Purple tomato leaves

[noz03]

This year I started growing tomatoes on my balcony for the first time. I have 3 plants and apart from one that I call the runt of the litter the other two are doing great, especially the cherry which I have to keep pruning it grows so fast!

Over the last week though I noticed that especially the cherry plant's leaves are starting to get purple spots on them! Similar to this(image from google):

I searched google and some people seem to think it is fungus, some say aging of the plant and some say it is malnutrition. So I don't know what to think!

I cut off most of the purple leaves a few days ago, quite a lot actually because I thought it was fungus, but they keep coming and I can't prune any more.

Anyone have any ideas?

The plants are in 3kg of soil per 3ft plant. I give them a table spoon each of organic fertilizer from chicken manure every month and keep them well watered. It's not super sunny where I live but they get some, and plenty of breeze so fungus now sounds unlikely.

Please help

[applestar]

I think yours look like this, which is identified as Magnesium deficiency here

Tomato leaf symptoms Diagnostic Key
https://vegetablemdonline.ppath.cornell. ... afKey.html

I'm guessing your Chicken manure fertilizer doesn't contain complete nutrients needed by the tomato plant and what was available has been depleted.

Typical quick fix is to add epsom salts (Magnesium Sulfate) -- I haven't done this in a while ... 1 Tbs per 1 gallon water?

I also think chicken manure is usually high in nitrogen but not as high in phosphorus and potassium, and most blooming and fruiting stage tomatoes should be given fertilizer that is higher in these other two elements. The higher N is contributing to the excessive growth.

[PaulF]

I agree that you have need of a different fertilization program. First, do the epsom salt infusion, but then follow up with a full spectrum liquid fertilizer. Several brands of plant food are available with a low N, higher P and K content, like 8-25-25 or similar. This is often called bloom booster or the like. In containers as you water the nutrients get flushed out and need to be replaced every ten days or so.

Don't trim any more leaves. As the magnesium and the other nutrients are absorbed the living foliage will come around. If the leaves are dead, then trim those. Back completely off the chicken manure and go with a balanced plant food with as little nitrogen content as possible. It won't take much time at all until the flowers begin to bear fruit.

[imafan26]

It is difficult to do organics in pots. Organic fertilizers have low npk which is not a bad thing, but not all of it is available and requires soil organisms to convert it to a form useable by the plants. The microbes will also compete for any available nutrients. If you do organic in pots you can use something like tomato tone. I am surprised you got anything to grow with chicken manure in the pot. Any manure or compost in pots has been a deadly combination for me. You will need to supplement with weekly feedings of fish emulsion or liquid kelp. Epsom salts 1 tablespoon per gallon of water should be enough. Magnesium is a minor element that is only needed in small quantities but can be made less available if your soil is alkaline. Adding chicken manure to the soil will make it more alkaline.