Grow your produce in containers and raised beds

March 17, 2019

Not everyone has the space available for a vegetable garden. Container gardening is a great alternative. Many years ago, when I lived in an apartment in the city, I grew vegetables and herbs on my little balcony. I had so many potted plants out there that it looked like a rainforest.

Growing vegetables and herbs in pots can actually be less time-consuming and easier than conventional in-ground gardening, but it comes with special considerations. The most important aspects of container gardening are the container; the soil; and the watering and fertilizing regime.

Containers are readily available in a wide range of sizes, styles, materials, and cost. Terra cotta pots are traditional, but they are not ideal. They are heavy, fragile, expensive, and the soil in them dries out very quickly. Plastic terra cotta look-alikes are best if you really like their appearance.

Whichever pot you decide upon, bigger is better. For vegetable plants, I wouldn’t use anything less than 3-gallon pots, or better yet, 5-gallon pots. The black plastic pots that trees are sold in are ideal. You can buy them at gardening centers, or ask a local landscaping company if it has some leftovers you can pick up. Old 5-gallon buckets also work great, but make sure you drill drainage holes in the bottom.

Next, let’s discuss soil. Believe it or not, many potting soil mixes are not ideal for potting plants in! There are no standards for what is in potting soil, so it might be missing nutrients, have the wrong pH, or not hold water very well. The ideal soil for pots should provide nutrients, have a near-neutral pH, and retain moisture, but drain well.

You can make your own potting soil with equal amounts of three basic ingredients: organic matter (such as peat moss or compost), sand or perlite, and good-quality topsoil. Topsoil can be bought at gardening or landscape supply centers, or you can dig it yourself from your property or from that of a willing landowner.

Finally, watering and fertilizing are needed much more frequently in container gardening than in-ground gardening. You will probably need to water daily. During hot weather, you might need to water twice a day! The rule of thumb, so to speak, is to stick your thumb into the soil, and if it feels dry, water it thoroughly.

To retain moisture, apply a couple of inches of mulch around the containerized plants, on the soil surface. I use hay or dead leaves for mulch, but there are many other options available. Mulch will also help with weed control in your containers.

With regard to fertilization, you can add slow-release fertilizer to your soil mixture when you make up a batch. I most often use 10-10-10 inorganic fertilizer, which is 10 percent nitrogen, 10 percent phosphorus, and 10 percent potassium (or potash). Add 2 to 3 tablespoons of this per 5 gallons of soil. Then, use a liquid chemical fertilizer once a week, mixed into the water you use to water your plants.

If you are going organic, it is more complicated. For nitrogen, you can add 3 tablespoons of fish emulsion per gallon of water that you use to water your plants, once per week. For phosphorus, mix a half cup of bonemeal to every 5 gallons of soil before planting. For potassium, mix a half cup of greensand or a quarter cup of kelp meal to every 5 gallons of soil before planting.

If you don’t want the hassle of frequent watering that comes with container gardening, or if you want something with more space for larger plants, consider raised-bed gardening.

You can think of raised-bed gardening as large-scale container gardening. The ”container” is an open-bottomed box, made of wood or concrete blocks, that rests on the ground. It’s filled with good-quality soil, just like that described for container gardening.

Raised beds are ideal when your ground soil is extremely rocky, heavy in clay or sand, frequently wet, or poor in nutrients. Raised beds don’t require tilling. And if they’re built high enough, raised beds reduce the amount of bending over and kneeling down that’s needed in a conventional garden.

The typical width of a raised bed is 4 feet. This allows you to reach into the middle of the raised bed without stepping into the bed. You can build them any length and height. For vegetables, it’s best to have the bed at least 8 or 10 inches high.

Many people build their raised beds out of pressure-treated lumber, because it is slow to rot. I use 2-by-10 pressure-treated lumber. However, if you want to do organic gardening, use cedar or other rot-resistant boards, or concrete blocks. I wouldn’t use wooden railroad ties or power poles because they are treated with nasty chemicals that could leach into the soil.

The site for building your raised bed upon should be tilled first, to break up the sod or compacted soil. Next, lay the boards on their sides and fasten them together at the corners with weather-resistant screws. Measure the diagonals to ensure the box is squared up (the diagonal measurements should be equal).

Then, drive wooden stakes into the ground where each corner will be, but leave part of the stake aboveground in accord with the depth of the bed. Then level the “box” all around, and screw the box to the wooden stakes.

Finally, fill your raised bed with good-quality soil mix. Plant your new raised bed garden, and as the plants grow, use a couple of inches of mulch for moisture retention and weed control. Water and fertilize as you would in container gardening.

In the absence of a conventional garden, you can still grow your own vegetables and herbs in containers and raised beds. Simply let it all go to pot.

Greg Pryor, Ph.D., is a professor of biology at Francis Marion University and enjoys a self-sufficient lifestyle on his 100-acre homestead. Email him at gpryor@fmarion.edu.