Can You Store Fertilizer in The Garage? (Four Storage Considerations)

Fertilizer can’t be stored just anywhere.

Very much like the food they help grow, some fertilizers will expire sooner than expected if stored in poor conditions.

You could be tempted to store it in your garage together with the rest of your gardening supplies.

But, Can You Even Store Fertilizer In The Garage?

Yes, you can. However, there are a few things you must get right if you want to stay safe and protect the quality of the product. For instance, some fertilizers double as explosives and can be a danger to your home safety. Also, there are several types of fertilizers: liquid, dry, and compost fertilizers. Each type has a different shelf-life but can reduce with poor storage. Then there are fertilizers infused with herbicides or pesticides which need to be handled a little differently for the added agent to work.

Four Fertilizer Garage Storage Considerations

1. Temperature

Temperature is the most critical storage factor if you are dealing with liquid fertilizers.

Liquid fertilizer is harder to store because it’s prone to lose potency if stored in extreme temperatures.

If the temperature conditions in your garage aren’t right, say, it’s too hot, your fertilizer might be useless by the 5th year of storage.

However, if you store it the right way, it will likely live up to the actual 8 – 10-year shelf-life. Freezing temperatures are just as bad.

Keep Your Garage at 50°F (10°C) – 80°F (26°C)

Wide temperature fluctuations are known to crystallize liquid fertilizer, reducing its effectiveness.

Dry fertilizers are vulnerable to wide temperature variations as well but not as profoundly as their liquid counterparts.

Consider configuring your garage to provide a stable temperature anywhere in the range of 50°F (10°C) – 80°F (26°C).

You may as well insulate the containers to reduce the impact of temperatures fluctuations in unexpected situations, say, in the case of power failure.

Insulate Your Garage

The winter temperatures can destroy your liquid fertilizer.

Starter fertilizer blends (liquid) will almost certainly freeze in the winter if you don’t insulate or warm your garage.

On the other hand, liquid 28% Nitrogen fertilizer won’t freeze partly because of its high Nitrogen content. Read the manufacturer’s instructions to protect your fertilizer accordingly.

2. Humidity

Compost manure doesn’t have a definite shelf-life but you need to keep it away from excess water (which may leach the essential nutrients).

Dry fertilizer too lasts forever (nitrogen, potassium, and phosphorus won’t expire).

However, dry fertilizers infused with an agent, say, herbicide or insecticide tend to be delicate.

They also tend to have the shortest shelf-life of any fertilizer. Liquid fertilizers are sensitive to moisture.

So What’s the Perfect Humidity?

The best humidity for all fertilizers is 40% RH or below.

Most dry fertilizers are sensitive to moisture because of the hygroscopic nature of the components. Excess moisture causes them to harden up (caking) at which point they’d be useless.

For that reason, configure your garage for moisture control which may include dehumidification.

3. Risk Of Explosion And Fire

Ammonium Nitrate-based fertilizer (commonly referred to as CAN – Calcium Ammonium Nitrate) can be dangerous depending on how you store it. Ammonium Nitrate is an explosive industrial chemical with wide application in mining and quarrying.

Hell On Earth!

On the evening of 4th August 2020, a poorly stored stash of Ammonium Nitrate fertilizer exploded in a fireball, almost flattening the city of Beirut .

Over 200 people died and 6,500 were injured.

Avoiding Trouble with CAN Fertilizer

This fertilizer is capable of unleashing mayhem both in pure and contaminated form.

Here is basic housekeeping for your garage:

  • Keep your garage dry because the risk of an explosion increases when CAN comes into contact with moisture.
  • Don’t use organic matter (e.g. sawdust) in your day-to-day cleaning activities. Go for something inert, such as sand.
  • Consider removing forklifts and cars out of your garage to prevent ammonium nitrate from coming into contact with fuel, greases, and oil
  • Don’t let anything get impregnated with the fertilizer. This includes ropes and pallets. Also don’t allow it to build up in hollow items such as pipes and bottles. Remove these items from your garage to avoid accidents.
  • Avoid welding and cutting because the resultant sparks could ignite the fertilizer
  • Contaminations should be washed immediately

Incompatible Materials

Certain materials pose a considerable risk of fire and shouldn’t be allowed near ammonium nitrate.

These items must be kept away at all times if you want to avoid an explosion. Most of them are combustible but others aren’t.

Here’s the list:

  • All flammable/combustible fluids e.g. petrol, diesel, paints, and greases
  • Items with pressurized contents such as gas cylinders
  • Pesticides that contain oil
  • Sulfur and its products
  • Organic matter e.g. animal feeds, hay, sawdust, straw, etc.
  • Highly reactive or corrosive liquids e.g. acids, alkalis, oxidants, etc.
  • Powdered metals
  • Urea
  • Heat-generating items especially those that heat up in presence of water e.g. quick lime
  • Materials you aren’t sure how they’d behave near ammonium nitrate e.g. weed killers, pesticides, etc.
  • Chlorides

4. Type And State Of The Fertilizer

Liquid fertilizer is harder to store than dry/granular fertilizer.

Storage tanks for liquid fertilizer are often large and must be well spaced for easy retrieval and changing.

On another hand, dry fertilizer is supplied in bags that are easy to stack on top of each other on wood pellets in your garage.

Other Storage-Related Issues

You might need to make the following adjustments to your garage:

UV Light

First, ensure that your fertilizer is out of direct sunlight.

UV light reduces the shelf-life of some liquid fertilizers although it isn’t much of a big issue like temperature and humidity. Repair your roof if some parts are missing.

Also, keep your garage as dark as possible if you plan to store your liquid fertilizer in transparent containers.

Remove the light-permitting polycarbonate roofing and keep the door closed most of the time. Note down the expiry date of your liquid fertilizer and store it in opaque tanks.

Contamination & Leaks

Keep the container closed and airtight to keep out contaminants and air. This will also help prevent spillage and leakage.

Don’t Change The Container

It can be tempting to repackage your fertilizer to fit in a corner in your garage.

There are two risks with that –

  • firstly, fertilizer is more open to contamination during repackaging.
  • secondly, you may end up confused about the type of the product, guidelines of use, and cautionary notices.

As it’s usual with liquids, your liquid fertilizer will settle and form sedimentation (mostly from the minerals) with time.

You can prevent this buildup by shaking your fertilizer once in a while.

Can You Keep Fertilizer In A Multipurpose Garage?

It wouldn’t be particularly a great idea to park your car or create a gaming enclave in the same garage used for storing any fertilizer.

While it may look like a safe thing to do (now that you’ve observed all safety precautions in the book), you can’t be sure of what could strike.

Dedicate the entire garage to the storage of fertilizer if you want to protect the quality of the fertilizer and avoid accidents.


To summarize everything, you can store fertilizer in any garage provided that you observe the necessary safety precautions.

There are a few changes you will need to make to your garage to protect the quality of the fertilizer.