How much John innes base fertiliser should I add?

[newstart]

I have half John innes No.1 and a half multi purpose mix in 9cm pots. I want to see if I can keep them in these pots longer by adding a john innes base fertilizer. Ratio is- N 5% P 7.7% K 10% as they are now running short of nutrients-The above mix is not ideal. How many granules roughly should be added to the above mix. I confess the 9cm pot to be 4 months old with some. I don't want to pot on bigger for the time being. My alpines are medium to fast vigour types. I have some slightly slower growing Sedum. Are they slow because they want pure John innes compost or is 'Cape Blanco' for example a slow to medium growth variety. I am aware I have to be careful with fertilizer at this stage.

Any ideas Thanks!

[Giles]

How about using something like 'Osmocote' which gives a more controlled slow release of nutrients than J.I.Base,has a better nutrient balance, and is less likely to burn the roots?
If you can't get get it from your local garden centre, you can get it from 'GardenDirect'.
'Sincrocell' is a similar product.
Admittedly they are both more expensive.

[iann]

The standard fertiliser rate for JI #1 is 3g mixed with 1l of soil.  You can of course adjust that to whatever strength you feel your plants need.  The original JI base fertili8ser isn't really designed for use after the fact, but you can if you want.  Most JI soils use a modern formulation with a similar NPK but synthetic ingredients which would work better just sprinkled on top of a pot.  You can also use other slow-release fertilisers like Vitax or Osmocote.

[derekb]

How about using something like 'Osmocote' which gives a more controlled slow release of nutrients than J.I.Base,has a better nutrient balance, and is less likely to burn the roots?
If you can't get get it from your local garden centre, you can get it from 'GardenDirect'.
'Sincrocell' is a similar product.
Admittedly they are both more expensive.

Giles have you tried dealing with Garden Direct lately I put an order on their web site went to pay it said we no longer take payments from your area phone this number, I tried got an answer phone saying they would get back to me this was about a month ago but have heard nothing so I gave my order to somewhere else it was about a £60.0 order. It is a shame as I have been dealing with them for about 30 years, when I had my shop I was an agent for them and stocked most of their range.
Derek