I’m often asked about growing flowers or vegetables, especially tomatoes, in pots. This question came up at a recent tomato class sponsored by the local agriculture programs.
Growing plants in containers can be very simple.
There are a number of reasons that someone would want to grow flowers or vegetables in containers. The first is space. The first place that my wife and I lived was in an apartment with a small concrete patio where we grew a few tomatoes, peppers, squash and flowers.
The second reason for using containers is planting for interest and color.
The third reason is to overcome problems of poor drainage, lack of sun, or soil-borne pathogens such as bacterial wilt or nematodes.
A final reason for using containers is the flexibility and mobility they provide. Plants in containers can be changed rapidly, and the containers can have continuous color. Also, the containers can be moved from one spot to another when a splash of color is needed in another area of the garden.
There are a couple of considerations when choosing a container.
The first is drainage holes. Containers used for plants need drainage holes to remove excess water from the plants. If the containers don’t have drainage holes, then holes will need to be drilled in them.
The second consideration is size. I have seen plants grown successfully in a small container, but they need more care than plants grown in larger containers. Plants grown in larger containers tend to be healthier, faster-growing, and produce more flowers.
Besides the size of the container, the soil mix will determine the success in container gardening. A mix that is porous and drains well is needed. Most of the quality commercial mixes meet this requirement with a combination of vermiculite and peat moss as well as either perlite or ground pine bark. The last two ingredients are used to improve drainage and create a porous soil. If the soil doesn’t drain well, it can become saturated and the plants will develop root rot.
Commercial mixtures work well when there is only a few containers to fill. If there are a large number of containers, then the soil mix can be bought in bulk from local sources. Also, some gardeners mix their own soil. There are many different formulas for soil mixes, but one that works well will contain a mixture of 50 percent soil and 50 percent organic matter. One of the best organic matter amendments to use is ground pine bark that has a one-quarter to three-eights-inch particle size. Peat moss can be used as the organic matter source, but the coarser type of peat needs to be used and not the fine, muck types. If peat is used and the soil holds too much water, perlite needs to be added to the mix.
One of the problems with growing plants in containers is providing them with enough water. Because the soil is well drained, there is a need to water more often. However, there are gels on the market that absorb water and slowly release it over time. This is the same gel that is in disposable diapers. These gels will allow a longer period between waterings.
Make sure that the recommended rate for the gel is used. These gels will expand as they absorb water.
Plants grown in containers have the same basic nutrition needs as plants grown in the ground. Gardeners who make their own potting soil mixture need to add fertilizer and lime to the mix. If fertilizer and lime were added, the plants will need to be fertilized two or three weeks after planting.
The best way to fertilize plants is to use a slow-release fertilizer that releases nutrients slowly as the plant absorbs water..