[SimonH]

What weedkiller can I use that will kill the weeds but not my potatoes?  Farmers potatoe fields always seem free from weeds!!

Simon

[Aunt Sally]

Are you growing so many potatoes that you can’t hand weed them ?

Keep them hand weeded while young and when they are big the weeds will be smothered.

[Anton]

I just keep on heaping soil up around them

[Yorkie]

Not sure there is one which will do as you ask, Simon

[SimonH]

Hi Aunty
Yes,  quite a lot.   Last year 130lbs! 

Simon

[Aunt Sally]

Worzel says we grow about 90K of potatoes each year. 

As I said above we hand weed when they are little and leave them to smother any weeds as they get bigger.

[AndyRVTR]

From my memory, farmers fields are sprayed with a pesticide to kill any growth prior to ploughing and prepping the ground before planting seed  potatoes so very little weeds will show. Once they start growing the canopy of potato leaves will act as a natural suppressant until harvest time!

[rowlandwells]

as I recall from my farming days I used to spray the potato crops with what they called a pre-emergent spray so we would ridge the potato's up then spray the ground that would keep the weeds at bay till the potato tops smothered the weeds but that spray would be an expensive option for any home gardener me thinks and its probably banned for non commercial use like the home gardener