Roundup
Can I use Roundup to clear before planting?
01/25/2015 08:00 AM Filed in: Garden
Looks like the answer is yes! Allow 3 to 7 days after application depending on the product and the plant.
From http://homeguides.sfgate.com/soon-can-replant-after-using-roundup-88067.html...
Roundup Weed and Grass Killer Concentrate Plus can be used to prepare an entire vegetable garden plot or remove a lawn, while Roundup Ready-To-Use Weed and Grass Killer III works well on smaller jobs. You should wait a minimum of three days, from the time of the last treatment, with either of the products, to plant edible plants like vegetables and herbs or fruit-bearing plants.
From https://pubs.ext.vt.edu/456/456-018/Section_2_Home_Vegetables-4.pdf
At planting: Trifluralin (Preen Garden Weed Preventer, Miracle-Gro Garden Weed Preventer, or other labeled formulation). Apply at seeding of broccoli, Brussels sprouts, cabbage, carrots, cauliflower, celery, collards, black-eyed peas, field peas, garden peas, lima beans, mustard greens, snap beans, and turnip greens. Apply before transplanting celery, broccoli, Brussels sprouts, cabbage, cauliflower, eggplant, peppers, onions, and tomatoes. Apply to established cantaloupe, cucumber, and watermelon that have at least four true leaves. Apply to established asparagus prior to spear emergence. Apply after planting potatoes. Trifluralin will not control existing weeds. It does provide pre-emergence control of annual grasses like crabgrass, foxtail, and goosegrass, and small-seeded broadleaf weeds like purslane and pigweed.