If you're planting in pots why not just use the best potting compost?
John Innes no 3 for adult plants, maybe mixed with 20% multi purpose compost to aid water retention or fine grit if you need it to be very free draining. Plants such as roses and clematis will need extra fertiliser added as they are hungry plants.
If you're planting ericaceous plants then you need Levington's type compost for things like rhodos, azaleas, skimmias etc.
If you're planting alpines then it's a whole different ball game but do bear in mind that whatever you're planning, all commercial composts have a limited amount of nutrients in the mix - good for around 90 days usually - so you'll need to replenish fertilisers every spring for permanent plants in pots and use a liquid feed weekly thru the growing season to get decent results.
Vendée - 20kms from Atlantic coast.
"The price good men (and women) pay for indifference to public affairs is to be ruled by evil men (and women)."
I already use John Innnes no.3 and ericaceous (Levingtons) and feed monthly, but was bit concerned about about drainage in larger pots. Thanks to you and everyone's help I think I will be ok. Once again thank you everyone
Drainage is best achieved by a few crocks in the bottom to keep the holes clear and then standing on pot feet so excess water can run away freely. After that, it's best to use the compost a plant needs - fertility, texture, alkalinity or acidity - and then add multi purpose compost to increase water retention or fine grit for extra drainage depending on its moisture requirement.
Vendée - 20kms from Atlantic coast.
"The price good men (and women) pay for indifference to public affairs is to be ruled by evil men (and women)."
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John Innes no 3 for adult plants, maybe mixed with 20% multi purpose compost to aid water retention or fine grit if you need it to be very free draining. Plants such as roses and clematis will need extra fertiliser added as they are hungry plants.
If you're planting ericaceous plants then you need Levington's type compost for things like rhodos, azaleas, skimmias etc.
If you're planting alpines then it's a whole different ball game but do bear in mind that whatever you're planning, all commercial composts have a limited amount of nutrients in the mix - good for around 90 days usually - so you'll need to replenish fertilisers every spring for permanent plants in pots and use a liquid feed weekly thru the growing season to get decent results.