingy at the time)

Well with such large collections, one has to be stingy or things would get out of hand quickly.
Use window screen to sift out fine particles

[stefan m.]

Well the top dressing worked out well for me. DIdnt have too much mold problems, some algae problems, but the peroxide spray took care of that problem pretty well. I also added extra sand to some of the dry++ plants like lophophora , ariocarpus, etc etc.

[nona]

Seedlings can grow in anything the first few months. You just add a few drops of liquid fertilizer. And when the seedlings are of suitable size you either leave them and start fertilizing or repot them into a richer soil. I found that seedlings grow best in coarser particles of around 3-4mm.

Good info to know. Thanks.

[nona]

Had written a response but lost it thanks to the auto logoff feature

To summarize I'm now adding a small amount of fine organic material (commercial cactus mix through a 1mm kitchen sieve) to my grit. The idea being it holds the moisture and keeps it well distributed. In a grit only medium it was hard to gauge moisture and invariably I'd end up with too much. Will report on how the new scheme works. (Using same small grit as pictured earlier as I had bought a lot of it!)

[nona]

Long time since I last posted here as I had nothing positive to report. I had little doubt my problems stemmed from excess humidity in the germination enclosure during the hot months. How to get around it had me stumped until now.

I'm presently using 50 ml round disposable food containers - one for each seed type. Each is filled to approx 8mm with a mix of composted bark (large bits removed), 2mm grit and water. This is flattened and seed placed on top. Over this I apply a thin layer of fine white sand until all parts of the compost mix is obscured. Each seed container (without lid) is then placed in a large (3.5L) plastic food container and covered. This then goes under the lights. Ambient temp is 30 'C or just under. Being summer one side of the light box is left open.

The sand mulch appears to be the critical component keeping moisture within the mix and out of the atmosphere. Oddly enough I used a sand covering when I first began growing from seed but later omitted it believing it to be cosmetic. It may explain the increasingly poor results I obtained in subsequent years! While it's early days yet the mass rotting of newly germinated seeds appears to have been arrested.

Update #1:
Things are progressing nicely. Seeds are germinating with no sign of rot despite very hot day and night temps. The only change I've made is to add a small amount of fine white sand to the mix. By filling in the gaps I hope to retain more moisture in the mix. The only variable left to be determined is how much condensed moisture to allow stand in the box.

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