Weeds in patio bricks

(Question)

What can I safely use on the numerous weeds growing between my interlocking patio bricks short of picking them by hand? Conditions are dappled shade in Scarborough . I tried cleaning vinegar and water, half and half, which did nothing. Cleaning vinegar is 10% not 5%. The area is quite large and I sprayed a small area just to test but nothing happened. I don’t want anything toxic. Thank you.

(Answer)

Thanks for contacting Toronto Master Gardeners.  In her excellent book Pocket gardening: A guide to gardening in impossible places, Marjorie Harris suggests that you carefully pour boiling water on the weeds before they go to seed. This will definitely reduce the number of weeds you have to remove manually.