Eliminating what makes moss grow will kill it off. Sunlight is detrimental to moss. It soon bleaches it out and dries it up. If at all possible, open up the area to receive sunlight. Clip overhead tree branches. Prune nearby bushes that shade the area.

Growing Medium

Pavement cracks quickly fill in with naturally occurring elements that grow moss through the actions of weather. Sand, dirt, decomposing organic garden matter get deposited in pavement cracks through wind and water. Even sweeping and hosing down the pavement make these deposits. Moss spores soon follow suit and grow.

A power washer will clear out growing moss and the growing medium that has accumulated. After the pavement has completely dried, repair cracks to prevent further damage and the recurrence of moss growth.

Pavement composition matters. Bricks and porous stones or man-made pavers are moss magnets. They naturally hold moisture and nutrients for moss growth. If these types of pavement are used, consider cementing or grouting them in. Then treat them with a sealer on a yearly basis.

Moisture Supply

Moss needs a fair amount of constant moisture to survive. Pavement cracks naturally supply moisture. Water is channeled through these cracks on its journey to seek its own level. Water action will continue to erode the cracks making them larger over time.

Check the drainage for the area where moss is present. If the pavement has sunk or lies lower than its surrounds, water action is probably responsible for the pavement cracks. Poor drainage leeches the base right out from underneath the pavement. Uneven ground causes stress fractures in the pavement. During winter, freezing and thawing will cause ground upheaval which also leads to pavement cracks. It may be necessary to install a proper drainage system to restore level pavement and prevent further deterioration. Proper drainage will eliminate moss growth.

Nutrients

Again, weather action supplies nutrient rich deposits into pavement cracks sustaining the growth of moss. Use a power washer to remove buildup and existing moss. When dry, repair cracks.

Apply a new layer of sand mixed with baking soda or lime into the spaces between pavers. Moss prefers acidic conditions. Changing the PH of the affected area should eliminate the moss growth.

Household products that have successfully been used to eliminate moss include Dawn dish detergent, Tide laundry detergent, ammonia, cat litter, and swimming pool bleach. NEVER mix ammonia and bleach. Always test an inconspicuous area first especially with bleach. A handheld torch will kill moss. Be careful of nearby plants. If it kills moss, it will kill other plants too. It may take several applications before moss is eliminated. Then a schedule of applications will be necessary to keep the pavement cracks moss free.

Lack Of Foot Or Vehicle Traffic

Moss will not sustain where heavy foot and vehicle traffic occurs. If the cracked pavement where the moss grows does not get used very often, it may not be a necessary element. Remove it.

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Photographer: Horia Varlan