Choosing to grow potatoes in containers can be a good option for those with limited growing space. But while this can be a good strategy, it is important to remember that container growing can be more demanding in terms of your time and energy than growing in the ground.
To grow potatoes in containers successfully, it is important to:
- Choose the right seed potatoes for your needs.
- Plant seed potatoes at the right time.
- Select the right containers.
- Fill your containers with a suitable growing medium.
- Place the containers in the appropriate position.
- Make sure you get the watering right.
- Ensure ongoing fertility for your potato plants throughout the season.
- Remain vigilant for pests and diseases.
If you take care of these basics then you will find that you will be more successful, and will be able to harvest more potatoes from your container garden.
Choosing Potatoes to Grow in Containers
When you grow potatoes in containers, it is important to consider especially carefully which potatoes you will grow.
In the UK we usually divide potatoes grown here into three categories:
- First earlies (which take around 10 weeks from planting to harvest).
- Second earlies (which take around 14 weeks from planting to harvest).
- Maincrop (which take around 20 weeks or longer from planting to harvest).
Generally speaking, you will usually find it easier to grow first or second early potatoes in containers, rather than a maincrop type. These earlier potatoes are harvested earlier, when smaller, and are good choices for small spaces.
Most potatoes can be grown successfully in suitable containers. But those harvested at an earlier stage will take up less space and be easier to handle when container growing.
I like ‘Swift’ ‘Maris Bard’ and ‘Charlotte’ for container growing. Though there are many different varieties of potato to consider. Choosing certified seed potatoes is usually the best policy.
When To Plant Potatoes in Containers
Potatoes are typically planted in spring, outdoors around the last frost date in your area, or undercover in a greenhouse or polytunnel a little earlier.
Though not strictly essential, chitting potatoes (placing them in a cool, bright location for sprouts to form) before planting can be a good idea. Start chitting 6-8 weeks before you plan to plant your potatoes in containers.
When growing in containers, you can also consider planting potatoes for Christmas in June or July, moving the containers under cover before the first frosts and taking care of them before harvesting for the festive season.
Choosing Containers for Growing Potatoes
As a general rule of thumb, it is best to allow 10 litres of capacity for each seed potato that you plant. So, in a container of 50 litres capacity, for example, you can plant 5 seed potatoes. This is just a rough guideline, but should help you begin to work out how many seed potatoes you can grow in the space available.
Many different containers can be used for growing potatoes. You could consider grow bags, solid pots or planters, or a range of planters or container made from reclaimed materials. If you reuse containers or materials, you might not need to buy any containers at all.
Filling Containers to Grow Potatoes
Unlike with growing other crops in containers, when you grow potatoes in containers, you will not fill the containers to the top all at once. Instead, it is best to fill just the bottom 15cm or so of the container(s) you have chosen.
Place the seed potatoes on top of the materials in the base of the container, and then add another 15cm or so of growing medium on top. After the shoots emerge from the top of this medium, you will gradually ‘earth up’ the potatoes as they grow.
You can use a multipurpose peat-free potting mix to fill your containers if you wish. But you can also fill the containers as you would build a compost heap or lasagna bed, using a range of organic materials.
I have found it beneficial to place a piece of turf upside down in the base of the container for potatoes. This helps with water retention, especially when growing in a more porous bag or container which loses water more quickly. I layer comfrey leaves or seaweed over this, then add the seed potatoes, and a layer of homemade potting mix (1/3 loam soil, 1/3 homemade compost, 1/3 leaf mould).
I continue to ‘earth up’ with this potting mix, mulching over the top of the container as I go with other leafy organic matter.
Where to Grow Potatoes in Containers
Remember, it is also important to make sure that you choose an appropriate position to grow potatoes in containers. A site in full sun will deliver the highest yields. And you should ideally choose a reasonably sheltered spot.
It is a good idea to think about placing potatoes in containers close to a water source, and perhaps close to the composting system and other resources to make your life easier.
It can also be a good idea to think about what else you might be growing in containers close by. Even when growing in separate containers, companion plants could help in providing optimal growing conditions, and reduce pest problems by attracting beneficial wildlife to your space.
Watering Potatoes in Containers
Remember, when you grow potatoes in containers rather than in the ground, they will typically need to be watered more frequently. Make sure that you water consistently, watering at the base of the plants rather than from above, for best results.
Don’t let the growing medium dry out during the growing season. Equally, however, make sure drainage is adequate, and the containers do not become waterlogged. This will also potentially cause problems and reduce your yield.
Ensuring Fertility When You Grow Potatoes in Containers
Mulching/ earthing up will not only allow new tubers to form from higher up on the stem. It will also ensure good slow release fertility through the growing season.
You can also give your potatoes a boost with organic liquid plant feeds during the season, to aid to strong growth and good tuber formation. A seaweed liquid feed or compost tea can be ideal, added when watering 3 times or so during the growing season.
Pests and Diseases to Look Out For When You Grow Potatoes in Containers
Look out for pests and disease, making sure that you monitor your potato plants carefully for any signs of a problem.
When you grow potatoes in containers, just as when you grow them in the ground, they can be plagued by certain pests and diseases. One of the most problematic diseases often found in UK gardens is late blight. Potato blight is a serious fungal disease which causes blackening of stems and foliage, and which can spread to the potato tubers themselves.
Water correctly, practice good garden hygiene, and remove any affected material as quickly and carefully as possible.
Harvesting Potatoes in Containers
If you take care over the basics mentioned above, you should find that you achieve pretty good yields and can harvest a good number of potatoes from each container. The variety, as well as the specifics of the location and growing conditions will determine how many potatoes you can expect to harvest.
The good thing about growing in containers is that harvesting is very easy. You can simply reach into the medium inside the container and feel around for a tuber. If it feels like it is a good size, you can then tip up the container, and allow the medium to fall out and reveal the harvest.
Share your own experiences with growing potatoes with us below.
Elizabeth Waddington is a writer and green living consultant living in Scotland. Permaculture and sustainability are at the heart of everything she does, from designing gardens and farms around the world, to inspiring and facilitating positive change for small companies and individuals.
She also works on her own property, where she grows fruit and vegetables, keeps chickens and is working on the eco-renovation of an old stone barn.
To get in touch, visit https://ewspconsultancy.com.