Reusing Potting Soil from Year to Year

When it comes time in spring to plant annuals in containers, you may wonder about reusing potting soil that was left in the pot from the previous growing season. Here's what to know:

Healthy soil is essential to plant health. For most plants kept in containers, you want soil that is loose and full of nutrients. It must be fertile and drain easily. It can't remain soggy, but it should retain some moisture between waterings.

Related: "Planting Annuals: Two Key Tips"

Potting mix should never be reused if the previous year's plants showed signs of disease or sustained a heavy invasion of pests. You should also always use fresh seed-starting mix when propagating plants, and use fresh mix when potting up seedlings.

If your container plants remained healthy and maintained their vigor the previous year, reusing potting mix is okay. However, you'll want to refresh it:

Remove half of the mix from the pot. You can put this portion in your compost pile, spread it in your garden or use it to partially fill an empty pot or pots.

Going back to the original container that's now half full, add a few inches of fresh potting mix. Use a hand shovel, claw or other right-sized tool to stir the fresh mix and old mix together. Keep adding more fresh mix and stirring until the level is at the right spot for inserting your new plants. Then fill around them with fresh mix.

If you put the discarded mix into empty pots, repeat the above step to fill and plant them, too.