Gardening – In praise of the humble spud

One crop our garden is almost never without is the humble spud. Even in winter we have potatoes growing in large planter bags leaning up against the greenhouse. Although potatoes have had a bad rap over the years, as the carbohydrate-rich tubers don’t mash well with current food fads, in fact, they are a powerhouse of nutrients, particularly with the skins left on, and are an exceptionally economical food source. There are many varieties of potato and just as many ways of growing them, but irrespective of which variety you plant and what growing technique you use, there are some basic rules of growing to achieve a productive crop.

Firstly, potatoes need to be grown in full sun. Any shade will result in smaller tubers and less of them, plus an increase in diseases. Secondly, in our region, the growing season is pretty much year-round, as the growing tops of late planted crops can tolerate a light frost. It’s best to plant after the coldest part of the winter is over, though as you won’t get any growth until the soil temperature has reached 7.5°C. A good indicator is when weeds start to grow!

Most roots form near the base of the stem above the seed potato and push downwards into the soil.

The roots need to grow down into a light, well-drained but moisture-retentive soil that is slightly acid (pH 5.8-6.5). Potatoes grown in soils with higher pH are more prone to the bacterial disease potato scab. Potatoes love compost, but too much organic material around the newly forming tubers can increase the chances of potato scab, so make sure to mix the organic matter into the soil below the seed potato, where it will feed the roots.

The new tubers will form on the stem between the seed potato and the soil surface. This upper part of the plant can grow in just about anything; the important point is to mound extra soil or other material, such as straw, around the plants as they grow every 2-3 weeks until the plants begin to flower, to increase the length of the stem and therefore the number of tubers that develop.

Potatoes produce their best crops when they are kept well-watered throughout the growing season, but especially during and immediately after flowering, when the plant is creating new tubers. Water early in the day so the foliage has time to dry completely before evening to avoid diseases. When the leaves turn yellow, stop watering to allow the tubers to mature before harvesting.

Harvesting for new baby potatoes can start two to three weeks after the plants have finished flowering, but for larger tubers, wait until all the foliage has died off. If you’re a little impatient, tubers can be “tickled” (or “bandicooted” if you’re an Aussie) by gently loosening the soil, reaching under the plant, and removing the largest tubers, leaving the smaller ones to continue growing. Happy days!