my guess would be a MAG deficiency... try adding some dolomite lime... Check the PH of the soil if you can... could be a nute lockout. My plant did that exact same thing and I added lime as a top dressing and pushed some water down.... Lime has calcium and Magnesium and will act as a PH buffer to not get a nute lockout... You still have to keep an eye on the soild PH though.. Hope this helps
Elway
elway07 Reviewed by elway07 on . is it going to die ok heres the problem. i have 1 plant growing in a greenhouse in the garden (uk). growing in coco husk & fed with hydro tops grow solution a & b. 4ml to 1 ltr water. the plant is about 4ft tall & was looking nice & green.but now the leaves are starting to go a lighter shade of green & the leaf stems are turning in color to purple.just on some of the leafs,not all.but the leafs look like they are dying off.is this normal for this to happen on a outside plant. i have flushed out the roots & Rating: 5