Did you spray anything on the plants? Some things can burn the leaves, and it looks like something settled on the edges of the leaves and burned them.
I'm not the expert, so I hope someone answers you to put your mind at ease.
I expected to see sun burn, but since it is only on the bottom leaves, and at the far edges, that puzzled me. Do all of the plants have it, and is it everywhere on the bottom leaves?

Sorry... i forgot to tell that the plant is in a window, and it could be sun burn because the bottom leaves are catching more sun. But the new leaves at the bottom are looking more healthy than the older ones. My first thoughts was for the sun burn, but there are bottom leaves that dosen't catch too much sun but are also brown :( so i'm a bit confused.

I didn't sprayed the plants with anything.

Other thing that is different is the tube that brings water to the plants are turning very green. can be algae problem?

Thanks,
Lu�s

It is, in my experience, common for the older leaves to brown and die as the plants grow. the rest of the plant looks quite nice. If it were my plant, I'd simply cut off the browning leaf segments and watch to see if and/or how it progresses.

However, if you're fairly certain it's not normal, you could look into these things:

If it was too strong a nutrient, you'd also be seeing the effects in the upper leaves. if not, that's probably not it plus it takes a lot to over fertilize a tomato.

It's possible there is some kind of nutrient deficiency that wasn't present earlier and the plant is taking the necessary nutrients it needs from the older leaves to use on new growth and / or fruit.
Have you been changing your nutrients at regular intervals?

It could also be the older roots are dying off, possibly being constricted by the newer roots. since the older roots feed the older leaves (in general) that could be causing what you're seeing. how big is the bottle of clay pellets you have this in? does the medium appear root bound?

have you examined the brown leaves for bugs? sometimes you need a 10X or better magnifying glass to see little things like mites. From the picture, it doesn't look like mite damage, but that's not to say it couldn't be something else.


as for the green on your tube, that IS likely algae. it won't hurt your plants though it does compete for nutrients. algae only grows where there is adequate light, so you might try covering the pipe with something that'll block the light. I like to put a piece of black pipe (used for landscape irrigation) over my clear pipes to deter just such a thing. Really though, if it's only in your pipe and not all over the place in your nutrient solution, you needn't be too concerned with it. well except for aesthetics.

I concur with grizz.

That cherry tom doesn't look like it is a vigorous grower, but it does look pretty and healthy. You probably have nothing to worry about.