Purple at 18 days

Hello guys, i was just inspecting my seedlings (5 White widow 1 one Sour cream) that i began germinating 18 days ago... In the middle of all of them, there is a purple patch and the new leaves that are coming through look green at the top but purple for the rest of it....
What is this problem (if it is a problem) and how can i fix it? i am very tight on recources and my buget and if it is a huge problem, il have to kill them or leave it

Bump

i read about how this could mean strain... at 18 days i dont want to start giving nutes just yet and i did plan to be organic... so any idea's what this could be? its the same on 3 of my white widow plants... on closer inspection, 3 WW plants have it, two dont and the sour cream dosn't so it could be good or bad... maybe its alittle early to tell? thanks

could be temp as well i know soem strains get purple due to tem p

deoss69 said:

could be temp as well i know soem strains get purple due to tem p

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i used to have an HPS in there... it could get up to 30 degrees but now ive got a blue CFL in there... It was alil warm so ive moved the light up abit and i hope this should fix it thanks

its not heat that gives them purple its the cold temp drops when lights are off

A seedling can be given nutrients has soon has it has it's true leaves.The plant will out grow any that are not been given any i have tested this my self even if it is just superthrive.My plants are set of in a little nurients i'm not saying go mad but 1 drop to every ltr of water will give the seedling a head start of any that are not been given any.I germanate my seedling in water with superthrive in it and my plants always have great root mass.Flush the plants with a little water but ph it has the water in your area may be high set the ph about 5.5/6.0 during veg.The coulour could be a result of salt build up or more likely a result of the plants genetics.