A3: They can go back on the lawn when the liquid has thoroughly dried onto the grass, unless there are poisonous weeds such as ragwort, buttercup etc present. Grazing animals will avoid eating these weeds in their natural state. However, once the weed starts to die (be it from use of a weedkiller or naturally) changes in the way the weeds taste may make them more palatable and they may be eaten by mistake. It is these dying weeds that cause the risk to grazing animals rather than the weedkiller. Where this type of weed is present, or if you are unsure if toxic weeds are present, we recommend keeping grazing animals off the area until the weeds have died and have their remains have been physically removed.