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 patio is very level and is in great shape.
A: It happens every spring when weeds start to emerge. To have weeds growing between the cracks of pavers of patios and walkways is common. Although unsightly, it’s not really a problem and can be easily controlled.
It sounds as though the person who installed the pavers did right even though he was unlicensed. As we’ve said many times, a contractor’s license is no guarantee of good-quality work. It does provide other important benefits, such as governmental oversight and the likelihood of bonding and insurance should someone get hurt on the job or should the contractor not perform the work properly.
Weeds are the result of seeds driven by wind and water migrating into the cracks and under the pavers after the hardscape is installed.
Moss, on the other hand, is a plant that thrives in damp, shaded locations. You don’t say, but we’d bet that the patio is shaded and probably a joy to be on during the summer.
You really have two issues: weed control and moss removal. They require different solutions. You’ve already tried one method of weed control — pulling them. But as you’ve found, it’s labor-intensive and time-consuming. There is an easier way. We’re advocates of the moderate use of herbicides.
A spritz of Roundup from a spray bottle will take care of weeds in a few days. Roundup not only kills the foliage but also kills the roots. Be cautious, though. Roundup kills almost any plant material it touches, so don’t spray on windy days and don’t get it on anything but the weeds you want to kill. Roundup is available at hardware stores and home centers in a ready-to-use spray bottle or liquid concentrate.
To prevent future seed germination, sprinkle a little pre-emergent, such as Preen, on the joints before the weeds germinate. The two-step process of Roundup to eradicate and Preen to prevent germination should take care of the weeds.
The best way to remove moss from a patio is with a pressure washer. A high-pressure stream of water blows the moss off the pavers. Pressure washers are available to buy at home centers for a few hundred dollars. They are also available to rent at your local rental shop.
Pressure washing the patio will have the added benefit of blowing the weeds out of the cracks. So washing before Roundup is the order of events.
If you don’t want to go to the trouble or expense of using a pressure washer, mix a solution of chlorine bleach and granulated Tide detergent. One cup of Tide to a gallon of bleach should do the trick.
Mix the solution until the Tide dissolves. Pour the solution on the patio and scrub with a stiff brush. Let it sit for 20 minutes so the solution can do its work and rinse thoroughly with a garden hose equipped with a nozzle that will concentrate a strong stream of water. The water coupled with the solution should wash away the moss.