Skip to content

How to use old potting soil – instructions and tips on how to ecologically refresh the soil.

A new growing season is just around the corner and you’re wondering if you can dispose of or reuse old potting soil? Fortunately, there are some frugal and environmentally friendly ways to recycle the nutrient-rich soil from wilted plants. But where to put old potting soil? Keeping it may look very cost effective, but can it work when planting new flowers? Here are the key steps you can follow to get this gardening job done with little hassle during the spring season.

What you should know before recycling old potting soil

where to put old potting soil after plant withers

Reusing your old potting soil can make quite a bit of sense for a new planting from a financial and environmental standpoint. First and foremost, however, there are a few things to consider before rejuvenating your old potting soil, so to speak. First, determine whether the plants you previously grew in that soil were light or heavy growers. This will tell you which crops need the most or least nutrients. Next, note any problems with the soil that occurred last year. For example, some plants are notorious for bacterial infections or insect infestations. If your old potting soil has fallen victim to pests or disease, it’s best not to reuse it either.

allow flowering plants to thrive in the garden through proper plant care

In addition, still check the soil level in each flower pot. Depending on what each plant has been through, it may need to be replenished. You can do this with perlite, lime or gypsum – these will last longer and don’t require new potting soil. Also look around for organic potting soil. Organic soil is better for your garden or for houseplants, so it’s best to see if there’s a way to replace inorganic potting soil with an organic one. Finally, determine the pH of your soil . You can use a home pH test kit to do this. The ideal pH for potted plants is between 6.2 and 6.6.

Materials and garden tools needed

use appropriate gardening tools like rake and fork for old potting soil

  • Cover sheet large enough to fit all the soil you will be working with.
  • New potting soil.
  • Rake or a garden fork.
  • Strainer for the soil (you can also make one yourself by using some wood and a wire mesh plate with 1 cm holes).
  • Perlite, lime or gypsum to improve the pH in the soil.
  • Slow-release fertilizer (you don’t need much, using about one spoonful per 4 liters).
  • One or more large buckets with small holes in the bottom.
  • Container large enough to hold the prepared soil.

Step 1: Lay out old potting soil

refresh old potting soil and let it harden in new flower pots

The most important thing to do first is to make sure that the soil you want to revitalize does not contain debris or weeds. Spread the old potting soil on the tarp and break up the pieces with a garden fork or rake. Once you’ve done that, you can remove any debris. After you have crushed the soil first, you can use the screen to get rid of larger pieces of debris and weeds. You don’t have to remove all the old roots from the potting soil, as they will eventually dissolve. In addition, this will be able to give additional nutrients to the new plants.

Step 2: Wash off excess salts

improve composting with organic fertilizers

This next step is quite simple. Use a bucket with holes in the bottom and fill it with soil. Once you have done it, you should add water. Hang the bucket somewhere high until the water stops draining. Then put the soil back on the tarp and let it dry. Once this is done, again crush the pieces very well with the garden fork or rake. Finally, repeat the process of soaking the soil, letting it dry, and then loosening it again.

use organic potting soil to grow plants


If you do not have a bucket with holes, you can take any larger bucket and make holes with nails. However, you can still wet the soil on the tarp and let it dry in the sun that way. However, this method will increase the drying time. After a day or two in the sun, you should cover the old potting soil with a plastic bag to prevent weeds from starting to grow in it. To know if the soil is dry enough to work with, you can shape it into a ball. If you snap your fingers on it and break the pieces apart, it’s ready.

Step 3: Mix new and old potting soil.

gardener mixes old potting soil in nutrient rich soil

This is where the package of new potting soil comes in. Mix your old potting soil with the new one, making it a 50/50 mix. You should use the sieve to remove any clumps or debris that may be in it. If you don’t have a strainer and are a DIYer, you can make one yourself by using a few pieces of wood and a wire mesh.

Step 4: Test and adjust the pH of the soil.

test nutrients and ph value in soil

Before you proceed, you need to make sure your soil pH is just right by testing your soil. The ideal point for garden soil is between 6.2 and 6.6, and you should use a home soil pH test. If you find that the pH is below 6.2, you should add perlite, gypsum or lime to make up for it.

Step 5: Fertilize the new soil

dispose of old potting soil or mix and fertilize with new soil

Next, you can add fertilizer. However, when doing so, make sure you don’t use too much of it, as this could cause more problems. The optimal amount is one teaspoon per 4 liters of soil. You will need to add the fertilizer after each pH adjustment.

Step 6: Allow the new soil to cure.

planting in plastic flower box

Finally, fill your containers with refreshed potting soil. The best containers for this are made of plastic. You will need to keep the soil in a dark and dry place for a few weeks before using it so that it can cure properly. This easy-to-follow guide should help your potted plants without having to buy new potting soil every season. While it may seem like something you don’t have to do, it could save you a lot of money in the long run. And if that’s not incentive enough, remember that it’s also good for the environment.