How Long Can Granular Fertilizer Be Stored

Growing a lush, green lawn is a labor of love that also demands a bit of technical know-how, including the proper way to store fertilizers.

These potent mixtures are formulated to promote healthy plant growth and usually include nitrogen, phosphorus, and potassium—the essential nutrients to improve soil fertility or replenish what plants absorb from the soil. 

Does Granular Fertilizer Expire?

Have you ever asked, “Does fertilizer go bad?”

Generally speaking, no. Fertilizers have a long shelf life, lasting for years with proper storage. They are made up of elements that remain stable over time, meaning you can store and use them, season to season. However, there are exceptions for fertilizers with active ingredients or short-lived additives, such as those in weed and pest control products. These specific fertilizers usually have a shelf life of 1-4 years, as their potency diminishes over time.

Simply put, the shelf life of your fertilizer depends on what you buy. Check the expiration date on the product label, as it varies for different products, so you have the most accurate information for proper storage.

Fertilizer Shelf-Life and Proper Storage Tips

There are many types of lawn fertilizers, including liquid and granular fertilizers, which can be further categorized as organic or synthetic fertilizers. These distinctions also influence fertilizer shelf-life.

Liquid fertilizers can last up to 10 years when stored properly. 

Liquid fertilizers have a long shelf life. While it’s recommended to use them within three years of purchase, they remain effective between 8-10 years or even indefinitely when stored properly.

So, it's important that you keep them from freezing. Otherwise, the elements can separate, thus reducing the potency of fertilizer nutrients. After prolonged storage, you may see solids settling at the bottom of the product—it doesn’t signify expiration, though. Always shake liquid fertilizers before using them to ensure a uniform application.

Liquid or water-soluble fertilizers mixed with water can last up to 2 weeks.

Fertilizers are shelf-stable for an extended period until water is introduced. Once mixed with water, liquid and granular fertilizers can remain effective for about two weeks. However, it can vary depending on the type of fertilizer and the weather. They can become less effective in hot and dry conditions.

Diluted organic liquid fertilizers usually last 1-2 days, while synthetic fertilizers already mixed with water can last up to a week when stored in a cool, dry, dark place.

Sealed liquid organic fertilizer can last indefinitely when stored properly.

Organic liquid fertilizers are usually made of kelp or fish emulsion and have an indefinite shelf-life unless mixed with water. However, remember that the longer the emulsions are stored, the harder you'll have to shake to agitate the ingredients.

Granular fertilizers don't expire when stored properly

Granular fertilizer boasts a stable chemical balance, ensuring that its properties remain consistent over time. However, when exposed to humidity, bacteria, and unstable storage temperatures, it may start to deteriorate, losing its potency. This underscores the importance of proper storage in preserving the effectiveness of granular fertilizer for grass, as well as that of all fertilizer types.

READ: How Long Does Grass Fertilizer Take to Work?


How to Store Fertilizer Properly

In summary, lawn fertilizers don't come with a fixed expiration date. When stored properly—in a cool, dry, and dark place—they can last several years and retain their effectiveness, whether they are liquid or fertilizer granules.

While certain fertilizer nutrients, like nitrogen, may start to break down after an extended period, that doesn't necessarily mean that the fertilizer has gone bad. It may just be less potent than it was in its earlier years. To prevent the premature loss of your fertilizer's efficacy, we are concluding with some tips on how to properly store your fertilizer:

  • Store your fertilizer in a cool, dry, well-ventilated place and out of direct sunlight. Prolonged exposure to heat and sunlight can compromise its effectiveness.
  • Keep it out of reach of children or pets.
  • Store the fertilizer in its original packaging when new and sealed.
  • After using, transfer the fertilizer to an airtight container to protect it from moisture and other external elements.

Fertilizers are hygroscopic, which means they absorb moisture from its surroundings. When that happens, the most immediate effect is that the fertilizer may clump together, leading to uneven distribution of nutrients into the soil. Some of the nutrients may also start to dissolve, leading to a premature release of the nutrients.

While some moisture may not immediately spoil your fertilizer, it can surely affect its ease of application and efficacy. But with proper precautions and storage practices, you can extend your fertilizer shelf life to ensure that your lawn receives the nutrients it needs for healthy growth.

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