Most of my Lithops have doubled this year. It takes a while for them to lose their old leaves, probably because of the humid weather we have here in Denmark.
If anyone needs a guide on how to keep their Lithops alive, here’s how I do it:
Keep in mind, I live in a temperate climate (zone 8a), which means I have to water my plants less often.
Watering and soil:
Starting off with the most important bit. This is where most people make the most mistakes, killing their Lithops within the first few months after they bought it.
Lithops are heavily succulent and mostly consist of water. They differ from regular succulents in that they don’t stop drinking when they’re full. The cells inside of the plant basically burst and the plant melts if it has taken in too much water at once. This is why I grow mine in 100% grit with no potting soil.
In Denmark, pumice is very hard to find, so I use cat litter instead. Not the clumping stuff, but Moler (diatomaceous earth/clay), which is pretty much only available in Scandinavia. Pumice, crushed lava rock or turface works just as well. If it dries out within a couple of days, it’s perfect.
I water mine no more than 2-3 times a year, and only in spring and fall when they have started to look like raisins. If you live in a warm climate, you may need to water once a month in spring and fall. They go dormant in summer and winter to protect themselves from extreme temperatures. Don’t water at all during the dormancy period. They can live without water for more than a year, so don’t panic.
Also, don’t water when they’re splitting in fall/early winter and growing a new leaf set, like in the picture above. They draw moisture from the outer leaf set to keep themselves alive. These leaves will eventually dry out, leaving only a dry, papery husk behind. This (and when the plant is wrinkling, indicating that there’s room for more water in the plant cells) is when you’re allowed to water again.
Place your Lithops in full sun. If you have a window with direct sun from morning to evening, it’s perfect. They stretch and turn green if they need more light, making them more susceptible to rot and diseases. Grow lights can work if they’re strong enough. I’m not an expert here, though.
You can grow these outside if they’re protected from frost, which is what I’m doing. Lithops like temperatures between 10°C and 35 °C.
I keep mine partially outdoors on a glasspane-protected balcony to let them experience all of the 4 seasons. If grown indoors, they may go dormant, split and flower whenever they feel like it, making it a bit harder to control watering.