Least toxic/most effective way to degreen patio and kill off persistent weeds.

[movingtobelfast]

We have an old patio that is grotty and really needs relaid, but can't afford it... because most of the mortar is gone we have a lot of worms 🐛 and general critters (it's a London terrace paved v small garden though). Need to clean up the patio for tiny dc to bumble about, plus also possibly selling in next six months. I have been recommended to use plain thin bleach on the green but this sounds a bit nuclear? But so do most of the actual degreening sprays.

Also have some pebbles and railings at front of house with weeds already coming through plus persistent tuft of grass - what's the best thing to get rid of them, does boiling water really work?

[poundinthewood]

In desperation I once dumped a load of salt and grit for icy paths onto the centre of my driveway where years of compaction made it impossible to kill the weeds by conventional methods. Over a few weeks everything died, and nothing grew there afterwards. It was pet and wildlife safe and 100% successful. I use it regularly now.

[blankmind]

Do you have a pressure-washer? Could you hire one?
Depending on the surface, they can shift algae and moss with just literally the pressure of water on real stone, wood, tarmac and other surfaces.

On composite stone, pressed concrete etc. like the sort used on terraces a bleach solution applied, left to stand then scrubbed before pressure washing vastly improves very green and black areas.

because most of the mortar is gone
If you do pressure-wash it, you must wear safety goggles, because where the jet of water hits the spaces where the mortar was, it can fly back in your face and will contain soil and sharp bits.

Also have some pebbles and railings at front of house with weeds already coming through plus persistent tuft of grass - what's the best thing to get rid of them, does boiling water really work?
Scrape off all the pebbles, lay some weed proof membrane from DIY sheds, wash pebbles and replace on top.

[aircooled]

If you use a pressure washer get one with a circular drum bit that has a rotating brush inside - kinder to mortar in the joints than a direct jet.

I'm about to use something called Algon which you spray on the paving to kill the green slime. It claims to be `organic' and therefore eco/child friendly. I bought it at my local hardware store.

[Lostpangolin]

Jeyes fluid diluted and a stiff brush.

[SeaRabbit]

Algon works well. It's basically very strong vinegar. It's not that expensive and even diluted is stronger than vinegar you buy in food shops.

[Mrsallovertheplace]

I use boiling water on ours, kills the weeds in between the flagstones and I just pull up what's left the next day.

[Fluffycloudland77]

I use salt for weeds and thin bleach for algae.

You have to rinse bleach well.

[Applesauce29]

I use the salt method. Grit salt is great, but a few bottles to ordinary table salt also works. And brushing with a stiff brush. (Pick out the tall weeds first tho to speed up the process)!

[ChuckDaffodils]

I use soda crystals and a stiff brush for algae on slabs and decking; and I'd dig out the current weeds, and mix up some new mortar and pop that down [on a sunny weekend] and it should stem the tide of weeds until you have sold up.

[Lostpangolin]

If you need to regrout, mix your cement and sand and brush it into the joints on a day when the slabs are dry. It'll absorb moisture from the air and you won't have the mess to clear up

[Madbengalmum]

Salt for weeds and bleach solution is brilliant for algae. 0.5 part bleach to 10 parts water, but you will have to repeat a couple of times.