As we enter the late summer and early fall, there are a few critical things to remember regarding weed control in your yard and garden. Many summer annual weeds are beginning to produce

seeds at this time of year. Now is a great time to think about the impacts of the soil seedbank on overall weed management programs.

Most of the weeds that people battle in their yards and gardens germinate and come from the soil seedbank, which is the sum of all the viable weed seeds present in the soil at a given site. People don’t often think of the weed population as being made up of both growing weeds and dormant seeds in the soil, but this is a key component of weed management. Effective weed management starts with keeping seeds out of the seedbank in the first place, whether by preventing existing weeds from reproducing or by limiting the import of new weed seeds from offsite through things such as contaminated mulches or media. If there aren’t many seeds, there won’t be many weeds. Conversely, if there are lots of seeds, there will be lots of weeds.

When growing a garden, it is easy to overlook weeds growing on the perimeter and margins. Often, time and effort are invested in keeping weeds away from the crop itself while weeds on the edges of the garden plot are allowed to grow. Keeping weeds away from the crop is extremely important to protect yield; however, it is also critical to control weeds on the margins of the yard and garden as well.

Pulling a few weeds, such as this chamberbitter, can prevent larger weed problems in the future. Photo by Colton D. Blankenship

A single weed can produce many thousands of seeds depending on species and conditions if allowed to grow unhindered. Overlooked weeds on the perimeters of gardens and landscapes can contribute millions of seeds into the soil seedbank, which makes managing weeds in subsequent years even more challenging. Pulling a few weeds this year can save the need to pull thousands of weeds in future years.

It is important to remove weeds before they are allowed to produce seeds. If weeds have already started to produce seeds, it is beneficial to put a bag or covering over the weeds before pulling them to limit the dispersal of seeds over the area. If weeds have produced seeds, avoid removal via string-trimming or mowing as those practices will disperse seeds over a wide area.

For perennial weeds such as nutsedge species, consider applying herbicides after the garden crop is finished but before mowing or tilling the garden area. Ensure that selected herbicides are labeled for the intended use and do not have carryover concerns for planting future garden crops or ornamentals. If perennial weeds are not managed, infestations are likely to worsen over time.

Late summer and early fall are critical times for keeping seeds out of the seedbank. Time and effort invested in managing weeds now will pay dividends in the future via reduced weed pressure and lower overall efforts needed to keep yards and gardens free of weeds.