Posted: 11/10/2014 at 14:59
"Mulching" is simply placing a layer of matter on top of the soil and is done for two reasons, firstly to reduce water loss by evaporation and secondly to reduce weed seed germination.
However, if the mulch is organic matter, a third benefit comes into play in that worms will pull the mulch down into the soil and improve its structure and fertility. Multi-purpose compost is as good as anything else in this respect.
You can mulch at any time you like, but if you have clay soil which you have dug over to allow the Winter frosts to help break up the clods, you would not lay a mulch over it as that would prevent the frost from doing the job. You should also avoid mulching dry soil as it will make it harder for the rain the penetrate, so only mulch soil which is already in a normally moist condition.
Until digested and excreted by worms, mulches add little in terms of nutrients so add fertilizers as a separate task, as and when needed.
Hope that makes thing clearer for you, Marigold.