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Container Gardening 101: Growing Vegetables in Pots | The Old Farmer's Almanac

Container Gardening: Growing Vegetables in Pots

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Tomatoes are an excellent candidate for container gardening.

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Learn How to Grow More Vegetables in Less Space!

Robin Sweetser
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Container gardening is a fantastic way to grow vegetables, especially when you lack yard space! If you have a small gardening area or only have access to a patio, balcony, driveway, or rooftop, consider trying your hand at gardening in pots.

Why YOU Should Try Container Gardening

Container gardening allows those of us who don’t have room for raised beds or a huge garden plot to grow our own food, too. Want to have more control over growing conditions and fewer weeds? Container gardening is a great way to maximize your gardening space and streamline your gardening tasks. 

Container Gardening 101

Where to Put a Container Garden

The beauty of a container garden is that it can be placed almost anywhere. Even if it’s only one or two pots on the side of your driveway or in the corner of your balcony, gardening in containers allows you to maximize all of your available space. 

Just as with a standard garden bed, consider things such as sunlight exposure, water accessibility, and protection from wind when deciding where to put your containers.

  • To maximize your veggie harvest, you’ll want to place your pots in an area that gets full sun (i.e., 6 to 8 hours of sunlight per day). Lettuce, spinach, and other greens can grow well in less sunlight (3 to 5 hours per day), but for fruiting plants like tomatoes, peppers, squash, or eggplant, full sun should be the goal. Southern and western exposures will provide the most sunlight and warmth, while northern and eastern exposures will be shadier and cooler.
  • It’s also a good idea to put your pots somewhere that you can reach with a watering hose. Keep in mind that container gardens tend to need more water than standard in-ground gardens, and there’s nothing worse than having to lug a gardening can across your yard a dozen times every morning—and then having to do it again in the evening! Having an easily accessible source of water nearby will save you a lot of time and effort.
  • Protecting containers from direct wind keeps them from drying out as much and prevents accidental tipping over. Depending on the size of your containers and the plants you’re growing, they may get top-heavy as the season goes on, which makes them more vulnerable to tipping over in strong winds. Place containers in sheltered locations or plan to secure them (e.g., with cinderblocks, stones, or ropes).

Finally, think about the microclimates that exist on your property. Microclimates are small pockets of space in which the climate of the immediate area doesn’t match the greater climate of your location. For example, an asphalt driveway will hold onto warmth longer than a patch of grass will, so any pots placed on the driveway will be exposed to that extra warmth. On one hand, this could mean that the pots dry out more quickly, but on the other hand, the plants may grow better thanks to the warmer soil.

Choosing the Right Container

The most fundamental part of container gardening is—surprise—picking the right container! From plastic pots and cinderblocks to whiskey barrels and wheelbarrows, almost anything that holds soil can be gardened in. However, when it comes to growing a productive container veggie garden, there are three key aspects to keep in mind while picking a suitable container:

1. Drainage

A container should have a drainage hole or some other way to allow water to pass through it. Water-logged soil promotes bacterial and fungal growth, which will stunt plants’ productivity or kill them outright. Your climate factors into this as well; gardeners in drier areas may want to choose containers that retain more moisture, while those in more humid environments way want containers that allow for more air flow.

2. Size

In general, the more space you can offer your plants’ roots, the better they will grow. Most vegetables need at least 12 inches of soil to grow well, but larger vegetables will require more space. A 5-gallon container is a good size for growing something like a tomato or squash plant, while a smaller container would be perfectly fine for shallow-rooted plants such as lettuce or other greens.

Bear in mind that larger containers will be heavier and harder to move, and may be too heavy for somewhere like a balcony. Small containers, on the other hand, are more mobile and versatile, but also tend to dry out faster, requiring more attention on hot days. 

3. Material

The final important factor to consider is what the container is made out of. These days, containers come in all sorts of types, each with its upsides and downsides. Here are a few of the most popular container materials:

  • Plastic: Plastic pots come in all sorts of shapes, colors, and sizes, which makes them one of the most popular choices for container gardening. Plastic pots also tend to be the cheapest option. They are relatively lightweight, hold in moisture well, and are easy to clean and reuse for many gardening seasons down the line. If you’re growing edibles, be sure to choose pots made out of food-grade plastic so that chemicals won’t leach into the soil.
     
  • Ceramic (terra-cotta): Ceramic pots are another popular choice. They tend to be more decorative than plastic pots, but are also quite a bit heavier—especially when filled with soil. Ceramic pots come in glazed or unglazed styles; the main difference being that glazed pots hold in more moisture than unglazed pots. The great thing about ceramic pots is that the clay is porous, which allows some level of air and water to flow through it. This ensures that soil doesn’t get overly wet, but also means that soil in (unglazed) clay pots will dry out more quickly than in plastic pots. Additionally, ceramic pots are susceptible to cracking in cold weather, so they should be emptied and stored in a sheltered area through the winter.
     
  • Fabric: Fabric pots have become more popular in recent years thanks to their lightweight nature and the breathability they offer. They often come with handles, too, which makes moving them around very easy. Plus, they can be washed and reused fairly easily. The fabric allows air and water to easily flow through it, which is beneficial to plants’ roots, as they are encouraged to become more fibrous and, therefore, more efficient at taking in water and nutrients. One downside to fabric pots is that they dry out rather quickly, so consistent watering will be required.

Again, almost anything can be used as a container, so get creative! Hanging baskets make good use of extra space, and herbs, cherry tomatoes, and strawberries grown at eye level can be easily tended and harvested. Use whiskey barrels (a wooden half-barrel can yield an amazing amount of food), buckets, baskets, boxes, bath- and other tubs, window boxes, and troughs—anything that holds soil. Just be sure that it has drainage holes in the bottom and is a size that you can manage.

Watch the video below for more information on choosing the right container:

Soil for Containers

In order to grow healthy plants, you need healthy soil. Plants in containers need the best possible nutrients, aeration, and drainage in order to encourage healthy root growth and to produce a good harvest.

Do not use soil from the garden! Most garden soils are too heavy, can become easily waterlogged and compacted, and harbor disease and insects. Instead, use a “soilless” potting mix that’s specifically formulated for use in containers. It will be quick-draining and lightweight, and shouldn’t contain any diseases or pests. 

Soilless potting mixes tend to consist of some combination of peat (or coconut coir), perlite, and vermiculite, as well as other additives such as ground limestone and granulated fertilizers to provide nutrients. Here’s how to make your own soilless mix at home.

Got compost? Humus is a fantastic material to add to your container mix, as it contains plenty of nutrients and loosens the media. Read all about making compost!

How to Water Containers

Because they are more exposed to sun and wind, containers tend to dry out more quickly than traditional gardens or raised beds. Especially during the hottest days of summer, many plants grown in pots must be watered as often as twice a day!

Containers can be watered in a number of ways—hoses, watering cans, drip irrigation. Choose a method that makes the most sense for you and the size of your garden.

A few watering pointers:

  • Water in the morning (or as early as possible). Ideally, container plants should be watered as early in the day as possible. Watering early in the day provides plants with enough moisture to get them through the hotter midday hours. It also ensures that their leaves dry off by the time that night falls; having moisture on leaves at night can encourage the spread of disease.
     
  • Water deeply. Plants need water at their roots, so simply spraying the surface of the soil with the hose isn’t enough. Water plants—especially those in containers—deeply and thoroughly to ensure that water reaches down to their roots. After a watering, the soil should be saturated and water should run out the bottom of the pot. Alternatively, try watering from the bottom: Place a tray under the pot and fill it with water. The soil will absorb the water through the drainage hole(s). Repeat until no more water is absorbed, then dump out any excess water from the tray.
     
  • Don’t water too frequently! It may sound counterintuitive, but watering a plant with a small amount of water very frequently is worse than watering with a large amount infrequently. Frequent, shallow waterings encourage plants to develop weak, shallow roots, while infrequent, deep waterings encourage them to put down deeper, healthier roots. Most plants can tolerate—and actually benefit from—having a little break between deep waterings, so don’t be afraid to let the soil dry out a little bit between waterings.

Other key things to keep in mind are the size of the pot and the weather. Smaller pots will dry out a lot more quickly than larger pots, and will require more frequent waterings. Hot, sunny days are naturally more drying than cool, cloudy ones, so expect to water more during heat waves. Overall, pay attention to the speed at which your container soil dries out as well as how your plants react; you will soon get a sense for how often you need to water!

One way to keep container plants adequately cool and moist during hot summer days is to double-pot them: Place a small pot inside a larger one and fill the space between them with sphagnum moss or crumpled newspaper. When watering the plant, also soak the filler between the pots. Caution: be sure to check your double-potted plants often, as the extra layer can also be a nice spot for pests to hide!

Lettuce is excellent for container gardening.

Fertilizing Containers

Water flows through containers quickly, flushing nutrients out with it. This can be a good thing, as it will flush out any buildup of salts in the soil. However, this also means that it’s necessary to replenish those nutrients by feeding container plants more regularly than those grown in the ground.

In general, we recommend adding a slow-release fertilizer to your potting mix at the start of the gardening season. This can be done by either mixing it into your potting mix at planting, or by sprinkling fertilizer on top of the potting mix (i.e., “top-dressing”) right after planting. This will give your plants a good head start on growth. 

While they’re actively growing, flowering, and fruiting, use a liquid fertilizer to feed container plants at least twice a month, following the instructions on the label. It’s always a good idea to test your soil first, if possible, to gauge whether or not additional fertilizer is necessary. An occasional application of fish emulsion or compost will add trace elements to container soil as well.

To keep vegetable plants growing, feed them organic soil amendments, like liquid seaweed, fish emulsion, or manure tea. Read more about fertilizing container plants here!

Supporting Container Plants

While we won’t discourage you from chatting with your plants every now and then, in this case, we mean physical support. Support tall or climbing vegetables with trellises, stakes, netting, twine, or cages. Here’s how to build your own trellis or wooden supports

A teepee of bamboo stakes will hold pole beans or snap peas well. Cucumbers trained to climb up a nylon mesh fence will develop fruit that hang down and grow straight. To avoid damaging the plants or their roots, put supports in place at the time of planting. 

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Which Vegetables Grow Best in Containers?

When it comes to being grown in containers, some veggies do actually do better than others. Vegetables that can be easily transplanted are typically great candidates, as they will adjust easily to the potted environment. Transplants can be purchased from local nurseries or started at home.

In general, gravitate toward vegetable varieties that are considered “dwarf” or “container,” as they tend to stay smaller and are better suited to the container lifestyle. Check in your favorite seed catalogs; many list varieties of vegetables bred specifically for growing in containers. Among tomatoes, for example, choose “bush” or “determinate” varieties, as they will grow to a set height and won’t get unwieldy in a container.

Nasturtium FlowerAttractive in window boxes, edible flowers such as nasturtiums, calendula, and signet marigolds also add color to the plate!

To maximize space and thus your harvest, try planting low-growers and tall climbers together in the same container. The climbers will eagerly scramble up a trellis, while the small plants spread around their base. You’ll hardly need to weed because there won’t be any room for weeds to gain a foothold, and during the height of summer, some low-growers (leafy greens, for example) will thrive in the shade provided by the taller plants.

Mix quick-maturing plants, such as lettuce or radishes, with longer-growing ones, like tomatoes or broccoli. Learn more about growing salad greens in containers here!

Group plants with similar needs for sun and water, such as pole beans, radishes, and lettuce; cucumber, bush beans, and beets; tomatoes, basil, and onions; and peas and carrots

Check out our video for more information on which plants will thrive in your container garden:

Finally, here are some suggested vegetables for containers, along with recommended container sizes and varieties:

Beans, snap
Container: 5-gallon window box
Varieties: Bush ‘Blue Lake’, Bush ‘Romano’, ‘Tender Crop’

Broccoli
Container: 1 plant per 5 gallon pot, 3 plants per 15-gallon tub
Varieties: ‘DeCicco’, ‘Green Comet’

Carrots
Container: 5-gallon window box at least 12 inches deep
Varieties: ‘Danvers Half Long’, ‘Short ‘n Sweet’, ‘Tiny Sweet’

Cucumbers
Container: 1 plant per 1-gallon pot
Varieties: ‘Patio Pik’, ‘Pot Luck’, ‘Spacemaster’

Eggplant
Container: 1 plant per 5-gallon pot
Varieties: ‘Black Beauty’, ‘Ichiban’, ‘Slim Jim’

Lettuce
Container: 5-gallon window box
Varieties: ‘Ruby’, ‘Salad Bowl’

Onions
Container: 5-gallon window box
Varieties: ‘White Sweet Spanish’, ‘Yellow Sweet Spanish’

Peppers
Container: 1 plant per 3-gallon pot, 5 plants per 15-gallon tub
Varieties: ‘Cayenne’, ‘Long Red’, ‘Sweet Banana’, ‘Wonder’, ‘Yolo’

Radishes
Container: 5-gallon window box
Varieties: ‘Cherry Belle’, ‘Icicle’

Tomatoes
Container: 1 plant per 5-gallon pot
Varieties: ‘Early Girl’, ‘Patio’, ‘Small Fry’, ‘Sweet 100’, ‘Tiny Tim’

See our individual Vegetable Growing Guides for advice on growing other common vegetables.

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