Lithops 101 – A crash course in: Lithops care needs, growing cycles, and why you need to know them BOTH to keep them alive.
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Lithops, Līthops, Split Rocks, Butt Plants… whatever you like to call them, they’re easily one of Earth’s weirdest plants making them highly popular with succulent lovers.
They’re also popular for dying. A lot. In fact, I bet we’d be hard pressed to find someone who has never killed a Lithops unless they’ve just never had one before and that doesn’t count. I know I took at least three victims before I really ‘got’ them and learned to respect how little they needed me to survive.
Due to our vastly different climates and growing situations, whether indoor or out, arid or tropical, and everything in between, it’s virtually impossible to give universal advice on general succulent care, let alone Lithops. Would you believe me if I told you watering them once a month can be too much? It’s true, and it can mean the death of a Lithops if watered at the wrong time.
But these little weirdos are great at expressing their needs and once we understand their body language and growth cycle, it becomes much easier and less stressful to keep them happy.
Natives of the driest areas of South Africa, they live their low-key lives, or should I say low-leaved, among plains and outcrops where they mimic the rocks common to their location to hide from thirsty critters. And while they’re from the Southern Hemisphere, most Lithops adapt to the seasons where they’re being cultivated.
Once you understand their growing patterns, it’s easier to accept why they need so little water.
Let’s start with their flowering phase. Most Lithops need to be at least 3 years old before they’ll flower. They usually bloom sometime between late summer through fall.
After their flowers fade, they begin growing a new plant beneath the outer leaves, but you can’t see it yet.
Through winter and into early spring, the new plant continues to grow while the outer leaves begin to wrinkle and shrink. The new leaves subsist solely on the water and nutrients from the old leaves, and for this time, the roots are basically put out of service.
When the new growth becomes large enough, the outer leaves begin to split and dry out until the new plant fully emerges. Roots that dried out are replaced by new roots. Depending on the climate, Lithops in hot summer settings may go dormant or partially dormant until it’s time to flower again. This cycle repeats each year, with new growth bursting through the old. Knowing all of this, when you buy a new Lithops and it looks like it’s not flowering or splitting, if you still aren’t sure of which growth stage it’s in, you can look to the season for a clue.
Now let’s get into the care needs for these oddballs. As with most succulents, the most common causes of a Lithops demise are overwatering and inadequate light.
In nature, Lithops have adapted to their harsh conditions by growing with only the very top surface visible above ground. The light needs to be bright in order to reach the chlorophyll safely stored deep down inside the subterranean leaves. While most people don’t pot their Lithops as deeply as they grow in the wild, they will still need at least 3 to 5 hours of bright light, preferably direct, and as many more hours of bright indirect light as you can provide.
If you don’t have a grow light, you’ll want to find the brightest spot you can, away from any rain, but also protected from full sun when it’s hot outside. Remember, morning sun is gentler than afternoon, so east-facing windows and patios are ideal when the light isn’t blocked by other objects.
Lithops etiolate and grow taller when they’re not getting enough light. If this happens to yours, gradually extend its exposure to more light so it can photosynthesize enough to produce a new plant and keep the next generation true to form.
Before we talk about watering Lithops, let’s cover their container and soil requirements.
For such small plants, Lithops can put down some pretty long roots, so it’s important to pot them in a container deep enough to accommodate them. Clay or plastic pots both work as long as they have ample drainage holes and the planting medium is very high draining. I do recommend clay pots for those new to Lithops as a precaution against moisture retention. I use both.
As for soil, Lithops really need a potting medium that dries within 3 days or less. Most commercial plant retailers sell Lithops in the same soil used for non-succulent plants, but this doesn’t mean we should leave them in that dark organic dirt. I honestly suggest having a really high draining soil ready before purchasing any Lithops, and the less organic matter in the mix, the better. I personally use 100% pumice, shale, porous ceramic, or a mix of all three- no brown organic matter whatsover. My climate is terribly humid most of the year and it takes longer for ‘dirt dirt’ to dry than Lithops prefer.
So if you live in a humid location, please believe me when I say investing in a bag of good draining amendment is probably the best and easiest way to keep your Lithops alive and reproducing. There are alternatives to pumice, like shale, Turface, and bonsai soil—even a combination of perlite with a bit of topsoil is better than regular potting soil or whatever this dark stuff some places sell Lithops in is.
Not only does potting in non-organic materials reduce the odds of overwatering or moisture retention, it helps prevent fungi and bacteria, and makes the pot virtually uninhabitable to pests like fungal gnats and root mealybugs. Knock on wood, I’ve never had any issues with pests on my Lithops, and I’ve no doubt my choice of potting medium is key.
If you live in an arid region, or grow indoors with the required light, and you can master the growing cycle of Lithops well enough to know when to avoid watering, then you can get away with more organic material in your mix. Otherwise stick to non-organic as close as you can.
It’s common to see a lot of Lithops planted together in one container. It looks fantastic but this potting situation can become problematic if the Lithops are at different stages of growth, or one is in need of water but its neighbor is fully hydrated. I’d wait until you’re comfortably familiar with the different species and growth cycles before putting them in the same pot, then go for it!
Ventilation is also important in stiflingly hot climates, especially when humid, like Houston. It is mid-May and I’ve already activated my oscillating fan on my porch. When I start to feel like I’m slowing down from the heat, I assume my plants are feeling it too. I have another for when things really start heating up.
Now we’re ready talk about watering Lithops. I covered everything else first because without the right light, soil, and container, any amount of water at any time will probably kill them. Watering at the wrong time in their growth cycle can be the kiss of death for a Lithops, but the odds decrease if everything else is in place.
The best way to tell if your Lithops need water during the time when it’s okay to water, is by observing them. They’ll start wrinkling or puckering, or maybe even appear to be sinking deeper into the pot. If you give them a gentle squeeze, they feel softer than when hydrated.
The tricky part about all of this is they do the same thing when they’re about to shed their old leaves to allow the new growth to come in. That’s why it’s so important to know what stage of growth they’re in before you water them.
All you really need to remember is to only water after the old leaves are dry and stop watering after the flower begins to die. Flowering typically occurs between late summer and the end of fall. New growth occurs during fall and spring, and old leaves dry out between late spring and early to mid-summer. Those are all wide open estimates, but a good rough guide nonetheless.
The main reason you shouldn’t water after flowering and while new growth is forming comes down to the way Lithops utilize water. As I mentioned, the old leaves are the source of nutrition and water for the new plant that forms within.
The roots are basically put on pause for this time. If you water them during this phase, you risk confusing the plant into using water from the roots while it is actively absorbing the old leaves, which can engorge the plant beyond repair. You also risk root rot since the root system’s activity is suspended and the excess moisture surrounds the plant with nowhere to go.
Again, after the old leaves have dried up, you can give your Lithops a deep watering. This will probably be around late spring to early summer, but the timing can vary. Put the pot in a saucer and slowly give it about a 8-16 ounces of water. Wait until it runs through the drainage holes. Dump the saucer. That’s it! Water it again if it shows signs of wrinkling after 3-4 weeks but only enough to run through the drainage holes once.
If a month has passed without your Lithops showing signs of wrinkling during the summer months and you haven’t watered them, you can moisten the top layer of the pot to help give the roots a bit of moisture. There’s a chance it is becoming dormant from the heat or natural cycle, so too much water can cause it to swell and split…and die.
Giving Lithops the right amount of water during the right time will sustain it through its flowering, fruiting, and new growth cycles. This means it can sustain its life and reproduce without being watered for six months or more, especially in humid environments.
These are splitting. The water in the outer leaves is being absorbed by the new growth. Watering these now would interrupt the absorption and the outer leaves will probably rot around the new growth rather than dry up.
Once the old leaves are dry, I’ll give them a deep watering and wait until they show signs of needing another drink. Humidity takes care of part of my job, and I find myself with nothing to do but look at them most of the time.
They’ll probably go dormant at the peak of summer, but will still need a small bit of water to keep the root hairs alive.
Again, mine haven’t flowered but they’re a year older now and the chances are that much higher. If I do get flowers, I’ll water sparingly until the bloom begins to fade and wait until the following spring for the new growth to emerge. With luck, I’ll get to repeat the process yet another year.
Even in the driest climates, watering once or twice a month at most is the norm. If you can respect that fact about this plant, and you can give it enough bright light, then I know you can keep it alive.