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Old 19-05-2008, 09:36 AM posted to uk.rec.gardening
Nick Maclaren Nick Maclaren is offline
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First recorded activity by GardenBanter: Jul 2006
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Default cactus compost vs compost / sand mix

In article ,
Martin Brown writes:
| 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. ...

Or even grit. I sieved some sharp sand, to make some cheaper fine
sand for filling holes in patios, and it left a fair amount of grit.
You can also buy that, expensively :-)

If it remains actually wet for even many hours after soaking, it
doesn't drain freely enough - probably not even enough for plants
like Stelitzia!

| 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).

Being under water is less damaging than being saturated and NOT
being under water, for all of live plants, dead wood and steel.
The reason is that there is less oxygen, and so fungi don't thrive;
most decomposition happens just below the soil/air boundary,
because it has ample water and enough oxygen.

Nick Maclaren.