Check with the manufacturer. Many pesticide-type products have an 800 number so you can call with questions. Keeping the product cool but not cold at all times and well sealed will of course extend viability.

I wouldn't toss them unless being a poor choice for container gardening is an inherent issue. As long as they're dry, they should be fine. The 2 primary concerns about your soil would both pivot on moisture issues - whether the soil was saturated or remained wet for an extended period. The result of lengthy saturation and the anaerobic (airless) composting that takes place under those conditions includes the production of organic acids that can lower pH to unacceptable levels. Soils that remained damp for an extended period, but not soggy, might have suffered structurally due to soil materials breaking down from the composting process, and the value of a soil (to the plants it supports) lies primarily in its structural integrity and how well it is able to retain that integrity for the intended life of the planting or the interval between full repots. All plants are sensitive to certain fungi, but mostly under certain cultural conditions. For instance, as long as you don't over-water, it's very unlikely that there is anything lurking in your old soil that would hurt the plant that wouldn't also be in the next product you might buy. Virtually all plants live in perfect peace next to thousands of different bacteria and fungi that are harmless under favorable cultural conditions but could become pathogenic under unfavorable cultural conditions, with the main player in that balance between good and bad being air:water retention issues. Al

Hi! This may be too late to post, but just in case you're still curious... I had the same question and learned the answer from a reliable soure (University of Washington). They claim that the talc version of the r/h has an 8 month shelf life, even if refrigerated (which I'm assuming extends it to the max). See link below if you want to read it (PDF) It's on page 5: Beware! It's a PDF file so if you have acrobat reader it may load deadly slow...try getting the firefox free software 'foxit' to open PDF. It's free and about 200 times faster. You can find it on the Mozilla home page. Cheers! Gonzo Here is a link that might be useful: University of Washington info on rooting 'hormone'

We are told by 1 pool builder white plaster when cared for properly has as long of life as Hydazzo or Diamond brit, but most others telling us to upgrade. The color of poo I like is easily produced by normal white plaster just FYI. Should we consider saving the cost of upgrading?