Compost for potatoes in pots

Hi. I am planning to grow some potatoes in pots this year, but I am not sure which compost I should use? Does it need to be high quality? Or can I use a grow bag? Or reuse some old compost if I then feed and water the plants?
Thank.

I used a mixture of home made compost and soil for my first foray into growing with potato bags last year.  Worked very well.  I found that the soil helped with moisture retention,  as keeping potato bags moist enough can be a challenge.  One tip though, compost is much lighter than ordinary soil.  Make sure you don't want to move your bags after adding soil, they become very heavy, even before the potatoes have grown.

I tried bags as I was over enthusiastic on the seed potato ordering front last year.  I am using them again this year so that I can try several varieties, but still have 4 rows of my standard crop.

If you do use old compost make sure it’s not from tomatoes (same family) Ipersonally would use fresh. At our garden club show,members have a heaviest potato competition with a seed potato & grow bag provided. A lady from the allotments has won the last 2 years by a long way with just using her own made compost from the allotment.