Does Fertilizer Go Bad Or Expire | How Long Does It Last?

You’re cleaning out your garage and organizing your storage shed, and you’ve found a couple of bags of fertilizer. It’s been a while since you managed either space and now you’re not sure how long those bags of fertilizer have been sitting around. Now you’re wondering, “does fertilizer go bad or expire? 

The answer depends on various factors. So, before you just throw that old fertilizer out, let me explain the details of whether or not fertilizer can go bad.

How Long Can Fertilizer Be Stored When Sealed?

The answer to this question depends on the form of the fertilizer. Liquid fertilizer for lawns or plants can last up to ten years when stored properly. You want to keep it out of the sun and avoid exposing it to cold temperatures that could cause it to freeze.

Does granular fertilizer go bad? Not necessarily, as it has no finite expiry date as long as it’s stored according to the manufacturer’s instructions. There are exceptions to this. If your fertilizer has pesticides or herbicides, you may want to check the packaging for an expiry date since these elements can lose their potency over time.

By the way, our site is supported by visitors like you. Some links on this page may be affiliate links which means if you choose to make a purchase, I may earn a small commission at no extra cost to you. Thanks for your support! You can find out more here.

Does Fertilizer Go Bad Or Expire Once Open?

Some of the bags you discovered in your spring or fall cleaning were open. Now you’re wondering if that affects the lifespan of your fertilizer. If you have stored your dry fertilizer adequately, you don’t have to worry about it expiring. Here’s a breakdown of the life expectancy of the available different types of fertilizer:

  • Microbial inoculants: 2 years
  • Dry crystallized fertilizer: Indefinitely
  • Dry granular fertilizer: Indefinitely
  • Weed & feed fertilizer: 4 years
  • Liquid organic fertilizer: 5-8 years
  • Liquid mineral fertilizer: up to 10 years

How Long Does Dry Fertilizer Last Once Open?

At the expense of sounding like a broken record, dry fertilizer doesn’t have an expiry date. No expiration is valid whether the bag is open or not. Once the bag is open, if the package doesn’t come with a resealable option, you’ll want to find a proper container to store it that keeps moisture from getting in.

How Long Does Fertilizer Last Once Mixed With Water?

If you find a bottle of fertilizer mixed with water, you need to find a way to dispose of it safely. You should avoid storing fertilizer once it’s mixed with water. The only use that you may have for mixed fertilizer is to bring depleted soil back to life. The earth won’t be ready for vegetation in the early stages, but you can use the leftovers to revitalize your soil.

If you don’t have soil that needs a pick-me-up, you should safely discard the mix.

How Long Does Liquid Fertilizer Last Once Open?

If you store your bottle of liquid fertilizer appropriately and make sure the lid is screwed on properly, it will be good for as long as the label says. Like its dry counterpart, one of the keys to the longevity of liquid fertilizer is how it’s stored. As long as you haven’t left the liquid fertilizer exposed to extreme cold or hot temperatures, it should work as long as the company promises it will.

Is It OK to Use Old Fertilizer Past Its Expiry?

If the fertilizer you found has an expiry date, you’re using it at your own risk if you use it past the date. Using a fertilizer that has passed its expiry date puts you at risk of releasing too much or too little of the nutrients you want for your plants or lawn. Using old fertilizer can end up causing more harm than good, so you’re better off safely disposing of any expired fertilizer you come across.

If you’re not sure how to safely get rid of your old fertilizer, keep reading to find out how.

Storing Fertilizer Once Opened

You might have realized that your fertilizer storage is a big deal, whether it’s in dry or liquid form. When storing your fertilizer, there are some things that you want to be aware of. You don’t want to store your fertilizer close to combustible materials or chemicals to ensure there isn’t a lethal reaction. You also want to make sure that wherever you keep your fertilizer has proper ventilation.

Because moisture can affect dry fertilizer, you want to make sure the surfaces you’re placing your bags of fertilizer on are dry, free of holes, and level. If you plan to stack your bags, you want to ensure you’re not stacking them too high, risking collapse and a bag breaking and causing waste.

If possible, you should store your fertilizer in an environment that has low humidity. Fertilizers can lose their nutrient and chemical properties when exposed to high humidity. The ideal space for your fertilizer storage should be 81 degrees Fahrenheit and have a relative humidity of anywhere between 30-40%.

Since that kind of temperature and humidity control might not be possible, you can also safely store your fertilizer using a protective coating that can minimize caking and moisture pick-up. This type of protection can also control dust and enhance your fertilizer’s viscosity. The protective layer can come as oil, particulates, polymer systems, and water-soluble liquids.

If you have pets or feral cats in your neighborhood, you’ll want to make sure that you’re storing your fertilizer in a place that isn’t easily accessible to pets, rodents, or other animals. The last thing you want is to find dead bodies of animals that have gotten into your fertilizer and poisoned themselves. There are more humane ways to control any pests that may be around your home.

Storage is vital to sustaining a long shelf-life for your fertilizer. Proper storage also ensures the safety of you, your family, and any pets. While it may seem like a pain to cover all these bases to store your fertilizer, you’ll save money and maintain a safer home when you take the steps outlined above.

How Can You Tell If Fertilizer Has Gone Off?

Some of the signs that your fertilizer has gone off vary depending on the type of fertilizer you have. Here are some signs your fertilizer has gone off that apply to all fertilizers and others specific to the kind of fertilizer.

General Signs to Look For

Signs that your dry fertilizer may be questionable include a change in the texture of the fertilizer. If the granules are in a bottle, you’ll want to be wary of any bulging.

An odd smell is another sign that something’s off. You also want to be mindful of any change in the color of the fertilizer. In addition to changes in color and smell, you’ll want to check for any signs of a bug infestation and mold growth, which are signs you need to throw out your fertilizer.

Signs to Look For in Liquid Fertilizer

Synthetic liquid fertilizer rarely goes bad before you use all of it if you buy what you need. The simple solution here is to only buy as much as you need to avoid having a surplus and risking it exceeding its expiry.

When looking at organic liquid fertilizers, you have to be mindful of the presence of fungi, bacteria, and mold growth. Signs that you want to be wary of include an unusual odor, bulging in the bottle, and a change in liquid consistency.

How do I Know if My Granular Fertilizer has Gone Bad?

If you see signs of a bug infestation or that rodents like mice or rats have been in your bag of fertilizer, you’ll need to get rid of it. The excrement from insects and rodents can cause harm to your lawn and garden, so the fertilizer has been made useless.

Signs My Microbial Inoculants have Gone Bad

Microbial inoculants are sensitive to their environmental conditions. They don’t do well in temperatures below 60 degrees Fahrenheit or above 80 degrees Fahrenheit. Similar to organic liquid fertilizer, you run the risk of mold, fungi, and bacterial growth. The growths will feed on the good bacteria, leaving nothing for your plants.

Does Dry Fertilizer Go Bad If Wet?

Unwanted moisture isn’t suitable for any fertilizer. As I mentioned when talking about how long fertilizer can last when mixed with water, you don’t want to store the mix. Exposure to moisture, whether from rain or humidity, can degrade the fertilizer, making it ineffective or degrade.

Fertilizer spikes are prone to breaking up and losing their unique appeal as a spike that is hammered into the ground as a slow-release fertilizer.

Does Fertilizer Go Bad If Frozen During Winter?

Extreme temperatures are one of the biggest challenges for liquid fertilizer. When you leave liquid fertilizer exposed to extreme cold temperatures that cause it to freeze, the fertilizer is rendered useless. Once frozen, it means the liquid fertilizer won’t be able to perform as it used to since the cold has rendered it ineffective.

Does Organic Fertilizer Go Bad Faster Than Synthetic?

While organic fertilizer may be better for the environment, it doesn’t have the longevity of synthetic fertilizers. Manufacturers of synthetic fertilizers use refined materials with a longer shelf-life, producing them in bulk. Bulk production is cost-effective, and those lower costs lead to savings for the consumer.

Organic fertilizers consist of animal matter or bi-products, manure, and vegetables. Since manufacturers of organic fertilizer can’t mass-produce their products like synthetic fertilizer manufacturers, the cost of organic fertilizer is higher.

Liquid chemical fertilizers can last up to ten years, whereas liquid organic fertilizer has a shelf-life of 5-8 years. If you’re looking at microbial inoculants, the lifespan is even shorter, lasting two years.

While the lifespan of organic fertilizer may be shorter, gardeners use it because they know that it improves the soil, not just the plants in the garden for the season.

Compost, the most organic fertilizer, doesn’t go bad. Your compost may lose nutrients after four months, but the loss isn’t enough for a significant impact on your garden. If your compost is one or two years old, you’ll notice considerable shrinkage. The shrinkage is due to the compost continuing to break down. It isn’t a sign that the compost has gone bad, but it is a sign to use up that compost quickly!

If your compost is smelly, it’s a sign that your compost needs some help because it’s off-balance. The compost is either too wet or compacted, and you can resolve the problem by turning your pile and adding some fast-decomposing material like sawdust to your compost pile.

How to Dispose of Old Fertilizer

If the fertilizer you have has gone bad or has expired, you can’t dispose of it in your regular household garbage. Your fertilizer is considered hazardous waste, so you have to be careful about how you get rid of it. Here are two ways to dispose of your old fertilizer:

  1. Contact the National Environmental Hotline for information on proper disposal. They’ll probably put you in touch with the hazardous waste event in your area.
  2. Hire a hazardous waste disposal company. If you’re not familiar with one in your neighborhood, a quick Google search will point you in the right direction.

If your fertilizer isn’t old, but you have more than you need, you can always give it away to a neighbor who could use it rather than have it go to waste.

Conclusion Does Fertilizer Go Bad

If you have bags of old dry fertilizer and you’ve stored them properly, you don’t have to worry about them going bad or expiring unless it has herbicide or pesticide in it. Check the bag for expiry dates if you think your fertilizer has weed or bug killer in it. If you find an expiry date and it has passed, you’ll need to discard your fertilizer safely.

Liquid fertilizer can last up to ten years, so if you stored the bottles somewhere where they haven’t been exposed to extreme cold or hot temperatures, you can use the fertilizer up to its expiry date.

You don’t want to use a fertilizer that is past its expiry date. While it might be tempting to use it because you don’t want to waste it, you shouldn’t. You risk damaging your lawn or garden because of the altered potency of the fertilizer once it has expired.