How to grow potatoes
New Zealand is a nation of potato lovers and spuds are an enduringly popular backyard crop. And no wonder when they are absolutely delicious stuffed, boiled, mashed, baked, roasted or fried, plus so easy and satisfying to grow.
SOW AND GROW
When to plant: July to March in warmer areas; September to February in cooler areas
Position: Full sun
Harvest: 9-21 weeks
Good for pots Good for beginners
GET STARTED
Always use certified seed potatoes, rather than just bunging in the tentacle-sprouting spuds at the bottom of your pantry. Seed potatoes are virus-free; while planting supermarket spuds is running the risk of introducing viruses or diseases into your plot.
In warmer regions you can buy seed spuds in winter, chit them for three or four weeks and then plant outside, but bear in mind that the leafy tops are frost tender.
Chitting just means allowing potatoes to sprout, which breaks their dormancy. It’s as simple as laying them out on newspaper or in egg cartons in awarm room, out of direct sunlight (so they don’t turn green) and waiting two or three weeks for the sprouts to appear.
STEP BY STEP
Dig out 15cm deep trenches. Run the rows from north to south, so the morning sun warms one side of the mound, and the afternoon sun the other. Add a layer of sheep pellets, wilted comfrey leaves and seaweed if you have them, and potato fertiliser along the bottom and lightly cover with soil, then put the potatoes on top and backfill (but first rub off all but the best four sprouts emerging from each tuber).
Earlies can be spaced about 30-40cm apart.
Main crops need to be spaced twice as far apart. You can mound up the soil immediately after planting and keep mounding as the potatoes grow, but that is extra work for you.
You can also just bury potatoes deeply when you plant.
Apart from that, just water them if it gets hot and dry. Mulch heavily as the weather warms up. If growing in pots, keep the containers themselves in part shade and the leafy tops in sun.
POTATO BASICS
Potatoes are usually grouped according to how long it takes to harvest them.
Early varieties have been bred for quick growth, taking about 10 weeks from planting to harvest and generally producing smaller yields. Main crop potatoes can take up to 20 weeks to fully mature. You can also grow the potatoes classed as taewa, or Māori potatoes (also known by some southern hapū as mahetau; called para-reka by Ngāti Porou of the East Coast; and peruperu by some northern tribes). These are the potato varieties grown in New Zealand prior to 1840.
POTATO GROWING TIPS
Good drainage is key for spuds. Prepare your soil by digging in organic matter well in advance but don’t use very fresh compost – if your compost is still generating heat it can burn the sprouts right off. Don’t add fresh manure or lime either, as spuds are more prone to potato scab if the soil pH is high.
It’s perfectly possible to grow potatoes in pots, though the yield will be lower. A 10l bucket (with drainage holes added) is fine for a single seed spud; or plant three or so in a large, deep 50l tub. Just put large pots in their final location before filling with growing mix.
STANDOUT VARIETIES
The best potatoes for pots are earlies such as ‘Rocket’ and ‘Swift’, which are quickgrowing. They give a decent number of waxy baby spuds 70-90 days after planting. For yield, it’s hard to beat ‘Liseta’. ‘Jersey Benne’ was not high yielding in the trial, but can be relied upon for great tasting tubers.
For a great early main, it’s hard to go past ‘Ilam Hardy’ which is adaptable enough for almost any situation. ‘Heather’ has smooth purple skin and awonderful taste. The New Zealand-bred ‘Karaka’ has excellent disease resistance.
The most popular main cropper is ‘Agria’ but Kiwi-bred ‘Summer Delight’ and ‘Summer Beauty’ are hard to beat for huge tubers and disease resistance. ‘Rua’ tastes great.
‘Purple Heart’ and ‘Purple Passion’ were both bred in New Zealand by scientists at Plant & Food Research who crossed taewa and modern potato cultivars. Or just grow the original taewa, yam-shaped purple ‘Urenika’. Other taewa worth trying: the waxy late variety ‘Huakaroro’ which has creamy skin and flesh; purple-skinned ‘Kowiniwini’; and yellow-fleshed ‘Ngautiutiu’ makes amazing hot chips. Heirloom spuds well worth hunting out include ‘Pink Fir Apple’ (delicious nutty flavour) and the buttery tasting ‘Ratte’.