Crop of the month: Potato

The Moon was full last night so let’s celebrate harvest. You can see other posts in this series by following my ‘harvest’ tag. This month, instead of the start of a crop’s harvest, I’ll write about one that’s recently ended. Here in Britain the potato harvest ended a few weeks ago.

The potato (Solanum tuberosum) is versatile and productive. It has been grown on these islands since the 16th century, promoted by Walter Raleigh although he probably wasn’t the first British person to taste it. So the potato has been here only for a few centuries. But since it arrived, how it’s settled into our land and culture!

In many parts of these islands, growing conditions are good for potatoes. Particularly in the lowlands. You can see where potatoes are grown by scrolling through UK Agriculture’s maps of UK arable producing regions. Those maps include Northern Ireland. For the larger area of that island, the Irish Food Board tells us about potato growing in the Republic of Ireland.

We like potatoes but what do potatoes like? Good drainage – this isn’t a desert plant but it’s not a marsh plant either. Plenty of sun but not tropical sun. Deep soil, quite rich but not so rich that the potato tubers branch themselves around clods of muck. Medium-high pH (that is, slightly alkaline) to discourage the dreaded late blight (Phytophthora infestans). I’ll say more about blight later in this post. Meanwhile, a standard crop rotation for Britain puts muck or compost into the soil one year for fertility, lime the next year for alkalinity, then spuds in the third year. Potatoes grow well in large containers too. So if you have land, or even a few containers, you can grow your own spuds.

Of course most of our potatoes are grown commercially. Potato growing is an industry important enough to have its own levy board. Farmers’ taxes pay for the Potato Council which advises and promotes the industry. Like all the levy boards, the Potato Council is part of the Agriculture and Horticulture Development Board (AHDB).

Nearly all of us here eat the products of this industry. It’s unthinkable that we’d ever run short. But Olivia Cooper at Farmers Weekly says that 2012 hasn’t been a great year for spuds. Rob Clayton, Director of the Potato Council, says that 2012 was a watershed year for the potato industry with farmers forced to sell potatoes for less than the cost of production. So it’s not only the dairy farmers who suffer a price squeeze this year.

These are hard economic times. This year a very wet summer here in Britain has made things even harder for farmers and growers. Crops were flooded and for potato growers, late blight took a heavy toll. Late blight affects tomatoes as well as potatoes particularly in wet weather.

Late blight is a touchy subject because it led to the starvation of many people – perhaps a million people – altering human culture on these islands and in North America when it caused the Irish Potato Famine. Since those terrible times P. infestans research continues. Farmers can participate in Blightwatch and they can spray against blight.

P. infestans is a fungus-like mould which survives in the soil for a few weeks and spreads on the wind. Knowing that biology, knowing the history of famine, knowing the economic realities of today, it’s understandable that some blame amateur gardeners for mismanaging blight and letting it spread. Here’s a film about blight on allotments in 2012.

Allan Stevenson, Chairman of the Potato Council, urges us to buy potatoes instead of growing our own. It’s his job to promote the industry and I rely on purchased potatoes when the crop from my allotment runs out, but I’m not convinced that people like me are responsible for spreading blight. The articles I linked to, in the paragraph before this one, say that potato growers lose 7% of their crop in a normal year, and that it’s risen to 10% this year. I think that’s because of the weather. In fact I think that the more people who grow potatoes, the better, so long as we follow advice about blight.

One thing that really does matter is that potatoes should be grown from fresh stock each year. This crop is grown from ‘seed potatoes’, small potatoes kept from one year to the next. It’s tempting to keep your own home-grown potatoes or even the ones which sprout in the fridge, but don’t do that. It can spread blight and other diseases. The Department of Environment Food and Rural Affairs (DEFRA) defines certified disease free seed potatoes.

In fact, growing from last year’s potatoes probably contributed to the Irish Potato Famine. Because monoculture is dangerous and because, at that time, the potatoes grown in Ireland were all of one variety. So do our UK farmers need to grow as many as possible of the potato varieties already available? Or should they also consider blight-resistant genetically modified (GM) potatoes? I’m still undecided about GM crops in general and I haven’t yet seen evidence to convince me that blight-resistant potatoes are the way forward for the British industry.

Meanwhile, like other British and Irish people I like a good spud. Soup, chips, roasties, mash, a million other potato delights. Potatoes were much eaten here during the years of wartime rationing. The National Federation of Fish Friers tell us how our great British fish and chips came to be here.

Here’s a seasonal recipe for carrot and potato soup. Vicky Frost at the Guardian tells us about twelve celebrity chefs’ roast potatoes while my fellow blogger Gary at Big Spud tells us how to make his perfect roast potatoes. Celebrity chef Jamie Oliver tells us the various ways he likes to make mashed potatoes.

From Ireland, Daily Spud tells us what’s going on in the world of potatoes. Since Ireland is such a great place for this great crop, here’s a film of another celebrity chef, Keith Floyd, telling us about Irish potato bread and potato cakes.

[Edit] Late blight attacks the tomato (Lycopersicon esculentum) as well as its relative, the potato (S. tuberosum). My fellow blogger Jenny at Spokes and Petals tells us that late blight is flaring up in parts of the States in 2013.


About argylesock

I wrote a PhD about veterinary parasitology so that's the starting point for this blog. But I'm now branching out into other areas of biology and into popular science writing. I'll write here about science that happens in landscapes, particularly farmland, and about science involving interspecific interactions. Datasets and statistics get my attention. Exactly where this blog will lead? That's a journey that I'm on and I hope you'll come with me.
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22 Responses to Crop of the month: Potato

  1. A truly comprehensive guide to potatoes thanks! I grew dahlias in my polytunnel this year as I was getting tired of blight on tomatoes – lost my whole crop 2 years running. The dahlias were fantastic, loads of really good blooms. But just the other day I noticed that there were suspicious blight indicators on the leaves. Do you think it’s possible for a dahlia to succumb to blight? I suppose they are a tuber too. Any ideas as to what to do about it?

  2. The humble potato is nature’s nearly perfect food. We could live on potatoes and water alone. A lesson for an over-populated planet.

  3. EqFe says:

    In the US we were always taught the potatoes need acidic soil in order to prevent scab. The potatoe is an odd plant, originating in the andes, it like cooler temperatures, but growing at the equator it also needs full sun. It likes much lighter soil than the hard clay I grow them in, and even with lightening my soil with compost, woodchips etc. and double digging, I only struggle to get the high yield that I’m used to using the intensive methods that I preferr. This hot year, the yield was only 75-100 pounds per hundred square feet.

    • argylesock says:

      Spuds in acidic soil? I’d never heard of that. Since you grow that way, perhaps this is why you don’t lighten your clay soil with lime.

      I considered writing about scab as well as blight. Maybe I’ll do that in another post, at some point. But I’m loath to start a ‘Disease of the Month’ series or suchlike because it could easily be ‘Moan of the Month’!

      • eqfe says:

        In Maryland the recommended approach to lightening soil is wood chips and gypsum. Gypsum being composed of lime and sulphur has a neutral PH. A commercial combination called “Clodbuster” is a combination of finely ground bark and gypsum. Since I get my woodchips free from town, I just drive to a farm supply store in Virginia for gypsum

  4. skezier says:

    Spuds are a good crop to grow but … mine used to get a lot of blight if the rain was relentless… Funny thing is that all the ‘native’ dishes this way are made around the humble potato…. used to be because they were cheap and easy to grow… now its cus they are nice lol.

    • argylesock says:

      Are you still getting blight? Or perhaps you stopped growing potatoes because of it. I’ve forgotten where you are – the West Country?

      It’s true that potato dishes endure because they’re so nice! I find it hard to imagine people’s diets here before Walter Raleigh gave us potatoes. For complex carbs, I believe that people ate bread (wheat or rye), oats, barley, peas and parsnips. Not sure when carrots became popular here. Hmm… I’ll add ‘What they ate’ to my to-blog list.

  5. skezier says:

    I think potato alone would not be too healthy but… Both here, in Scotland and Ireland the poverty long ago meant they did except for what ever they could supplement from the wild. My Nan was from mining stock and she told me some of the things they ate till her father found a better (and safer) job.

    I can’rt grow veg any more but the spuds used to often have to come up early for blight and it did seem linked to the amount of rain we had. Hey they would really have done badly this year lol. x

  6. Finn Holding says:

    Fascinating post. Reminded of a recent comment, would the farmers be in such dire straits if they weren’t being fleeced by supermarkets? It just doesn’t seem right that the folk who strive to produce our food are struggling so badly. I saw a comment on TV a couple of days ago that 33% of all farm workers in this country earn less than £10k p.a.. That’s all wrong.

    • argylesock says:

      Thank you for liking my post! Yes farm workers’ incomes are important. I should look for data on this. Is it mainly about UK residents or about migrant workers?

      Supermarkets are on my mind too and I’m gestating a post about them. On my ever-lengthening to-blog list!

      • Finn Holding says:

        It was UK farmworkers, not seasonal migrant workers.

        I guess I’m no capitalist because I reckon there’s plenty of money to go round if it were distributed more evenly, but it seems absolutely bonkers that the folk who produce the most important product on the planet get treated the worst. I wish the farmers could come up with a way to circumvent the con artists between them and the consumer. it would be better for them, better for us, better for the livestock and better for the countryside.

        I’m looking forward to reading your post about the supermarkets. I reckon I might be inspired to enter into the debate in the comments 🙂

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  10. Jenny says:

    Excellent post! Resources such as this are key to helping both large- and small-scale growers in understanding how to deal with plant diseases. The more educated we are the better equipped our toolboxes as we figure out how to combat new, old, and continually challenging agricultural issues.

    Also, thanks very much for linking to Spokes and Petals. Tomatoes are bread and butter crops for many diversified organic vegetables farms throughout New England, so this is an issue that I’ve run into many times. Despite my pronounced distaste for heatwaves I’m currently thanking my lucky stars for our hot weather, as it should stave the blight off…for now.

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