When you want to make sure your new plants have all the nutrients you need, potting soil is an excellent option. In addition to the soil, it has key nutrients such as nitrogen, phosphorous, and potassium. Before you use any extra potting soil you have, find out what the signs are that it has gone bad.
Does potting soil go bad? Yes! When you’re ready to get out into the garden, you may reach for that old bag of potting soil from last year. Before you use it, though, stop and assess its appearance. A white film is an indicator of mold, while a smell of rotten eggs is a sign of bacteria.
If you think the potting soil is still good, you can try using it. However, watch for pooling water or your plants slowly starting to die. If either of these happens, it means the soil has broken down and is now too dense.
It can’t drain properly and there is too much compact dirt around the roots, so they are unable to breathe in oxygen. An easy fix for old potting soil is to add more of the small white pellets, called perlite, which increases the airiness of the soil.
How do you know if potting soil is bad?
Sign 1 – Check your expiration date
There’s a good chance you’ve never actually looked closely at your bag of potting soil. However, there is a lot of information on it that you should check out.
It might be a bit hard to find but there will be an expiration date on your potting soil bag, either on the top or at the bottom.
While you don’t have to dispose of your potting soil if it is just a few months past the date, if it has been a few years, you might want to rethink using it.
Sign 2 – Not enough drainage
While plants need proper watering, they also need soil that allows excess water to drain. If this doesn’t happen, the roots can actually start to rot.
Old potting soil will start to compact together and as a result, water will pool and not be able to drain. You may not notice dried-up soil until you use it, but if you notice that your soil is soggy, it may be a sign the potting soil has gone bad.
Sign 3 – There seems to be less potting soil
This sign can be hard to determine at first glance because you need to have an idea of how much potting soil you had the previous year. And, if the bag is open, you might not remember how much you used.
A lot of potting soil is composed of peat. If peat moss breaks down, the dirt particles compact and become too close to the root system of your plants.
The result is that not enough nutrients and oxygen will have access to your plant’s roots. This means that your plants could potentially die.
Sign 4 – Mold growth
While not overly common, mold can definitely grow in a bag of potting soil. Mold grows where the conditions are warm and humid.
When you open an old bag of potting soil, give it a quick glance before you get to close. Signs of mold include a white layer that is not any of the extra nutrients in the soil.
Sign 5 – Bad smell
Bad odors are rarely a good sign, and this is especially true of potting soil. Your potting soil should smell earthy and like dirty.
If, instead, it gives off a smell of rotten eggs, this means that bacteria have entered your bag and made a home for it.
Similar to mold, bacteria like warm, humid places. If there was moisture in the bag when you put it away, this is an invitation for bacteria to form.
How to properly store potting soil
Potting soil should be stored in a cool, dark place. It should have no exposure to moisture or sunlight.
Depending on when you use your potting soil, the top of the bag may gather some moisture. Be sure to wipe this off before storing the bag or else mold or bacteria can inhabit it.
A garage or a tool shed are common places to store potting soil. If the bag is open, seal it off so no bugs can get in.
Can you revive old potting soil?
While the main purpose of potting soil is to be used with potted plants, it can be used in other areas of your garden. If you have old potting soil that doesn’t have any signs of mold or bugs, then you can use it in larger-scale gardens as you will be mixing it with other organic matter, thus breaking it up more.
For those that want to use their potting soil in pots, you can add a bit of perlite to liven up the soil. Perlite is the small white bits that are common in potting soil; its purpose is to keep the dirt light and improve drainage.
How long does potting soil last?
After opening a bag of potting soil, it has a shelf life of about six months. This means that if you use part of a bag of soil in the spring, you should not use it the following spring.
However, this is a guideline so use your best judgment. If the bag does not have a bad odor or the appearance of bugs, then you may be able to still use it.
The good news is that an unopened bag of potting soil lasts for an impressive five years. This is because the bag is sealed so moisture and bacteria are unable to enter.
So, if you see a sale on potting soil, it may be a good idea to stock up as you can definitely use it the following few years.
Potting soil is an easy and effective way to plant flowers and ensure they have the necessary nutrients to grow. If your potting soil has a smell of rotten eggs or a white film on it, these are basic signs that it is no good and should not be used.