BackyardBooster.com is reader-supported. When you buy through links on our site, we may earn an affiliate commission at no added cost to you. Learn more.
Does potting soil go bad? It does. But there are a few important things to know, especially knowing how to store potting soil properly!
People commonly use potting soil for both indoor and outdoor gardening projects. It provides plants a healthy medium to grow and thrive. Unfortunately, potting soil is often left behind in the bag after we’ve planted our plants.
You can certainly store potting soil and maintain its quality by keeping it in a dry place. However, even if the soil has lost its nutrients and other qualities, you can rejuvenate it in different ways to get the most out of it.
In this article, we will thoroughly explain how potting soil goes bad and what to do if you want to restore it. So, keep reading to learn some great tips!
What is Potting Soil?
Potting soil is a kind of soil that is made by mixing inorganic and organic material. It contains vital ingredients that plants need to develop.
People use potting soils for both indoor plants and outdoor plants. But for your outdoor garden, most people usually prefer natural garden soil.
If you’re looking to have a nice garden, you’ll want to make sure you have the best potting soil.
Many ingredients are added to the potting soil to maintain its nutrient content, moisture level, and texture.
One of its key ingredients is peat moss. It is added to help the soil maintain its moisture level. It also provides a few healthy nutrients to the growing new plants.
However, if you keep your potting soil in an open bag, then this peat moss will start decomposing soon. And if it has decomposed, the soil will lose its moisture content.
Other ingredients that are added in potting soil include pearlite, bark, sand, vermiculite, etc. Each ingredient has its own function; for instance, pearlite prevents the soil from becoming too dense, and vermiculite increases water retention. Each of these ingredients is important for the development of healthy plant roots.
You can usually find bagged potting soil at your local gardening or hardware stores.
Characteristics of A Good Potting Soil
To differentiate between good and bad potting soil, you need to understand the main features that define good potting soil.
Light in Weight
A good quality potting soil should be light in weight so that it does not suffocate the plant and affect its health.
If it is heavy, it will become compact after absorbing water. As a result, the roots of plants will get compressed and not get enough room to grow.
Contains Healthy Nutrients
Plants need nutrients that they absorb from the soil in which they grow. Therefore, a good potting mix needs to provide essential nutrients.
Commercially available potting soil has nutrients that are released slowly. This slow-release makes sure that plants get nutrients slowly with their growth.
However, you can also add an organic fertilizer in the container to make sure the container plants get all they need.
Has A Good Drainage System
The potting soil should have a good drainage system. It should be able to absorb only sufficient water that the plant needs to grow.
If the drainage is poor, the plant can get drowned in the water. Therefore, make sure the potting soil you use allows water to drain.
Does Potting Soil Go Bad?
Yes, soil can go bad. Most experts would agree that the quality of an open bag of soil starts to degrade after about six months. After about one to two years, the soil will have lost most of its important nutrients.
Technically, potting soil does not have a shelf life or expiration date. But different ingredients within the soil can start to decompose quickly if you do not store the soil properly.
Decomposition of these ingredients can directly affect the main characteristics of soil like its drainage, moisture level, nutrient content, etc.
Potting soil has organic matter, which will actually decompose even if you store the soil very well.
Therefore, well-maintained potting soil will stay in good condition for a longer period compared to the poorly maintained soil, but it will still lose its characteristics with time, regardless.
Keeping Your Soil in Good Condition
If you keep potting soil in plastic storage bins or some smaller bags exposed to open air and under the direct sun, then the nutrients of the potting soil will start breaking down sooner.
As a result, its moisture level will also decline. But, you can even use this kind of old potting soil for general purposes, so there is no need to throw it in your garbage cans just yet.
However, if you decide to use it for plants, keep in mind that they will not receive enough nutrients for proper plant growth.
Contrarily, unopened or unused potting soil that you’ve stored well can maintain its quality for 1 to 2 years. But, its ingredients like peat moss will still decompose even if the potting soil bag has never been opened.
So, you can utilize old soil by rejuvenating it the right way.
Under rare circumstances, potting soil can go completely bad. You can check it through various ways to tell whether the soil has gone completely bad or not.
How to Tell If the Potting Soil Has Gone Bad or Not?
It Produces A Bad Smell
If your potting soil is producing the smell of a rotten egg, it indicates that it has gone completely bad. There is no place for the smell of rotten eggs in your beautiful backyard.
It usually happens when you keep bags of soil in unsafe places not protected from rainfall.
Typically, rainwater enters the soil, and bacteria start growing in the wet soil.
As a result, it produces a foul smell. But the good thing is, you can still restore this soil for general purposes.
It’s a good idea to spread it on a tray and keep that tray in front of the sun. Bacteria will decay in the heat of the sun, and soil will be ready to be reused.
Mold Has Grown in It
Mold can grow in the soil if you do not seal the storage containers well. Moldy soil is dangerous for growing plants and should not be used for them.
If your soil is moldy, you’ll usually see white mold on the top layer of the soil (whether it’s in your garden or in your plant.
Do not use moldy soil in your garden. It is likely to attract fungus gnats, cause root rot, and enable many other diseases in your plants.
If you’re looking to rejuvenate some moldy soil, you can spread it under direct sunlight and allow the water to evaporate. Mold will automatically die off if the soil does not have water.
It Has Become Dense
As mentioned earlier, peat moss can start decomposing after some time. So if your soil has become dense and compacted, it means its peat moss has started decomposing, and the soil is not in good condition. Heavy hard clumps is usually a good indicator of expired potting soil.
How to Store Potting Soil
If you’re thinking of storing potting soil, there are a few considerations you’ll need to make before throwing your potting soil bags in storage.
Do you have unopened bags of soil or opened bags of soil to store?
If you have unopened bags of potting soil that you’re looking to store, don’t open them! Keeping your unopened bag of potting soil sealed is the best way to keep your soil safe.
Once you open it, you expose your soil to mold and other types of bacteria.
If you have opened bags of potting soil, you have two options:
- Keep the remaining soil in the bag and roll up the bag to prevent air and moisture from getting in or out, or;
- Empty the soil from the existing bag into an appropriate storage container.
Once you’ve decided how you plan to store your soil, you can use the following tips to ensure it lasts a long time.
Use Appropriate Storage Container
It’s best to store your bags of soil in a dry, dark container. Dark-colored storage containers, like Rubbermaid Containers or Sterilite Containers, work well for this.
- HEAVY DUTY BUILD – Ideal for storing large and bulky items, holiday storage, dogfood, heavy tools…
- NON- PERISHABLE FOOD STORAGE – Durable Rubbermaid Storage Containers are equipped with a stay…
- STACKABLE STORAGE – Stacks without cracking or buckling. Built in handles make these totes easy to…
- VIRTUALLY INDESTRUCTIBLE – Proven Rubbermaid durability, the impact resistant superior polyethylene…
Make sure your potting soil storage container is clean before storing your soil!
Dry the Potting Soil Before Putting It in The Storage Container
If needed, dry the potting soil before putting it in a storage container. Mold and bacteria thrive on wet surfaces.
To prevent mold and bacteria growth, we recommend removing moisture from the soil before putting it in the storage container.
For this purpose, you can spread soil under direct sunlight and let the water evaporate.
Keep the Storage Container in A Dry Place
If you have unopened potting soil, then keep it in the same plastic bag then put that bag in a plastic bin. Close the bin tightly and place it in a dry place to avoid unwanted contact with the water.
If you have opened the potting soil bag and want to keep the leftover potting soil safe, then pour the soil in large containers or smaller ones according to the quantity.
Again, place the containers in a dry place to avoid contact with water.
Note: If you have grass seed, check out our article on How to Store Grass Seed.
Tips for Rejuvenating Old Potting Soil
If you have stored some potting mix and now want to use it for planting activities, it is important to first rejuvenate the soil to get the most of it.
Rejuvenating your old potting soil will make your plants think they are enjoying some fresh soil. The following tips will help you in rejuvenating potting soil.
- Remove dried plants and other components. If you are using previously used potting soil, then one important thing that you should do is remove dry leaves, plants, rocks, etc., from the soil. Otherwise, dried leaves, etc., will start rotting in the soil, leading to bacterial growth or the development of a foul smell.
- Add coconut fiber or coconut coir to the potting soil if it feels dense and compacted. Peat moss is also a good option, but people prefer coconut coir because it lasts longer than peat moss. Additionally, it is more eco-friendly, and you will not have to add it again next year. Add potting soil and coconut coir in the pot in a 1:1 ratio.
- Even for unused potting soil, you can boost plant growth by adding organic fertilizers, compost, and worm castings to the soil. If you are on a budget, then you can make your own compost pile or organic fertilizers at home. There are many ways of making them available on the internet.
- Each plant has different needs, so you should provide the necessary nutrients according to the plant species you are growing. Use a soil test kit to check which ingredient soil lacks. Then add those nutrients or ingredients to ensure proper nutrient levels for your plant’s optimal growth.
What Is the Average Age of Unused Potting Soil Stored in A Container?
Unused potting soil maintains good soil characteristics for up to six months. After that, its ingredients start decomposing, and the soil gradually loses its ability to provide nutrients that are required for healthy plants.
Summing Up: How to Store Potting Soil
Potting soil has no expiry date, but its ingredients may start decomposing after some time. However, you can add the lost ingredients to the soil to restore its quality and reuse the soil for optimal plant growth.
Properly storing your potting soil is one of the most important things you can do to ensure a healthy garden. It will also keep your plants and flowers from developing nutrient deficiencies or other problems that are often caused by improper care.
Whether you use peat moss, bark chips, compost, or any other type of material as an amendment in your soil mix, make sure it’s stored properly until ready for use, so it doesn’t go bad too quickly!
Don’t throw away that old bag of soil just yet! With the proper storage techniques, you can save some extra cash by reusing that leftover potting soil next year!