Do I need to replace all the soil in my pots, or is some of last year's OK to leave in?
Although it's better to replace the soil in your pots at the beginning of each season, it's not vital. The primary reason for starting fresh each year is that insects and pathogens can overwinter in the soil, causing annoying problems that are easily avoided by dumping out the old soil, scrubbing the pots with bleach and using a fresh growing medium.
If you decide to keep last year's soil, there are a few things you'll need to do to turn it into a viable medium for this season's plants.
First, proper circulation of air and water in the root zone is vital to the health of your plants and soil left in a container for more than a season tends to compact. Your plants will benefit from you working a porous material, such as perlite or vermiculite, into the soil before planting.
Second, last year's plants will have sucked the nutrients out of the soil and without a complete set of nutrients, your new plants will go from robust to sickly in short order. You'll need to invest in some organic fertilizer and apply it thoughout the season at the rate suggested on the packaging.
If you have any questions or comments, please send them to me at vanessa@gardenmuse.ca.
Originally published in the Creston Valley Advance on May 14, 2009.
