Semi permanent hair colour and Grey hair!

[Isobela]

I use a semi permanent hair colour (24 washes) every 4-6 weeks and only wash my hair twice a week yet all my grey is showing through after about 4 weeks!

Is this normal? I've not used a permanent dye for about 20 years so I'm worried it's going to wreck my hair if I need to switch to a better fix...

Please help !

I use semi permanent and leave it on for about 2 hours or more. Now it lasts ages, in fact I last did it about 5 weeks ago and it's just starting to fade and show my greys again.
I got the tip from here so I'll pass it on!

Where is the grey showing? My roots always start to show after about 2 weeks. Can't do anything about that. But, yes, leave it on for about an hour.

I have a lot of greys and wash my hair every day by the way, so yours should go a lot longer.

Which dye do you use?
I didn't know you could leave it on that long- I'll try it next time!

Greys are mainly at the front, it's not root regrowth it's the whole silvery strands!

I use L'Oreal Casting- it comes out the same colour as if you leave it in for 20 mins, just not as quick to wash out.

Oh great that's the one I use anyway. I'll give it a go - thank you!

Casting here as well. I assume I'm 70%+ white/grey but this covers it
except where I miss a bit.