How Long Does an Open Bag of Fertilizer Last?

Fertilizer, most times, is purchased in large batches because people use it throughout the year, helping plants thrive in all seasons. Due to this, plant owners and gardeners must find a successful way to stow their fertilizer once opened. 

An open bag of fertilizer, on average, can last 4 – 10 years. Some fertilizers may only last for a year, while other types of fertilizer can remain usable for much longer. Dry and liquid fertilizers last the longest, while fertilizers with active elements do not have a long shelf life.  

When you purchase fertilizer, it can last you for a long while. Fertilizers can support your plant’s growth for many years if stored properly. Continue reading this article to learn more about the lifespan of different fertilizers and tips on how to store your fertilizer correctly. 

The Shelf Life of Different Fertilizer Types 

There are tons of plants in the world that live in varying environments. And many different fertilizers help support those plants. Some fertilizers have active ingredients while others do not, and there are many different formulas available on the market.

Fertilizers, in general, do not break down over time. Specialized formulas can expire after a short extended period, but most formulas will last for multiple years. 

The life shelf of a fertilizer will depend on a few elements:

  • The application formula. 
  • The type of fertilizer.
  • If active ingredients are present 
  • When the fertilizer was opened  

Granular Fertilizers 

Granular fertilizers are fantastic, and people love them because they are effortless to store and use. This type of fertilizer lasts the longest, especially if it is a generic granular fertilizer for plants. It shouldn’t be a cause of concern even when the bag is already open as long as it is stored properly.  

However, moisture is a critical aspect of all types of fertilizer and can impact their shelf life. Exposure to moisture can create a hardening effect on granular fertilizer. The fertilizer will appear like a hard rock, and it can be frustrating to use for gardeners. Luckily, it is easy to keep granular fertilizers away from moisture. 

They stay effective for long periods and can be applied to the soil for your plants. However, it is best to check the expiration date indicated on the bag. It is always recommended to replace fertilizer after such date.

If there is no expiration date indicated on the packaging, it is safe to assume that the fertilizer can last over ten years, as is common among most granular fertilizers. 

You may want to label the bag clearly with the date you opened it. Though it is unlikely that your fertilizer will remain unused for longer than ten years, it is best to purchase a new bag when the leftovers have been in storage for that long.

Liquid Fertilizer 

Liquid fertilizers are in high demand for many gardeners and are advertised worldwide because their are pretty easy to use.

Liquid formulas have a long shelf life. Unlike granular formulas, they do have an expiration date. Once the packaging has been opened, the liquid formula can last for 8 – 10 years. 

Many will use their liquid formula before then, so the expiration date is not entirely essential. But, if you have liquid formulas sitting in your shed or garage for a while, you may want to check to see when you purchased them. 

If you plan to use several-year-old liquid fertilizers, be sure to mix the solutions before you use them. Liquids can separate when sitting idle for an extended period of time like tea and other mixes do. The solid elements of your fertilizer will fall to the bottom of the container.

Microbial Fertilizer (Active Ingredient Fertilizer) 

Although it is not as common, some fertilizers in the gardening world have active elements. These active elements cannot last for a decade or more, unfortunately. 

Fertilizers with active ingredients are like medicine. After a while, the functional elements lose their effectiveness and will not work well for plants. 

If you have a fertilizer with an active ingredient, it is best to plan for a shelf life of 1 – 4 years. Fertilizers with active ingredients contain any of the following: 

  • Herbicides 
  • Pesticides
  • Bacteria
  • Microbes 

These ingredients help nourish the soil and do not fall under the generic category of plant fertilizers. They are also very sensitive to environmental conditions. 

How Should I Store My Open Bag of Fertilizer?

Fertilizer is resilient and can last for a long time, especially when stored properly. And luckily, there are specific ways to store fertilizer so that it may last for an extended period. 

You should store open bags of fertilizer in a dry and cool place. Additionally, you should seal the fertilizer properly and keep it away from extensive exposure to moisture. Keep the fertilizer away from windows, doors, or vents that can introduce moisture.

With little effort, fertilizers can last and stay in excellent condition. If you have a fertilizer you are planning on storing, here are a few great tips to follow: 

  • Store it in a dry and tidy place. Fertilizer, as discussed, should not be around moisture of any kind. Rain, wind, and other weather can bring large amounts of moisture to your fertilizer. If you can, store it in a clean area in your garage or shed where it is safe from the elements.
  • Keep your fertilizer away from the sun. Although the sun is not a considerable hazard, it is still best to keep your fertilizer in a shaded area for protection. Heat is not helpful for fertilizer, and any type of fertilizer should be kept in cooler environments. Unfortunately, natural elements can interact with your fertilizer very easily. 
  • Close the bag or box with a seal. Sealing your fertilizer isn’t entirely necessary, but it can act as a precautionary step toward helping your fertilizer remain protected in storage. Sealing can contain moisture and prevent build-ups in your liquid and granular formulas. Fertilizer also can spill, and it’s best to keep it in a bag or container where rust won’t form. 
  • Keep your fertilizer in its packaging. The packaging contains valuable information about your fertilizer, especially if you are new to the gardening world. Fertilizers stored for long periods can be forgotten about, and many may bypass the instructions for that specific fertilizer. This can cause problems for your plants in the future. 
  • Have proper ventilation in your storage space. The air quality is essential when storing fertilizer. It is best to make sure the environment is clean and relaxed, with constant ventilation. This can help your fertilizer last longer, especially fertilizer that has a dry formula. 

Does Lawn Fertilizer Last As Long as Plant Fertilizers?

Most plant fertilizers can last for many years and perform well when given to plants, even if they have hardened or clumped. However, many might wonder if the same thing is true for lawn fertilizers. 

Lawn fertilizer has a long shelf life lasting 4 to 10 years. If the fertilizer is stored and managed properly, it can last for longer than ten years as plant fertilizers can. Lawn fertilizers with active ingredients like pesticides or microorganisms will not last as long. 

Although lawn fertilizer is different in many ways, it still is a fertilizer that contains the essential ingredients that one would expect. However, it may have higher doses of certain ingredients.

Gardeners and plant caretakers should store their lawn fertilizer in the same way as plant fertilizer: 

  • Store it in a dry, cool place. 
  • Keep it contained in its packaging.
  • Replace it after its expiration date. 
  • Avoid moisture and spillage.  

Can You Use Expired Fertilizer on Your Plants?

When fertilizer has a lifespan of a decade or more, it can be challenging to know when your fertilizer has expired. Luckily, most fertilizers have an expiration date on the packaging that you can check.

You should not use expired fertilizer on your plants because the nutrients may not distribute properly. This can lead to fertilizer burn or malnourished soil. It is best to purchase new fertilizer for your plants if you can. 

It is not common for people to use expired fertilizer on their plants. And luckily, nothing severely detrimental will happen to your plants if you accidentally do. But, they may suffer the consequences of expired fertilizer in the long run. 

Here are some things that might happen if you feed your plants with expired fertilizer: 

  • Your plants may not receive the nutrients they need. Sometimes, the main ingredients will lose their potency after the expiration date and will not help your plants. Gardeners may give plants fertilizer, but the plants will not process the fertilizer as nutrients. This can cause malnourishment and a lack of growth. 
  • Your plants may become overfertilized. Expired fertilizer is not as balanced, and gardeners might not know how much nutrients they give to their plants. Due to this, it is easy for plants to become over-fertilized. This can create fertilizer burn
  • Your fertilizer may lump and smell. If your fertilizer has gone wrong, it will smell bad (e.g., like ammonia) and appear lumpy. In dry formulas, the fertilizer may also appear hard like cement. If this happens, it is best to avoid giving your plants fertilizer. You can check the date on the packaging to make sure before purchasing a new fertilizer.  

Final Thoughts 

Dealing with expired fertilizer is never a fun experience for anyone. Luckily, there are ways to preserve your fertilizer in the right environment to last for long periods. 

If you currently have fertilizer stored in your garage or shed, it is best to adjust your environment and seal the fertilizer up properly. Otherwise, it may not last as long as you would like. You can also consult with a professional to check if your fertilizer is still in good condition if an expiration date is unavailable. This can help make your life as a gardener a whole lot easier. 

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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