Hi All, I've been hardening off my toms in a cold greenhouse and only a few of them have bits of purple on the edges of the lower leaves. It seems to affect biggest plants.
I've read this could be a sign of lack of potassium (I was just about to start watering them with tomorite) or it could be due to the cold and I've read this is nothing to worry about? Does anyone know more about this please?
Hi Mandy. Hints of purple on the leaves of seedlings is very common. Cool weather can cause it. If they're in decent potting mix it shouldn't be a deficiency but it wouldn't hurt to give them a diluted feed - 50% of the recommended strength. Don't feed them again until the first flowers appear.
Don't use tomorite yet, not till the first truss of fruit has set. It is probably cold that has empurpled the leaves, a weak drop of seaweed solution will help if there is indeed a deficiency of anything.
I think it may be magnesium rather than potassium that they're lacking. But more likely it's just the cold - mine are the same, although the newest leaves look a bit greener (so far).
the newest leaves on mine are greener, it's not getting any worse so I'll leave them be. Tonight is their first night out at only 7 degrees (but in a cold greenhouse with missing bits)
That's on the cool side. Still, they're tough little blighters.