I put alot less in, nearer 25/75.
Can't find perlite in France so I plant plugs into bought compost from the supermarket. Works OK.
This is news to me -have never added perlite-dont understand why you would
I have never used it either, it seems a bit expensive and always get good results with seed/cutting/follow on compost only.
And I think it never decomposes either-so it is there for good
It is supposed to improve drainage and allow air to the roots, isn't it, thus enabling them to grow faster. I usually just use compost and find it works fine.
I would use it for cuttings, but once rooted then just plain compost.
I've never used it with plugs - however as we've discovered there's some dodgy compost out there nowadays, so if what you've bought seems inclined to stay soggy it might be a good idea to add some.
None necessary. I have just potted on the smallest gazanias I have ever bought and they are romping away in fresh potting compost. Beware experts trying to separate you from your money.
Perlite acts similar to vermiculite.
Where as vermiculite is usually spread on the top of seed compost and the first one or two potting up stages, to improve germination and reduce damping off. Perlite mixed in compost retains moisture by improving aeration and drainage. Roots need air to take up nutrients from the compost and perlite assists with this.
I use perlite mixed with compost for plants in pots instead of the water retaining granules. Whilst you can get by without it, using it does give plants a better growing media and reduces the need to water pots daily in hot weather. I'm very optomistic, me thinks we will get some warmer weather.
Shop around, it can be expensive. Wilkinsons are probably one of the cheaper places to buy perlite, I purchase mine at a local nursery at a fraction of the cost in the GC.