How to Keep Your Patio Weed Free (and Moss Free Too)
Patios are emerging from the dark winter and wet spring looking worse for wear. Algae and moss are causing major slip hazards and weeds are emerging from every poorly mortared joint. But sorting them out can be easy and highly satisfying.
Get yourself a comfy kneeler, sink to your knees and do your weedy business. Make sure you get every scrap of root out wherever possible as perennial weeds (dandelions are one of the worst culprits) will regrow. Annual weeds are best removed before they start to flower and set seed. It will save you a whole heap of problems later in the year
Getting your fingernails dirty is one way, a trowel is another - but the best way is a weed brush. It will brush between the cracks in paving and blocks to remove stubborn weeds and the weed knife will slice through thicker stems.
You can use chemicals to remove weeds on patios. Some are contact killers in that they kill plants when the chemical touches the leaf. Others are labelled 'systemic'; this means they get into the plant, or weed, via its leaves and travel around killing as they go. One based on glyphosate is best. It enters the plant and travels around from the tips of the leaves to the root tips. You can target the weed killer directly onto the plant.
Gels are available and are the easiest way to apply the weed killer. And remember that weed killers don't know their dandelions from their dahlias, so will indiscriminately kill both. (Weed killers for grass, however, do 'know' the difference between any grasses and broad-leaved weeds!)
It goes without saying, but I'll say it anyway, always read the instructions on any chemicals you use and follow them to the letter. Don't think that by, for example, adding 'one for luck' is a good idea. It isn't. End of lecture.
Algae and Moss
I love a good pressure washing session. Unfortunately, I don't have an attachment to stop the wild spray drenching and coating everything in debris, but it sure does a great job on sprucing up the stone patio. Paving that was formerly slippery with algae and moss is quickly sorted. The difference is sensational. It also always smells like the seaside when I've finished.
I have to admit to also using my pressure washer on garden furniture and larger garden ornaments as the sun doesn't reach the patio in winter and early spring, and algae adores such conditions.
Simple brushing will disturb any algae and moss, preventing them from getting a hold on your patio. It also clears leaves and other detritus (the odd errant sausage from the BBQ perhaps?) and will even knock off any loosely rooted weeds. It's also good for your general gardening workout. Once a week is good.
Re-sanding and Re-pointing
When weeds have been pulled up and algae banished, you are often left with mortar that is incomplete or sand that has vanished. You need to re-fill those cracks, crevices and potholes to ensure weeds, via seeds blown in on the wind, don't take hold and colonise again.
This can take a matter of days. Re-sand block paving, brushing kiln-dried paviour sand into all the gaps between the blocks. Get ready-mixed or mix up your own mortar and fill in gaps in larger paving. The only weeds you then get are ones that land on the sand or mortar as opposed to coming up from below.