Big Potatoe Troubles

My very first year gardening, some success, some semi-success. Up until 2-3 weeks ago my potatoes looked fabulous (though I am sure I didn't earth-up enough). Suddenly, with all the rain (I think) the foilage has started to get black spots, turn yellow and wither.
I dont know whether it is the dreaded blight or just that the soil did not have enough nutrients. I only managed to find a specific potatoe feed a few weeks ago on the web and ordered it.

I would post some pictures, but it ask me for a URL. How do you do this?

Also, if it is blight, can I stil eat the potatoes? I know to dig everything up and dispose of the humos. the variety is Edwards.

 

Potatoe Pictures at 2 stages. The mottling and yellowing has been happening slowly over 2-3 weeks. Does this mean it is not blight?

Stage 1



Stage 2

 

Have they flowered? If so it could be just that the plants are wilting and dying off and your spuds are ready for harvest - at least that is what I think (my first time growing potatoes!) I know that is what is happening to mine and my spuds are lovely :D

 

Potatoes is the one thing I've grown successfully many times over many years, in a variety of conditions, and I've never seen that before but it fits the description of blight.

When spuds are malnourished (a few missed from harvest grown in the same soild the following year), in my experience the top side is just a bit stunted. I've had a crop one year where everything looked great but there were little bore holes in the spuds (slugs perhaps), and I had one crop where everything was great except the yield was low (soil too heavy I reckon, it was almost pure clay).

I've never let the plant finish because I like to harvest slightly early for the flavour, so I can't comment about what the plants look like after flowering (I harvest just at the first hint that the flowers are finishing, and then just take the spuds as I need them rather than harvesting the lot).

If it is blight, remember not to grow spuds in the same patch next year.

 

Thanks Everyone. I have just gone outside and looked at the underside of leaves and I cant be sure that there is a silvery edge to the spots, more like a weeping away of the green.

However, should I err on the safe side and cut away all the foilage? I checked the tubers, only about 12 small to med size on the one I dug up and they seem OK, if smaller and less plentiful than I had hoped. Will they continue to grow if I remove foilage? I doubt it is doing much for the tubers anyway.

Also, I only have a small plot for my veg about 20' by 18' which slopes from top to bottom with about a 2' depth difference between the top and bottom edges, and this makes me think that the rain over the past months has just washed what nutrients there were away.

I have seperated it off into 4 squares with sleepers. In doing so my thought was to allow for rotation, but I am wondering if the sleepers will satisfy the 'requirement' of not planting spuds in the same area.

 

You have got me wondering if my raised beds are seperated enough to count for crop rotation, they are about 2 feet apart in a square formation (4 beds) anyone any thoughts on this?

 

I'm no expert, so everyone feel free to tell me if I'm wrong, but my understanding of crop rotation is that it has two purposes.

1. Different crops take/return different nutrients from/to the ground, so doing crop rotation you maintain the overall balance of nutrients.

2. Moving your crops each year creates a moving target for pests and diseases specific to a particular group of plants.

So, if my understanding is correct, then the distance between plots should be an issue for the first point, but may be for the second. But then if you have not suffered any major pest or disease plagues then the spacing shouldn't be too much of an issue for the second point neither (though if it is a serious fungal threat like tatey blight then I guess the trick is to burn all the foliage and miss out on spuds for a year or two - but again, there are plenty here with far more knowledge than me to tell you if I'm right or wrong).

 

Thanks for that. I have decided to invest in a large number of potato barrels/sacks (got 3 for £14) and just bought 5 x 36ltr sacks of compost from Woolworths for £1 each.
As far as I know the sacks should last about 3 years or so and this should negate my potatoe problem and also give me more space for general veg planting.

Now I have to plan out what is going in and when - boy ... I am having fun.