Compost for potatoes

I grow my potatoes in wahtever I have available - this year I have a bin full of used compost from last year's containers and I'm mixing it with fresh compost out of the hotbin, a bit of well rotted horse manure that I happen to have lying around, and some vermiculite. I'm adding blood fish and bone to the bottom layer to replace anything that's got used up from the old compost. As I am filling 10 30l pots and 2 potato bags I'm glad to have plenty of reusable compost otherwise it woudl cost a fortune.

Last year I grew potatoes in a variety of composts from fresh MPC to 100% hotbin compost to previous year's old compost and found there wasn't a lot of difference to the crop, so I wouldn't be too concerned about planting them in very expensive stuff. I haven't ever used chicken manure but I don't see why it shouldn't be ok - someone else may be able to advise on this better than I can.

As said above^^^^^ it really matters not as you will have to supplementary feed after about week six any way. The main thing is to keep them well watered a spud is 80% water so lack of water lack of harvest.

Don't put your trust in rain, once the haulm has grown it is the best umbrella in the world.