planting last year's pots

Asked February 18, 2018, 6:39 PM EST

Do you recommend dumping all the soil and filling with fresh? I add organic fertilizer, slow-release but how about perlite, too? Thanks!

Sussex County Delaware container gardening

1 Response

Thank you for your question about your potting soil. It is recommended that you replace potting soil each season. Here's what one Extension article says:

"Also, can soilless media be reused from year to year? To a certain extent, yes. If the plants in the containers were healthy during the growing season with no major disease issues, you could remove the plant material at the end of the season and reuse the media next season. You may have to add some additional new media to fill the container. There will come a time when the media in the container will need to be replaced. Over the course of time, the organic materials that the soilless media is made from break down and decompose to the point where you will lose the drainage and aeration properties that are inherent in soilless container medias. When that happens, discard the media to the compost pile or to the garden and refill the container with fresh media."

Most potting soil mixes already contain perlite, vermiculite or pumice, all of which just open pores for air and water to penetrate to the roots, but none of these have any nutritional value. If the potting soil is 'new,' its organic material will already have nutrients decomposing to give your plants 'food,' but adding a slow-release fertilizer probably won't hurt anything. Hope this is helpful. Good luck!