The damage is mostly to the bottom part of the plant. The tops look fine, but this is affecting almost all of my plants.

They caught the ghay.   Google tomato blight.  Maybe that's it.

I am not an expert, but I have grown better tomatos in some pretty bad dirt. I would bet you have a fertilizer issue.



YOu are too opsec secret squirrel to post your location, so I will assume you are trying to grow them on the face of the sun and would suggest some fucking sun shade.

Could be several things, but first guess is that they aren't being watered well enough and regularly.

Do you feed fertilizer and if so, so you spray it on the leaves? Looks like nute burn.

Don't talk meanto him, you might scare him back under his rock.  

http://www.ar15.com/member/member.html?id=945

To the OP, fertilizer is needed.

TRG   <--- http://www.ar15.com/member/member.html?id=981

http://vegetablemdonline.ppath.cornell.edu/DiagnosticKeys/TomWlt/Septoria_Tom.htm

try this

Looks like they need to ketchup

I second blight and would cut off any affected leaves before it gets worse. Blight is some bad stuff and can stay in the ground for years.

You're not growing potatoes next to the tomatoes are you? That's a sure recipe for catching blight.

Thanks for the replies. I live in WNY where we've had a tremendous amount of rain this season, so I haven't had to water much. When I do water, I use a drip irrigation system so the leaves don't get wet from watering. I haven't used any fertilizer yet. Up until last weekend, I had a fabric weed barrier covering the entire garden except where the plants grow through. I had to remove it because it let too much light through and weeds were growing underneath it. I'm going to try to find some straw for mulch instead.

After doing more research, it looks like either blight or Septoria Leaf Spot are possible causes. I probably have the plants too close together and I haven't rotated the crops in that area for a few years. I'm sure that didn't help.

I do have potatoes about 30 feet from the tomato plants, but they are in a separate tilled plot. Do you think this is too close?

Your potatoes are far enough away from your tomatoes so you're good to go with that.

Instead of using straw for mulch use grass clippings provided the lawn they came from isn't chemically treated (other than normal fertilizer). The lawn clippings break down and provide nitrogen to the garden. The clippings are also a better choice for weed control because straw lets light through which will make you pull more weeds.

You need to add some fertilizer considering you haven't yet.

And yes, you need to find a different spot for your tomato plants next year. I try and plant my tomatoes where my beans were the previous year.