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Does Potting Soil Go Bad? [3 Ways to Tell for Sure!]

There is nothing more frustrating than a plant that fails to thrive. Or seeds that do not germinate due to poor quality potting soil! 

While we go to great lengths to nurture our garden and vegetable plots, it is too easy to neglect our potted plants and the nutrient-rich soil they need to flourish.

So – here is one of the most popular questions gardeners ask us. Does potting soil go bad? Or not?

Does Potting Soil Go Bad? Or Can You Save It for Next Year?

Yes. For sure! Potting soil goes bad if your plants extract all of the nutrients. But – there are a few more variables to consider. The truth is that soil is a complex blend of organic and inorganic materials. It also contains a thriving mixture of microorganisms that keep the soil and our plants healthy.

Like any system, the soil needs constant maintenance to keep it in good shape. In the natural world? Soil maintenance happens through many complex processes, where new organic matter is continuously incorporated to become part of the soil.

(Things like garden worms, fallen leaves, and organic compost help replenish natural soil.)

But when it comes to our potted plants, many chains in this system are broken. Your potted plants get cut off – and isolated! The demanding nature of potting soil means that potted soil can expire. 

In other words, yes. The potting soil goes bad! And will not be healthy enough to grow strong and vigorous plants.

So, whether you are trying to decide whether your plants need repotting, emptying old containers, or have found an old bag of potting compost in the shed, let’s find out how to tell if your potting soil has gone spoiled. sing nothing but three simple techniques!

sage and marjoram mixed herbs in pots
Does potting soil go bad? Over time, yes! Some potting soil doesn’t contain many nutrients and needs frequent amendments. Other potting soils contain slow-release fertilizer. That way – your potting feeds your plants slowly over time. Our favorite potting soil mixes contain fertilizer prills. Prills are tiny capsules (with resin casing) of fertilizer that release slowly.

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3 Ways to Tell If Your Potting Soil Is Bad

Here are the three best ways to test the health of your potting soil. Is your potting soil spoiled or depleted? These are the dead giveaways.

  1. The Potting Soil Gets Dense and Compacted
  2. The Potting Soil Smells Bad
  3. Your Plants Are Not Growing

We go into much further detail regarding these potting soil snafus – and how to solve each problem below.

We hope these help you grow happier and healthier plants!

1. The Potting Soil Is Dense and Compacted

Compact soil is a common problem in potted plants, where the volume of soil within the pot becomes too dense and firm.

In the natural world? The soil is constantly being moved underground by insects and microorganisms. This process cannot happen in your pots, and as water passes through the potting soil, it will become compacted.

If you cannot push a finger effortlessly into the top inch of your soil, it has become compacted and unhealthy. Compacted soil is a common problem when using compost that contains peat moss, as this breaks down and becomes compacted over time.

A Solution to Dense and Compacted Potting Soil

Your compacted potting soil needs the chance to expand! Break it free from the confines of the pot and gently loosen any large, firm lumps of hardened soil. To add some structure back into your soil, mix in a generous helping of coconut coir.

healthy tomato plants growing inside
Always seek fluffy and soft potting soil. And – carefully read the label of any potting soil you buy! Not all organic soil is okay for potted plants. If you choose the wrong potting soil – your potting soil may get too heavy and compact! Potted soil compaction makes it difficult for your plants to breathe – and grow. Not ideal for growing plants!

2. The Potting Soil Smells Bad

Potting soil that smells bad has most likely become waterlogged. Most homesteaders we talk to think garden soil is solid – and static. But this complex soil ecosystem needs air and water. Too much water means that the wrong type of bacteria will thrive, and the good bacteria will all die.

A Solution to Smelly Potting Soil

Waterlogged potting soil needs to dry out, so empty it from the pot onto a tarp (tarpaulin) or concrete slab in the sunshine. You can use this soil again, but it has gotten depleted.

It likely does not contain much organic matter and microorganisms. A good remedy is to mix it with some soil improver, well-rotted compost, or manure.

3. Poor Plant Growth

There are many reasons why some plants fail to thrive, but soil quality is often a key culprit. If your plants are in perfect environmental conditions but look stunted and poor? We bet the potting soil got drained of nutrients.

Remember that the soil in pots does not have the same opportunities to regenerate as the soil in the ground. The plant will soon take all the available nutrients, leaving a potted plant full of depleted soil.

A Solution to Depleted Potting Soil

Potting soil depletion is a situation where prevention is vital. You can keep your potting soil in good health by mimicking the natural cycle of soil health.

Add a top dressing of nutrient-rich worm castings or compost every few months to feed the soil. You can lightly mix this with the top inch or two of soil. The insects and microorganisms will do the rest. 

Artificial fertilizers can be used as a quick fix to boost the health of your plants, but they will do nothing to replenish your depleted potting soil.

If you think the soil in your pot is past the point of rejuvenation, you will need to empty the soil pot and replace it with new potting soil. But don’t discard the old soil! There are some tricks to bring it back to life.

young lime tree in pot with fresh potting soil
Soil isn’t just dirt! Good potting soil contains a mixture of soil, peat moss, coir, and vermiculture. Some soil also contains humus, bark, and other organic compounds. Potting soil also contains perlite. Perlite is perfect for increasing the aeration of the soil. Kind of like garden worms!

Potting Soil Going Bad? Read Our FAQs!

We know that making the right choice of soil for your plants can be a tricky business, so we’ve put together a comprehensive guide to how long your potting soil can last!

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Conclusion

We love growing a multitude of potted plants!

We grow everything from tomatoes, zucchini, and jalapeno peppers, to potted herbs and flowers.

We love them all!

We also know that all potted soil eventually goes bad.

We hope our guide helps shed light on how to rejuvenate potted soil – even if it depletes entirely.

If you have more questions about how to feed your potted plants, feel free to ask!

We spend much of the day gardening and love brainstorming potted soil with fellow homesteaders.

Thanks again for reading.

Have a great day!

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Author

  • Kate moved to Portugal last year and lives with her husband, two cats, six hens, and a glorious Brahma rooster called Mary. Earlier this year they purchased a half-hectare ‘quinta’ – traditional terraced land with olive trees, grapevines, and a house to renovate. They are currently living in a small campervan which is a challenging but fun experience! Kate has over 15 years of experience in the UK veterinary industry and is also a passionate gardener – turning a grassy field into a productive vegetable patch in just three months. Future plans include more animals, particularly sheep and goats for milk production to make cheese, butter, and yogurt! Kate and her husband are aiming to create a self-sufficient off-grid life on their quinta, fulfilling a life-long dream.