How to Grow Seed Potatoes
One of the great Kiwi Christmas traditions is new potatoes on Christmas day. Not only are they high in fibre and vitamin Band c, they are higher in iron and protein than any other vegetable. They are an easy crop to grow and there are plenty of varieties to suit all occasions. Follow our guide to grow a bumper crop of spuds for Christmas and beyond.
Buy certified seed potatoes! Potatoes from the supermarket will grow but are not certified as being disease free. This is important as diseases can also affect not only your potato crop but also tomato, pepper and eggplant crops too. Buying certified diseases free tubers are a guaranteed way of getting a crop.
Potatoes grown this way are essentially a clone and are a known quantity when it comes to harvest time. The potato you are growing will resemble the one that you paid for.
Chit your potatoes
- Chitting your potatoes is simply another way of saying sprouting them. Lay out your potatoes in a dry and airy place, out of direct sunlight but with indirect light.
- Avoid putting them in a dark cupboard as this will produce weak sprouts that break easily.
- It is dependent on temperature and type of potato before they are ready to plant. Once the sprouts are between 40 to 80mm long they are good to go.
- It is not essential to chit your potatoes but it greatly reduces the risk of your potatoes rotting in the ground and it moves things along quicker.
- Remove all the sprouts apart from the best four from each tuber. Start chitting about a month before planning to plant them.
Site selection and preparation
- Potatoes love a warm and sunny spot with free draining soil that is high in organic material. Compost is a great addition to your soil before planting them, blend in well.
- Potatoes really dislike heavy and wet soils so add Clay Breaker Gypsum as well as compost to break up any clay soils.
- Dig a trench that is about 15cm deep and plant your tubers about 40cm apart. As the shoots emerge, mound up the soil around them. Tubers develop from buried stems and increasing your buried stems will increase your potato yield.
Growing your potatoes
- Potatoes are gross feeders so feeding them in key growth periods is important. A great all round fertiliser is Intelligro’s Nitrophoska Extra, it has all the nutrients to keep your potato going or choose Intelligro's own Potato Fertiliser blend.
- Watering is important with potatoes. Keep the soil moist but not water logged. This is important at flowering time and when the baby potatoes are forming. Water early in the day to minimise fungal risks.
- Keep an eye on any pests and diseases that may affect your potatoes. Try covering your crop with some netting to keep out the potato-tomato psyllid which arrived in New Zealand in 2006.
Harvesting your potatoes
- Most potatoes can be harvested when the plants start to flower, however check the instructions that came with your seed potatoes.
- Harvest before the flowers form fruit to make sure that they put their energy into tuber production.
- Using a fork or even your hands if the soil is soft enough, dig around the outside of the mound and gently start lifting the plants and potatoes from the ground. Try to avoid digging into the potatoes.
- Plant different varieties to get a continuous supply over the growing season. Record when you plant them so that you can go back and check 60-100 days after planting to see if there are tubers.
- Always check the growing instructions as some early varieties are ready for harvest before others.