Imelda and Brian Cyr, certified O'ahu Master Gardeners, shared advice on container gardening, the theme of today's Second Saturday event at the University of Hawai'i Urban Garden Center in Pearl City:

Plants purchased at the local garden center are often sold in small plastic pots. These pots, while good for the purpose of selling plants, are not good for growing the plants long-term. The plant will need to be repotted to provide suitable conditions to thrive. Your success is dependent on the type of container, the potting mix and knowledge of the plant and associated pests. Fertilizer and water requirements must also be considered.

Containers: Porous types, such as those made of terra cotta clay and woven baskets, allow for air and water movement. Soil in these pots can dry out quickly. Nonporous containers, such as plastic, glazed pottery and metal, do not lose moisture nearly as fast. Semi-porous containers include wood and concrete. Almost anything can be used, provided it's clean and has holes in the bottom to allow drainage. This helps prevent root rot by keeping roots out of sitting water. If no holes are present, drill a few. Container size is a consideration. The rule of thumb is the larger the container, the longer it will take to dry out and the less watering it will need. Small pots and hanging baskets require more watering. However, planting into a container no more than 4 inches larger in diameter than the plant is also recommended.

Potting media: Choose a good, clean, lightweight potting mix from your local garden center. Native soil is not recommended for containers because it is too dense. Reusing the potting mix is not recommended as the mix becomes compacted over time with fewer spaces for air and the root system. It may also harbor disease-causing organisms that may create problems. If you want to make your own organic potting mix, visit this eXtension Web site: www.extension.org/ article/20982.

Plant selection: Virtually any type of annual flowering bedding plant or flowering perennial can be grown in a container.

When considering vegetables, look for descriptive words like "bush," "compact," "dwarf" or "determinate," as these describe varieties most suited for growing in containers. The ideal vegetables for containers are those that take little space, such as carrots, radishes, lettuce and parsley or those that yield produce over a long period of time such as tomatoes, peppers, herbs and eggplants. Many herbs are perfect for containers. Some smaller herbs, such as thyme, chives, oregano and basil, can be grown together.

To grow small shrubs or trees successfully, larger containers will be needed. Also, choose plants that are naturally slow-growing and are small or dwarf in growth.

Watering/fertilizing: A rule of thumb is to water as soon as the top inch of the soil feels dry when you wiggle your finger in it. If at all possible, avoid wetting the foliage of plants to avoid disease. Fertilizing is easiest using a good, slow-release fertilizer. These products consist of water-soluble fertilizer that is encased in a semi-permeable resin coating. When they come in contact with water, small amounts of nutrients are released to the soil for use by the plant. So, each time you water, the containers are getting "automatically" fertilized.

To learn more, visit the UH Urban Garden Center in Pearl City today from 9 a.m. to noon. There, you can see live demonstrations on soil preparation at 9:30 and 10:30 a.m. No registration required. The garden center will also be holding a poinsettia sale to support the O'ahu Master Gardeners, an educational outreach program of the University of Hawai'i. Visit www.ctahr.hawaii.edu/ougc or call 453-6055 for more information.