Toggle navigation

Potato and Sweet Potato

Photo -

Spring is a good time to start a patch of both regular and sweet potatoes. 

Linda Ross tells how to plan for buried treasures.


Plan on planting 20 potatoes per person, as one seed potato yields between 10-50 potatoes, depending on climate and rainfall: the higher the rainfall the more spuds. The first step to home-grown potatoes is called chitting. Lay the potatoes on a large tray in a dark warm spot to sprout with two or three growing points. Choose a sunny position and add plenty of blood and bone, organic matter, compost and a sprinkle of potash to soil and dig in well. Dig several long trenches 40cm deep. Place the potatoes in the bottom of the trench 20-30cm apart with the sprouts facing up. Place 10cm of loosened soil over the top. As the potatoes grow, hill up the soil around them to exclude light. This will increase the number of potatoes produced and ensure the potatoes remain under the earth. They will go green if they come in contact with the sun and green potatoes can’t be eaten. Potatoes are a hungry and thirsty crop so feed liberally with fortnightly liquid feeds and weekly watering.


Harvest time

Spring planting should produce delicious ‘new potatoes’ for Christmas. First the plants will flower and then the leaves will start to die down in summer. Potatoes can then be dug as needed. It’s important label the patch, otherwise with the leaves gone, you’ll be digging in a lucky dip. Forgotten potatoes left in the ground will sprout again in late summer, growing quite a bit larger than the first crop. They can be dug as needed through winter, though in wet winters they are best dug up and stored in paper bags or hessian sacks to prevent rotting. Keep away from rodents.


Photo -


Sweet potato

The question is not so much how to grow sweet potatoes but rather how to stop sweet potato from taking over the garden! Sweet potato is a very invasive creeper so, like pumpkin, it needs its own bed. Or, because it does make such a wonderful, quick-growing ground cover; it can used as a living mulch to keep weeds down over a large area. It suffers fewer disease problems than normal potatoes, and requires little water and fertiliser.

Plant sweet potatoes after the threat of frost has passed. The quickest way is to use cuttings from a friend. Remove all the leaves from 30 cm piece of runner, except for the tiny leaves at the very tip. Plant the runner under the soil with only the leaves of the tip above ground. The cuttings will root at every leave node under the ground. A sweet potato also grows roots from every leave node that develops as it grows: you can see why it can take over!

If you can't get hold of cuttings you can start growing sweet potatoes by planting whole shop-bought tubers. Place them on the ground, cover them with soil, and keep them moist. The tubers will develop shoots, called slips. Slips can be snipped or pulled off and planted out when they are about 15 cm in size; plant one per person. The original root will continue to produce more slips. All they require to grow well is regular water and monthly liquid feed.


Harvest time

Sweet potato will take around six months to mature, longer in cooler weather. You’ll know they are ready when the stem thickens. You can also feel for lumps under the surface and start digging.


Where to buy

Virus-free potatoes are available from mail order companies such as Greenpatch Seeds, Diggers Club, your local nursery or hardware store (look for Mr Fothergill’s range). 


Text: Linda Ross

About this article

Author: Linda Ross