Newbie needs some advice

Hi guys... this lady is Blue cheese, she been in soil for 19 days with only water
She is in a10l pot an ha been getting 1/6 of light

Not sure when to feed her ....... I have Canna Veggie for her madeup in a large tub
How much? How often an when should I start plz

Thanks in advance

Light is 18/6 sorry damn comp

usually when the first 2 leaves that popped up yellow it's time to start nutes (2-3 weeks from sprout). whatever nutes you're using start out at 1/4 strength the recommended dose then continually strengthen the dose week by week

Hard to see in those dark pictures, but yeah I normally start feeding around 3 weeks after sprout. That is also soil dependant.
Some soil, especially cheaper, easier to get soil, has nutrients added. If you are using something like that, you won't want to feed it at all.
Just keep an eye on the leaves, if you start seeing them fade, it will be time to start feeding.

Just keep in mind that your plant communicates with their leaves. If it is happy, the leaves are healthy and reaching for the light.

But also, and confusingly, too many nutes bleach the leaves yellow.
The tips start to look 'burnt'.

Can you test the EC or CF or PPM of TDS of the nute/water mix you give them.

For the first month you want the EC at 0.8 - 1.0
(which is also CF = 8 - 10, PPM = 400 - 500)

Good luck and keep us posted.