How to monitor roots on your container plants

When container-grown plants receive the right amount of light, moisture and nutrients, they are usually among the most care-free plants in your garden. Because we keep them in places where we see them often and interact with them daily as we check their needs for water, small problems can be spotted quickly and fixed at once. Here are some tips on fixing health issues with your container plants when the roots are causing the problems.

Large plants grown in containers seldom attain full size, because their root area is restricted.

While most of the best plants for containers willingly accept this limitation, it's important to unpot the plant and check its roots when it seems unable to take up water or simply stops growing.

Crowded roots are the most common problem, but occasionally insects or diseases are to blame.

1. To look at the roots of a container-grown plant, allow the soil in the pot to dry out, then lay the pot on its side and tap it gently.
2. Jiggle the plant to remove it from the container without pulling too hard on the main stem.
3. If the roots are badly matted, spiraled around the inside of the pot into a tight mass or so thick that you can hardly see the potting soil, it's time to repot the plant.

Using a new container

1. If you are "potting on", or repotting in a new, larger container, select a pot slightly larger than the existing one but still in proportion to the plant's size.
2. Fill the pot with fresh soil, loosen the plant roots by teasing them away from the soil ball and continue planting as you would with a new specimen.

Using the same container

1. If you want to put the plant back in the same container, you'll need to trim the roots.
2. Lay the plant on a bed of newspaper or a plastic sheet.
3. Gently pull away some of the soil, hold the plant upright and slice from top to bottom with a sharp knife all around the outside of the root ball to cut off old roots and stimulate new growth.
4. Fill the pot with fresh soil and replant as you would a new specimen.

Missing roots indicate that a soil-borne disease has invaded, and there is usually no cure. Dispose of the plant and soil in the garbage, thoroughly clean the container by scrubbing with a solution of warm, soapy water and household bleach, rinse the pot and start over by filling the pot with commercial, sterile potting mix and setting in a healthy plant.