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You Can Deal With Potbound Plants

Many of us grow tropical plants in containers to beautify our porches, patios and decks. These plants often live two lives — spending summer outside when the weather is warm and going inside the house during the cold of winter. Plants placed outside on porches, patios, decks and balconies grow vigorously through the summer. This is because excellent growing conditions outside, including abundant light, good air circulation and high humidity, encourage the plants to grow enthusiastically.

As a result, your outdoor container plants may have outgrown their pots and become potbound. September and early October are ideal for repotting tropical container plants that you have summered outdoors.

The term potbound is used to indicate plants that have tightly filled their pots with roots. Most plants will tolerate being somewhat potbound. Actually, in the case of some plants, being potbound encourages blooming. This is true for bougainvilleas, for example. Also, many bromeliads, succulents and cactuses grow better in relatively small pots.

Plants that are potbound generally require more frequent watering and careful attention to fertilizing. Once the roots fill the container, they are limited in the amount they can continue to expand and grow. Even though the roots run out of room for growth, they must still provide adequate water and nutrients to the plant as it continues to grow larger. As long as adequate water and mineral nutrients are provided, however, plants in this condition may remain happy for quite a while.

Eventually, however, the roots become so packed in the container that the plant begins to suffer. The roots stop growing actively, and as a result, the upper portions of the plant begin to suffer as well. Common symptoms of a plant with an excessively potbound condition include frequent wilting, stunted growth, smaller new leaves, poor quality flowers or lack of flowers, and yellowing and dropping older leaves. Many other problems can cause similar symptoms. So how do you determine if a plant is actually potbound?

There are several things to look for. First, you will see a dense growth of roots on the soil surface (some surface roots are normal). In extreme cases, the soil may be so full of tightly packed roots that there is resistance when you try to push your finger in the soil. Tilt the pot over, and look for roots growing out of the drainage holes.

Finally, to be absolutely sure, lay the pot on its side. For plastic pots, hit the sides with your hand forcefully a few times to loosen the root ball. In clay and ceramic pots, run a long knife around the inside of the pot. When the root ball is loosened, place one hand over the soil with the stem of the plant between your fingers, and tilt the pot so the plant slides out supported by your hand. You could also lay the pot on its side, grasp the plant, and gently pull it out.

Once the root ball is out of the pot, you will be able to clearly see how potbound the plant is. If the roots do not look like they have filled up the pot, you can slip the root ball back into the pot and do nothing. If all you see is a dense network of roots with little potting soil showing though, this indicates the need to repot the plant. If the plant is still growing well and looks healthy, you may put off repotting until a later date if you like. But a plant that is not doing well because it is potbound should be repotted immediately.

When repotting a plant into a larger container, the new pot should generally not be tremendously larger than the pot it has outgrown. The new pot should allow only about 2 to 4 inches of new space between the root ball and the sides of the new pot.

Over-potting a plant — putting it in a pot that is too large — can lead to root rot from overwatering. And aesthetically, the size of the plant needs to be in pleasing proportion to the size of the pot. In other words, a relatively small plant looks out of place in a relatively

About the author

Dan Gil

Dan Gil

Dan Gill is an Associate Professor in Consumer Horticulture with the LSU AgCenter, a position he has held since 2001. He earned B.S. and M.S. degrees in horticulture from Louisiana State University in Baton Rouge.

Before moving to Baton Rouge to take on statewide responsibilities, he was headquartered in New Orleans as an extension horticulturist from 1980 to 2001. While there, he became established as a reliable source of helpful, useful advice on lawn and garden topics through his media work.

He is the spokesperson for the LSU AgCenter’s Get It Growing project, a statewide educational effort in home horticulture utilizing radio, Internet, TV and newsprint. Gardeners throughout Louisiana read his columns in local newspapers watch his gardening segments on local TV stations, listen to him on local radio and access content on the Internet.

In the New Orleans area, Dan appears weekly on the Channel 4 Morning News, writes a weekly gardening column for The Times-Picayune and hosts the Saturday morning Garden Show on WWL 870-AM, a live call-in radio program that reaches southeast Louisiana and the Gulf Coast.

Dan is author of Month-by-Month Gardening in Louisiana and co-author of the Louisiana Gardener’s Guide, Month-by-Month Gardening in Texas and Texas Gardener’s Resource. His “Only in Louisiana” column appears monthly in the Louisiana Gardener Magazine, and his articles have also appeared nationally in Fine Gardening Magazine.

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