my leaf tips are turning red

i have 4 seedlingsa dna they all seem to be showing signs of defiency...first seedling is browning at the bottom and eventualy crumbling but new growth is on the top leaves. a next plant has redish yellowe leaves on the bottom and antoher has dark and light leaves..i will post picks asap..can any help me out they all come from the same plant. i used an indoor pottin soil for them may nutrient lockout be the answer? to high concentration should i have gone with outdoor soil..

ok we need to know how old your plants are , what soil is it has it got fertilzer in it ? what size pots they in , how often do u water ?

they are 2 weeks old in organic soil no fertilizer..theyre in large movie theatre cups and i water 2 -3 times a week..

the red leaves are mostly on the bottom and the other plants have like wilting leaves...i dont no why already they are showing signs of stress and disease...right of the get go they have problems...i will post pics soon..thanks guys!

comon guys need some advice