Food Garden · How to Grow · Vegetable

Potato: How To Grow – Vegetable of the Month

Potato stats/requirements at a glance

Ease of Raising:5/5 – Very easy, plant & leave 
Water:3/5 – Moderate, every second day
Sun:3/5 – Full sun, can grow in shade
Training:2/5 – Needs some (spindly branches)
Fertilise/Feeding:3/5 – Moderate (monthly)
Time to Harvest:3/5 – Moderate (small potatoes at 2 months and larger 3-4 months)
Frost Hardiness:3/4 – Mildly Hardy (can’t take severe frost)
Most Problematic Nemesis:Dust Beetles
Container Plant:Yes – especially in small gardens
Solanum tubersonum, Potato, Botanical Print, Botanical Das Pfansenreich, 1900, Kurt Stubers Online Library
Solanum tubersonum
Potato Botanical Print
Botanical Das Pfansenreich
Kurt Stubers Online Library

Quick intro

If I could eat potato fries every day without consequences around my hips I would. Store bought potatoes are no match for ones fresh from the garden. Again, there are many varieties to choose from, traditional white potatoes, red, yellow and even blue! The red and yellow potatoes have superior flavour to the traditional white ones and should be more resistant to pest and disease as there are more closely related to wild potato species. There is no end to what can be done to a potato- from baked, steamed, fried, roasted, boiled, mashed and smashed.


Potatoes have and remain an important food crop worldwide. It comes fourth in food production after wheat, maize and rice. Remains of wild potatoes from 11 000 BC were found in southern Chile. Sixteenth-century accounts describe the use of potato tubers by Indians in the Andes of South America and were brought to Europe, likely by the Spanish conquerors, but the details are unclear. And then there was the infamous Irish potato famine during 1845-1846 as potatoes was a main stable for the Irish during this time and their potato crop was destroyed by a fungus (Phytophthora infestans – an Oomycete fungus, I did my Honours seminar on oomycetes). The crop the Irish had was susceptible due to it being an inbred cultivar. The famine led to mass emigration of the Irish population to England and America.

Potatoes, Solanum tubersonum, varieties, red, white, purple, pink
Potato varieties
by TotumRevolutum

Science Stuff

The humble potato belongs to a plant family already widely covered in my blog, the Solanaceae Family, which includes tomatoes, peppers, eggplants and the deadly nightshade… Its scientific name is Solanum tuberosum. Again, this plant, like the most of the Solanaceae family has toxic solanines (aka glycoalkaloids) in the green parts of the plant. So do not eat green tubers! If your potato has a green spot, you can cut it out before eating – tried it myself, the toxin seems to be restricted to the green spot – just make sure you get every green bit.

Growing Potatoes

The big thing about potatoes is getting it to form lots of tubers. All the books recommend ‘earthing up’ or ‘hilling’ the soil around the base of the potato. Earthing up encourages new tubers along the length of the underground stem and also protects the tubers from sunlight. Sunlight makes tubers go green and then they are poisonous! There are various ways to accomplish earthing up.

1 potato spud) You can dig about 30cm down into the soil in the garden, plant the potato their and leave it 5cm of soil in the hole. As it grows up you can earth up the 30cm of soil until you get to level ground and then earth up another 30-60cm of soil thereafter.

2 potato spud) You can use a barrel (planting the tuber in 30cm of soil at the bottom) and earth up until you reach the top of the barrel. There are specially designed potato barrels that you can purchase or you can use a regular black plastic barrel.

Potatoes, Solanum tubersonum, barrel
Potato Barrel

3 potato spud) You can use a potato grow-bag. Some have special pockets cut into the sides for easy access to potato tubers …

4 potato spud) I use upside-down plastic pots with the bottom cut out. As the first option takes up a lot of space, so I compact the soil into a smaller space (still enough for potato tubers). I used this method when I could not buy or import potato barrels or bags, as they are either too expensive or they cannot be imported.

Potatoes, Solanum tubersonum, pot plants

5 potato spud) The Family, Food + Garden website has a few more ideas on growing potatoes in boxes – you can check it out here.

I tried had relative success with the plastic barrels; I think that is due to the fact that you cannot get much nutrients (or earthworms) in the barrel with the potatoes. So I moved to the garden and use upside-down plastic pots – this works fairly well, depending I think mostly on the potato plant itself… and some bugs helping themselves to the potatoes… I can get anything from 0.4-1kg of potatoes from a plant. I read that you should get up to 2kg worth of potatoes from a plant!

Potatoes are grown from ‘seed potatoes’, which are small potatoes that are left to grow eyes (sprouts). You can also leave really small potatoes (not worth the effort of cooking and eating, usually the size of cherry tomatoes) in a warm windowsill. The seed potatoes are left in a bowl with plastic wrapped around in the sunny windowsill until they have sprouts that are 2-5cm (some of them will go green due to sun exposure). You can cut out the sprouts, with a little bit of potato flesh as a nutrient reserve, and plant that in the ground. So this way you can get multiple potato plant from one seed potato – just remember that you are effectively creating a crop based on clones (all plants from the same parent) as no sexual reproduction occurred, since tuber are produced vegetatively and you may get problems with resistance later on – but this will probably be >10 generations later, so as long as you replace the potatoes with some new ones every five years or so, you should be ok… alternatively purchase seed potatoes from the local nursery.

Otherwise you can use potato seeds – but these are more miss than hit. I was astounded to find that my potato plants produced fruits! Potato fruits! I first thought a gall mite or something got into my plants, but I checked on the internet and in my new oxford book of food plants and found that potatoes do produce fruits. Which I suppose makes sense, since technically all flowering plants will produce a fruit of some sort, it is just that I never heard of or saw a potato fruit before. The fruits are green and are therefore poisonous – so do not eat them! If you have multiple potato plants, they will pollinate each other without much intervention from your side. The fruits are very similar to tomatoes and are jam-packed with seeds. Under the seed collection and storage section I will go into more detail on the seeds themselves.

Potatoes, Solanum tubersonum, fruit, green
Potato fruits

Other potato tips

Them nasty maize beetle larvae! And the adults are cannibals, I was appalled to witness!

Black Maize Beetle, Heteronychus arator, potato pest
Black Maize Beetle
Heteronychus arator

Ok, so the maize beetles belong to the same family as chafers and dung beetles – Scarabaeidae. The photos I post of their larvae are similar to dung beetles, so make sure you don’t wipe out the dung beetle larvae as they are your friends. It is safe to say that if you find larvae like this with your potatoes that they are maize beetles.

There isn’t much you can do about them. When I dig up my potatoes I find lots of larvae and adults and holes in my potato tubes – usually chuck them nasties in the same pot – this was where I saw the adults eating the larvae- the horror! So I thought it deserving that they all go to the chickens – the chickens thought of me as a super chicken friend afterwards (the grubs get really big and juicy in chicken terms). Besides the chickens also require protein in their diet and at least I get some use out of the nasty things.

Maize beetle vs. Dung beetle, antennae, potato pest, maize beetle, dung beetle, Heteronychus arator, Scarabaeus
Black Maize Beetle (Heteronychus arator) vs. Dung Beetle (Scarabaeus spp.)

The maize beetles are cosmopolitans and are found in Africa, Australia and South America. However many potato growers will have problems with weevils, which I don’t – so not much help on that front unfortunately. I know that weevils don’t like dried bay leaves’ scent, so maybe try that?

Red potatoes seem to be better adapted to our hot climate and produces a decent crop. Also, the curl grubs do not like them – might be due to the pigment not being palatable (anthocyanin). The red potato plants may be green or have purple leaf veins and red stripes on the stems.

Harvesting and Storing

Potatoes are lifted from the soil with a garden fork to prevent damage about a month after the flowers have died (3-4 months after planting), you’ll probably have potatoes before carrots if planted the same time.

The potatoes can be left in the soil for winter storage. Otherwise dig them up, clean them good with some dishwashing liquid – with a soft brush to get all the soil out – check the potatoes over while you clean them for any fungal growth or black spots which might indicate disease and discard these. A good potato is one with nice smooth skin, some will have a scaly skin and are still edible. Washing with dishwashing liquid is basically a safe anti-disease (anti-bacterial and anti-fungal) treatment and a good rinse will remove the soap. Place the tubers in the direct sun for a few hours 2-4h, turning them regularly (once every half hour). This makes the skin dry out and harden slightly, readying the potato for storage in a brown paper bag or egg carton in cool dark place. Potatoes stored this way can keep for 3 months and check regularly for any disease. Otherwise boiled potatoes can be frozen and will keep for 6 months in the freezer.

Seed Collection & Storage

The potato fruit must be left to ferment (aka become rotten) on the plant – this usually means digging up the potatoes and leaving the plant to become a dry husk. The seeds are removed and cleaned. Pour enough water into the container to sort the seeds, bad ones float and good ones sink. You can allow the seeds to ferment (place in little water and allow to stand for about a week) this increases germination rate and helps with seed disease prevention. Then leave the seeds to dry for about 2 weeks on a sunny windowsill. The seeds are stored in glass bottles and properly labled.

The seeds is dormant immediately after collection and for immediate planting will require gibberellic acid treatment (this is a plant hormone involved in germination) – but no luck of this in my stores. Also, the plants grown from seed often do not carry a good crop. Seeds are planted in soil of 18-27oC (65-80oF) and the germination percentage is variable. I have tried growing potato plants from seed, and it doesn’t work… LOL! You can give planting from seeds a try, but seed tubers purchased from the local nursery would probably be best.


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