Organic things to add in a soil to germinate cactus and succulents

[yonnoy]

Hello, which of these organic things are good to germinate cactus with pumice (mammillaria, frailea, turbinicarpus, lobivia, aztekium, blossfeldia)? And how %?

Coconut coir/husk
Pine bark
Rice husk
Peat moss (sphagnum)
Humus (earthworm)
Diatomaceous earth

And which are good to germinate succulents with pumice (haworthia, lithops, dinterathus, titanopsis)? And how %?

[SoilSifter]

I don't have experience with trialing mixes containing the different media you list with all the different genera you asked about. However, I have tried a few seed starting mixes with some kinds of cold hardy cacti seeds. In the end I settled on using a mix of 1:1 of ground coconut coir and granite grit. Then I switched to using a mix of 2:1:1 of pumice, ground coconut coir, and granite grit. I've never tried using pine bark, rice husk, earthworm castings, or diatomaceous earth. I think the pine bark would be in chunks that are too big to be good for a seed starting mix. Having some peat moss in a mix should be OK but peat moss has a reputation of being difficult to re-wet after it has dried out. Coconut coir can be like that too but less difficult to re-wet.

[CactiJim]

I don't have experience with trialing mixes containing the different media you list with all the different genera you asked about. However, I have tried a few seed starting mixes with some kinds of cold hardy cacti seeds. In the end I settled on using a mix of 1:1 of ground coconut coir and granite grit. Then I switched to using a mix of 2:1:1 of pumice, ground coconut coir, and granite grit. I've never tried using pine bark, rice husk, earthworm castings, or diatomaceous earth. I think the pine bark would be in chunks that are too big to be good for a seed starting mix. Having some peat moss in a mix should be OK but peat moss has a reputation of being difficult to re-wet after it has dried out. Coconut coir can be like that too but less difficult to re-wet.

Yeah, I agree with Soilsifter. Peat moss is a pain to rewet but I use 1:1:1 of perlite, coconut coir, and vermicompost. I honestly am still experimenting with my seed starting mixes to see which is giving me the best results but I don’t really think it matters too too much.

[7george]

Organic matter makes difference for growing seedlings only. Seeds will germinate at any surface but better use mineral only mix. Cacti are more picky, succulents are not but depends on plant family. I'd use coarser peat up to 30%.

[CactiJim]

Organic matter makes difference for growing seedlings only. Seeds will germinate at any surface but better use mineral only mix. Cacti are more picky, succulents are not but depends on plant family. I'd use coarser peat up to 30%.

Could you elaborate more on what you mean by mineral mix? I know it’s probably self-explanatory but could you give examples of a mineral only mix? Here is what I have at my disposal:

-burgundy lava rock/fines/cinder 3/16 inches or ~4.5mm
-black lava rock/fines/cinder 3/16 inches or ~4.5mm
-pumice 3/16 inches or ~4.5mm
-cement sand
-turface/calcined clay 1/16 inches or ~1.5mm
-coarse sand 1/16 inches or ~1.5mm
-perlite
-vermiculite

Organic
-coconut coir
-peat moss
-Miracle gro cactus mix
-Espoma cactus mix

I could make a seed starting mix with just these materials? No organics at all?

[7george]

-coarse sand 1/16 inches or ~1.5mm
-perlite
-vermiculite

This (or similar, including zeolite) is the mix I have used successfully many times, the size of the particles (incl. sand) has to be comparable to seeds size. Some growers are using even pure vermiculite for many cacti species.

Some photos (not my seedlings except 3rd) :
https://i.postimg.cc/XYqW4D09/IMG-20181018-094217.jpg
https://i.postimg.cc/gk3wXGr8/IMG-3867.jpg
https://c1.staticflickr.com/3/2912/3378 ... 0e19_b.jpg
https://i.postimg.cc/25zfTCps/IMG-20190327-111930.jpg
https://i.postimg.cc/Px1pNspC/20190118-154749.jpg
https://i.postimg.cc/W15yGGfs/2.jpg

So the mixes can be quite different.

[keith]

I don't use organic to germinate cactus , dinterathus or Lithops seeds it grows fungus. Even seed shells grow fungus . Diatomaceous earth isn't what I would call organic. its fossils mostly silica. you can use that with small pumice and sand.