No.idea what wrong

[Hog_M@Gundy]

It's not peat based.

Biobizz light is a peat based medium. Also, at this age I'd think the plants would need more water than once every 4-5 days.

 

[Kojiro]

Dialed back the water to only 2 litres. Thought it had worked, leaves perked up, but couple of days later they're down again.

 

[Mañ'O'Green]

It's not peat based.

According to this it is?

 

[Auto Tay]

Biobizz light is a peat based medium. Also, at this age I'd think the plants would need more water than once every 4-5 days.

Especially in that air pot or whatever those are called. My 2 gallon soil plants in flower need water everyday

 

[Kojiro]

Finally got back on here!!!

OK. Plant got better (first pic) 13th march.
Second pic 20th March.
Then by 27th March (third pic) lots of leaves had gone yellow over the 2 days prior to pic. Buds have turned purple. I know it might be fade, but it happened over 2 days. This was after the last feed.

 

[Kojiro]

Finally got back on here!!!

OK. Plant got better (first pic) 13th march.
Second pic 20th March.
Then by 27th March (third pic) lots of leaves had gone yellow over the 2 days prior to pic. Buds have turned purple. I know it might be fade, but it happened over 2 days. This was after the last feed.View attachment 1578395

Finally got back on here!!!

OK. Plant got better (first pic) 13th march.
Second pic 20th March.
Then by 27th March (third pic) lots of leaves had gone yellow over the 2 days prior to pic. Buds have turned purple. I know it might be fade, but it happened over 2 days. This was after the last feed.View attachment 1578395
View attachment 1578394View attachment 1578393

Sorry pics are in wrong order. 1st pic is at bottom.

 

[Kojiro]

Biobizz light is a peat based medium. Also, at this age I'd think the plants would need more water than once every 4-5 days.

Yep. Sorry my mistake.

 

[Kojiro]

Especially in that air pot or whatever those are called. My 2 gallon soil plants in flower need water everyday

I thought the leaves curling and twisting was because of over watering. When I reduced water it improved.

 

[Kojiro]

6.3 is good for peat based soils.

I was going by this :

 

[Mañ'O'Green]

Your chart for soil still shows everything available at 6.3 PH and peat runs better at the lower range than compost soil that is happier at 6.5 PH.

Ps your plants look fine.