Organic Weed Control
Certain types of weeds can indicate problems with your soil which if corrected may eliminate or reduce those types of weeds. Visit http://oregonbd.org/Class/weeds.htm
Pre-emergent (prevents germination of seeds): corn gluten meal, sold under various brand names, has been shown to prevent seed germination as well as the chemical products sold for this purpose. Corn gluten meal should be applied in the cool of spring (when daffodils are blooming) and for even better control again in the cool of fall. It is safe and will add some nitrogen to your soil. Avoid using on newly seeded areas or just before seeding. It may be necessary to wait six weeks before planting seeds but plants can be planted at anytime.