Make sure your containers have sufficient room to grow sweet potatoes. Your plant will probably have enough roots and tubers to fully occupy a space 18 inches by 18 inches. Ideally, your container should be two feet square or 2.5 feet in diameter. Wood, pottery and plastic all make good containers – it will be heavy, so make sure it’s sturdy. You can also use grow bags.
Sweet potatoes that grow long vines and great big tubers are unlikely to do as well in a container as the smaller varieties. Here are some possibilities, including ornamental types that don’t produce tubers and are grown for their foliage:
- Blackie – a purple vine trailing up to six feet, ornamental sweet potato vine.
- Margarita – chartreuse, only one to three feet, ornamental sweet potato vine.
- Sweet Caroline – five foot vines, smaller tubers than most.
- Sweet Caroline Bronze – up to five feet, coppery-red, ornamental sweet potato vine.
The Right Soil
In the garden, sweet potatoes need fertile soil but usually don’t need fertilizer. They are actually known for growing in poor soil. In containers, the primary key is soil that drains well. Commercial potting soil or potting soil mixed half and half with good garden soil is suitable. Place a layer of gravel in the bottom of the container to promote better drainage.
Growing in Containers
When you confine a sweet potato to a container, you must pay extra attention to watering. Unglazed pots and grow bags transpire easily and in hot, windy areas, may lose water quickly. However, wet soil means root rot, so make sure your containers have bottom drainage. Keep the soil just damp. Make sure your containers are in full sun. Use a balanced liquid fertilizer or manure or compost tea at least once a month.
Most sweet potatoes need about 100 to 120 days to develop tubers. You’ll want to leave them in the pots as long as possible for maximum size. Once the vines and leaves begin to yellow with the approach of cooler weather, it’s time to harvest. Tip the container out onto a tarp or patio and remove the tubers. Cure them for about 10 days in a warm, well-ventilated room before storage.
Sweet Potatoes Indoors
You can grow sweet potato vines indoors, although you are unlikely to harvest tubers unless indoors means in a greenhouse. You can simply grow the potato in a container of water or grow the plant in a pot. Make sure you choose the sunniest window and warmest room. Change the water about once a week.