I suggest that you contact the manufacturers for the best answer to your question. But, as I recall, the shelf-life of those concentrates could be anywhere from 2 to 8 years. Longevity of yard and garden chemicals depends largely on how they've been stored. Cool, dark, and dry pretty much sums it up.

Extreme temperatures drastically shorten the life of these chemicals, as does exposure to sunlight. No, making a stronger mix will not solve the problem.

Call the companies and they will give you the best advice. It's a good policy for all of us to purchase only the amount of certain products that we are reasonably sure we'll use in one year.

We shouldn't be responsible for storing these hazardous chemicals. I worry about a fire, for example. Or what happens if a container bursts or begins to leak?

Thanks rhizo!

But, as I recall, the shelf-life of those concentrates could be anywhere from 2 to 8 years.
shelf-life...that is the term I couldn't remember, thus couldn't research it very well.

Cool, dark, and dry pretty much sums it up.
Yes, has been stored well.

Ok, in doing some more searching using 'shelf life' I found where the question was asked on another site and a Consumer Response Representative from The Scotts Company and replied.

He said:
Roundup Weed & Grass Killer Concentrate has a shelf life of a minimum of eight years. The product may
last beyond the minimum time period though. Many variables in storage conditions can affect the shelf
life of a product. Roundup Weed & Grass Killer Concentrate will not be fully effective one
day and ineffective the next; the product will gradually lose its effectiveness over time. Store both
unopened and opened product containers in a cool, dry place and protect them from extremes in
temperature. Freezing temperatures, for example, won't affect the product, but may cause damage to the
container and could result in a chemical spill. Stored correctly, your product will last at least the minimum
number of years and probably longer.

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It's a good policy for all of us to purchase only the amount of certain products that we are reasonably sure we'll use in one year.
Going forward, when purchasing I'll consider a smaller container, or else maybe opt to split it with a neighbor who also has a high usage every year.

Thank you again.

Sue

4 years ago, My friend a pro landscaper gave me his professional weed killer, about a quart, he said to mix it with at least 3 qts of water before using, I can't ask him the brand as he doesn't live here anymore, I stored it properly all this time, think its still good?