Purple Veins Tomato Leaves

[susgreaves]

Hi All,

I have a desperate tomato question - let me know if this is the wrong place to ask this. Every year I have two tomatoes (this year, a Cherry and a Black Sea Man) growing in two pots in a little greenhouse and haven't really had any problems. This year they had a great start and have a bunch of tomatoes but the Black Sea Man just stopped a few weeks back and now I can see some clear symptoms of something and I'm not sure what it is. The undersides of the leaves have purple veins and the top sides have little darkenings around the edges. It's a lot of the leaves, mostly the young leaves. I've attached a couple photos of one of the leaves.

No real other symptoms. No insects (that I can see...). Leaves aren't wilting or yellowing. The Black Sea Man is in the smaller pot (5 gallon pot) but I've never had problems before. Then again, I've never had such an amazing start. We're in the Edmonton Alberta area and we had summer weather in April and May. I was wondering about a deficiency. Could the huge growth spurt in the spring have "depleted" the soil? I thought maybe phosphorous deficiency because I've had that before with purple undersides but that's usually the entire space under the leaves, not just the veins. I plan on getting something to test the soil but we live so far from the city and I was wondering if anyone has any ideas or maybe this is something very obvious and I can get started with something.

Thanks!

 

[YumYum]

First thing to check in a possible nutrient deficiency problem is the pH of the soil and then go from there because if the pH is way off, the plant won't be able to pull up that nutrient from the soil as well as it should even though there is plenty. You have to run the pH lower in potting mix than you do in soil.

 

[Oliver Buckle]

I'd say Yum Yum is on the right track with nutrient deficiency. I can never remember which nutrient gives which symptom, but I am pretty sure it is a trace thing rather than NPK. I would give it a bit of seaweed extract and see what that does.

 

[susgreaves]

Thanks for the advice! I estimated the pH to be around 6 with ph strips and water since I don't have a proper testing kit. Possibly as low as 5. The soil also fizzed a little in vinegar and fizzed vigorously in baking soda water but that's probably not very accurate. I gave them both some seaweed extract but if the soil is 5 to 6 pH, is that acidic enough to cause poor uptake of nutrients? Can I fix the pH in a potted plant this late in the game?

 

[YumYum]

If the pH is around 6.0 in potting mix then that should be good. You probably just need to fertilize.

 

[DirtMechanic]

Put your finger in the soil and if it is wet stop watering it so much. Use a flowering \ blooming liquid fert that has a high middle number on the phos plus micronutients.