Daniel Gill, Merrill, Thomas A. | 7/28/2007 2:36:59 AM
By Dan Gill
LSU AgCenter Horticulturist
Growing plants in containers outdoors is popular for a variety of reasons, and such plants can be used to enhance your outdoor landscape.
In-ground beds are not always available where you would like to grow plants – as in the case with paved courtyards, decks, apartment balconies and patios. Plants in containers can be used in those situations, however.
Flexibility and change are two other outstanding features, since container plants allow you to alter the landscape quickly by simply changing the arrangement or location of containers.
Nearly any plant may be grown in a container as long as you provide the cultural requirements the plant needs. You can choose from small-growing evergreen or deciduous trees, shrubs, ground covers, herbaceous perennials and annuals. Tender tropicals also may be good candidates, since growing them in containers means they can be brought into protected locations during the winter.
The amount of light they will receive is an important factor in deciding which plants would be suitable in a particular location. Whether the location is sunny or shady, you must choose plants that will thrive in the conditions where they will be located. Also, consider the size of the area and choose containers and plants that will be in proper scale.
Only your imagination and taste set the limits on what you can use as containers for your plants.
The variety of manufactured containers is large. Found objects varying in size, material, color, shape and design also can be used for plantings.
In most instances, I would advise using containers with muted colors and simple designs, however, since brightly colored and heavily decorated pots will detract from the plantings.
In addition, my advice is to choose larger-sized containers whenever possible, since small containers are usually out of scale with outdoor landscapes. Smaller containers also mean more frequent watering.
Speaking of watering, make sure the containers you use have one or more drainage holes in the bottom to allow excess water to drain out of the pot when you water. This is critically important.
More than anything else, the potting medium used in a container needs to drain well yet retain sufficient moisture to promote good growth.
There are two basic categories of potting media that are suitable – soil mixes and soilless mixes.
Soil mixes contain soil along with organic matter and sharp sand, perlite or vermiculite to improve drainage. Make sure you purchase soil mixes specifically labeled "potting soil" for use in containers.
Soilless mixes have no soil in them and are composed of peat moss, perlite and vermiculite in varying proportions. Their advantages are excellent drainage, good water retention, light weight and freedom from soil-borne insect, disease or weed problems. The main drawback is that they are relatively low in nutrients – a problem that can be easily corrected, however, by the use of slow-release fertilizers or soluble fertilizers.
Plants growing in containers are far more dependent on you for adequate water than plants growing in the ground.
Water whenever the potting medium begins to feel dry when you stick your finger into it. Be sure not to wait until plants wilt.
Watering frequency will vary depending on the type of plant, time of year, temperature and size of the plant in relation to the size of the container among other factors.
When you water, water generously until water runs out of the drainage holes. To facilitate watering, the soil (or soilless potting medium) should not be level with the rim of the pot. Having the top of the soil slightly lower than the pot rim provides space to hold water while it penetrates into the medium.
A constant supply of nutrients should be available when the plants are in active growth.
The best choices for fertilizing container plants are either soluble fertilizers or slow-release fertilizers, since they are less likely to burn plants when used properly.
Soluble fertilizers are easy to apply, especially when you use a hose end applicator, but they must be applied every two weeks to maintain a constant supply of nutrients.
Slow-release fertilizers provide nutrients over many months from one application. That means they can cut down on the labor required to be sure your plants have the nutrients they need.
Container plantings enrich our landscapes in wonderful and unique ways. With proper selection and care they can provide year-round beauty to liven up a variety of landscaping situations.
Get It Growing is a weekly feature on home lawn and garden topics prepared by experts in the LSU AgCenter. For more information on such topics, contact your parish LSU AgCenter Extension office or visit our Web site at www.lsuagcenter.com. A wide range of publications and a variety of other resources are available.