I grow mimi in large pots, not grow bags as such, and get great clean crops.
I find it is cheaper doing it this way as I reuse the pots year after year and use my own home made compost.
This is what I do:
Once chitted,
Be careful not to allow the sprouts to get too long as they may break when planted. One or two chits per seed spud is fine.
Next I get the pots ready. I use large plastic pots that will last years. Make sure they have good drainage holes in the bottom, add more with a drill if required, and then add a layer of well rotted manure to the bottom:
Next add a thin layer of multi purpose compost to sit the seed potatoes one. (I do not sit the seed potatoes directly on the maure as this can burn the new roots, others do sit them direct on the manure and seem happy, personal choice I guess). In these sized pots I put two seed potatoes per pot. Sit the potato with the chits facing upwards:
The final step is to just cover the seed potatoes with a layer of compost taking care not to damage the chits. Then make sure you label the pot and give a little water depending on how moist the compost is:
Keep the pots in a warm, frost free greenhouse, earthing up as the sprouts break the surface of the compost until you reach the tops of the pots. Keep the compost moist to begin with, especially until the first shoots break the surface.
Move the pots outside after frosts have finished and keep well watered. Feed with a general purpose fertilize if you wish and as harvest approaches root around with your hand in the compost to check the size of the tubers. Start to harvest when they are the half the size of hens eggs. Do not try to store the tubers for more than a day or two as they quickly loose their exceptional flavour.
There is no beating home grown new potatoes cooked straight from the ground. They knock “Jersey Royals” into a cocked hat on taste.
Also growing in pots/compost removes many of the problems such as slugs/eel worm and they are very easy to clean, just run the new spuds under a tap and pop them in a pan or water with a sprig of mint to cook……yumm!
Jerry