Growing Potato

Solanum tuberosum : Solanaceae / the nightshade family

Jan F M A M J J A S O N Dec
P                 P P P

(Best months for growing Potato in New Zealand - cool/mountain regions)

  • P = Plant seed potatoes
  • Plant tuber. Best planted at soil temperatures between 10°C and 30°C. (Show °F/in)
  • Space plants: 30 - 40 cm apart
  • Harvest in 15-20 weeks. Dig carefully, avoid damaging the potatoes.
  • Compatible with (can grow beside): Peas, Beans, Brassicas, Sweetcorn, Broad Beans, Nasturtiums, Marigolds
  • Avoid growing close to: Cucumber, Pumpkin, Sunflowers, Tomatoes, Rosemary
  • An 'earthed-up' row
  • Potato flowers
  • Potato harvest

Seed potatoes

Potatoes sold in nurseries and produce stores are certified seed potatoes. Seed potatoes are small potatoes (usually fairly dried up and wrinkled) which are free of viruses and other diseases. You are more likely to get a good crop from certified seed potatoes.

Before planting expose seed potatoes to light to start shoots growing. Avoid direct sun as this can burn or par-cook the seed! Let the potatoes grow shoots up to 1 cm long - this can take a few weeks. In hot or dry climates sprout seed potatoes in seed trays of dampened potting mix.

Large seed tubers can be cut into pieces - just make sure each piece has at least one 'eye' or shoot. Let the cut pieces dry for a few days before planting or else they will probably start rotting.

Growing in the ground

Prepare the soil by digging in plenty of well-rotted animal manure or compost (don't use fresh manure as it will 'burn' plants). Dig a trench for the seed potatoes about 30 - 40 cm wide and 10 - 20 cm deep. Add a bit more compost/manure to the bottom of the trench and cover with some soil. Put seed potatoes 20 - 30 cm apart in the trench, shoot-side up. Fill in the trench to cover the potatoes.

As potato shoots start to appear, cover them up with soil from either side of the trench. 'Hill up' the crop this way a few times in the first four or five weeks of growth, which gives the potatoes an nice loose mound of soil in which to grow. Now leave the shoots to develop on to form leaves.

Keep potatoes well-watered. The soil should be damp enough to stick to your fingers.

No-dig and container growing - ideal for home gardens.

If you don't have a ton of space then no-dig and container growing both work well for home garden growing. Using container growing you can produce potatoes in any handy space, even on balconies.

No-dig

Make a no-dig bed of potatoes by layering newspapers (or flattened cardboard boxes) at least six layers thick on an area to be planted. Spread your seed potatoes on top of the newspapers about 30 cm apart, trying to get the shoots pointing upwards.

Cover the potatoes with layers of compost, weed-free straw, rotted animal manure, and other mulch materials, until the potatoes are covered by about 20 - 30 cm. Don't flatten the cover down.

Water well. As the potatoes start to grow through, add more layers of mulch material and keep watered. After about four weeks of growing through and covering up, let the potatoes grow on without covering. As the mulch breaks down keep adding more mulch to keep the tubers covered.

Container growing

Get a container at least 40 - 50 cm deep with holes in the bottom for drainage. Shrub-sized flower pots work well. An old wheelbarrow will work if holes are drilled in the bottom. You can also make a 'container' using loose bricks or chicken wire.

Put about 10 - 20 cm of mixed compost and potting mix in the bottom of the container and put your seed potatoes on top, about 30 cm apart. Cover with about 10 - 20 cm of compost mixed with mulch (straw, grass clippings. Water well.

As the potato shoots start to grow through, cover up with more compost and mulch mix and keep watered. Keep on covering up for about four weeks (but stop if you reach the top of the container!)

For both no-dig and container growing, keep the mulch well watered - wet enough to stick to your fingers but not sopping. If the potatoes dry out they will probably go scabby.

  • The longer potatoes grow, the bigger the tubers will be.
  • Don't grow potatoes in the same place as other solanaceae crops as they share many diseases - for example, don't grow potatoes to follow a tomato crop, or vice-versa.
  • You can start harvesting a few tubers as soon as they are big enough to eat - dig around under the plants and retrieve a few, and cover up the rest to keep growing.
  • Potatoes exposed to light will go green, so keep them covered up with straw and soil as they grow. Green potatoes are poisonous!
  • Potatoes accumulate cadmium and other heavy metals, so avoid fertilizers which contain these elements. Similarly, avoid using tyres as containers for growing potatoes as they can leach heavy metals.

Culinary hints - cooking and eating Potato

Peeled or unpeeled and scrubbed, potatoes can be boiled, baked, fried and roasted. - The only way they are not used is raw.

Keep in a pot of cold water after peeling, otherwise they will discolour.

Your comments and tips

16 Sep 08, Liz (New Zealand - temperate climate)
Steve, it would be best if you use the manure in making compost. It has a high nitrogen content which can damage plants if used direct.
26 Dec 08, Liz (New Zealand - temperate climate)
Johnny, as long as you have plenty of earth over the roots, your potatoes will be fine. The idea of covering them as they grow is to increase the number of potatoes on each plant.
02 May 09, Graechel (New Zealand - cool/mountain climate)
Re Tamworth potato. Be a devil and try whatever whenever. I use garbage bins suitably placed under tree and to get reasonable sun. Have had decent results from early planting and planted new crop today. It is amazing what will grow where conventional wisdom says "no way". Just don't leave out directly in the frost. Same with pineapple. Go on...have a go.
20 Jul 09, Sarah (New Zealand - cool/mountain climate)
Lisa, just leave your potatoes in the tyres for their entire growing season - i doubt they like being moved much since they are a root crop. you can increase the size of your crop by adding more tyres on top and filling with soil or potting mix, whatever you're currently using. leave a bit of green growth poking through though - say around 5cm or so. you could easily stack 4 or 5 tyres high.
20 Jul 09, Sarah (New Zealand - cool/mountain climate)
Ivan, if i remember rightly, your potatoes will be ready to be dug up once the leaves start turning yellow. for main crop potatoes - those that grow later in the season, you can wait until the tops die down completely before you dig, and this will help them to keep longer. if your spuds are earlys - growing early in the season, just start digging when the yellowing starts.
20 Jul 09, Sarah (New Zealand - cool/mountain climate)
Regarding the earlier comments about frost, i once flatted with a woman who forgot to harvest the container potatoes she was growing before the frosts arrived - and it can get down to -5 here, although -2 or -3 is more usual - and they came away again the next spring. i have no idea how the crop turned out, since i moved out before she dug them up, but it's worth bearing in mind that potatoes are the storage unit for the plant. if your plants get frosted, it just might mean that you have to wait until the next year for your crop.
27 Oct 09, nial (New Zealand - cool/mountain climate)
hiw long does it take a potato to grow
09 Jan 17, Stephanie Easthope (New Zealand - sub-tropical climate)
HI Nial It depends on the variety. You can get 'early' or 'main' crops. Early varieties take about 90 days from planting to harvest, although I find I can get a good crop in just 60 days, but I am in Auckland so the temp may help. Main crops can be 120-190 days depending on the variety. If you do a google search on seed potato varieties, there are some nz websites that have tables showing the different types and how long they take to grow. Steph
17 Jan 17, Sharron (New Zealand - sub-tropical climate)
Hi. Do you ever grow 'early' potatoes late? ie just use them whenever you would like a quick crop of potatoes? And what is your favourite for flavour? I'm growing Arran Banner now. I just got a community garden plot in December and I found a bag for peanuts. They are doing well, planted mid December, but they are forming flowers already. Cheers
10 May 10, Liz (New Zealand - temperate climate)
Click on the 'Vegetables and Herbs' tab and you will find sweet potato under S. Individual vegetables only show up on the home page calendar when they are due to be planted.
Showing 1 - 10 of 68 comments

Have a look at this site https://www.gardenersworld.com/how-to/grow-plants/how-to-earth-up-potatoes/

- Liz

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This planting guide is a general reference intended for home gardeners. We recommend that you take into account your local conditions in making planting decisions. GardenGrow is not a farming or commercial advisory service. For specific advice, please contact your local plant suppliers, gardening groups, or agricultural department. The information on this site is presented in good faith, but we take no responsibility as to the accuracy of the information provided.
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