How to Rejuvenate Old Potting Soil?

When it comes to growing plants, a lot of it is trial and error. For example, will my room’s natural level of humidity work for these plants? Am I watering it too much? Not enough? Is it getting enough sunlight? Why is it turning yellow? I have had a couple of plants that just weren’t cut out to live in my fast-paced environment… In other words, they died.

But what do I do with the soil? We can reuse it! Not right away though. Before reusing the soil, it is recommended to sterilize or pasteurize it. This will help in removing any pests and microbes. We have to make sure that we remove any dead roots or plant debris, and break up any clumps before sterilizing it.

There are 2 things you can do:

1. Bake the soil: Remove any roots and debris from the soil before baking them at 180-200 degrees Fahrenheit for 30 minutes. Alternatively, you can microwave it for 90 seconds. Heating the soil will cause it to release a pretty gnarly smell so be ready for it.
2. Solarize it: Get large black plastic bags or 5-gallon buckets with lids then place them in a sunny spot outdoors for 4-6 weeks. The heat will build up inside the containers and kill the bacteria inside. This will probably be the easiest of the two methods listed.

We are not quite ready to reuse the soil after it has been sterilized. Potting soil can lose its nutrients and structure over time, making it less effective for growing plants. So, how do we reverse this?

1. Add organic matter: Mix in some compost, work castings, or well-rotted manure to add nutrients and improve soil structure.
2. Add perlite or vermiculite: Adding perlite or vermiculite can improve soil drainage and aeration, which can help prevent soil compaction.
3. Slow-release fertilizer: Add to the soil to provide the necessary nutrients for plant growth.
4. Mix in new potting soil: If the potting soil is too old and degraded, it may be best to mix in some new potting soil to help rejuvenate it.

Also, keep in mind that some plants may require specific soil conditions, so it’s important to choose the right type of soil for the plants you are growing. Before reusing the soil, moisten it thoroughly and let it sit for a few days to allow the ingredients to settle and the moisture to distribute evenly. By following these steps, you can rejuvenate your potting soil and provide a healthy growing environment for your plants.