Zinnias and potatoes

I was out last night measuring my zinnias for the zinnia trials and thought I’d snap a few shots to share with you.  They are doing quite well—they are all big, healthy-looking plants with fairly numerous blooms.  A couple of them are sort of nondescript colors, but I didn’t take pictures of those.    Most of them are bright reds, corals, and pinks—just what I love seeing in the garden (especially the vegetable garden, which is usually mostly green).

Zinnias

Zinnias

More zinnias

While I was out there, I was noticing my potatoes. . . they’ve been  doing fairly well (I think), but since I’ve never grown potatoes before, I’m not sure what they are supposed to look like at this point.  You can see in this photo that it looks like a few of the plants are sort of turning brown and starting to lay down a bit. . . can that be good?

Potatoes

Do any of you have experience with potatoes you can share with me?  How do I know when they’re “ready” to dig?  Do the plants give me a clue, or do I just dig them whenever I have time?  I confess, I’m hoping that the sort of poor-looking plant in the photo is just how you tell when they’re ready to dig up.     But I’m thinking that’s probably just wishful thinking on my part and really that plant is simply not doing well.

I would greatly appreciate any helpful suggestions you seasoned potato-growers might have!