You can purchase potting soil from the local nursery, or you can make your own. However, there are times you could end up with too much, and you leave it sitting in your garden shed for a year or two.
Come the following year; you may grab your bag of potting soil, and begin to wonder if it’s okay to use or not. In this guide, you can find out all you need about gardening with old potting soil.
By the end, you’ll see that old potting doesn’t have to go to waste, and there are things you can to stop it going bad. (Learn about perlite for soil)
How Long Can You Keep a Bag of Potting Soil?
Generally speaking, the question of does potting soil go bad? As long as your potting soil doesn’t come with a bad smell.
Or it is infested with insects, or it has any harmful disease to plants, then chances are it is okay to use to grow your plants.
However, while it can be used, it doesn’t mean you will have the best condition of the soil to grow your plants immediately.
Much like used soil, you’ll need to revive your bags of potting soil to give the roots what they need to grow.
Bags of potting soil or potting mix generally expire their shelf life of 6 months, at this point the condition of the soil begins to degrade. If you have used potting soil, it should be replaced every year or two.
Storage is crucial, and you should keep potting soil in lidded containers away from heat or high humidity. Close the original bag and secure it.
The storage container needs to be kept out of the rain or direct sun to prevent bacterial growth. (Read Does Grass Seed Go Bad)
Is It OK to Use Old Potting Soil?
You can be using bagged potting soil after a long time, yet you will need to condition it ready for use. Old potting soil loses many of the nutrients it contains.
Potting soil may be revived quite easily, and you can use it by following it here. Good potting soil will be lightweight and won’t compact easily. Plants and soil will be confined to small spaces, so roots need to breathe in the soil.
Potting soil should allow good drainage, so plants don’t drown.
It is easy to make your own vermiculite potting soil with four parts peat moss and one part vermiculite with one part perlite.
These provide lightweight, breathable, and moisture-controlled environments for plants. (Read Adding Potassium To Soil)
When you ask, does potting soil go bad, you’ll find this won’t because it doesn’t contain too many nutrients. These you will need to supply for your plants to thrive.
The organic material here is slow-release as they break down slowly. It is best to add worm castings or compost before you add to your containers. Do this, and you have enough nutrients for most of the growing season.
You can save old potting soil and reuse so long as you make sure it has nutrients before the next season. (Learn What are the Best Types Of Soil For Gardening)
How Do You Know When Potting Soil is Bad?
Peat moss is the only real component of potting soil that expires. If you know your mix doesn’t contain any peat moss, it can last for years. If you want to use it, just add water and organic matter.
It is worth noting; if you have old potting soil and you added slow-release fertilizer, this will deteriorate after around 12 months. The fertilizer coating breaks down.
If you think your soil has seen better days, and you don’t want to use it for your plant, you don’t need to discard it.
You can use it for worm castings, and then you can add these to your new potting mix. Alternatively, you can add your old potting mix to your compost. You can just as easily spread it around your garden area way from plants, and it will be absorbed
Can Potting Soil Mold?
If you think your potting mix goes bad and you see mold. There are reasons for this happening.
Mainly, it is too much water in your plant pot. You will spot white fuzz on the surface of your potting mix. While this is from overwatering, you can cure this by easing off on the watering until it dries out.
Besides this, you will find fungi is present in any organic gardening mix. While it isn’t very nice to look at, many gardeners swear by ‘living soil’ as to be the best for a plant. (Learn How To Amend Clay Soil For Vegetable Gardening)
On the other hand, you could find your plant isn’t getting enough sun or air circulation. Move it to a sunnier area and let it feel some wind. Before you water again, let the top two inches of soil become dry.
One issue some gardeners have is when they store potting soil over the winter. Here are a few tips to help keep your soil in good condition until next years growing season.
- Remove old roots or other organic matter as this can rot.
- Make sure there isn’t too much moisture before you add this to your storage container. Let excess water drain, so it is slightly dry.
- Try using a trash bag or plastic bin you can seal tightly.
- Once your potting mix is sealed tightly away from damp and sunlight, it may never expire. Just revive it in the right way as you would with your regular garden soil.
- Get some more potting mix and add to your old mix, you can add more perlite and vermiculite. Even adding some compost can help introduce much-needed nutrients.
- Your soil will be dry, so add water until it is all moist. Squeeze a handful, and you should see a few drops of water. If it trickles, then you have wet it too much.
- Add organic fertilizer or more compost to a level of 1 to 2 inches in depth. If you have worm castings, add these and watch your indoor garden grow with new life.