How To Grow Sweet Potatoes In Pots

Growing sweet potatoes in pots is a brilliant way to enjoy this delicious and healthy crop, even if you only have a small garden, patio, or balcony. With the right container and a bit of warmth, you can produce a satisfying harvest at home.

Growing Sweet Potatoes in the UK

I think one of the best ways to asses the needs of your plants is to look at the conditions they grow in naturally. Sweet potatoes are believed to have originated in Central or South America, so they thrive in warm, sunny climates, which is pretty different from the UK!

This tells us three things that sweet potatoes want: warmth, sun & moisture. Think more hot and humid than hot and dry.

While the UK climate isn’t naturally ideal for sweet potatoes, it’s entirely possible to grow them successfully here, especially if you use containers and choose the right varieties. Some sweet potatoes do better in our slightly less tropical weather.

Because they like consistent warmth, pots are a great choice in the UK. They can be moved to sunny spots or brought into greenhouses or conservatories during cooler spells. As long as they’re kept warm and frost-free, sweet potatoes will grow well right through to early autumn.

In cooler regions of the UK, and this is what I do in Lancashire, grow them in a greenhouse at all times. Sweet potatoes really like warmth; they do best in temperatures above 21 °C.

Choosing the Right Container

Sweet potatoes need plenty of space to develop their tasty tubers, so choose a large container. Aim for one that’s at least 40cm deep and 40–50cm wide. Good drainage is essential, so make sure your pot has large holes at the base.

Fabric grow bags also work well, allowing air to reach the roots and help prevent waterlogging. Wherever you place your container, ensure it gets full sun for as much of the day as possible — sweet potatoes love warmth and light.

Preparing the Soil

Use light, free-draining compost to give your sweet potatoes the best chance. A mix of multi-purpose compost and a little extra perlite works well. This prevents the soil from becoming compacted and helps tubers to grow easily.

I like to use a good-quality compost, Moorland Gold, for these pots, and I also mix in a little 6x chicken manure.

Avoid too much instant nitrogen, as it can encourage lots of foliage at the expense of root development. A slow-release fertiliser is ideal.

Planting and Growing On

Sweet potatoes are grown from 'slips', which are shoots that sprout from a mature tuber. You can buy slips online or grow your own at home by suspending a sweet potato half-submerged in water until it starts to sprout. (If doing this, ensure the sweet potato is a variety suitable for growing in the UK!)

Once your slips are around 10–15cm long and have some roots, they’re ready to be planted. Plant one per container and plant deeply so that only the top few leaves show above the compost. Water them in well and keep the compost consistently moist but not soggy.

As they grow, your plants will produce long, vine-like stems. You can let these trail over the edges of your pot or support them gently with canes or a trellis.

Harvesting Your Crop

Sweet potatoes are usually ready to harvest around 4–5 months after planting. In the UK, this means lifting them in September or October, before the first frosts arrive. Yellowing leaves are a good sign that your crop is nearly ready.

To harvest, tip out the entire contents of the pot and gently search through the soil for your tubers. They can be surprisingly large and often hide deep in the compost, so take care not to damage them.

After harvesting, you are not done; sweet potatoes actually need to "cure" before you get that staple sweetness. To cure, leave the tubers in a warm, dry place for about 7–10 days. This helps to toughen the skins and sweeten the flavour. Once cured, store them somewhere cool and dry, but not in the fridge.

Planting Step-by-Step