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You should not dispose of old potting soil: with these tips you can recycle and reuse it!

If you’ve ever grown anything in a planter, indoor flower pot or raised bed, what to do with the old soil is a very important decision so you can garden successfully next year. There are several ways to reuse your old potting soil: Here are helpful tips on what you can do with it.

Can old potting soil be reused?

Can old potting soil be reused?

In general, it’s okay to reuse potting soil if the plants you grew in it were healthy. However, if you have experienced pests or diseases on your plants, you should sterilize the mixture to avoid infecting your plants next year. First, remove all roots, larvae, leaves and other debris from the old potting soil. Then decide on the best method to eliminate microbes and insects.

Sterilize and recycle old potting soil – clever tricks.

Sterilize and recycle old potting soil - clever tricks

Fortunately, there are some simple measures you can take to get your potting soil back in good shape for at least another year or two.


One method of sterilizing soil is solarization. This involves placing old potting soil in large buckets with lids or black plastic bags that are tightly sealed, and placing them in the sun for 4 to 6 weeks. Just enough heat builds up in the buckets or bags to kill bugs and pathogens.

Sterilize in the oven

You can also sterilize old potting soil in your oven. Place them in an oven-safe pan, cover with foil and bake at 85 to 95 degrees for 30 minutes. It’s also important to check the temperature of the soil with a meat thermometer to make sure it stays below 95 degrees. Higher temperatures can release toxins. When ready, remove the soil from the oven and keep it covered until cool.

Sterilize old potting soil in the microwave.

Fill old, moistened soil into microwave-safe containers. Cover them with microwave-safe lids (never use foil) that you can poke ventilation holes in or tear open to allow steam to escape. Heat them at full power for about 90 seconds per 1 kg of soil. Remove the containers, cover the vent holes with tape, and allow the soil to cool completely before using.

What to do with old potting soil?

Compost it

Compost the soil

Old potting soil can be easily incorporated into your compost pile. Make sure your compost pile contains a good mix of ingredients so it decomposes quickly and creates a balanced compost.

Use the soil as fertilizer

Old potting soil for new plants

Although your old potting soil lacks nutrients, it still contains traces of compost and beneficial humus and has few weed seeds compared to garden soil. Therefore, this soil is ideal for covering newly planted vegetables and seeds that are slow to germinate. This topdressing with old potting soil can help retain moisture so your plants can thrive.

Old potting soil for new plants

What to do with the soil? Reuse - possibilities

The easiest way to reuse old potting soil? Simply remove old plants from their containers, loosen the soil and replant them. If you’ve used the same soil for several years or it has developed a white surface crust, you may need to mix it with 50 percent new soil and/or apply fertilizer. Of course, you don’t have to reuse potting soil only in your flower pots. You can also use it in the following places.

  • In flower beds.
  • In vegetable gardens.
  • Around old trees: just be careful not to use too much soil around the tree.
  • When growing herbs.
  • If you are creating a new garden bed.

You also have a great option for creating a new garden. This particular technique uses layers of organic material to create a new plant bed directly on top of the existing sod. To do this, lay out some cardboard or newspaper, cover it with your old potting soil, and then place several layers of shredded leaves, untreated grass clippings, old manure, kitchen scraps, straw and other organic matter on top. It will be ready for planting in the spring.

Host a plant swap meet

You can keep a few trash bags full of used soil in the fall. Then in the spring, you can use this old soil, for example, to pot daylilies and other perennials to share with friends. Since these plants will find a permanent place in a garden, they won’t stay in the pot long enough to notice the lack of nutrients.

Use your old potting soil for the lawn

Use your old potting soil for the lawn

Do you have bare spots on your lawn where grass just won’t grow? Spreading old soil on top of freshly sown grass seeds is a great way to keep them moist and get them to germinate. Just remember to water regularly and mark the spot so you don’t step on it.