You don’t need a vegetable garden to grow vegetables. Almost anything you can grow in the ground can be grown in a container on your patio. Okay, corn, large pumpkins and melons and full size apple trees would be the exceptions. But that still leaves a lot of options.
Before you reach for the potting soil, here are a few special considerations to keep in mind, when growing crops in pots.
❦ Containers: You can use just about anything as a planting container, from high end, self-watering pots to a plastic trash bag. Whatever you choose to use, give some forethought to:
❦ Size: Large plants have large root systems. You can easily grow a beefsteak tomato in a pot, as long as you provide at least 5 gallons of soil for its roots to spread out. Too small a pot will stunt the plant’s growth. Small pots also heat up faster, so you could even wind up frying the roots. And the less soil there is, the more you will have to water it. So opt for a substantial sized pot.
❦ Drainage: It’s essential that there is some way for water to drain. Even though soil in containers dries out more rapidly than it would in the ground, you do not want water collecting at the bottom of the pot and rotting the roots.
Containers that sit on concrete and other non-porous surfaces may need to be lifted with plant feet, to allow water to escape.
If you are worried about staining your deck surface with the draining water, you can place a saucer under the container, but be prepared to empty it of standing water. One of the easiest ways to deal with large containers on patios and decks is to put them on a plant dolly. Most allow for draining and you can easily wheel them on and off the patio, as needed.
❦ Color and Material: There’s more to the color of your container than aesthetics. Dark colored containers will absorb heat. Sometimes this is a plus, such as when you want to grow eggplant and the extra heat will encourage more fruit set. But often the soil in dark containers get hot enough to burn plant roots. If at all possible, place the container in shade, but allow the plant to reach the sun.
The material your container is made of will also affect the temperature of the soil. In general, plastics and other synthetics absorb more heat than natural stone and ceramic pots do. Be especially cautious with metal containers, which not only heat up, they also reflect light onto the plants.
❦ Soil and Fertilizer: One of the best things about growing vegetables in containers is that you can control the quality of the soil. While it’s tempting to just dig some soil from the yard, even the best garden soil is not a good option for containers. Plain soil is just too heavy and compacts quickly in a containers, blocking the flow of water and inhibiting airflow.
Some type of potting mix is preferable. Look for a light mix with a ground bark or peat base. You don’t need a wetting agent and you don’t need a soil with fertilizer in it. Starting with a simple potting mix will allow you to adjust the soil to the needs of whatever vegetable you are growing. Tomatoes and other fruiting crops prefer more phosphorus, while leafy vegetables are heavy nitrogen feeders. You should be able to find a slow release granular organic fertilizer that can be added at planting time or you can rely on a water soluble fertilizer every 2 – 4 weeks.
❦ Water: Be prepared to water often, once your plants get growing. As the plants reach mature size, the roots are probably filling the entire container and may require daily or even twice daily watering, on hot days. Don’t wait until your plants go limp, to decide it’s time to water. Poke your finger a couple of inches below the soil surface. If it is dry down there, it is time to water.
❦ Sun: Most vegetables prefer a full day of sun; 5 – 6 hours of direct sunlight. However because of the extra heat from being confined in a container, your vegetable plants might like an afternoon respite in partial shade. Let them tell you if they are getting too much of a good thing. If the leaves or fruits start to get papery white patches, they are getting sun scald and need some shady protection during the hottest parts of the day.
Be extra cautious with plants growing on cement, tiles, and other reflective surfaces. The light is bouncing at them from all directions and they can fry in no time.
❦ Weight/Wind: Tall plants, like tomatoes, fruit trees and bushes, and pole beans, can get top heavy. If won’t take a very strong gust of wind to topple the entire container. Besides the annoyance of having to right the container, toppling can easily break the plant or ruin the fruits.
If your containers are in a windy site, you’d be wise to weight them down. You can place bricks or rocks on top of the soil or anchor the containers to a nearby structure.
Another way wind can be a hazard is that it can shred leaves and knock fruits off the plants. If you are going to be container gardening on a high terrace or rooftop, providing some type of wind block can save you a lot of heartache.
Most outdoor living spaces are sited on a west or east facing spot, which should be ideal for growing vegetables in containers. Just know that it’s not as easy as plopping a plant in a tub and then walking outside every morning to harvest tomatoes. Vegetables in containers are completely dependent on you for their basic needs. If you can remember to water, you should have no problem realizing that romantic notion of having delicious, fresh food at your fingertips.