There are several advantages to growing potatoes in containers rather than in the ground. Chief among them is it's easier to protect the plants from the critters that love to eat them, such as voles.
Container potatoes are also a fun project to do with kids. The plants grow fast and produce a good yield for the space required. Harvesting potatoes in a container is like a treasure hunt for kids: Just turn over the container, and let them sift through the soil for delicious rewards.
The only real disadvantage to growing potatoes in containers is you have to be more vigilant about watering, as container soil dries out faster than the ground. It is important to keep your soil moist but not waterlogged. If you check the soil moisture often and water deeply, you should have an abundant potato harvest.
When to Plant Potatoes in Containers
Timing for planting potatoes in containers is not much different from planting them in the ground. The general recommendation for in-ground potatoes is to plant them about two weeks after the last frost in your region. You may be able to bump the planting date forward a little when planting in containers, as the soil will warm up faster when exposed to the sun above the ground. However, be prepared to cover or bring your potato containers indoors if a late spring frost is predicted.
Before Getting Started
The process for growing potatoes in containers, grow bags, or the ground is a little different than it is for other vegetables. Potatoes are grown using a "hilling" technique in which the stems are gradually buried by heaping additional soil around the plant as it grows upward. The lower buried stems will develop additional root structures (potatoes) as the hill grows higher. For this reason, hilling is essential to getting the maximum harvest from each potato plant. Burying the stems also prevents the potatoes from being exposed to light, which makes them turn green.
When growing in containers, the hilling process looks a little different, but the basics are the same. When first planted, the seed potatoes are just barely covered with soil. As the plant grows, additional soil is heaped around the plant at regular intervals until the container is filled.
Equipment / Tools
- Garden trowel
- Seed potatoes
- Container (such as a large plastic bucket or grow bag)
- Potting soil
Prepare the Potting Soil
Use high-quality potting soil that is fast-draining, especially if you're using a plastic container. Organic soils are always a good choice as well.
Mix an organic, slow-release fertilizer into the potting soil. In addition to this up-front feeding, use a diluted liquid fertilizer, such as fish emulsion, every couple of weeks as your potatoes grow. Potatoes grown in containers need plenty of water, which can leach out nutrients from the soil. For this reason, plants that are grown in containers generally need more feeding than they do when growing in the ground.
One of the advantages of using an organic fertilizer is that it's much more forgiving if you accidentally pour too much. If you use too much conventional fertilizer, it can easily burn your plants.
Prepare the Seed Potatoes
There are a few theories on preparing seed potatoes for planting, and one is not necessarily better than the others. Some people wait for their potatoes to sprout and then plant them whole, while others just plant the seed potatoes immediately.
A more "approved" method by experienced gardeners is to cut the seed potatoes into pieces, each containing at least two eyes—growth nodes where shoots will appear. Wait for the cut surfaces to "callus over" by leaving them to sit for a couple of days before planting.
Position the Seed Potatoes
Place the container in full sun. Fill the container with about 4 to 6 inches of potting soil that has been blended with compost and fertilizer. Place the prepared seed potato pieces onto the potting mix with the eye buds facing up. The plants will grow fairly large, so make sure to give them some breathing room. For example, a container that is around 20 inches wide can handle about four small seed potatoes. It may not seem like much when you're planting, but the size of your potato harvest will surprise you.
Cover the Seed Potatoes
After you have positioned the seed potatoes, cover them with a couple of inches of prepared potting soil. Don’t get too enthusiastic here because you don’t want to plant them too deep. About 1 to 4 inches of soil is perfect. The cooler the climate, the less soil you should put on top.
Tend to the Growing Potatoes
Potatoes will not grow without sun and water. Make sure your container receives at least six to eight hours of sun a day. Water your newly planted potatoes well. Remember that one of the keys to growing potatoes is keeping your soil moist, but not wet.
Check the container at least once a day. To check the moisture level, stick your finger at least an inch into the soil (or up to your second knuckle). If it feels dry, it's time to water. If it’s very hot or windy, you may have to water your potato container gardens more than once a day.
Make sure to water deeply by waiting until water runs out the bottom. It is counterproductive just to water the surface of the soil. The nice thing about containers is you can visibly see when you've watered deeply enough. Simply watch for water to seep out of the container's bottom, and you'll know that they have a sufficient amount of water.
"Hill" the Potatoes
Once your potato plants have grown about 6 inches, you need to "hill" them. This is done by adding a couple of inches of prepared soil around your potato plants, covering the growing stems at the bottom. Be careful not to break the plants in the process. The goal is to bury about one-third of the plant, covering the lower leaves with soil. The buried stems will produce more potatoes, so this hilling procedure is essential to a good harvest.
You will need to repeat this hilling process a few more times as your plants grow. You can also stop once the soil reaches the top of your container. Potato plants grow incredibly fast, so keep an eye on them and don't let them get ahead of you.
Harvest the Potatoes
You can begin to harvest potatoes anytime after the plants have flowered. Carefully reach down into the soil of your container and pull out a few new potatoes at a time. Late in the season, as the plants turn yellow and die back, you can harvest all of the remaining potatoes at once. The easiest way to do this is to turn the container over, dumping it into a wheelbarrow or onto a tarp. You can then freely paw through the soil to find all of the potatoes.
You may find a few really tiny potatoes, but don't chuck them. Those can be some of the best and sweetest potatoes of the year, and they're perfect for tossing whole into a stew.
Potatoes with green skins contain a bitter chemical known as solanine, which is mildly toxic. Discard potatoes that have green skins, or cut away those portions before eating them.
Storing Harvested Potatoes
Cook your potatoes right away, or store them for later use. For storage, begin by brushing off the dirt then let them dry for a couple of days. They're best stored in baskets or paper bags that allow them to breathe.
Working With Potatoes
It is possible to grow potatoes in any large container, from large pots or nursery containers to big garbage cans. Even trash bags or stacks of tires will do, though you have to be cautious about these because they can get very hot in the sun.
Smart Pots are a fantastic option for potatoes as well. These growing containers are lightweight, environmentally friendly, and made of fabric, so your potatoes get air as they grow. They also have great natural drainage, ensuring your potatoes will never sit in water and rot.
Whatever you use for a container, make sure it has good drainage. If it doesn’t come with drainage, add some by creating holes in the bottom.