Hi Chris, thanks for the question. 

Disease is a definite consideration; however, there are some other considerations to consider.  Do you have any Black Walnut trees? Tomatoes and peppers are susceptible to Black Walnut toxicity, but cucumbers are tolerant.  Some plants are more inclined to suffer from certain nutrient deficiencies or toxicities. Have you had a recent soil test? If not you can get a mailer at https://homesoiltest.msu.edu/.  Have you recently amended the soil or add mulch?  What medium/soil did you put the pots?  Has anything recently changed in your landscape near your garden? When did the plants fail?  Just after planting? As far as diseases, a fungal wilt like Fusarium or Verticillium are possibilities.  To identify a disease,  any signs or symptoms would need to be identified, pictures can be a big help.  Verification may require a sample of a failing plant.  Any additional information you could share could be helpful.

Hi again.

Thanks for the additional information.  After evaluating your process, one thing stood out leading to a question of soil pH.  To counteract the acidity of 6 cubic feet of peat only requires around   2⅔ lbs of dolomitic lime.  In addition, burned leaves will also increase the soil pH.  Soil pH increase with lime can take time.  Adding excessive amounts over years can cause the pH to creep higher and higher until some plants can no longer tolerate it. Some nutrients become unavailable to the plants when pH is higher or lower than recommended.  A new soil test could confirm this.  I will continue to evaluate the information you sent, especially the pictures to determine if there are any suspect diseases.

Forgot to send this article along with the last post:

More reasons for soil testing - Agriculture (msu.edu)

Thank you, I will wait until my soil sample results come back and forward the results.

Hi Chris,

Just give me the report number /code when you receive it.

Hi Chris, 

Sorry, I thought you got the tests through MSU.  I belief you can forward these through the system.  You can take a screen shot and forward like a picture.  

Hi Chris,

Looking at the pictures, the plants seemed to show some sun scald damage but nothing that would cause the plants to fail. As to the pH, although it is a little high, it shouldn't cause this big of a problem.  Looking at the soil test report, it showed that organic matter was relatively high.  High organic soil can hold a lot of water.  How have you been irrigating your garden? Has your garden had a lot of rain?  What is your base soil like (sand, loam, clay)? Since so many of your plants (not all in the same family) have succumb to the problem, this would seem to suggest a cultural problem. What does the death process look like for the affected plants?  How are you fertilizing the plants?  Are you starting these plants from seeds?

Hope to hear from you soon.

Chris,

In most cases of disease, you shouldn't see the plants die in a matter of hours.   Damping off can happens rather suddenly.  This causes the collapse near the soil line.  At later growth stages it is sometimes referred to as wirestem and may not be fatal.  The wilt diseases won't kill a plant in hours but can take out both tomatoes and peppers.  When the plants die, it is a good idea to do a "post-mortem".  Look at the roots, examine the leaves and stems.  Slice the stem to look for browning or streaking.  These can be clues to what the problem is. Check out these links:

Damping Off (psu.edu)

Possible Causes of Sudden Wilt and Death in Tomatoes | Nebraska Extension in Lancaster County (unl.edu)

Fusarium and Verticillium Wilts of Vegetables (usu.edu)

Identification and Management of Soilborne Diseases of Tomato | Ohioline (osu.edu)

If you go ahead with another soil test, it would be a good idea to add minor nutrients to the tests.

What is your water source (city, well)?  Do you soften your water?  

HI Chris,

Yes, MSU does have a mail in soil test (Get Started | MSU Soil Test); however, MSU uses A&L Great Lakes Lab for their testing.  I am not sure how you would add minors the standard home test.  You may have to go the commercial route if you go through MSU. Soil testing through MSU Extension - Soil Health.  You can contact the SPNL lab to determine how to go about adding tests <personal data hidden>.   

I would still be interested in knowing if you may have changed water sources, and how you are irrigating.

Chris, 

Let me know what you find out.

Thanks for the update.