Sweet potato can be planted all year round in the tropical regions of Australia.
It is grown from either “slips” which are basically seedlings which grow out of the tuber (which is the part you use in cooking) or from runners. To get your sweet potato to grow slips, it can either be placed in soil or water. If using soil, ensure it remains moist and if using water, remember to top it up every few days.
Keep an eye on the tubers while waiting for them to sprout – if any soft spots develop, just cut them off with a sharp knife. The rest of the tuber will be fine.
After a couple of weeks, your tuber will start sprouting vines and roots. Once the slips have developed, you can separate them and plant them out into the garden. Slips should be planted in their final location.
Runners are even easier, but you need to have access to a sweet potato vine. Chop off lengths about 30cm long, remove all the leaves except for a couple at the tip, and then cover the entire runner. Each leaf node will put down roots and you will end up with more sweet potato than you know what to do with.
Keep in mind that the sweet potato vine is a ground cover and will take up a fair bit of space so don’t plant it too close to anything which can’t handle a little competition. In true permaculture fashion, the problem is also the solution – sweet potato is an excellent living mulch as it is thick enough to stop most unwanted plants getting a foothold in your garden.
You can start harvesting your sweet potatoes about 3 months after you plant them. You can either harvest them all at once or you can just bandicoot up what you need and leave the rest to continue growing.
After harvest, place your sweet potatoes somewhere cool and dry for a couple of weeks to let the starches convert into sugars. The skins will also toughen up a bit during this period which means they will store better.