If you are new to gardening, you may wonder whether lawn fertilizer goes bad or not. The answer is that it depends on the type of fertilizer you are using and the conditions in which you store it. 

In general, fertilizers tend to have a stable chemical balance which means they can last a very long time, and they are made of nutrients that do not break down. However, lawn fertilizers tend to be sensitive to storage temperature and humidity and are susceptible to bacteria and microbes. 

They are also sensitive to sunlight, rain and snow. If any of these factors become a problem, your lawn fertilizer will change its physical properties and lose its overall effectiveness. In some cases, it can even become harmful to lawns. As long as granular fertilizers stay out of extreme weather conditions they should stay stable.

With all this being said, let's dive into the details so you can determine how best to store your fertilizer to maximize its shelf life.

How Long Does Lawn Fertilizer Last?

The shelf life of any lawn fertilizer depends on whether it is dry or liquid fertilizer and whether it is an organic or chemical fertilizer. 

Does Granular Fertilizer Go Bad?

Dry fertilizer tends to come in granular form. It looks like tiny pellets or grains, and it can be scattered over a field or lawn just as a seed is. The pellets sink into the soil over time and slowly dissolve, at which point the nutrients transfer into the soil and fertilize your lawn.

The most common type of fertilizer is a dry organic fertilizer, and it most often contains potassium, nitrogen, and phosphorus. These three naturally occurring chemicals are ideal for plant health, and they are less harmful to grass than other non-organic chemicals. 

Organic dry fertilizers will not burn your lawn even if you overuse them because they are slow working and mild-natured. 

Because the chemical balance within granular fertilizers is stable, they do not change their properties over time and go bad. However, if they are exposed to humidity, inadequate storage temperatures, or bacteria, granular fertilizers will begin to break down and lose their potency.

Does Liquid Fertilizer Go Bad?

Liquid lawn fertilizers are popular because they work more quickly than dry, granular fertilizers. They do not need to break down and dissolve as dry pellets do, so they can start fertilizing your lawn immediately. However, they also tend to have a shorter shelf life than dry fertilizers.

There are two main types of liquid fertilizer, mineral and organic.

Mineral fertilizers are made through a chemical process and are particularly potent. If stored correctly, they can last between 8 and 10 years (check expiration date). You need to remember to give them a good shake before each use.

Organic liquid fertilizer is made from various organic matter, and it often has a shorter shelf life than its mineral counterpart because it does not contain the same stabilizing chemicals. 

The best advice is to check the bottle to gauge the shelf life of a new brand of this style of fertilizer. Once opened, the degradation process will begin immediately, and there is little you can do to slow it down.

Once bad, organic liquid fertilizers can harm or 'burn' your lawn.

Does Compost Go Bad?

Compost is an excellent source of natural fertilizer. As a general rule, it never "goes bad" so long as it is kept in the right conditions; however, it will begin to decompose and break down over time naturally. 

The hotter and more humid the environment, the faster your compost will break down, so try to keep it cool and dry.

How Do You Know if Fertilizer Has Gone Bad?

The best way to tell whether a lawn fertilizer has gone bad is to study its physical properties. The key factors to look out for include:

• Has its texture changed?

• Has the smell changed?

• Has the color changed?

• Are bugs or mold present?

• Is the bottle bulging?

What Happens When Liquid Fertilizer Goes Bad?

Liquid fertilizer, particularly organic liquid fertilizer, is vulnerable to bacteria and mold. Once you open the original packaging, the lack of chemicals and pesticides in this fertilizer means that organisms and microbes will begin to invade naturally and without much trouble.

The mold and bacteria may create gasses that cause the bottle to bulge and the liquid to smell strange. Over time, the smell may become more pronounced and nasty, and the thickness of the fluid may increase. You should avoid pouring it on your lawn at this stage as the bacteria can be harmful to grass and soil.

What Happens When Dry Fertilizer Goes Bad?

When dry fertilizer goes bad, it becomes clumpy and harder. It is easy to spot because it becomes more challenging to scatter and pour. 

However, this does not mean that the fertilizer is no longer helpful, only that humidity and temperature have caused the pellets to sweat and cling together. To reverse the state, you need to dig and break up the clumps and leave your fertilizer to dry out in a cool, dry place.

The same is true if your granular fertilizer develops mold on its surface. The mold can be removed by removing the top layer and drying the fertilizer out.

If animals and insects infest your dry fertilizer and leave feces in it, avoid using the fertilizer as the bacteria they spread can be harmful to plants and soil. 

What are the Best Storage Methods for Lawn Fertilizer?

The best way to store your fertilizer is to read the bottle, bag, or label and follow the manufacturer's instructions as closely as possible. That being said, here are a few cardinal rules that you can follow to maximize your fertilizer's shelf life:

• Always store your fertilizer in its original packaging because this contains the ingredients and chemical information specific to each product.

• Store your fertilizer in a cool, dry place that is not damp and is free from water sources and puddles. Ideally, the humidity level should be no higher than 70%.

• Store your fertilizer away from direct sunlight.

• Store your fertilizer in a locked area away from pets and children.

• Ensure that your fertilizer is stored somewhere with ventilation, even if it is just an open window.

• Store toxic substances separately from organic ones and keep locked away.

• Be sure to seal the bag or lid of your container tightly and securely between each use. 

Does Miracle-Gro Lawn Fertilizer Go Bad?

https://www.amazon.com/Miracle-Gro-Water-Soluble-Lawn-Food/dp/B000P0FHQ2/

Miracle-Gro lawn fertilizer is one of the most popular brands of liquid fertilizer on the market. It lasts around three years before it goes bad.

Does Scotts Fertilizer Go Bad?

https://www.amazon.com/Scotts-38620-Builder-WinterGuard-Fertilizer/dp/B017VN8XB6/

Scotts Turf Builder is one of the most popular brands of dry, granular lawn feeds out there. According to the company, it never goes bad and should have an infinite shelf life so long as you keep it in the correct storage conditions.

Final Thoughts:

Lawn fertilizers tend to have a pretty extensive shelf life so long as they are stored in the right conditions. As a general rule, it is best to use them within a year of opening them and read the label carefully.

For professional help with fertilizing your lawn, call Cory's Lawn Service. We can help! Get in touch with us for a free quote today! 

Our team of lawn professionals is focused on delivering top-notch customer service, maintaining beautiful lawns, and giving customers more time to spend on what is most important.