Once the gardening bug bites, growing bigger and better plants becomes your raison d’être, and you soon find yourself surrounded by more materials than you know what to do with – including some leftover Miracle-Gro at the back of the shed. But are these still usable?
Does Miracle-Gro expire? Miracle-Gro plant food has an indefinite expiration date provided that the products are properly sealed and stored in a cool, dry place to prevent moisture or heat damage. However, specific shelf lives are set by manufacturers to ensure optimum nutrient efficacy and even dispersal upon application.
In essence, Miracle-Gro will last for several years in the right conditions, but you owe it to your plants and wallet to use plant food in the recommended period while the fertilizer ingredients can still deliver stellar results.
Below, we’ll discuss the shelf life of 5 Miracle-Gro products plus storage tips and common questions surrounding Miracle-Gro use.
Shelf Life of Miracle-Gro Plant Food
According to the maker, Scotts Company LLC, traditional Miracle-Gro plant food generally has an indefinite shelf life as long as it is stored correctly.
As for liquid plant food products, Miracle-Gro reps have suggested these are viable for 8 years but are best used within 3 years of purchase.
If kept unsealed, this feed lasts indefinitely, but using within 3 years will provide optimum nutrient efficacy and ensure the salts don’t crystallize.
If you notice that the blue crystal salts appear mushy or sticky in the bag, this is a sign that the pouch was left improperly sealed, allowing air moisture to become absorbed.
This might make it tricky to measure out your quantities, but it won’t affect the quality or safety of the application.
Always reseal the pack after opening to extend shelf life, and store in a cool, dry place, such as a kitchen cabinet or basement at average room temperature (68-72°F) as this will minimize hardening due to moisture damage.
As synthetic granular fertilizer, this has a coating surrounding the active ingredient that helps to slow down nutrient intake, giving it an indefinite shelf life if stored and sealed properly.
However, the minerals contained within the formula will break down over time, rendering them less effective, which is why Miracle-Gro sets a recommended use of 3-5 years.
Kept in moist, humid conditions, this fertilizer may clump together and attract mold growth, but it should still be fit for use.
In this condition, spread the fertilizer in a dry location to kill off bacteria before using it near plants. Always seal the cap after use, and store it out of direct sunlight at room temperature.
This liquid plant food is made with specially stabilizing chemicals to prevent degradation, so it is designed to be effective for up to 8 years.
Bear in mind though that liquid formulas are at risk of crystallization when inactive, which is why manufacturers set 3 years as a recommended use-by date.
After 8-10 years, liquid fertilizer ingredients will turn rancid, which can be difficult to distinguish from its powerful odor when freshly opened.
The product may also have a different consistency when it has turned – in which case it should be discarded.
To enjoy its maximum shelf life, always shake up the bottle before each use – Miracle-Gro gardeners also advocate “submerging the bottle in hot water” to dissolve liquid that has crystallized.
The Performance Organics range consists of both compost and liquid/granular/water-soluble organic fertilizer products.
If kept properly sealed, the compost fertilizer should last several years but should be used within 3-5 years as the matter will decrease in volume and efficacy as it decomposes.
Organic liquid fertilizer (and the granular and water-soluble types) will be usable for 5-8 years when the container is kept securely shut to prevent moisture and oxygen from entering and speeding up biodegradation.
High heat will also cause liquid fertilizer to deteriorate and change in consistency/odor, so storage is recommended between 41-95°F.
Store Performance Organics products away from sunlight and transfer compost quantities into separate airtight containers to avoid constantly moving the bag which could cause tears/leaks.
This plant food is made from the active ingredients nitrogen, phosphate, and soluble potassium carbonate, which are designed to have a long shelf life of around 8 years when kept unopened in a cool, dark location.
Exposed to the elements or high heat, the liquid compounds will react with indoor air moisture and begin to break down faster than usual, which will be safe but ultimately less effective to use.
Be sure to check for a noticeably rancid smell or change in the liquid’s consistency over time, and discard if this is the case.
Shake the bottle well before each use to prevent crystallizing clumps, and store it in a humidity-controlled area like a pantry or greenhouse to protect it from freezing, which could change the nature of the nutrient composition.
What Happens If You Use Expired Miracle-Gro?
Assuming the Miracle-Gro product is sealed, was stored in a cool, dry environment, and has no discernible foul smell (Miracle-Gro should smell faintly of ammonia, which disappears once mixed in with water), then it should be safe to use on your plants after the expiration date.
Essentially, the fertilizer element of the expired Miracle-Gro product becomes useless after the expiration date, so gardeners are advised to use them within 2-3 years of purchase to get the desired results.
Does Miracle-Gro Soil Expire
The majority of the ingredients in Miracle-Gro soil formulas are naturally occurring and chosen specially to duplicate a plant’s ideal growing conditions, so they do not have a definitive expiration date.
However, the beneficial fertilizing nutrients will lose their potency when stored incorrectly.
Miracle-Gro soil products are commonly comprised of the following ingredients:
- Sphagnum (peat) moss
- Ammonium nitrate
- Ammonium phosphate
- Potassium sulfate
- Calcium phosphate
Over time, compost will naturally decompose and simply cause the nutrients to escape, while peat moss has no real expiration date and will remain safe to use when kept in dry conditions.
The chemical elements within the formula are designed to be stored in a cool, dry location under 110°F to avoid potential combustion risks and damage from increased moisture/humidity.
Does Miracle-Gro Go Bad If It Gets Wet?
Miracle-Gro is made with hygroscopic soluble salts, which means they absorb moisture from the air, so if an unsealed container is exposed to the atmosphere for long periods, this will result in a sticky product.
Thankfully, according to Miracle-Gro customers, even when granular fertilizer appears moist, it has been perfectly fine to use.
As for liquid feed, the manufacturer states that this will be perfectly safe to use whether wet, discolored, or solidified.
How To Dispose of Old Miracle-Gro?
To safely dispose of your old Miracle-Gro plant food, contact your local solid waste company to inquire about the collection of chemical waste products.
Some gardeners advocate adding old Miracle-Gro fertilizer to their compost pile, but this is best avoided as the high amounts of nitrogen may cause the compost to heat up rapidly and even risk spontaneous combustion.
How Long Does Miracle-Gro Take To Work?
Water-soluble Miracle-Gro works immediately while granular fertilizer works within 12 hours.
It’s hard to pinpoint when Miracle-Gro takes effect as its primary role is to deliver nutrients to the plant, but this is one factor alongside specific soil, water, sunlight needs, etc. required for each plant species.
Which Miracle-Gro Is Best for Tomato Plants?
Miracle-Gro Water-Soluble Tomato Plant Food is preferred as this contains an NPK fertilizer analysis of 18-21-21 to deliver low nitrogen and high phosphorus, which is vital for photosynthesis and converting the nutrients into usable proteins.
Customers also favor it for its disease-resistant properties in addition to superb fruit production.
To summarize, granular Miracle-Gro plant food has no strict expiry date as long as it is stored correctly in a cool, dry place to protect it from moisture damage.
The fertilizer component will simply become ineffective after years in storage.
Miracle-Gro’s liquid and foam plant food meanwhile may last for up to 8 years unopened, but the same storage rules apply to maintain potency.
For this reason, it’s wise to use Miracle-Gro on your plants within 3-5 years of purchase.