You can also apply herbicides in the spring. Quackgrass Elymus repens. Carefully transplant the seedlings to their permanent locations when the seedlings are 3 to 4 inches tall.  Source: <a href=https://eaphl.ru/how-lengthy-do-weed-seeds-keep-good/>https://eaphl.ru/how-lengthy-do-weed-seeds-keep-good/</a>