potatoes, potatoes

Harvests, Pests & Pathogens, Root Vegetables


On Sunday, a week after cutting down most of my badly blight damaged (Late Blight) potato plants, I found more blight damage. Actually all my varieties now show a lot of blight spots. But the earlier varieties are worse off. The Russet foliage (a late variety) is nice and green still, but leaves have lots of brown/moldy looking spots. The Red Gold (early variety) plants were yellowed falling over and with brown/moldy leaf spots. Its normal for the plants to die back, and I don’t know how much the blight has affected this timing.

I cut off all foliage from the Red Golds and left the Russets and Green Mountain for now. Then we harvested a single plant of Red Gold. I was really pleased with the tubers! A dozen pretty red potatoes, the smallest were golf ball sized, 2 lbs total weight.

We also harvested all of the fingerlings that had volunteered in my paths. A total of 4 lbs of nice small potatoes. How exciting. And its nice to have open paths again.

There was no sign of any blight damage to the tubers. I will wait to harvest more since leaving them in the ground at least two weeks is supposed to kill the blight spores in the living plant material. Plus the potatoes keep fine underground, better than in my kitchen. I’ll harvest as I need them. Or when I want to replant the bed.

And then, last-of-all, I got out the yellow spray bottle of Copper soap and heavily sprayed all the foliage of the potatoes and tomatoes. Maybe that will help the Russets get a bit bigger.

fingerlings and red gold harvest cleaned up potato bed
freshly racked path

Here are photos of the Late Blight damage on the potato foliage:
late blight on potato foliage IMG_9417
Late Blight on Russet foliage Late Blight on Russet foliage

potatoes (Solanum tuberosum)
late blight (Phytophthora infestans)

10 Comments. Leave new

  • hi Kathy

    I'm just curious. . . how big is your family.? Your gardens are extensive. Do you consume or store and preserve most of the vegetables that you grow? Or do you give a lot of it away?. You have me very interested in growing potatoes! I'm going to have to look into whether I have the room for it next year.

  • Only 3 in the family. (But it has been said we eat like rabbits…) We eat 90% of my garden's produce. Sometimes I give things away. And there's always the compost bin since sometimes its hard to plan how much you need. I don't can anything.

    Here's what I do for storage:

    Vegetables I grow that last a long time in the bottom drawer of the refrigerator (2-4 months) are: carrots, beets, celeriac, parsnips and winter radish.

    Vegetables stored in the basement in a dry place: winter squashes, pumpkins, onions, garlic, dried chilis, dried shell beans and potatoes.

    Frozen vegetables: grated summer squash, basil pesto and tomato sauce.

    Everything else gets eaten fresh, given away or composted.

  • Wow, what a potato harvest! So sorry that the public gardens have blight, that really is a shame.

  • Kathy,
    My (early) potato plants are dying back too. If I leave the potatoes in the soil, can I still slash down the plants above ground? Or should I just leave them? They're wilting and browning, and I am still afraid of blight, and also, I'd like to compost them…

  • It's interesting Kathy … even in NE Ohio where we have not had the rain that you have had, our heirloom tomatoes are showing some small signs of blight … as they normally do about early September. I guess that's why so many people went over to VFN Hybrids.

  • Dawnie (CT)
    July 15, 2009 9:17 PM

    So sorry that you have extensive blight, Kathy. I was out weeding yesterday and still don't see any. If I have nothing at this point….what are my chances of getting blight from here on out?

  • My plants seem to be recovering from the blight. The tomatoes that I left in the garden seem pretty good still. Maybe the drier weather will blow it away. Who knows.

    Katrien, You can cut down the plants and leave the potatoes in the soil until you have time to dig them. This spring I found some I missed from last year and they were still fine.

    I think I read that its better to wait at least two weeks to dig them if you have blight so the spores in the stems will die before they have a chance of getting into the potatoes as you dig them.

    If you want to compost the infected growth, you will recontaminate your tomatoes and potatoes next year. Dispose of the growth in the trash, forgo tomato and potatoes next year, or resort to fungicides next year.

  • Had a problem with my Yukon Golds this year. Many of the plants died off before flowering, but I still had some small potatoes to enjoy.

  • Tina (Chicago, IL)
    July 18, 2009 4:11 AM

    I've been following your blog ever since I decided to start my own gardening this year, and I have to say that your gardens look amazing! On the subject of late blight, you probably know this by now, but there's actually some kind widespread late blight that's affecting your region (see NY Times article, Outbreak of Fungus Threatens Tomato Crop ).

  • Been reading up on eating potatoes affected by blight and one article said that it had been proven that eating potatoes affected by blight can cause birth defects…. I suspected that my potato plants had blight, so cut the plants off and left the potatoes in the bags I was growing them in… and now that I have harvested the potatoes they have lesions on them… so sadly I think I will err on the side of caution and "bin" them!


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