How Long Can Granular Fertilizer Be Stored?

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There’s an ongoing battle between plant owners with nothing to do with which plant is better or what it should be called.

This battle is, of course, over fertilizer.

Storing Granular FertilizerPin

We won’t get deep into the debate here, but one of the biggest debates is whether liquid-soluble fertilizers are better or worse than granular fertilizers.

One particular difference is in shelf life, and while we’re going to avoid the greater debate, this is one point well worth looking at in detail.

So let’s take a look at how well granular fertilizers hold up in storage, then compare this to the shelf life of some other popular fertilizer types.

How Long Can Granular Fertilizer Be Stored?

When properly stored, granular fertilizers can remain usable indefinitely.

However, the methods you use for storage are key, and knowing if that storage has been compromised can help you identify whether the fertilizer has gone bad.

Synthetic vs. Organic Granular Fertilizers

One important distinction we need to make is that there’s a big difference between synthetic and organic granule lifespans.

Synthetic granules will last indefinitely, and no longitudinal studies show the granules going bad after even decades of storage.

However, organic granules rely on organic materials and generally have a shelf life of about 5 years.

This is because they contain microbial life essential for the granules to break down properly.

Beyond this difference in lifespan, there is very little difference between the two; we will only distinguish between them when necessary.

The Best Way to Store Granular Fertilizer

Storing granular fertilizer isn’t difficult, and following a few simple rules will allow you to keep the fertilizer in perfect condition for years.

When possible, keep the fertilizer in its original bag.

This provides a layer of protection, prevents granules from escaping, and can help you identify the type of fertilizer you’re storing.

As many people have plants that need different fertilizers, that last point can be especially important.

Secondly, you will want to place the fertilizer bag in an airtight container.

Plastic and metal work equally well, and keeping it airtight will avoid the risk of pests or fungal spores getting in and ruining the granules.

Finally, choose a cool, dry place to store the fertilizer container, preferably away from sunlight.

A garage, basement, or shed can all be great choices if they don’t get too hot in the summer.

How NOT to Store Granular Fertilizer

So now that we’ve looked at the best way to store granular fertilizer, let’s look at some of the things you SHOULDN’T do.

First of all, never leave the fertilizer bag in direct sunlight.

The sunlight can heat the bag, cooking away some nutrients.

This is especially true of organic granular fertilizers, which may begin to break down in the sunlight.

Another risk is allowing the granules to get wet.

Synthetic granules will tend to clump if exposed to high humidity or moisture, and while they can be broken apart again, they’re not as easy to use once this happens.

Meanwhile, organic granules can become infected with mold or begin to break down, slowly spoiling the entire bag.

Heat will cause the nitrogen content in many ingredients to break down into gas, which can further affect the quality of your granules.

As you can see, this is why it’s important to store your granules in an airtight container somewhere cool, dry, and away from the sun.

Doing so will preserve the granules, but failing to do so can reduce their quality or even ruin them.

Comparing Lifespans for Other Fertilizer Types

Finally, let’s take a brief moment to look at a few other types of fertilizer to see how they compare regarding shelf life.

Synthetic liquid-soluble fertilizers can last long when stored properly, with a potential lifespan of 8 years or more.

Dry crystallized fertilizers can last indefinitely when stored properly.

Depending on the product, organic liquid-soluble fertilizers can last up to 8 years.

Mineral-based liquid fertilizers can last for up to 10 years.

Last but not least, fertilizers that contain a microbial element or herbicides, such as weed and feed fertilizers, will last between 2 and 4 years when properly stored.

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