Not every yard is suited for in-the-ground gardening. Sometimes containers or raised beds are better options. In rental situations or areas with poor or thin soil, garden space must sometimes be “created.”
Internet articles often make both sound incredibly easy, possibly because the content creators were gardening in a different climate. Like many horticultural dilemmas, no one answer fits every situation. Considering the pros and cons from a variety of gardening perspectives may help the individual gardener figure out the best solution for their situation.
For vegetables, larger containers are usually better, for a variety of reasons related to water and nutrient retention, soil insulation and more. Large containers, however, become more difficult to move. In raised beds, the deeper the soil profile, the better. New gardeners are often surprised at how much the soil in a new raised bed will settle over the course of a gardening season. It’s helpful to top it off at the beginning of subsequent growing seasons. Numerous other factors can come into play in choosing containers or raised beds.
Containers, even large ones, will be more prone to freezing soil when temperatures drop. Containers will freeze, which can damage plant roots. Larger volumes of soil, such as in a raised bed, will have more insulation and be less prone to drastic temperature changes.
The importance of soil warmth is often underestimated relative to seed germination and early growth of vegetable plants. In a raised bed, black plastic or landscape fabric can be used to raise soil temperature, aiding more even germination and protecting young seedlings.
Season extension in container gardening often means a workout every evening as plants are moved from the sunny driveway to the garage — then again every morning when plants are moved back out for the sun. If just a few containers are involved, or large containers have wheels, this practice is manageable.
Raised beds are often easy to fit with PVC piping and plastic covers, enabling the gardener to extend the growing season without a daily weightlifting routine.
A third option might be a combination: large, wheeled containers for sensitive tomatoes, which dislike cool nights, and a plastic-covered raised bed for leafy greens and carrots.
Container plants may need to be watered as often as twice daily. If they’re getting enough sun for good vegetable production, container soils dry out quickly. The combination of more frequent watering and frequent moving for protection can make container gardening more labor-intensive than raised beds.
Raised beds can be fitted with drip irrigation for more efficient, root-zone watering. If possible, both containers and raised beds should be located such that watering is convenient and easy to access.
Summer sun and winter freeze-thaw cycles are both brutal on containers. Plastics become brittle and crack when moved; clays and ceramics freeze, thaw, and disintegrate. Even expensive containers may only last a few seasons. Metal containers would last longer, but are not ideal for plant production. Heavy-duty five-gallon buckets are not particularly attractive but offer moderately priced, reasonably long-lived containers.
Raised beds usually represent a significant expense at the onset but usually last much longer. Containers might make sense for short-term living situations or first forays into vegetable gardening. Raised beds require more work and money at the beginning, which may pay off over time.
Containers are easier to move into a protected location — garage, greenhouse, spare bedroom — during the winter. Depending on the plant, additional lighting may be necessary for best performance.
Raised beds won’t offer outdoor yearlong gardening in colder climates, but if timed correctly, summer-planted and nearly mature turnips, carrots and rutabagas can be held in “stasis” in a protected raised bed for quite some time after a few light frosts or short freezes. This enables a much longer harvest time — and better chances of success with root crops, which are poorly suited to container gardening. Herbs, leafy greens, and green onions are some of the easiest to grow in containers.
The OSU publication “Growing Your Own” is free online and contains more info for those interested in either containers or raised beds.