.. than to use weedkiller.
I can hear you all groaning from here - stop it! Yes, I know that the temptation is to get out there and lay about you with the weedkiller: who enjoys stooping over a patio for an hour or more, digging out beastly weeds from the cracks?
No, not even me: patio weeding is one of my least favourite jobs, because as well as killing your back/knees, it takes ages, and is very unrewarding, in that once you've done it, it doesn't look superb, it just looks normal again. However, it is something that I do quite often, and over the years I have realised that it is actually better to do it by hand than to let the Client spray it to death.
For several reasons, which I shall detail for you here.
1) aesthetics: if you spray it, you will then have to watch the greenery slowly dying for the next fortnight, until your patio is criss-crossed with dead, brown and black rubbish, which looks dreadful.
2) cleaning up: you will at some point have to scrape out and sweep up this debris, unless you want to look at it for several months - so you might as well have weeded it by hand in the first place.
3) only partial success: unless your patio has a very light sprinkling of fresh young weeds, weedkiller will not get all of them, and a few weeks later the older, larger, more deeply-rooted weeds will be popping up again, stronger than ever. This particularly applies to the worst weeds such as brambles, cinquefoil and alchemilla mollis (my pet hate for patio weeding), all of which will lurk deep in the joins and cracks, and will spring up and grab your ankles in no time.
4) even if your weedkiller kills all the weeds, it will leave a mass of organic matter in the joins or cracks. All that dead plant material, even though it was "poisoned", is nothing more than fertiliser for the next generation of seeds. So by spraying instead of pulling, you are laying down the foundations for the next round of weeds.
4) and finally the eco-argument: we use quite enough chemicals and poisons on our land, and this is one place where we can exercise restraint and can choose not to use them.
There is also the consideration of run-off: if your patio is edged by lawns or flower beds, then excess weedkiller can run off the slabs, or can run along the joins, and end up poisoning your precious plants or your lovely lawn, particularly if you spray over-generously, walk over the wet patio then walk across the grass... oops! One of my Clients did this once - he'd sprayed a brick path, and then walked over the lawn. How did I know? He'd left a trail of dying grass footprints...
So how should you tackle this problem?
Arm yourself with a small hand tool - I use my Daisy Grubber - plus gloves, knee pads or a kneeler,
Start at one edge, or one corner, and go all along one side of one slab, using the tool to lift out all the weeds. I either shove it in vertically, then wiggle it about to loosen the roots, or I place it underneath the main stem and use it to lever them out.
Then move on to the next one, and repeat. It doesn't matter if you do all the N-S cracks and then all the E-W ones, as it were, or whether you start in one corner and work across - just make sure that you join up all the bits that you do, and don't miss any.
If the joins are clogged with soil, scrape that out as you go, and once you have finished, you can brush some sand, or some small pea shingle, into the gaps.
Once it is done, get some Pathclear - yes, we're back to weedkiller again! Except that this is a preventative measure: get some Pathclear and carefully spray it along each of the newly-cleared cracks. Don't wildly squirt the whole patio, that's wasteful and unnecessary: just spritz along each join or crack. This will help to prevent new weed seeds from germinating, and should keep it clear for the rest of the season.
Here's one I did earlier, half done:
This particular patio can't be treated with weedkiller, and can't have the Pathclear treatment either - as you can see, it adjoins a lake and I am obviously not going to use any weedkiller so close to water, in case of run off into the lake.
So this particular one, I have to do by hand, about once a year. But it's worth the effort: and by doing it once a year, the weeds are never big enough to put up much of a fight.
So there you have it, four (or five) perfectly good reasons why it is better to weed a patio by hand.
Oh, but try not to do it on the hottest day of the year...!