More often than not, homeowners prefer revitalizing old potting soil to buying a new potting soil mix. Indisputably, a new potting soil mix is expensive.
So, soil rejuvenation may be your best option if you want to save on costs. Nevertheless, note that revitalizing your old potting soil is not simple as most people think. First, you need to replenish the soil through sterilization.
Then, make some specific amendments to improve the quality of the soil. In this article, we discuss some ways of revitalizing your old potting soil.
Sterilizing Potting Soil
As mentioned earlier, you have to sterilize your soil if you want to revitalize it. Soil sterilization is often meant to get rid of all harmful microorganisms and pests in the soil.
You have to conduct this process even if you think your soil is healthy. Currently, there are two major types of soil sterilization. They include baking and solarizing.
- Solarizing:
This process is pretty much straightforward. All you have to do is collect and insert soil in large plastic grow bags. Then, place the bags out in the sun for approximately four to six weeks. Heat will gradually accumulate in the bag and kill all harmful microorganisms.
- Baking:
The other method of sterilizing your soil is to bake it. If you choose this technique, collect soil and place it in a baking or oven-resistant container. Then place it in the oven at 200 degrees Fahrenheit and leave for 30 minutes. Do not exceed oven temperatures above 200 degrees Fahrenheit since they can release toxins into the soil.
Best Soil Amendments
After sterilizing the potting soil, it’s now time to restore all the nutrients in the soil. So, how do you do this? First, mix the soil with a quality slow-release fertilizer.
Doing this will keep the soil healthy and allow your plants to grow well. In addition, consider adding organic compost to the soil.
There is also the option of adding leaf mold. Gardening experts advise adding one part of compost or leaf mold for every four parts of potting soil.
As you apply compost or leaf mold, avoid using excessive amounts. Otherwise, your soil will become compact. After you amend your potting soil, it would be best to use it to grow other types of plants.
For example, if you previously grew tomatoes using this soil, consider using it to grow other types of plants like flowers or herbs such as thyme or Epazote plant.
Tips for Reusing Potting Soil
- During soil sterilization, use clean planters, containers or bags. Take time to disinfect the containers and bags before adding the soil. If you use containers, scrub the interior and exterior surface thoroughly to prevent any contamination. Use a bleach mixture and a gentle brush to do this. Then, rinse off the containers and give them time to dry. Typically, the containers should have no traces of bleach after cleaning.
- Do not revitalize your old potting soil if your plants had pests and diseases. Sterilization won’t help disease-infested soil. It would be best to discard this soil. Alternatively, mix the soil with a compost pile or use it to fill bare garden spots.
Factors to consider before using revitalized old potting soil
The total time the soil has been in the pot:
Before repotting your soil, you have to find out how long the soil stayed in the flower pot. Typically, it is advisable to work with soil that has been used for planting for about one to two years. However, you have to add nutrients to the soil to improve its quality. Soil can quickly lose its nutrients over time.
The soil level in your pot:
At times, you’ll have to buy a new potting soil mix even when you want to revitalize the old soil. The old potting soil may not be enough for planting. Consequently, you may have to top it up.
Always mix the new potting soil with the old potting soil for best results. Also, note that bagged potting mixes comprise cheap pine bark. This organic ingredient often lowers the level of soil with time.
So, you may have to consider topping the soil with organic ingredients and fertilizers to prevent it from reducing the level of the soil.
Soil structure:
Before using revitalized potting soil, you have to evaluate its structure. Generally, the soil structure should foster excellent water retention and drainage. Also, the soil should not be compacted.
If the soil has poor texture, consider improving it by adding organic ingredients. When adding natural ingredients to the soil, avoid adding excessive amounts. Otherwise, you would tamper with the quality of the soil. If you are not sure, look for an online recipe to know the right quantity of organic ingredients to add to the soil.
Previous pest and disease attacks:
Another factor to consider before using revitalized old potting soil is pests and diseases. Identify whether bugs and diseases previously attacked the plants.
Generally, disease-causing organisms can live in the soil for many years. Thus, sterilizing the soil won’t help.
It would be best to discard such soil or use it to make your organic compost mix. Additionally, when handling such soil, ensure you clean and disinfect the container you use.
How do you revitalize old potting soil?
Refresh Old Potting Mix with New Ingredients:
You can use several ingredients to replenish the old potting mix. Some include coconut husk fiber and compost. Coconut husk fiber often helps in boosting water retention properties.
Organic compost, on the other hand, adds healthy microorganisms to your soil. Additionally, consider adding vermiculite to encourage healthy aeration and nutrient retention. Liquid seaweed also makes the soil rich in healthy microbes.
Use Refreshed Potting Mix to Top-up Other Pots:
Other than using the entire potting soil in one pot, consider using it as topsoil. Follow the below steps if your wish to use revitalized old potting soil in other planting pots.
- The first step is to water the old potting soil while it is still in the container. Doing this will make it simple to sieve and transfer. Nonetheless, ensure the soil does not become damp or soggy. Instead, it should be moist.
- Start removing the potting soil from the planting container and place it on a wheelbarrow or large plastic bucket. Make sure you line the wheelbarrow with a plastic sheet. Also, wear protective garden gloves and a mask during this process.
- Once the potting mix is in the bucket or wheelbarrow, mix it with new potting soil. It is advisable to use a 50:50 ratio if you are on a fixed budget. However, you can use a larger percentage of new potting soil if you can afford it.
- After mixing the potting soil, use it as topsoil for other planting pots.
Top Dress your Lawn:
You can reuse old potting soil by filling the bare spots in your planting pots. Also, if you have depressions on your lawn, consider adding an old potting soil mix.
Use old potting soil to make a raised garden bed:
You can reuse old potting soil by creating a raised garden bed. Remember, raised garden beds will need more soil. So, use it as an additional mix. Even so, ensure the soil is free from pathogens.
Add to Clay Soils:
Generally, clay soil is bulky. Therefore, it has poor water retention and drainage properties. Fortunately, you can improve the quality of this soil by mixing it with old potting soil.
Old potting soil is highly rich in organic matter. Therefore, it can improve the soil structure of clay soil. Consequently, mixing old potting soil with clay soil makes it favorable for planting.
Final thoughts
Today, there are many ways to revitalize your old potting soil. The first step is to sterilize the potting soil. Doing this removes all harmful microorganisms present in the soil.
Then, use a slow-release fertilizer or organic compost to enhance the quality of the soil. From there, you can use it for indoor planting or as topsoil in other planting containers. Even so, ensure you carefully evaluate the soil before reusing it.