Soil is the most vital element used to provide plants with the essential nutrients for growth and development.
Potting soil consists of organic matter of different types, which includes worm castings and peat moss.
If you are an enthusiastic gardener and you own several plants, you will know that you often end up with heaps of soil after repotting plants.
I have been reusing my potting mix for several years, and today I’m sharing all the tricks with you.
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How to Reuse Potting Mix?
The best way to reuse old potting mix is to combine it with fresh soil. Top up the old potting mix with 50% of new ingredients such as fertilizer, potting soil, compost, and vermiculite and fluff up the soil to increase the permeability. Pasteurize (Sterilize) the mix prior to reusing if you spot any impurities such as pests or pathogens. This will protect the new plants from any pest or infection potentially lurking in the soil. Reuse the potting mix to top up plants or use it as a soil mix for new plants.
Preparing Your Potting Mix for Reuse
Eliminate Old Plant Matter
When you use the potting mix from an old plant, it is important that you remove all traces of it. Remove the roots, twigs, and leaves from the soil, if present.
Fluff the Soil
Carefully turn the soil using a gardening spatula. Doing this will help to detect any pests or bugs.
If your soil has lots of pests in it, you should dispose of it. Otherwise, pests can spread to healthy plants.
If you only spot a few bugs there is the possibility to pasteurize the soil.
Turn the soil to make it light and fluffy. Fluffy soil provides breathing room and drainage space to your plant’s roots, allowing it to grow healthy.
If the soil is hard and compact, it won’t provide room for new roots to grow.
Therefore, this is a crucial step.
In case you detected pathogens while fluffing, rather than throwing the soil away, you can pasteurize it.
Bake the soil in the microwave or a regular oven at around 180-200 degrees Fahrenheit (82-93 degrees Celcius) to sterilize it.
This emits an unpleasant smell and at times over dries the soil. This hinders the soil’s ability to retain water.
What you can do instead is take the container filled with soil and solarize it. To do this, cover the container with a black plastic bag or cover it with a big bucket.
Then place your covered container in the sun for about four to six weeks.
This will kill pathogens and bugs in the soil effortlessly, and you can use the potting mix again after this procedure.
Adding Nutrients to Soil
After you have turned the soil, add the necessary nutrients to it. You can buy plant fertilizer from a local store.
Use the fertilizer of your choice that contains the necessary nutrient and the right NPK ratio for the plants you are planning to plant.
When you’re combining soil that already had fertilizers, know that the fertilizers only last for 3 to 6 months.
The perennial plants and green vegetables are the most demanding. Bushes and flora that are adapted to lower fertility rates can sustain with less fertilizer.
A blend of poultry manure, feather meal, and some other ingredients is going to work just right.
As compost is dense and can lead to compaction, you should use it very carefully.
A blend of some fertilizer, three-part of potting soil, and one part compost is advised.
Blend The Fertilizer Well With the Soil
After adding the fertilizer, mix the soil well. This helps to even out the nutrients in the whole soil mix.
If you do not mix well, the nutrients are not going to be distributed properly.
This can lead to over-or under-fertilization.
Make Space for the Plant
After you have done all the necessary steps, the last step is to repot your plant. Simply make room in your container for the new plant.
You can use gardening tools, your hands, or a stick to make a hole to fit the new plant or plants.
Ways to Reuse Soil Mix
Revitalize Old Potting Mix
- You can combine pre-soaked coir with potting mix to reuse it.
- Vermiculite can be included for drainage, nutrient maintenance, protection, and ventilation.
- Compost and worm castings also assist in adding essential, nutritious microbes to your old soil mix.
Use Restored Potting Mix to Top-up Other Containers
- Add water to your potting mix. This will moisten it. It is much easier to mix moist soil, and it will be less dusty.
- Add new ingredients such as nutrients, vermiculite, new potting soil, manure to it, mix well, and even it out. You can use 50% of both new and old potting mix.
Now, this potting mix can be used to top up other pots in your garden when their soil levels decrease.
Facts About Reusing Potting Mix
The pH level of the soil changes with time and becomes more neutral. Peat-based soil becomes more acidic with time. Some plants don’t like acidity.
How to Store Soil Mix?
Always store the soil used for growing edibles separate from the soil used for growing flowers.
This way, the spread of pests and diseases is restricted and does not travel from one plant to another.
Any container that will keep your soil dry is perfect. You can use heavy-duty plastic bags, bins, small garbage cans, or even plastic boxes.
Keep your soil at freezing temperature if you have the possibility as this makes it inhabitable for pests.
Frequently Asked Questions about Reusing Potting Mix
Can you use potting soil again?
Potting soil can be reused. Top up the old potting mix with 50% of new ingredients such as fertilizer, potting soil, compost, and vermiculite. Pasteurize (Sterilize) the mix prior to reusing if you spot any impurities such as pests or pathogens. This will protect the new plants from any pest or infection potentially lurking in the soil.
Is it safe to reuse potting soil from a dead?
Potting soil from a dead plant can be reused. For this purpose, sterilize the soil in the sun covering it with plastic sheets for about 4-6 weeks. This way, any remaining pests or diseases in the soil will be removed.
Daniel has been a plant enthusiast for over 20 years. He owns hundreds of houseplants and prepares for the chili growing seasons yearly with great anticipation. His favorite plants are plant species in the Araceae family, such as Monstera, Philodendron, and Anthurium. He also loves gardening and is growing hot peppers, tomatoes, and many more vegetables.