Sad Lithops...

[Beth C]

Hello everyone
I haven't posted on here Ina few years but have been faithfully lurking...I grow a range of small Aloes, Crassulas, Haworthias, etc. plus various mesembs indoors in coastal Nova Scotia....
I have some Lithops that are getting progressively smaller as time goes on. They also don't bloom reliably anymore. The oldest is around 10 years. They are in desperate need of repotting, but I am unsure of what soil mix to use. They are grown indoors in winter and outside under shelter in summer. I They are currently potted in a mix of 1:1 c&s soil and perlite in small clay bell pots. I can no longer find the brand of c&s soil I used to use, so am looking for alternatives. Also I keep reading that mesembs like a denser soil than any other succulents. Would a 1:1 mix of lean garden soil and perlite be acceptable? It is also impossible to get peat- free potting soils around here. I use gritty mixes for my other succulents. Would a bit of fine Turface be beneficial? I just killed a Lithops this past month, it had been potted in a gritty-type mix with larger Turface particles upon purchase last spring...

Anyway, I seem to be rambling. What do the experts suggest I use in my situation?

Happy growing
Beth

[Peter B]

I'm sorry to hear of your 'sad Lithops'. They do need an open mixture. As you can't obtain a peat free John Innes type soil it makes life a bit difficult. The perlite is fine, you don't need sand but some 0-4mm grit would be useful. I would not use a garden soil personally. I dont know what Turface is so I can't comment but I use cat litter that you have read about on the forum. Whether you have that type of material for sale in Nova Scotia I don't knowe but it needs to remain solid and not become mushy on contact with water. You do need to find some type of loam if possible, even if it has peat in it as you can sieve it to remove the larger particles, but I don't use it in a 50-50 basis. I use grit, loam, cat litter and perlite in equal portions plus an occasional half strength feed.

What does strike me about your culture details is that you seem to be growing them in too small a pot. Lithops like depth as their roots make straight for the bottom of the container. Another question is when do you water? They are summer/autumn growers, and I water from the beginning of June to the end of September (no more than about 6 times during that period, most of which time you will have them outdoors. When you say under cover is that just from above so they ae open to wind or are they in the equivalent of a greenhouse? If they are open to moving air and in small pots they will dry out very quickly and maybe they are not receiving enough moisture. Plants in small pots rapidly use up whatever nutrients there are in any soil so if you haven't repotted for a long time there will be no goodness in the soil mixture. I am not quite sure what you mean by a 'denser soil' but Lithops tend to grow in a shaly, quartzy type of soil and get their nutrients from this soil with the help of bacteria so it is an open substrate. In the rainy season, which is often short, it is not unknown for Lithops to be under water, in the shallow quartz pans in which they live, for a few days before the water dries away (personal information from Dr Des Cole). This is not advocating flooding your pots but it shows that Lithops don't mind the occasional soaking.

I hope this is of some help.

Peter B

[Lindsey]

You've been given helpful advice. I hope your Lithops will benefit!

Just a q... have you fed your Lithops at all? They are very slow-growing but do appreciate a "cactus" plant feed - low in nitrogen - if mot repotted that year.

[iann]

Turface is OK, similar to the cat litter we use here. Really you want some sort of loam. The "cactus soil" sold on the western side of the Atlantic is almost universally unsuitable. I've experimented with soil straight from the garden, mixed with cat litter and extra grit obviously, and the results have been OK, but it depends on having a suitable free-draining soil and can be a bit messy filtering out worms, etc.

I second the call for bigger pots, although a mild humid climate means you can't go too crazy. Infrequent deep watering seems to suit Lithops, far more than most mesembs. Infrequent means less often even than most cacti. Tiny pots make it less likely you'll rot your plant but much more difficult to keep it growing well. Not dying is a start, but shrinking each year isn't so much better. Remember they don't need a lot of fertiliser, but they do need some.

[Ivan]

... I've experimented with soil straight from the garden, mixed with cat litter and extra grit obviously, and the results have been OK, but it depends on having a suitable free-draining soil and can be a bit messy filtering out worms, etc.

Could you expand a bit on this Ian? Why did you stop using garden soil besides the worm thing?

My garden soil finally thawed out enough for me get some to use or at least experiment with. It is a wonderful sandy loam and has no peat in it. I have let it dry out completely and I have sifted it with approx 1-2mm sieve. (no worms) I am now debating weather to dampen it and BBQ it to approx 180ºF or 82ºC to perhaps get rid of any unwanted pathogens. I cannot find any suitable packaged soil that I think I can use.

[iann]

Could you expand a bit on this Ian? Why did you stop using garden soil besides the worm thing?

Because I don't need to. I have a ready source of sterilised loam with a consistent standard and a known level of nutrients. My garden soil is all over the place, stones of varying sizes, quite a lot of limestone, enriched in some places, very poor in others.

[Beth C]

Thanks for the advice everyone. I will look for deeper pots. What depth would people suggest? I've seen recommendations for 5 inch deep pots but that seems like it would be a huge pot... Unless I went to a plastic square pot, though I think I should stick to Clay at that size....
As for soil I will try equals part of turface, grit, perlite and sieved lean garden soil. I am leery because the one Lithops I potted in a similar mix last summer died over the winter...perhaps I just didn't water it enough....
Will repot soon once I find some suitable pots

[rodsmith]

Thanks for the advice everyone. I will look for deeper pots. What depth would people suggest?

I suggest you unpot one or two of the plants that are wasting away and see how long the roots are. You can then gauge the size of pot you need to use. There's no point in using a 5 inch deep pot if the plant with roots is only, say, 3 inches in depth. What you don't want to do is overpot them which could lead to overwatering and rot. I would suggest using pots that are 1 inch deeper than the current length of underground plant and with a diameter of about 1 inch more than the plant's diameter.

[Beth C]

Thanks you rodsmith, I will do that.

Happy growing,
Beth