Per manufacturing label it is recommend to discard mixed solution of Hi-Yield 38-Plus Insect Control 38% Permethrin within 24 hours.
Hi Yield 38 Plus is a good product, however, it is not labeled for spiders.
We would recommend a product called Onslaught FastCap Spider and Scorpion Insecticide. It is labeled for mosquitoes, spiders and ants. This would be an excellent product to use in your backyard. It can also be used inside as well as a crack and crevice spray if needed. It has a quick knockdown as well as a residual of 30 days.
We do carry Tick Block which contains permethrin that can be used to treat clothing only.
Mixing Hi-Yield 38-Plus Insect Control - 38% Permethrin at 1.6 fl uid ozs. (3 1/4 Tablespoons) per 1 gallon of spray solution to make a 0.5% spray emulsion.
To prevent infestation of Ornamental Trees and Woody Shrubs, spray the bark to the point of saturation, but do not let runoff occur. Repeat treatment every 21 days during early Spring until Mid-Summer