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How to control weeds in your garden, lawn

Are your weeds getting out of control? With abundant sun, water and nutrients, weeds can quickly take over a garden or lawn if you don’t work at trying to control them. Pam Bennett, Ohio State University Extension horticulture educator, said the key is to prevent weeds from blooming and going to seed.

“Do whatever you can to stop that weed from blooming, whether it’s weeding, pulling or cutting,” she said. “The mantra is ‘Don’t let it go to bloom’ because if you do, the weed cycle will continue.”

An effective way to control weeds is to put down mulch. Areas should be mulched before the weeds start to pop up. For vegetable gardens, you can put down a couple of sheets of newspaper (don’t use glossy print materials) and cover with grass clippings. Avoid using lawn clippings that were treated with herbicides in the past month. The newspapers will break down and decay and in the fall, the newspapers and grass clippings can be incorporated into the soil, adding some organic matter. Bennett said that while the black landscape fabrics can be as effective as mulch, they can prevent desirable plants and flowers from growing.

The pre-emergent herbicide Preen is effective in preventing annual weeds from sprouting. Preen needs to be put down on a “clean bed,” i.e. either before weeds have started growing or after an area has been weeded and then watered to get it to work. Putting down Preen and then mulch acts as a double barrier against weeds. However, placing Preen on top of a mulch bed is not effective; it needs to have contact with the soil to create that barrier. Bennett said it’s important to make sure you have the right type of Preen product and to closely follow the instructions on labels.

For some perennial weeds such as thistle and dandelions, mulch and Preen aren’t enough. For these weeds, you need to try to starve the roots by repeatedly pulling and digging them out and not letting the plants flower.

A common question that Bennett gets is whether herbicides can be sprayed in flower beds or gardens. She said to check labels because most are not for use in the garden. If you use an herbicide in a flower bed, she recommends putting on gloves and using a paintbrush to apply the herbicide on the bad plant and to avoid doing this when it rains or is about to rain.