In recent years, several organic herbicide products have appeared on the market. These include Weed Pharm (20% acetic acid), C-Cide (5% citric acid), GreenMatch (55% d-limonene), Matratec (50% clove oil), WeedZap (45% clove oil + 45% cinnamon oil) and GreenMatch EX (50% lemongrass oil). These organic products can be effective in controlling weeds, but there are limitations. Organic herbicides kill weeds that have emerged but have no residual activity on those emerging subsequently. Further, while these herbicides can burn back the tops of perennial weeds, perennial weeds recover quickly. These organic products are effective in controlling weeds when the weeds are small but are less effective on older plants.
Vinegar is used for weed control on warm, dry days over 65 degrees F. Regular household vinegar is not very effective in killing most weeds. There is a 20% acetic acid that is very active weedkillers, but also must be handled with care. Spraying the strong solution on a plant strip off the protective coating on the foliage causing the plant to desiccate. Some people spray the vinegar on the soil to lower the pH to a nonviable level for the plants. This is disastrous for soil life. The effect lasts from several months to a year. It may take up to six months for woody plants to die completely. The soil would then need to be rehabilitated with lime and then 3–4 inches of compost in a blanket.
Another proactive approach is the use of winter or summer cover crops. Keeping the soil covered during the winter will help prevent the establishment of winter weeds such as shepherds purse, deadnettle, speedwell, annual bluegrass, annual ryegrass, and other perennial grasses that might interfere with future crops in the rotation. Competitive spring and summer cover crops will even keep patches of perennial weeds (such as nutsedge) from expanding in area. It is important to seed at rates high enough to establish a solid stand of cover crop. For cereals, 45 seeds/ft2 is usually adequate or about 1.5 times more than when seeding for grain.

Flame weeding is also an option:

https://agsci.oregonstate.edu/video/tips-flaming-weed-em-and-reap-part-1