[ade1865]

Hi. Have some tomatoes in growbags which are not doing very well. Couple of tomatoes on each plant and not really growing vigorously. Leaves look purpley ish I think. I'm guessing poor compost in the bags, or planted too close together or too wet or dry?

Any ideas?

[jambop]

Are they outdoors? I have seen this when early in the season we have had a cold spell. Tomatoes hate cold and when they get cold they do turn an odd colour. They other thing is ... grow bags. With plants growing in open soil I have never had a problem with tomatoes requiring to be fed but with a grow bag you are totally reliant on the fertility of the compost in the grow bag and could be a magnesium deficiency , if it is not up to snuff they may be needing some feed? I would give them some liquid feed as it cannot hurt them but if they have been exposed to cold conditions this might be the actual problem and the may well pick up when it gets warmer. Good luck

[ade1865]

Thanks Jambop

Yes they are outside and the weather has been up and down. I've given them a little feed made from boiled bananas. I'll look into some more feed though. Thanks.

[mumofstig]

As well as cold weather damage," tomatoes suffering from phosphorus deficiency exhibit symptoms such as leaves showing purple veins or with an overall purple color"
rhttps://homeguides.sfgate.com/causes-tomato-plants-purple-41716.html
Using Epsom salts as a foliar spray usually works.
Dissolve a level tablespoon of Epsom salts in 2 litres of water and spray onto the leaves