Things You'll Need
Swimming pool patch kit with vinyl patch
Waterproof, disposable gloves
A lawn mower grass bag can tear when a sharp stick or other object enters it, and an aging bag's thin material can develop a tear. It is much less expensive to repair the hole to protect the mower's operator and bystanders from objects flying out of it than to purchase a new bag. Cleaning the bag then using a swimming pool patch kit to fix it is an inexpensive and quick solution, and the patch should last years.
Remove the torn lawn mower bag from the lawn mower by lifting it upward and detaching the rails that hold it in place. Some mower models have a door that needs to be opened while the bag is lifted and removed.
Empty the bag of all grass clippings. Lay the bag on a flat surface with the tear facing upward.
Put 1/4 cup of dish-washing detergent into a bucket. Add 1 gallon of hot water to the bucket, and mix it with the detergent to create a bubbly, soapy solution. Use a soft-bristled brush to scrub the solution on the bag's tear and to about 3 inches outward from the tear in all directions on the bag's inside and outside. Rinse the soapy solution from the bag with water from a garden hose. Allow the bag to dry partially.
Cut a sheet of vinyl patch from a swimming pool patch kit, making a patch about 1 inch longer and wider than the tear in the lawn mower bag. Put on waterproof, disposable gloves, and squirt a layer of glue from the patch kit to cover the cut patch's smooth side entirely. Smooth the glue toward the patch's edges with a gloved finger.
Press the patch's glued side against the lawn mower bag's tear, and smooth the patch onto the bag. Place bricks on top of the patch, and keep them there for 12 hours, allowing the glue to cure. After that time, the repaired bag can be put back on the lawn mower.
Remove the lawn mower bag from its metal frame to make a repair that is near the frame's edge.
Latex swimming pool patches are waterproof and do not deteriorate in sunlight.