Are Echeverias better off in a garden than a pot?

Question

I followed all the possible advices:

1 - Good drainage holes

2 - Fast-draining potting mix, be it 50/50 coco-perlite, added coarse tuffa or river sand, or just using pure Perlite

3 - Let it dry for a few days before the next irrigation

4 - Keeping the center dry

5 - Looking for heat-tolerant and direct-sun tolerant species

The problem: Echeverias may rot suddenly without warning. It does not necessarily start at the root.

Exceptions: Echeverias in the garden have endured winter rains, hail and scorching summer. One species was more sensitive to rot, yet still performed better than the potted ones. They needed less water and endured wetting the center of the crown by rain or irrigation.

So what I may be doing wrong with my potted one? I live in zone 11. My climate is Mediterranean. The summers are hot and humid but have no rain from June to October.

Answer 1

One thing to keep in mind with any plant potted compared to the same type of plant planted in open ground is the volume of soil that can act as a "buffer" for heat and moisture. By a buffer I mean extra resources available when unusual things happen, like a sudden cold or hot or dry or wet spell.

Consider this thought experiment - you have a cup of water and a gallon of water and you try to heat them on the range with the same burner set to the same level. Which is the first to boil? Clearly the smaller one. When a cold weather spell hits your garden the pots cool down much faster than the garden does. If the roots are sensitive to cold then those potted plants react quickly but the garden planted stuff might be barely aware of the cold since there is a large volume to buffer the change.

Remember too that as the root ball fills the pot the outside roots get closer to the (side) surface of the pot. Cold progresses from the outside to the inside of a pot and from the top down for garden planted specimens. Since the outside roots will be the new fresh delicate roots they are the roots to get clobbered by cold first. In the garden the roots are somewhat going sideways but also down, and the bottom roots might be spared a shock.

If your pots are sitting on something that conducts heat well like metal or concrete then the bottom of the pot can get a lot of heat or cold.

So the moral of the story is to make sure that the potted versions have generous room to expand in their pots, and perhaps have a means of protecting them during rapidly changing weather.