Hello,

I don't know anything about weed killers so I've been reading a few
bottle labels. It seems that there are two types: one that kills
everything above ground and those that kill everything above and below
ground. The problem with the former seems to be that with the roots
still alive the plant re-grows. Now if that is the case, what is the
point of these above-ground only weed killers? Why doesn't everyone
just manufacture/sell/buy/use the above and below ground weed killers?

I understand that glycophosphate is highly recommended. B&Q's own
brand had a similar though not identical ingredient. Is that pretty
much the same?

I see that sodium chlorate is a cheap and readily available weed
killer. Is this an above and below or above only weed killer?

I'm looking for something to stop grass growing between the patio
paving slabs BTW.

Thanks in advance.