Potato Height

I grow my potatoes in Bags. The last few years have been ok quite a good yield, not as big as I would like but ok.

My question is, the stems grow in excess of 5 or 6 feet out of the top of the bag.

Is this ok or should i cut them down to try and keep the potatoes growing instead of this huge foliage.

Many thanks Mitch

That can be a result of filling the bags with compost only. Best to fill half and half compost/soil. Bags are often placed in less than favourable positions,  sun wise, with a similar effect.
Once the halums have grown, they're the only greens you're going to get. They won't "bush up" to any advantage with a hair cut

mine are growing foliage like there's no tomorrow, also producing flowers over a longer period. i've only starting growing since last year so don't a lot of experience weather it's a good or bad thing. i guess i'll find out when i dig them up, all i can say is that this year i have twice the amount of greenery compared to last year.

all i have done is change the bed to the space next door to where they were last year and used rabbit manure mulch. maybe just the weather this year making them produce more foliage.

the way i see it is that the tubers need the energy that the leaves give them, there fore the more the better. as i said not an expert by any means but i'll be leaving mine until they die back, unless blight hits before.