Does Lawn Fertilizer Go Bad? (How Long Does it Last)

It’s been a while since you last fertilized your lawn. You visit your storage shed and realize there is several bags of fertilizer stored a couple of years ago. Now you are wondering, does lawn fertilizer go bad?

Granular fertilizer will last for many years or indefinitely as long as it is stored well and the packaging is not damaged. When it comes to liquid fertilizer, unopened bottles can last somewhere between 4 to 10 years. However, mixing fertilizer with other ingredients like pesticides or herbicides will make it go bad unexpectedly.

Does Fertilizer Go Bad?

It depends on the form of fertilizer i.e. granular or liquid. Most granular lawn fertilizers contain a combination of three active ingredients, namely: nitrogen, phosphorus and potassium. Others also contain calcium, iron, copper or magnesium.

These minerals stay active and their composition do not change or degrade over a long period of time. However, it is different when you choose to use liquid or organic fertilizers. Their shelf life may not be longer as compared to dry granular fertilizer.

Granular fertilizers never go bad, you can unwrap a bag that has stayed in store for years and apply on your lawn and it works. The granules inside the bag may clump together when stored for a longer period of time but does not lower its effectiveness.

You simply break up the materials and apply it on your lawn. Be sure to use gloves when using hand to break it up or when spreading on the lawn. High humidity is the reason why dry granular fertilizer may cluster together. It is important to store it in a cool dry place free from moisture.

On the other hand, liquid fertilizers can go bad. All liquid fertilizers have an expiry date on their packaging. They contains additives that decreases their shelf life. Before spraying it on your lawn, check expiry dates to ascertain it is still within the stipulated period of time.

Liquid fertilizers made from organic materials tend to break down quicker as compared to their synthetic chemical counterparts. They may also settle over time. Shake the bottle well before using. If not careful, you may apply the liquid on the top and leave the real fertilizer settled at the base of the bottle.

Signs that a Liquid Fertilizer has gone bad

There are some tale tell signs that may show a liquid fertilizer has gone bad. They include:

1. Bulging Bottle

If you store liquid fertilizer for re-use but realize the bottle is bulging after several month or years, it’s an indication that it has gone bad. Once the bottle is opened, it is difficult to control how long the active ingredients will remain dormant. Molds will literally start feeding on the components while releasing gases that causes the bottle to bulge.

2. Change of color

Change of color is also an indication that the liquid fertilizer has gone bad. For instance, if the content was colorless, it may change color to light green or yellowish. It simply means that the active ingredients are undergoing a chemical reaction.

3. Mold growth

When you open the bottle and look inside, you can visibly see mold growth. It is characterized by a bulging bottle due to the gases released by the molds. Mold growth also results to discoloration and fuzzy appearance of the fertilizer.

4. Odd smell

Odd smell is always an indication that something is not okay. The liquid will take a strange consistency and a bad odor. If your liquid fertilizer is exhibiting this indications, do not apply it on your lawn. It may have some negative effects. However, if the ingredients are still active, you can fix it and apply it on your plants.

How long does fertilizer last in the soil?

Fertilizers can last in the soil anywhere from a week to several month. The exact amount of time is determined by the type of fertilizer you are using. Fertilizers are made of different chemicals and ingredients to suite their different purposes. There are several factors that determine how fertilizer last in the soil. They include:

The purpose of the fertilizer

Fertilizer are made to target a specific plant. There are plants that requires fertilizer application after every 2 weeks while others may require 1 application for the entire season. Fertilizer may be beneficial to certain plants when applied after every 2 weeks. This means that the fertilizer breaks down faster in order to be used by the plant.

On the other hand, slow release fertilizers are applied in the planting holes prior to planting. They break down slowly to release nutrient for entire plant growing period. Therefore, how long a fertilizer last in soil depend on how it breaks down.

If the fertilizer is granular or liquid

Granular fertilizer is in form of dry granule. It is applied into planting holes prior to planting or can be applied at the base of an already growing plant. It breaks down gradually to release nutrient into the soil.

While liquid fertilizer is applied directly on the plant. It is absorbed through the leaves and used by the plant immediately. It can be applied to the plant after planting or at any stage of the growing season.

Both liquid and granular fertilizers contain the same nutrients needed by the plant. However, there distinct difference is how each last in the soil. Granular fertilizer tend to last longer in the soil as compared to liquid fertilizers.

Whether the fertilizer is organic or chemical

Organic fertilizer is environment friendly, it does not contain synthetic chemicals. It also contain bacteria and other microorganisms that improves the overall health of the soil. Like other synthetic chemical fertilizers, organic fertilizer contains nitrogen, phosphorus, potassium and other nutrients needed by the plant.

Organic fertilizers are most beneficial to your plants. Although they take longer time to decompose before releasing nutrients, they last in the soil for several years.

How to store lawn fertilizer for longer

Shelf life of your lawn fertilizer depends on how you store it. The fertilizer will go bad easily if it is mixed with pesticides or when in contact with moisture. The following tips helps to maximize shelf life of fertilizer as well as preventing it from clustering:

1. Store lawn fertilizer in a cool dry place

When intending to store your fertilizer for a longer period of time, ensure it is stored in an area that is free from moisture. Store it above the ground in a wooden cabinet. It can absorb moisture when placed directly on a cold floor.

2. Keep the fertilizer in its original packaging

 The original packaging is designed to keep the fertilizer dry and free from contaminations. Changing the packaging can expose the fertilizer to moisture, sunlight or other agents that can lower its shelf life.

3. Ensure the bags or packaging containers are closed off tightly

It reduces chances of the fertilizer becoming in contact with moisture. It also remains in its original state when the bag is tightly closed.  

4. Ensure the liquid fertilizer won’t become frozen

Liquid fertilizers are likely to freeze especially during winter season. Keep the environment around the fertilizer at room temperature. The temperature should be optimal, too low temperatures can damage the fertilizer.

5. Keep the fertilizer away from pets, rodents and other animals

If you are having pets or other animals, ensure that you are storing your fertilizer in an area they can’t access. You do not want to collect dead bodies of animals poised by the fertilizer. Rodents also create holes in the packaging bags.

6. Store your fertilizer in protective coating

It can be challenging to maintain optimum temperature and humidity in your store. That is where the protective coating comes in. They help to prevent fertilizer from dust, clustering and absorbing moisture. This enhances the viscosity of the fertilizer.

7. Store away from other chemicals

Keep the fertilizer away from combustible materials or other chemical. The fertilizer may degrade in the process of reacting with other chemicals. Store in an area that is well ventilated and away from direct sunlight.

Final Thought

Dry granular fertilizer can last indefinitely as long as it is stores in a good place away from high humidity. The fertilizer may cluster together but it will still be effective and safe to use on your lawn or plants. While for liquid fertilizer, it has an expiry date on the packaging. Avoid using expired fertilizer on your plants as it can harm them.

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