At the end of the season, many gardeners find themselves with leftover potting soil. While it may be tempting to simply discard this soil, it is actually possible to reuse it. Reusing potting soil from last year is a simple process. The price of potting soil certainly can add up over the years, and there is no reason to discard of it or have it go to waste! (Well, there is one reason, and I’ll discuss that in this post).
Can you reuse potting soil from last year?
Simply put, potting soil can easily be reused for multiple years. However, if you grew anything that was diseased, I would recommend discarding the potting soil as opposed to reusing it. You’ll also want to avoid putting any diseased soil in your compost bin.
If you’re planning on starting seedlings, I would also recommend using fresh potting soil or seed starter to give them the strongest start possible.
How to reuse potting soil from last year (step by step)
The most important thing to remember when reusing potting soil is that it will be depleted of nutrients from the prior season. So, you’re really just replenishing the potting soil for whatever you may be growing in the current year. It’s a very simple process! Check out our Youtube video below:
Here is how to reuse your potting soil, step by step:
- Dry the soil out. This can be done by simply leaving it out in the sun on a tarp for a few days which will make it a lot easier to work with, and less messy.
- Sift the soil. Using a wheelbarrow and sifter (if you have one), dump the potting soil in and start sifting through it. Break it up nice and fine and remove any large roots, sticks or rocks. Stems and sticks can be composted. This process can be done at the end of the season, or the start of the season (it’s up to you!). You don’t need a fancy sifter, you can easily do this by hand. Give the soil a smell to ensure it smells earthy and not rancid.
- Amend the soil. Now that you’re left with a wheelbarrow full of sifted soil, it’s time to amend it and replenish it for the season. Add in compost and/or granular fertilizer at this time. We like to do a ratio of 20-30% compost to soil. In regards to the fertilizer, we typically toss in half the recommended amount per soil volume, and then address the plants individual needs throughout the season. Many people also mix fresh potting soil in with the old. You can also add coco coir at this time to add volume to your soil.
Remember: It is best practice to rotate your crops. This helps to prevent disease and pests from becoming rampant in your garden. For example, if you grew peppers in the soil last year, try growing flowers or something from another crop family the following year.
We have had great success using a combination of homemade compost and Garden Tone all purpose fertilizer. These two ingredients pair well to replenish old potting soil for another year of growth.
How to store potting soil at the end of the season
When it comes to storing potting soil, there is no need to overthink it. You can leave used potting soil in their pots (as long as they are well-draining and will not collect water). We leave our pots of soil outside until they are ready to use the following year. You can cover the pots, or leave them uncovered and let the rain wash through them. Then, we follow the steps above for replenishing it.
We do not recommend reusing outdoor soil for indoor plants. While it is possible, we try to limit the amount of pests in our indoor space, especially because we start many seeds in the late winter and early spring!
For fresh soil that has never been used, you can store it in a cool, dry place, such as a garage.
Other ways to use old potting soil
If you do not want to replenish your soil and use it for growing, there are other ways to put it to use.
- Compost it: If you have a compost bin, you can add your potting soil to it. This will add bulk to your compost. Remember to never compost potting soil that had diseased plants growing in it.
- Use it as filler: If you have low spots in your yard that collect water, you can use old potting soil to fill them in. Or, if you have a dog that likes to dig for critters around your yard, use the old potting soil to fill these holes.
- Use it as mulch: If you have trees or shrubs, you can use potting soil as mulch around their base.
- Use it in flower beds: You can use potting soil to fill in gaps in flower beds or pots. This is a great way to add height and dimension, without having to purchase new soil.
The process of reusing old potting soil is very simple. There is no need to run to the store every year and purchase new bags. How do you use your soil from season to season, and what do you amend your soil with?