Yes, Monterey Vegetable & Ornamental Weeder is a concentrate. The mixing rate is 1.5 fl oz in 1 gallon of water. One gallon of finished solution will cover roughly 1000 sq. ft.
Unfortunately Monterey Vegetable & Ornamental Weeder is not labeled to be used on or around onions. You will need to wait at least 4 months before planting onions after this product has been applied to a given area. If weeds are already an issue around edibles not listed on the label, we would recommend a glyphosate based product like RoundUp QuikPro to spot treat any weeds.
Vegetable & Ornamental Weeder is a pre-emergence herbicide for the control of annual grasses, it controls weeds by killing their seeds as they germinate and can be applied after planting as long as you are not planting seeds.
Monterey Vegetable & Ornamental Weeder can be used as directed on snap (green) beans during spring or fall.
Monterey Vegetable & Ornamental Weeder will not kill existing weeds as it is a pre-emergent herbicide that helps to control grasses and broadleaf weeds prior to germination. Avenger Weed Killer or RoundUp would be products that you could use for weeds actively growing. You would want to be sure to not apply it to any of the vegetables as it will kill anything that is sprayed with it.
It's better to till the soil before you make an application of Monterey Vegetable & Ornamental Weeder, that way you don't disturb the treated area afterwards causing inconsistent control. There's no wait time after tilling to make the application but you will need to wait at least 4 months before planting seeds after the treatment.
Monterey Vegetable and Ornamental Weeder is a pre-emergent herbicide that helps to control grasses and broadleaf weeds. This is one of the only products that is safe to use in vegetable gardens (including asparagus), and can also be used in flowers, trees, shrubs, groundcovers, and rock gardens.
Monterey Vegetable & Ornamental Weeder does need to be watered in after application within 24 hours with 1/2 inch rain or its equivalent in sprinkler irrigation so it should be fine.
Vegetable & Ornamental Weeder will hurt the seeds, because of its preemergent properties. You want to wait until the plants are actively growing and then apply the product. You should also only use a pre-emergent after planting so you do not disturb the soil where the barrier is.
Monterey Vegetable & Ornamental Weeder is only specifically labeled to be used on beach strawberries. Bonide Grass Beater Over-The-Top Grass Killer Concentrate is labeled to control crabgrass and can be used on all strawberries. You will use 1.38 fl. oz. per 1,000 sq. ft. This product can be used once a year and up to 7 days before harvest.
Monterey Vegetable & Ornamental Weeder would be a good product to use for the listed weeds around potatoes.