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Potatoes Rotting When Chitting

We used to chit our potatoes in an unheated spare bedroom where the lowest temperature was about 12 degrees. The windows faced north so we never got strong sunlight in there although it was quite light. Never had a problem and the potatoes chitted really well.

This year they’re chitting in my shed. The windows face south and temperatures can rise quite quickly in the sunshine. In the cold, the temperature can drop quite quickly. Not ideal but we don’t have a spare bedroom anymore and the shed was the best we could do.

To protect them from the temperature drops and strong sun, I’d got them covered with horticultural fleece. However, some of my Charlottes went rotten. The potato became very soft, leaking liquid, smelly and sprouting white fungus. In hindsight I should have taken a photo but I just fished them out and dropped them into the bin.

Now I’ve had a couple of emails similar to this one about chitting potatoes rotting:

Seed Potatoes Rotting

Just as my seed potatoes are starting to sprout some of them are rotting.  Several of them smell terrible and there is a horrible liquid starting to ooze out. This afternoon I discovered the problem and I have got rid of about 6 affected potatoes.  I suspect the problem is infectious and I shall lose more potatoes.  Until a couple of weeks ago I was keeping the potatoes in a rather chilly garage and very little chitting was happening.  I moved them to an unheated bedroom and the sprouts started to grow immediately.

Please could you or one of your members tell me if I should get rid of the lot and buy some more, or if I should plant those that still seem alright.  Also can you tell me if the rotting is to do with how I have stored them, or if they could have been infected before I got them.  They are Lady Christl earlies and Desiree main crop

Now I have to admit to not being certain but I reckon it’s been the cold snap that’s caused the problem. The potatoes became a bit frosted which caused damage to the cells with the ice crystals piercing the cell walls etc. This allows infection to take hold and pretty soon the problem is obvious.

I’ve just disposed of the rotten ones and am keeping a close eye on the rest. I think the mild winter with a cold snap has been the cause of the problem. Normally we defend against sub-zero temperatures but this year they didn’t really hit until most of us (well me at least) had given up worrying – hence frosted potatoes and the problem.

So my advice is dispose of the rotten ones, watch the rest closely but don’t throw them unless the disease spreads. I’d really welcome other opinions though – especially if you think I’m wrong as to the cause.


Posted in Allotment Garden Diary
12 comments on “Potatoes Rotting When Chitting
  1. Richard Howlett says:

    I too have succumbed to the mysterious rot. These were affected just as you and your correspondent described. I kept mine in a garden shed with a small (75w) tube heater on continuously, just a couple of small windows facing mainly north, so unlikely to have become frozen. about 30% were affected so threw them out and planted the rest; too early for me really, but nothing to lose as I see it. I live in North Norfolk.

    • judith coley says:

      @Richard Howlett:

      Thank you very much for all the helpful advice about chitting potatoes,and why some of mine are rotting. I will get the rest planted as soon as possible. We too live in East Anglia so perhaps the weather in this part of the country has been causing the problem.

      Judith Coley

  2. Karen Alred says:

    This is the first time we’ve tried potatoes as new to allottment and had the same problem. Ours were in the gardenroom which has roof windows as well as french doors & windows. The temps did get very low and I wondered whether I should have moved them in doors and wasn’t sure about them being in such strong direct sunlight. I have lost about 10% and just planted the rest today so fingers crossed, in Suffolk so hopefully no more major frosts! I may get some more, just in case but glad this isn’t just me.

  3. John White says:

    I buy seed potatoes for a horticultural society – about a ton in total – and have done so for over 20 years. This season, we took delivery just before Christmas and these were stored unopened in a frost-free building until the first week of January. On inspection, several sacks were wet and it was clear that many potatoes had rotted, giving off that foul smell reminiscent of blight. The problem seemed to be almost entirely with the variety Charlotte, although the quality and condition of several varieties was at best average.

    Our potatoes were sourced from the same supplier that we have used for many years and this is the first time we have had such a problem. I can only conclude that growing conditions last summer were in some way to blame. It will be interesting to see how the sound potatoes crop this year. I will certainly be planting my own in the next week or two.

  4. alison says:

    We’ve had exactly the same problem on our site. We’ve been wondering whether they got frosted before we got them. I’ve had to chuck about 2/3 of mine away. There’s a cross-site lotty meeting next week when this will no doubt be discussed, as most of us have the same supplier.

  5. Sprout says:

    I’ve also had this problem this year, I know for a fact that my potatoes got frosted ( left them on covered one night).
    So a few have gone soft, oozed fluid and fungus has formed on the damp area.

    Reason is the moisture in the tuber freezes and expands, breaking down the potatoes cell structure. when this thaws the resulting liquid quickly rots, and eventually seeps through the potato skin, the fungus then starts to grow on the liquid starch that was once a solid potato.

    I’ve also noticed that this problem seems to affect certain varieties worse than others. The variety Swift took quite a battering this year,
    but Rocket was hardly effected, these were side by side, and the lates were not touched

    I presume this has some thing to do with the moisture content and/or the cell structure of the seed potato, but I may be way off target with that.

    In the past, when this has happened, I’ve managed to save the larger, least effected seed potatoes by cutting the soft/rotting area off,
    and dipping the cut ends in Green garden sulphur powder (Used to prevent storage rot on Dahlia tubers)

    The effected tubers went on to produce perfectly good crops of spuds.

  6. Duncan Robinson says:

    I bought a selection of seed pototoes this year for my allotment; mainly from the high street stores, but I also bought a 2.5 kg bag of Edzell Blue from a large supplier of seed potatoes; 50 per cent of them looked like ‘bits’ had been gouged out of them (small sunken patches) I have never seen this before on seed potatoes – is this normal. 4 or 5 have not developed any chits and were going soft and one had white mould and was going soft. Perhaps they just give the rubbish to people only wanting a fairly small quantity, rather than farmers and allotment shops who order large sackfuls!
    I’m not sure if I will use the same company again! They were chitted on a west facing windowsill in egg cartons and seed trays as usual – never had any trouble in previous years.

  7. Madcat says:

    Interesting the number of comments that relate to Charlottes! I too bought charlottes from a supplier that I have used happily before. When digging in the sack to chose them, I found some duff ones and pulled them out so they could be ditched. With hindsight I should have walked away from that sack …. 🙁 but I was programmed to get my seed spuds and chose them from round the edges of the sack away from the rotten ones. not wise, not good. Must have lost a quarter of them just as you say. All the other varieties are fine. Only myself to blame for not thinking and saying no thanks.

  8. Trish Clarke says:

    We have our Charlotte on the lounge windowsill and haven’t had any problems,except they don’t look very pretty there

  9. Linda Joy says:

    This year I decided to buy Pink Fir Apple at our local Seedy Sunday event. When I got home to look at the seed potatoes, I noticed the bag was wet….and noticed a ‘weeping’ potato…which then came up with the white mould. I may have a photo of it, if you want it……?

  10. deborah scollan says:

    Left my charlottes and Roosters in egg trays in an unheated greenhouse and fleeced at night. They started chitting nicely and then after a few mornings of below freezing temps the white chits have turned brownish. I am watching closely after reading comments about rot above.

  11. Denise Franz says:

    1st I ordered potato seeds. I set them on my kitchen table in a dark box and left them there for a few weeks. They started leaking and smelling like fish. I was just waiting for them to sprout. I guess I should have put them outside in my shed.

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