I had some small purple potatoes I bought at the farmer's market last year that I stuck in compost in the can, and gradually built them up as the plants grew. There are about 6 plants in there.

Some of the plants look fine, or mostly fine, some others look like these:

There is insect damage to the affected plants as well:

And little black dots (probably eggs):

Can anybody help with figuring out what's up with them and what I should do, preferably things that won't also kill the earthworms in my mini-composter? I did also have a lot of ladybug larvae on the potatoes (yep, I'm sure that's what they were), and a little trouble with fungus gnats but not as bad as I've had in past years.

I think whatever it is has also infected my lemon balm and possibly my serviceberry, both of which were draped over by the potato plants until I moved them away from it and corralled the sprawling potatoes with my rusty garden decorations. My balcony is small, maybe 6'x8' and filled with veggies and herbs in pots, so I really do need to get this problem either fixed or at least strictly controlled, even if it means killing all the potatoes.

--GW

Looks to me like the plants are experiencing stress. This could be the stress of their natural life span and are just dying back as a result of that.

Your set up does not look optimum. The container does not look large enough to support 6 plants. Also the area you have it in looks like it would either get really hot, or is too shaded. For sure there is not going to be much air movement with it stuck in the corner.

It is too late to worry about all that now. Just wait for the plants to completely die back and then harvest your bounty. You might be surprised. In any case you should have learned some valuable lessons to use next year.

I'd wondered about the number in the container, but they'd sprouted and I didn't want to waste them, and it seemed like a lot of the container gardening advice for potatoes suggested upward of 6 or so in a container of the size I have. But now I know it should probably be 3 at max.

I went ahead and did as suggested and dumped some more homemade organic fertilizer in with them and 5+ gallons of water. We'll see how they do. :)

--GW

I was able to talk to the person I got the seed potatoes from, an organic farmer at the local market, and she informed me that the county has had an epidemic of early blight this year and I needed to immediately kill my plants in order to have any chance of having good potatoes. So I did that just now when the temps dropped finally. I also cut down my lemon balm and catmint, and just got rid of an unpotted peppermint which all seemed to have contracted blight from sitting under the potato leaves. My serviceberry tree also had some bad leaves for the same reason, but I'm not willing to cut that down to the soil just yet - I just cut off the offending leaves with some stem and it's looking a lot better (it had also suffered from excessive rain before this!). So far the two tomatoes look just fine, tho the larger has some wilted leaves on the bottom.

I expect my mints will make a full recovery, as the catnip was also affected but is doing fine now. Tho I find it kind of odd that the blight could have gotten to my potatoes - I have a second floor apartment balcony that's not anywhere near any potato fields. Must get carried on the wind long ways or something, or perhaps was in the compost I bought. I'll also have to do something to shade the wormies, I suspect, tho there is a thick layer of newspaper in there on top of the shredded newspaper.

--GW

I doubt that you had early blight (the serious disease). Possibly late blight, more likely just the plants winding down in their less than ideal situation, as noted. You can be happy that you did not see colorado potato beetle, though.

I was thinking maybe I could still use the garbage can for a fall crop, like kale, after the tubers are dug up some time this coming week. What do you guys think? No nightshade family plants, of course.

--GW