Pictures would help a lot. Questions - have you applied herbicides to anything close to the garden area? Has your neighbor? Have you used any fertilizers, if so, what kind?
hortster

If everything is pretty much as it was last year, it sounds more like a disease than a soil problem. I can't see that drastic of an effect happening all at once from a soil deficiency. Usually those get worse over time if you're not replenishing nutrients, rather than all at once. And would likely affect the whole garden, not just one crop, and then spread to another.

If it's spreading to adjacent plants from your potatoes, that's evidence of a disease that came in with the seed potatoes. Did you get them at the same place as last year? Anyone else you know have these problems? I don't know potato diseases, at least not that one. But taters and tomatoes are closely related, so diseases of one could affect the other. My gut feeling, from your description, is 'virus.'

We need pictures. Without some good images, we're just guessing. Have you taken any plant samples to your local extension office?

What have your Temps been? At night? What's your PH?

I would rip 'em all out and burn them or at least get them into my trash can.

It sounds nearly as bad as the evil pawl that has settled on Washington. doG save us! I have the same advice for dealing with the dirtbags in Washingron. Rip 'em out by the roots in November!

tox's comments seem like best bet. Have you taken a sample of the plants to the farm supply store where you bought them? Its possible that others have had a similar problem. But at very least, they will want to know what is happening to your plants.

Also, you know that story that has been going around about herbacides used to grow hay being passed through animals into their manure and even into the composted manure? Have you used manure/compost from a new source?

With "fern fronds" and brittle leaves that snap -- I vote for herbicide damage, even though unintended.

Sounds like a herbicide drifted on to your garden. I had it happen one year. Fields close to you? Neighbor do the lawn?

Curt~

The only way to know if this is a soil nutrient deficiency, or soil pH related, is with a good, reliable soil test. Contact your local office of the University of Idaho Cooperative Extension Service about having this done. You can also dig in with these simple soil test,
1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer your soil will smell.

5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.
to see what else is going on with your soil and what to do to work on and make your soil into a good, healthy soil that will grow strong and healthy plants.
What you have might also possibly be a plant disease, although most often that appears as blotchy leaves that then turn yellow, or maybe, possibly due to some herbicde although most often plants sprayed will wilt, not become rigid.

Here is a link that might be useful: UI CES

While that's good advice for any garden that hasn't been tested, a soil test is not going to pick up either diseases or herbicides.

Not much more we can do here until idgirl reports back with some answers.

It is true that a soil test will not pick up any diseases or the presence of herbicides, but it can be a very good tool in determining what the problme might be. If the soil test indicates that the nutrients are in balance then you can rule out nutrient deficiencies that often can mimic disease problems, which they really are.

I took a sample in to ZamZow's and we determined that I have a virus. He said I was lucky to have my potatoes come up at all as lots of people have had no luck this year with their crops. I may end up with bitter potatoes if they don't die off. I replanted some potatoes last week and so far, they look normal, and are leafy and a healthy green color.

If I did get in contact with a herbicide from my manure.....I did use a different supplier this year..... do I need to do anything special for next year?

Thanks for all the valuable information! I am so pleased with all the responses to my plea for help.