I noticed today that couple of leaves on this tomato plant had got brown on them. This has been growing in a quite small 2.5"x2.5"" pot and has needed to be watered every day. It has been growing under the same lights as all other tomato plants and hasn't been any closer than the others. So far it is the only one with brown on the leaves. Difference is that it has been in smaller container and has needed more watering. I have been putting a bit fertilizer in the watering can quite often. I have used calcium nitrate, Fertilome Blooming and Rooting, Ferticare HYDRO (NPK 6-6-25) and TA Calcium Magnesium, but not all of them at the same time and not at every watering, but maybe too often than necessary.

Underside of the brown spots are green and the spots are not dried up. I suspect that there is now excess of some nutrient, which caused it. Roots looked to be fine when I transplanted it now to a bigger pot. Has anyone seen this type of thing?

I think that this is a contact problem. Something came in contact with the leaves and caused the discoloration. The tips of the leaves are fine and then there is a definite line of where the problem begins and ends. The leaf on the bottom looks as if it only had a little drop of whatever caused this to fall on it.

I think that your plants will be fine. The new growth and center of the plant are unaffected.

MissS wrote: ↑Thu Apr 25, 2024 12:16 pm I think that this is a contact problem. Something came in contact with the leaves and caused the discoloration. the problem begins and ends.

My first thought was also that or that the lights have caused it, but I have a lot of tomato plants on the same shelf and leaves touching each other. This one was in the same ice-cream tub as two Benewah plants, which had same size small pots so they were crammed together in there. I have not been spraying anything on them and if it was caused by splashing on them with the watering can, the plants touching this would have got it too. I cannot think anything which could have been in contact with that one and not the others.

Now when I think I had that similar copper brown spots on a micro dwarf last year. I thought then that it had been too close to the led light, but I could have over fertilizer it also.

How often are you using calcium nitrate? I've noticed that it tends to cause problems if I do it more than about three weeks in a row on tomatoes (with foliar sprays), causing them to have a certain kind of chlorosis.

I gave my indoor potted grapefruit tree calcium nitrate in the soil for the second or third time, and I don't know if it's the reason, but I got light brown dry patches in the center of several leaves. The new growth after that was fine.

Anyway, calcium nitrate is awesome, and really gives a nice growth spurt, but it's one you have to be careful with (much more so than all-purpose 24-8-16 Miracle Grow).

I have not kept track how often I have used calcium nitrate, but the ones in the small pots got it more often than the bigger ones, since I have had to water them every day. Some of the peppers were showing nitrogen deficiency, so I used calcium nitrate on them and watered the tomato plants with same watering can.

I have tried to find more information about symptoms of excess nutrients in plants. Some cannabis related sites have information that excess calcium or iron could cause this type of coloration.

Today those areas on the leaves have become lighter brown and lookin almost like sunburn.
Since the affected areas are such which gets a lot of light makes me suspect that what ever it is, it may cause photosensitivity.

HeyZeus Alou! Tell us it's not Big Bubba or Super Sauce Hybrid...

The Gotch

Cornelius_Gotchberg wrote: ↑Sat Apr 27, 2024 10:31 am HeyZeus Alou! Tell us it's not Big Bubba or Super Sauce Hybrid...

The Gotch

It is a New Big Dwarf which sprouted later than others and that is why it was in a small pot longer than others. New growth is fine, so what ever caused it, is not a problem.

Big Bubba, Super Sauce Hybrid and Pink Gift are doing fine.

Super Sauce Hybrid is a bit mystery, since Burpee website lists it as indeterminate, but these plants look like determinate to me. One is already flowering and there is second flower cluster forming with just one leaf between the clusters.

Good to know that this might be a symptom of too much iron.
I'm trying to figure out an organic potassium supplement to try and speed up maturity in my late plants this season - the problem is, there's no 'pure' K in an organic fert.
Molasses is touted, especially by pot growers, so I was thinking of trying that.
But of course it is also loaded with minerals, including iron.
At least if I try it, and see brown spots on leaves, I'll know what to think about it.

Bower, be very careful using molasses.
We bought a tote that had contained molasses and (having read that it was good for plants) I saved some from the bottom of the tote and watered all my new plants (still in pots from the nursery) and killed the lot!!!! .

When I realized what had happened, I used the rest to water the weeds in our gravel driveway, and it did a spectacular job of killing them .

If the molasses is made from sugar beets, it can have residue of clopyralid, which is toxic to tomatoes and many other plants.
Few years ago one home gardener here found the issue hard way after almost killing his tomato plants with molasses intended for animal feed. First he did not believe me, but started testing and concluded that there was herbicide in the molasses.

Vinasse is an byproduct of sugar industry and has been use in many organic fertilizers and it was also found to have herbicide residue. I avoid now all commercial organic fertilizers, which smell like molasses. That is why I use just chemical fertilizers, because then I know what chemicals I have put on my plants and if I would kill them by using too much, I know that it was my own fault.

Thanks for the reminder... I guess I'll try kelp meal instead.