Old pots can hurt new plants

COLUMBIA, Mo. – Gardeners are well known for their thriftiness and commitment to protecting the environment. However, according to University of Missouri Extension horticulturist David Trinklein, a false sense of economy can sometimes work against the health of the garden.

One example is saving and reusing plastic pots from one season to the next. While this may seem economical, Trinklein says it carries risks. Chemicals and disease-causing microorganisms from previous plants can linger on pots and be transferred to new plants.

Sunlight also breaks down plastic over time, making it become brittle. This is especially true for low-quality containers or those with intricate rims and designs, which can provide hiding places for pests and plant diseases.

Cleaning and sanitizing plastic pots can be time-consuming and costly. You can disinfect pots with a solution of one part bleach to nine parts water, but the expense of bleach may outweigh the value of reusing the containers. Trinklein recommends cleaning any growing medium residue in the pots, soaking them for several minutes and then rinsing thoroughly with water to remove any bleach residue, which can harm new plants.

Disinfection is just as important for porous containers, such as clay or terra cotta pots. However, since they are porous, disinfection requires either boiling them in hot water for 30 minutes or heating them with steam.

As an alternative to cleaning and reuse, Trinklein suggests using biodegradable pots and recycling plastic containers through local curbside programs.

Garden tools also should be cleaned between uses, Trinklein said. Contaminated equipment can transmit bacterial, fungal and viral diseases, as well as nematodes.

Regular cleaning can also extend the life of gardening tools by protecting metal blades from rust and wooden handles from rot. Trinklein notes that experienced gardeners see high-quality tools as a worthwhile investment. “Quality is something that costs, but properly cared for, a quality tool literally should last a lifetime,” he said.

Gardening can be tiring, and with the distractions of modern life, it’s easy to forget or postpone tool maintenance. Trinklein encourages gardeners to make cleaning a habit. “Make it a ritual,” he said. “As you put away a tool, clean and disinfect it. It’s a good ‘best management practice.’”

Keeping tools sharp also makes gardening safer and easier. This applies not only to pruners and knives but to everyday tools such as trowels, hoes and shovels as well.