Tom wrote:
Hi, I ran out of cactus compost a while ago. Someone at the local garden
centre advised me to use a 50/50 compost and sand mix instead (they had
no cactus compost in stock).

You generally want something like JI No2 and sharp sand 50:50 or 40:60
depending on how hard you want to grow things. If you have a fast
draining mix for species that are sensitive to wet feet they live
longer. You can also water more freely if you know the excess will
quickly drain away (no good if they are on a windowsill though).

I did that but I notice that I watered all my cactii today and the 50/50
mix is already dry(ish) while the pure cactus compost I've watered is
still very very wet.

Is there a difference between the two? Any pros and cons of either?

You will pay a lot more for the "official" cactus compost and it is
easier and more controllable to mix your own.

Generally cacti and succulents can tolerate drought, but they don't like
being waterlogged and will rot from the roots upwards.

Having said that an error in my automatic watering system once left
several trays of lithops unde an inch of water for a week and it did
them no harm at all. Apparently in nature they have to tolerate this too
when there are flash floods (but I wouldn't recommend trying the
experiment for yourself).

Regards,
Martin Brown
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