Issue: September 22, 2007

Clean old flower pots before reusing

We want to repot the geraniums here in our office. Is there anything we should do to the pots before putting in new soil? We have no office budget for such things, so we prefer that it will be inexpensive.

Kathleen.
Lincoln Co.

Answer:

You may be able to get away with just removing the plants from the pots and washing the old soil from the pots. After that you can put the plants back into the same pots. However, this can cause problems if disease organisms are present.

A better approach would be to use new, clean pots. Equally effective would be to carefully clean and sterilize the pots with a 10 percent solution of chlorine bleach. Sterilize the pots by soaking them in a bucket or dishpan filled with 9 parts water and 1 part chlorine bleach. Let the pots soak for several hours. Then rinse the pots to remove the sodium hypochlorite (bleach). If the pots are made of plastic you can just rinse them under running water. If the pots are made of clay, soak them in clean water for several hours. Then they will be ready to receive the plants.

While the geranium plants are out of their pots, protect their roots from drying out. Wrap them in newspaper or put them together into a large dishpan. If necessary, moisten the soil slightly. The plants will remain in good condition for several days if left in a shady location. Plants other than geraniums may be treated in the same manner, but some plants will dry more easily than the succulent geranium plants. They may need a sheet of clear or white plastic over them to reduce water loss. (Don't leave them in the sun if covered with plastic. The heat accumulated under the plastic may damage the plants.)

Don't worry if some of the soil falls off the roots during this process. In fact, it may be good to gently prick out soil with a screwdriver or chopsticks before repotting. If the soil is old and has accumulated significant quantities of salt, you can gently wash much of the soil from the roots before repotting. When repotting, carefully work fresh potting soil into the roots.

After potting, water well, but not too often. It will take a few weeks for root growth to refill the pot. If the soil dries out too much or remains soggy during this period, the plant will not establish well in the new potting soil.

This is a good time to repot houseplants in preparation for winter. If problems develop due to salty soil, diseases or insects in the soil, it will be more difficult to do this process in mid-winter. On cold days you cannot do the repotting and pot soaking outside. Washing old soil from the roots of houseplants is much easier outside before cold weather arrives.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!