If you've ever had a succulent suddenly drop leaves, you may have an idea of the potential cause.
If not, I'm here to hopefully help you avoid that problem and save your succulent!
What causes healthy leaves to drop from a succulent?
We're not talking about leaves naturally drying up from the bottom and falling off. What we're talking about is full, healthy looking leaves suddenly no longer attached to the stem. This is not a good sign, but if you take action now you can probably save some, if not all of the plant.
The culprit is over-watering and the result could be stem rot. In the image below you can see a Graptoveria Albert Baynes with stem rot. This particular instance the rot was so far gone all I could do was preserve some healthy leaves and the top of the plant for propagation.
It doesn't look that bad, does it? Most stem rot you really can't see. The full extent is only clear if you cut into the stem.
So, let's step back for a second, to over-watering. A mild case of over-watering can cause healthy leaves to drop. Maybe you didn't wait until the soil was fully dry before watering, maybe there was too much humidity in the air for the plant in addition to being watered.
This is your early warning sign. If the leaves just drop and no rot forms, this is a best-case scenario. Be sure the soil is 100% dry for at least a few days before you water again. Succulents can survive underwatering much better than overwatering. When in doubt about whether your plant needs water, wait a few days to be sure.
How to check for stem rot
Since you already have exposed stem from the dropped leaves, this is fairly easy. Inspect the stem and look for any dark spots like those in the picture above. If it's too hard to see or you're not sure, gently poke at the stem to check for softness. Healthy stems should be very firm.
If you see dark spots, you'll have to cut into the stem. Cut straight across the stem with a sharp knife or scissors fully above the highest dark spot. Does the stem connected to the head look healthy, with no discolourations? If so, you should be in the clear to let the top of the plant callous over and re-root. The bottom part of the plant with rotten stem cannot be saved so feel free to dispose of it. The leaves from the rotten part of the stem may or may not be able to produce pups. It doesn't hurt to save them and see if they propagate.
So, take dropped leaves as an early warning sign of any problem and act fast to save the plant.