Casual Gardener: Eyes on potato hobby growers as blight season looms

It’s claimed the commercial potato sector is being put in jeopardy by those who grow spuds in their gardens and allotments

Commercial potato growers tend to spray their crops to prevent blight

IN SIX days’ time, on July 12, there’s going to be a big celebration across the north and in other parts of Ireland. The origin of this (agri)cultural tradition dates back centuries and involves something introduced from overseas which left its own distinctive mark on Irish history.

I speak not of religion or Dutch royalty, but of potatoes: specifically, the first early varieties that will be harvested in the coming days, some 16 weeks after they were sown.

The cross-community rule of thumb with first earlies, such as Colleen, Foremost and Orla, is to sow them on or around St Patrick’s Day and harvest from July 12 onwards.

In some sheltered coastal areas, it’s possible to sow and harvest earlier, as in the case of Comber Earlies, which are lifted every year from May onwards. The favoured varieties in this pocket of Co Down with its own microclimate are the locally-bred Dunluce, the popular Scottish ‘heritage’ (pre-1950) variety, Home Guard, and the relatively high-yielding English variety Rocket.

First (and second) earlies will not yield the same quantities or store as long as their maincrop counterparts, but they do have their advantages.

Maincrop potatoes are bigger but they are more susceptible to blight than earlies. PICTURE: ALAMY/PA

Whereas maincrop can take up to 20 weeks to mature, and are bigger as a result, the fastest earlies can be ready in almost half that time. These ‘new’ potatoes will be smaller and sweeter, eaten with their jackets on.

Earlies take up less space, lending themselves to small plot suitability as well as container growing, while harvesting them in July also frees up space for other fast growing crops, or veg, that’s happy to overwinter.

However, for me and many other so-called hobby growers, the key selling point for earlies is that they are much less susceptible to blight, largely because they’re usually out of the ground by the time Phytophthora infestans takes hold in late July and August.

Blight is the potato (and tomato) grower’s worst nightmare. Spread by airborne spores, the disease thrives in humid conditions, destroying plants within days and quickly rendering the tubers inedible.

Potato plants with blight
Potato plants with blight

Whether it was the actual cause of an Gorta Mór is moot, but blight was the trigger and key factor in the deaths of around one million Irish people between 1845-1852.

It is an emotive subject and one that appears to be creeping back up the news agenda.

A recent potato workshop, jointly hosted by Cafre (College of Agriculture, Food and Rural Enterprise ) and Teagasc, the Republic’s agrifood advisory service, heard that hobby growers are putting the island’s commercial potato sector at risk.

It appears Phytophora infestans is evolving and fast becoming resistant to many of the blight fungicides available.

However, because hobby growers tend not to spray their crops, it’s claimed allotments and back gardens have become “reservoirs” for new, potent fungal strains.

The economy of the potato
Potatoes (Maskot/Getty Images/Maskot)

It’s argued in some quarters that these mutations could “wipe out the commercial potato sector”.

No-one has yet to suggest what would be a deeply unpopular ban on hobby growing, but it can’t be far away.

The more sensible opinion formers advocate a cross-border awareness campaign that enables non-commercial growers to understand how their small-scale hobby crop could have widespread, large scale implications.

Driving a (potato) wedge between commercial and hobby growers by scapegoating the latter will create bad feeling and likely do little to curb the curse of blight.