what plant age to start using Lucas formula

[naphtali5725]

hi all,

how old should plants be, before starting to use the GH 3 part Lucas formula 8/16 ml per gal in Ebb/Flo?

i started using half strength 4/8 (320 ppm) about a week after sprouting.
about a month after sprouting i went to 8/16 (820ppm), and my plants look like they are starting to yellow, burnt leaf tips, and i keep the PH between 5.5/6.5 res temp is 71, i have oxygen stones in the res as well

res is 20 GAL, tray floods every 4 hours for 15 minutes, and no flood from 10pm-->6am

1000 HPS but i have the ballast at 750... light is on 24 hours for now

kind regards

 

[Jimmycricket]

Are you sure the leaf tips are burned and not showing signs of Potash deficiency?

Also if your putting in twice the nutes but the PPM gos from 320 to 820 your meter is faulty. Twice the nutes will increase the PPM to a level equal to or less then twice what is was before.

 

[the420lizard]

what on earth is lucas formula?

 

[Jimmycricket]

Lol it is a way to use less types of nutes from General Hydroponics.

 

[naphtali5725]

meter is fine, the 820ppm is expected at those strengths in a 20 gal res.

didn't answer the question... how old do the plants need to be, before giving nutrients via the lucas formula.

thanks anyway, i'll figure it out

 

[Dusty Kiefers]

Hey bud I run lucas formula right at 12/12 I use a.n. J.j. Veged a couple clones like 10 days and straight to

luca about 900 ppm heres one

 

[naphtali5725]

Thanks Dusty!! i basically did the same

kind regards