Herbicides: No weed too tough to kill

Future-Proof: Navigate Threats, Seize Opportunities at ICNY 2018 | Jan 22-26 at the Marriott Marquis, Times Square, New York

Q: Four years ago my husband and I had concrete pavers installed to replace a very large 60-year-old patio in our backyard that was cracked and dangerous. We love the look and feel of the pavers, but every year at this time we have big problems with moss and weeds growing in the cracks between the tiles. This gets worse each year. I use a gardening tool to dig out the offending material. Although it seems to work, at least until the following year when it is wet and shady again, it is extremely time-consuming and tedious. I'm guessing (and hoping) that this type of yearly maintenance shouldn't be required. We were new homeowners when we hired the person to install the patio and made the mistake of not checking to see whether he was a licensed contractor (we later found out he wasn't). Maybe he should have done something he didn't? It is my understanding that the pavers are set on a bed of sand, and no mortar was used in the construction of the patio. Other than the plant growth, the pa...