A sufficient buildup of herbicide residue, capable of injuring or killing newly introduced species, may be present in the soil. Avoid drift by only applying herbicides on calm days. When possible, use a coarse droplet spray applied at low pressure. Strive to use herbicides early in the morning when winds are likely to be calm. Excessive temperatures can also be avoided in the morning hours.
Intense heat can cause phenoxy type herbicides to volatilize and injure nearby nontarget species.
When available, choose herbicide formulations which pose the least risk of drift or other forms of contamination. For example a low volatile ester or amine type formulation of 2,4-D is appropriate when spraying around sensitive, broadleaf ornamentals. Follow this precaution even when plants are dormant. Buds are capable of absorbing phenoxy-type herbicides in sufficient amounts to produce distorted leaves. Nurseries are often located in rural areas close to agronomic enterprises.