[micou]

All my tom seedlings/plants seem to have this to some greater or lesser extent. It's not getting any worse, but it does keep turning up. I had a search and it seems as though it could be lots of things. What's the collective forum diagnosis?

[8doubles]

Probably magnesium deficiency.
Easily remedied with Magnesium Sulphate aka Epsom salts !

Happens every year to mine !

[Headgardener22]

Could also be sunburn. Do you get the leaves wet when you water? It focusses the sun (and its been bright recently) and damages the leaves.

[micou]

Could also be sunburn. Do you get the leaves wet when you water? It focusses the sun (and its been bright recently) and damages the leaves.

They're in a growhouse at the moment so not much direct sunlight and I normally water them from underneath (which is why that one is actually sitting in a pond getting a good soak  ).

I will take the precaution of not leaving them in full sunlight till they get a bit more used to it, though.

[micou]

Probably magnesium deficiency.
Easily remedied with Magnesium Sulphate aka Epsom salts !

Happens every year to mine !

Right. Does one add it to water, or the soil, or what?

[8doubles]

Probably magnesium deficiency.
Easily remedied with Magnesium Sulphate aka Epsom salts !

Happens every year to mine !

Right. Does one add it to water, or the soil, or what?

Up to you ! Some dilute a tablespoon full in a watering can , i just sprinkle some on the compost and water it in .

[micou]

The second option sounds suitably idiot-proof - I'm going to go for that one. Cheers!