Can you start off by telling us where you are and whether these herbs are indoors or out? Also what herbs are they and what do you do about watering? Are they in the ground or in containers? If in containers how big are they and do they have drainage holes?

Without this information nobody can make useful suggestions as there are so many reasons herbs can fail.

You can upload photos using the camera button below. Failing that you can link to a photohosting website using the link button.

Thanks for responding. I got the photo function to work so you can see the spots on the basil leaves which are losing their green color and how that progresses to darker spots which eventually turn completely brown and have a lace-like look (as if something was eating them, although I have not seen anything on the leaves). Then the plant dies.

I have basil (lime, sweet, purple and cinnamon) planted at various times in several locations. Some are inside in the window of the sunroom; some are outside in pots on a deck; there are some in a large planter in a mostly sunny location near our pond. All containers have drainage holes and all are off the ground. Locations have full to mostly sun. None are directly in the ground. They are watered when the soil begins to dry out or when it rains. There has not been much rain in my area (Ohio) this year, so I have watered accordingly.

I believe the problem started with the lime basil, although that may not be the case. I planted the lime last this year, so it could be a coincidence. I now have the problem on most of my other herbs (savory, watercress, sage, salad burnet, cilantro, thyme, chocolate mint and lavender). So far, the only ones unaffected are the chives. The plants outside in the huge planter (an old wash tub on legs) near the pond seem to be doing best, followed by the ones on the windowsill inside.

I have been raising herbs for about 7 years and have never seen this before. I've scoured the internet for clues but nothing seems to fit. Any ideas? Thank you so much.

Goodness -that doesn't look happy does it? I have to say if this basil were mine I'd just dump it. It is tiny anyway and you could start fresh plants from seed in the time it would take to nurse that back to health - if it were possible. I haven't a clue what problem could be affecting all those plants from different families but it sounds more like a cultural issue than disease since it is affecting unrelated plants such as watercress and lavender. Sorry not to be of more use.

No, it's not happy at all, but, thanks for your thoughts and trying to help. Yes, I guess I'll need to throw it all away, and would have already, but really want to find out what has happened -- especially in the event it occurs again. Earlier plants (which are very large now) were doing well until recently. I'm hoping it is all just an aberration which will never occur again. Thanks again.

Interesting. I agree with Floral that it's not likely to be a disease if it's affecting completely unrelated plants, especially salad burnet as well. The only thing I can think of in that sort of category would be an oomycete pathogen.

Have you had a look at the root balls on any of them? If not, try taking a look at one of the worst affected.

The speckling looks a bit like insects. Have you taken a torch out there at night? I had some beetles chewing my basils one year, and I spent ages trying to find the culprit because they only visited after dark.

Have you done anything differently this year? Changed mulches or changed fertilisers or something? Is the water from a reliable source? You could test the soil pH...

Thank you for your comments Sophie. I discarded the herbs several days ago so am not able to check the root balls but will keep this information in the event it happens again. I did notice since my original post that in all cases, whether basil, sage, lavender, etc., the stem was turning brown and was moving up the plant in small increments.

Pity they've gone. I would have been interested in this browning. Sage and Lavender are sub shrubs so their stems naturally go woody. Basil, while not a shrub also gets brown and woody at the base as it matures.

Of importance might be that the plants in question were all quite young, too young in the case of basil for the stem to turn brown naturally. As the browning continued up the stem, the leaves would also turn brown, whither and die. As I think about it, my gut tells me that the problem began after planting some lime basil (from a seed packet not formerly used). All the aforementioned seedlings/plants were in close proximity to each other and the lime basil was the first to succumb--perhaps the seed was diseased. In any case, I appreciate your thoughts and comments.

Is it possible that they got some Round-up drift-spray? This is the way plants die from Round-up.