Thursday, 7 June 2012

3. Lithops Potting Mix

I think Lithops do well in a potting mixture which is largely sandy and very well drained. Water should run through it freely without forming a dam in the pot and it should not stay wet for days on end. However, there should be a small percentage of smaller particles in the mixture or it may happen (especially when repotting / transplanting) that the roots end up hanging in an air pocket without making sufficient contact with the soil. You find that even after repeated watering the plant just doesn’t take off. The roots need to make proper contact with the soil and having too many large air filled spaces makes this difficult.

I use (by volume):
*1 part washed small gravel
1 part washed medium sand
3 parts washed fine sand. It should flow freely and not resemble talcum powder.
1 part coco peat / coir or peat moss
1 part potting “soil” which is in fact well composted bark
1 part unwashed gravel (probably contains about 5% soil)
0.5 parts sandy soil.


Components

Mixture
Components

Mixture

When combined the mixture consists of roughly:
35% non absorbent stone
35% sand
24% organic material
6% sandy soil
(by volume)

That should enable the mixture to provide adequate moisture without becoming waterlogged and staying wet for long periods. It should feel coarse and gritty and should not form a ball when squeezed. I add about 1 teaspoon of dolomite lime to about 5 litres of the mixture to provide calcium for strong teeth and bones and magnesium for bright eyes and a bushy tail. Whether they grow because of it or in spite of it I can’t say.

Keep in mind that I grow outdoors in a bright, hot southern hemisphere climate. Indoors one may need to slightly increase the quantities of non absorbent stone and decrease the amount of soil in the mixture because it may not dry out as fast. It will always involve some trial and error.

Enjoy planting!

*
Update 26 June 2012
I've increased the amount of washed small gravel to 2 parts.

7 comments:

  1. Thank you for sharing this. It is really helpful. Now I understand why your Lithops look so healthy and happy; it’s because of a great substrate! I have recently sowed some Lithops seeds with a potting mix recommended by the seller, who is a leading Lithops grower and expert in Australia. Unfortunately, I could not find a key ingredient for the substrate (small scoria), and had to crush large size scoria myself, which resulted in rough and random pieces. After preparing the bed and then sprinkling the seeds, I covered the seeds with some sifted potting mix and crushed fine scoria (as fine as I could crush it), but unfortunately some of the scoria was not fine enough, and some of the seeds were left exposed, and when the seeds sprouted, some of the roots could not anchor or dig into the ground, and some even grew horizontally trying to find a crevice to dig into, without success and shriveled. Now I know how important it is to cover the seeds with a layer of supporting matter, and will use propagating sand as a substitute. Hopefully, my next batch of seeds will not go through such a difficult time trying to start life. :-) By the way, have you met Walter, my first Lithops? Would you be able to help identity him? Photos of him are on my site. Thanks again for your help and time, and sharing your knowledge.

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  2. Nevermind. My first effort at germinating seeds was equally disastrous. Fortunately they are really not difficult once you understand them a bit.

    I took a look at Walter and while I haven't looked at Lithops taxonomy at all, just from the pictures I've seen on the net, it seems to me he could be a L. aucampiae. Which particular one I wouldn't even try to guess, but something like http://www.lithops.info/en/gallery/lithops_c54.html seems likely. I've never looked into the difference between L. lesliei and L. aucampiae regarding patterns and they often look rather alike to me even though L. lesliei does seem to be a bit more spotty and L. aucampiae a bit more stripey. That summary probably aggrieves every taxonomist on the planet, living or dead, but nevertheless my first guess is L. aucampiae.

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  3. Thank you. Rika from 'Lithops Stories' (http://lithops-stories.blogspot.com) also thinks Walter is a L. lesliei or L. aucampiae as well. The two species do look very similar through my eyes. I've received new Lithops, purchased from a great Australian grower/seller, and they look great! I will post photos of them on my site tomorrow, and they have been identified by the grower! :-) Would love for you to check them out. They have been named also, but you'll have to read the post to find out. Thanks again for your help and best wishes to you! Lithops are so cool!

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  4. Thank you for this excellent article! It is so hard to find good info on the culture of S. African succulents. You are helping a lot of people on planet Earth grow these little treasures. I'm a complete newbie at this, but I don't want to lose any of them, so info from experts such as yourself is very valuable to me.

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    Replies
    1. I'm glad it helped.

      Expert... ha-ha. Many would disagree :-)

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  5. Interesting Paddarotti. Nice to see what other fellow SA people do with their mixtures. Dankie!

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    Replies
    1. You're welcome. Hope it's useful.

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