Ericaceous Compost

[anna-gram]

Can you put potted plants in multi-purpose compost on top of ericaceous compost?

[theprof]

If you're planning to add a layer of mp compost to a pot of ericaceous compost and then transfer the plant to that, the answer is no.

Ericaceous compost is lime free and quite acidic. Multi-purpose compost usually contains lime and has a pH of around 6.5-7.0. It's too alkaline for lime sensitive plants.

[Chipchopper]

Depends what the plants are, I'd say, and whether they are suitable for acidic conditions.

[theprof]

Hmm careful perusal of the OP's question seems to show that the anna-gram would like to tranfer a potted plant to another container containing ericaceous compost of an uncertain depth, topped up with multi-purpose compost.

It goes without saying that the flourishing of the plants will depend on whether they are lime-haters, lime-lovers or indifferent. However, their suitability for acid conditions has little to do with it. Should there be a deep layer of mp compost in the container sitting on a shallow amount of ericaceous compost, the plant roots might not even penetrate the bottom compost and therefore remain unaffected by the acidity. Their suitability for growing in ericaceous compost is therefore immaterial and can be ignored.

The acidifiers in ericaceous compost will gradually leach out after every watering leading to progressively reduced acidity. The acidity will not pervade into the multi purpose compost under any circumstances unless the composts are mechanically mixed.