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It is surprising how quickly you can use up a bag of potting soil when you have pots and pots to fill, and buying bag after bag of the stuff can get quite pricey quite quickly (not to mention all that plastic waste).

If you have annual plants in pots, hanging baskets, or containers that you remove after the growing season, or you have had a couple of your potted plants inexplicably die off, the temptation is to pull out the old plant and turn right around and replant something in that same soil.

However, there are reasons to stop for a moment and consider the consequences of doing such as thing. Don’t worry! There are lots of ways of reusing spent potting soil or even rejuvenating it into a state as good as new.

Save your pocket, save your time, and save the planet a little by checking out these ideas to help you curb the number of yearly bags of potting soil you have to buy.

Risks in Reusing Potting Soil

Transfer of pathogens and disease- The soil that you have just removed a dead plant from might look just as did at the start of the season, but it is important to notice if the plant that you removed from the soil was healthy or not.

If it was a plant that became sickly and died in the soil, there is a good chance that whatever pathogen that killed it remains in the soil. For this reason, you do not want to transfer that disease to another, healthy plant.

That said, certain blights and diseases affect very specific types of plants, so as long as you aren’t replanting the same plant or something from the same family again, everything should be fine.

Reduced nutrition in the soil- There is also the simple fact that soil contained within a pot has a finite amount of nutrition in it. The plant that resided there before will have gone to town on all the minerals that there present in the beginning. By reusing this soil for another plant, you are depriving it of essential fertilization.

How to Rejuvenate Old Potting Soil

Let it dry– Immediately dumping and covering used potting soil until next year can invite mold to grow if it is not dried out properly. Instead, tip your used potting soil out onto a tarp or into a wheelbarrow and let it dry out completely. It will make it much lighter to move around, too.

Remove roots– While your potting soil is drying, you will have the chance to remove as many old root clumps as you can. This will make it easier to work with down the line. Small bits of the root are fine to leave. If you are going to dump the whole lot in a raised bed, you can just leave all of the roots there to rot down.

Add new soil or compost- One way of reusing your old potting soil is to cut it with new potting soil at a rough ratio of three parts old to one part new. This way, you will revive your old soil and won’t have to buy as much new.  You could also do the same with your own compost.

The ratio of old to new soil is something that you can decide for yourself. Perhaps the soil is already a couple of years old and in desperate need of revitalization, or the previous resident was a particularly hungry plant.

You can also add other appropriate soil amendments such as Epson salts, lime, coconut fiber, etc.

Store it over winter– Store soil that you wish to use next year in containers that will keep it dry, or dump it directly into new beds. The cold winter temperatures won’t do it any harm.

Other Ways to Use Old Potting Soil

Source: MIgardener/YouTube

Use it at the bottom of plant pots– If you have a huge container to fill, use old potting mix at the bottom before topping it off with fresh soil.

Use it to top garden beds– Take that old potting mix and spread it across garden beds before you mulch. This simply adds some bulk to the beds.

Use it to fill the bottom of raised garden beds– If you know you are going to be making some new raised beds for next year, used old potting mix to fill in some of the space. Use it in bulk so that you don’t have to use as much of your precious compost. You could also use it as a layer in lasagne gardening.

Dump it in the compost bin- It won’t add nutrients at this point, but it adds bulk and a bit of organic matter will help your compost spread a little further.

Use it to fill in divots in lawns- If you have some unsightly divots in your lawn or holes where dead plants have been dug up, use potting soil to make repairs.

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