A Potato Plant from the Ground Up

where your garden potato grows from

Potato plants are amazing - a gift to gardeners and a staple food crop.

You'll find information here about:
how potatoes grow, the conditions they enjoy, the potato seasons and some notes on potato plant pests and diseases.
More information on growing potatoes is here.

The Mysterious Underworld of Potato Plants

Seed Potato, Chitting, Sprouting, Stolons, Stem Tubers, Potatoes
It all starts with the potato tuber that you eat or buy as a seed potato to plant.

Note: I explain why you shouldn't plant tubers you buy for eating.

Take a look at one and you'll see (unlike a root) that the surface contains dormant buds or 'potato eyes'. They are more or less concentrated at one end, the 'rose end', and spaced in a spiral arrangement around the tuber.

The potato tuber is actually an underground stem - the buds you see, shoot up into stems and leaves. Tubers of this type are collectively known as stem tubers. They are produced from underground side stems as storage organs for your potato plant.

When the temperature rises the potato tuber's buds begin to grow out. Gardeners describe this as chitting when they place the tubers in the light. Chitting sets up early and second early potatoes to take maximum advantage of lengthening days and produce embryo potato tubers.

During chitting the shoots, or potato eyes, swell up into fat knob like structures. These carry the leaf shoots. When one or more firm thick stems have extended about 1inch long the tuber is planted in the ground or a container.

But if some varieties are left a little longer you can also observe the stolens growing from the base and carrying small branches (pictured above). You may see embryo tubers which eventually swell up into the new potatoe tubers.

Container growing should aim to preserve these young stolons in good condition so they continue to grow and become available to enlarge into potatoes after you've pick your first spuds.

If you prefer to get a lesser number of larger sized potatoes then you're best reducing the number of shoots before you plant.

The picture on the right shows a harvested potato plant. You can see the thick blanched stems that supported the green leaves above ground. Side stems (stolons) coming off these carry the potato tubers that you pick to eat. You can also see fibrous roots that absorb food and water for the plant and potatoes to grow.

Growing Conditions

Preferring a cool climate, potato plants grow best in a nutrient rich, moisture retentive and well-drained soil. They also prefer more acid soils with an ideal ph of 5.5.

A sandy loam is said to be best, but peaty organic soils, and alluvial soil will also do. Gardeners may grow potatoes on lighter clay loams by adding plenty of bulk organic matter to open up the soil. Chalk is a problem to potato gardeners as lime causes scab. Try a raised bed with organic enriched loam or peaty compost, and of course scab resistant varieties.

You can chit the potato tuber in a light room before you plant it. The potato plants begin to grow in garden soil at around 8 - 10^oC - 48^oF. Don't forget you can also plant early potatoes in containers temporarily located in a greenhouse or conservatory before going outside. The plants should be covered over with fleece before any frost. Frost damages the shoots setting the plants back, but they will recover.

It is important to earth up around the potato shoots to help the embryo potato tubers grow. Also the potato tubers themselves become green if exposed to light. This green colour is chlorophyll but it causes an increase in a poisonous compound called Solanin that can make you feel ill.

Potato Season

The growing potato plant eventually produces flowers (although some varieities may not) and the potato tubers enlarge. New potatoes can be picked a couple at a time just a few weeks after flowering commences. When the foliage begins to yellow and die down the crop can be harvested whole. Check important details on my page harvesting potatoes.

Depending on the time the potato plants take to crop, varieties are recognised as First Early, Second Early and Maincrop. The main limitation is in giving enough time to crop before temperature and day length are prohibitive.

All potatoes can be planted about 2 weeks before the last frost, maincrop may be left until April or early May. 'Maincrop' can produce a higher yield of larger potatoes some suitable for baking and most suitable for storing into the new year.

First Early potatoes crop in 60-110 days. These can be harvested from about the longest day and into July. First Early are ideal for growing in containers and pots as they produce a smaller crop. They are often used as salad potatoes.

So for the earliest summer potato crop 'Earlies' should be put out for chitting from mid January, as this may take 6 weeks before they are ready to plant.

Second Early potatoes crop in 90 to 120 days and they can give you a larger crop of new potatoes to eat fresh or store.

When planted early 'First' and 'Second Early' potatoes can miss out on late potato blight disease. If you especially like one these varieties you can plant them later too.

Maincrop potatoes are ready in 120 - 140 days. Although they take longer to mature they are worth waiting for. You need a bit more room to grow them in the garden.

Late Season potatoes can also be planted in August for harvesting at Christmas. This provides fresh potatoes for Christmas and New Year roast dinners.

Relationship and Origin of the Potato Plant

Potato plants originate in the Andes of Peru and Bolivia where many different kinds are grown by villagers.

The Spanish Conquistadors brought them back to Europe, but Sir Walter Raleigh is accredited with introducing them to England around 1586. Quoting a report written by Thomas Hariot, Raleigh's second in command (left in charge of settlers who were rescued by Francis Drake), the potato is described as:

"a kind of roots of round forme, some of the bignes of walnuts, some far greater, which are found in moist & marish grounds growing many together one by another in ropes, or as thogh they were fastnened with a string".

It seems that these first potatoes were brought back among plant specimens and planted in Raleigh's estate in Ireland. But it took sometime for them to become popular.

Nowadays we find potato plants have become one of world's major crops ranking alongside cereals. Through plant breeding, the tubers of modern potato plants have been changed into substantial sizes ranging from rounds to oblongs, of varied skin textures, with nutritious flesh easy to cook and adapt to many tastes and dishes.

Potatoes From The Garden Make Real Healthy Eating

It was once told that potatoes are fattening. Not so! Sometimes people refer to a 'couch potato' to describe people who laze around watching TV. - Nothing could be further from the truth.

Your potato contains no fat and no cholesterol for you to worry about.

it provides nearly half of your the daily vitamin C (rice & pasta have none),

nearly twice the amount of potassium as a banana,

plus fiber and vitamin B1 and B6.

only take care not to eat too many fried spuds - Jacket potatoes are perhaps the healthiest way to cook them, but mash is great too and you can also make mash by scooping out a crisp baked potato.

And of course no one can call you a 'couch potato' when you get out into the garden and grow them.

Potato Plant Relationships

Potato plants and tomato plants are closely related. They both belong to the same plant family Solanaceae along with Aubergine (Egg Plant), Capsicum (Sweet Peppers, Chili Peppers, and Paprika), Nicotiana (Tobacco), Petunia, Belladonna (Deadly Nightshade) and others.

You'll notice that potato plant leaves are somewhat similar to their cousin's tomato leaves. It's best not to grow potatoes next to one of it's relatives or vice versa, as this increases the chances of passing on disease such as the fungal and viral infections that have adapted to infect this plant family.

Plants of the potato family contain alkaloids which are poisonsous. Never eat or make tea from the leaves of these plants as this is where most of the Solanin is found. Simply keep potatoes in the dark to prevent them going green.

It's best to discard green potatoes. With a large spud and just a bit of green I'm personally tempted to remove any green and a good bit more before cooking or eating the potato. I think the main problem is that it can spoil the taste, but some people and children may be more sensitive to the toxin. Check here on how to avoid growing green potatoes.

Potato Plant Diseases and Pests

Undoubtedly the poisons in leaves help the plant resist attacks from pests such as insects.

Blight however is an important fungal infection. Early season blight caused by Alternaria is not so bad, with black spots surrounded by yellow patches that can turn the leaves brown.

However, the later season blight can be devasting especially as it causes rot in the potato tubers when in store. Water soaked areas looking like a faintly washed out green appear on the infected leaves along with yellow and black patches. Fungal spores wash off the leaves into the soil where they infect the potato tubers. Sometimes crops can be destroyed overnight. Affected potato tubers looked bruised and will rot to a smelly mush.

Potato blight spreads rapidly when leaves are wet, the humidity is over 75%, temperature above 10^oC. I believe it is important for organic gardeners to play their part in stopping the disease spreading.

This can be done by growing resistant varieties, keeping an eye on the weather and cutting away affected folliage quickly. Certainly burn all affected material and wash containers and bags. Unfortunately I can't recommend the copper based Bordeaux Mixture even though it is permitted. It appears to have troublesome effects on human health. It's lime content is not so good for potatoes either.

Potato plant pests of note include: Eelworm and the famed Colorado Beetle. These can feed equally well on Aubergines (Egg Plant). Slugs can also be damaging.

Remember to grow potato plants in different soil beds year on year and put them on the longest rotation that you can manage.
Also keep them well apart from tomatoes, egg plant and the like.

Growing potato plants in bags and containers helps to isolate them from soil pests and gives the garden soil longer to rest after a previous crop.

I usually leave several years between substantial maincrops and make do with smaller potato beds and potato bins in the meantime.

Check these links.

Next   >  About Growing Potatoes  - match your garden and potato eating needs to methods of growing them in your garden.

The Garden Seat - books by experts to help you grow potatoes

Wouldn't it be nice to sit down and watch your soil being turned over ready for planting. I can't quite manage that but the cultivating tool on this link is the next best thing for making easy work of it - then you'll have more time.

My Wheelbarrow

Find top quality seed potato suppliers for growing potatoes at home.

  Gardening Catalogs - U.S.A.

  Power Plant Pro & Seeds - for Canadian Gardeners

  Gardening Catalogues - U.K.

Garden Gate

The main plot for information on growing organic potatoes is on this link including:- potato growing methods to suite your garden needs, chitting potatoes, planting potatoes, hilling or earthing up, potato bags, tubs and potato barrels, no-dig raised bed potatoes, certified seed potatoes, potato varieties, harvesting and storing potatoes. ... ... ...

Find organic gardening suppliers in your country here .

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ALSO on The Organic Gardener:-
Find organic fertilizers and bagged manures and how to use them in an organic garden.

My Neighbour's Garden Plots

Home Of The Organic Gardener

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