Potatoes - The Results Are In.

6th August 2016

The view over the farm buildings and veg plot from up the ladder

I woke up inexplicably early today so decided to take advantage of the forecast sunny day to creosote the cladding on the house.

The fine was ideal for harvesting the potatoes too, as they need to bake in the sun for a while to improve their storage time. In truth it is a little early in the year to be harvesting the spuds, but blight has dictated proceedings this year.

And so we step back three weeks to when the tell-tale signs of blight swept through the potato crop. Within a couple of days a few brown blotches on the leaves can turn into rows of withered plants. If it gets into the stems it rapidly spreads down to the tubers.
The only course of action is to chop off all growth above ground and hope that it has not spread underground. Of course, this puts a halt to any further growth of the tubers, so the earlier blight comes the smaller the potato harvest.

This year the blight came early.

As if this is not depressing enough, there are plenty of other things that can go wrong with a potato, especially in a cool, wet year. The only benefit of so much rain earlier in the year was that the tubers would hopefully have been swelling quickly.

Once the tops have been removed, you need to leave the potatoes in the ground for two to three weeks so that they do not come into contact with live blight spores on the soil surface when you harvest them. Otherwise they will rot in storage. The fishy smell of a blighted potato tuber is unforgettable.
The longer they are left in the ground though, the more susceptible they are to slug damage, so it is a balancing act which also depends on waiting for a fine, sunny day.

A fine crop of Markies

So today was D-Day, the moment of truth. It took me several hours of hard digging to unearth all the spuds. Some varieties were a joy to dig as the fork lifted to reveal clusters of large, healthy tubers. Others were disheartening with very few usable potatoes. That's one of the reasons why I grow nine varieties, as they all have different qualities and different resistance to disease and pests.



So, here's what can go wrong!

Look carefully and you see the slimy,

melting cheese gunk that is a blighted potato.

Any blighted material needs to be dealt with.

Ideally it is burned, but this is not so easily done!

I put it all into a couple of closed unit plastic compost bins,

never to see the light of day again!

Splitting. Only the Picassos did this.

Still edible, but it did give a route in

for pests and diseases.

(See the slug?)

Slugs

Some varieties seem much more susceptible.

Can cause serious damage in a wet year.

These neat holes often open up into a network of tunnels on the inside.

They don't go to waste though as the geese and the sheep hoover them up gratefully..

A few always get caught by the fork.

Though not many, it always seems to be the best specimens!

And now for the performance by variety. Remember that yields reflect a bad blight year when the tops were taken off in mid July, which would be expected to hit the maincrop varieties worst.
Also, every year is different and performance varies greatly between varieties and in different soils.

Markies potatoes laid out

on the grass to dry.

Markies - Main Crop
A trial crop based on other people's strong recommendations. This variety is supposed to make for tasty chips - always good! Despite the early topping off there was a good yield of medium to large potatoes. Blight had only got into a couple of the tubers. There was some slug damage, but overall very little.
Picasso - Main Crop
I only grew these because I had a few kg left over from the bulk order I do for smallholders. Personally I wouldn't grow a variety that is favoured by farmers. It usually means that it thrives under a regime of chemicals, not necessarily the best for an organic grower. Unfortunately most of the smallholders are very conservative in their potato choices.
The Picassos had split much more than any other variety, caused by rapid growth in wet weather. This had allowed access to pests. Few tubers were blighted, but maybe 20% had slug damage. The yield was fair but nothing exceptional.

Blue Kestrels set out to dry on the soil surface.

In the foreground,

my entire usable harvest of Bonnies!

Bonnies - Second Early
Probably my favourite potato as a baker. Produces a good yield of large, round, attractive tubers. Unfortunately, not for the first time, the usable yield was disastrous. Blight had got into maybe 30% of the tubers and about 90% of what was left had become slug food. The slugs seem to love this variety. The end result was no more than a dozen very nice tubers from as many plants. Bonnie has had its last chance!
Blue Kestrel - Second Early
Having experimented with Kestrel last year and been impressed with the taste and the firm texture of the potatoes which lasted well in storage, I decided to try Blue Kestrel this year. I only grew ten plants, but this year at least it has turned out as one of the two absolute stars. The tubers are very attractive and many were large enough to make excellent baking potatoes. Being a Second Early is always going to help n a blight year. Blight had only got into three individual tubers and, unlike the Bonnies which they grew next to, there were virtually no slug holes. If the taste and storage are anything like last year's Kestrels then this will be on the list every year. Mind you, I said that about Bonnies once, when we had a dry year.

Charlotte - Second Early
I cannot believe how much this variety costs in the shops. It is one of the cheapest seed potatoes to buy from the wholesaler and has performed brilliantly every year. Yield was excellent and the quality of the tubers outstanding. There was virtually no blight in the tubers and virtually no slug damage. This makes Charlotte a brilliant insurance policy for a poor year, though it would more than earn its place in the veg plot in any year.
Dunluce - First Early
I tend to alternate between this variety and Arran Pilot for my bulk standard early potato. Being a First Early it has done all its growing before blight ever hits. However, earlies don't store so there are always quite a few left in the ground when the other potatoes are ready. This is where I like Dunluce and Arran Pilot, for they simply grow larger but retain their great flavour. This year's Dunluce have stayed relatively blight and slug free in the ground too. As would be expected with plenty of rain, the yield and tuber size has been good.
Red Duke of York - Early
A favourite of mine. An early red potato which is excellent for chipping and roasting. Doesn't produce massive tubers, but they are brightly coloured and good quality. This year there were more tiny tubers than usual but the yield was still fair. It has not stood in the ground as well as the Dunluces and blight has got into some of the tubers. So not the best year for this variety but it still performs well enough to firmly hold its place.
Pink Fir Apple - Late
This was the absolute star of the show last year, producing sacks of large tubers. The tubers seem to be pretty blight resistant and incur little slug damage. However, this can be an all or nothing potato, and this year it was nothing! I couldn't risk not cutting the tops off, but being a late developer it was inevitable that the tubers would not have had time to develop. As it was I got about a plate full of mini Pink Firs!
This potato still remains a firm favourite of mine and I am happy to run the risk every year as it is more than worth it when it pays off and this is the first time that I've had no crop to speak of.
Desiree - Main Crop
Despite it being a fairly bulk standard variety, I love Desiree potatoes. They are versatile and produce a good yield of attractive tubers, with a fair percentage of whoppers for baking.
In the shops it has been largely replaced by its descendant, Romano, but I find that Desiree preforms better for me.
The blight reached the leaves of the Desirees last so it didn't really have time to get into the tubers. The tubers had not quite had time to swell to full size, but I still got a fair crop and there was relatively little slug damage. Not the best year, but I've still got enough to keep me going.

So, overall it was a pretty challenging year potato-wise but I still ended up with about five sacks of potatoes which will be plenty to get us through till the first First Earlies come out of the polytunnel next spring.
A couple of varieties bombed and a couple were outstanding. Slugs seem to increase year on year in my veg plot, though nothing like as bad as the plague year we had in 2012. In a wet year though, they probably cause more crop loss than does blight.
When I choose next year's varieties, slug-resistance will remain a high priority.

Definitely on the list will be Charlotte, Blue Kestrel, Desiree, Dunluce/Arran Pilot, Pink For, Red Duke of York and a new entrant, Markies.
Definitely off the list are Bonnie.
As for Picasso, I basically got them free but if I had to pay I'd look for another variety.

Boris and Arthur could have helped with the digging,

but decided instead to go digging for moles in amongst the climbing beans.