The way to check if herbicides got to cold is that they separate, look if the product is lumpy, streaky, or cloudy. And, another more hazardous danger is freezing and splitting the container resulting in a messy spill.
I have never had an issue with cold storage in PA zone 6b. Guidelines from Montana State University as follows:
No storage temperature restriction: Metolachlor products, EPTC, Surpass, Achieve, Maverick. Most dry formulated herbicides in DF or WDG formulations.
Do not store below 40 degrees Fahrenheit:
Assert, Avenge, Campaign, Command, Discover, Extreme, LI-700, Nortron, Prowl, Pursuit Plus, Sonalan, trifluralin.
Do not store below 32 degrees Fahrenheit
Agri-Dex, Basagran, Far-Go EC, Flexstar, Goal, paraquat, Grazone P D, Hyvar, Kerb, Liberty/ATZ, Lorox DF, Poast, Pramitol, Progress, Puma, Pursuit, Quest, Raptor, Redeem, Reflex, Reglone, Stinger, Thistrol, Ultra Blazer, Velpar.
Do not store below 20 degrees F Fahrenheit
Fusilade DX, Plateau, Ro-Neet, Weedar 64.
Do not store below 16 degrees Fahrenheit:
Camix and Lumax.
Do not store below 10 degrees Fahrenheit:
Amitrole T, Arsenal, Curtail/M, Crossbow, Dakota, Fusion, glyphosate, Rodeo, Roundup.
Do not store below 3 degrees Fahrenheit:
Atrazine 4L, Low Vol ester, Bronate Advanced, bromoxynil, bromoxynil Atrazine, Shotgun.
