So I have these ten seedlings all of which are soon to be moved outdoors. My setup is 2 cfls, 35 watts about six inches above the plants. They're about two weeks old, I have moved five of them into a potting container with the other five being in red solo cups. The problem with the seedlings is that the majority of them have yellowing on the tips of the lower leaves and some have brown spots on the edges of the lower leaves or a bit towards the middle. Any tips or advice are greatly appreciated.
What soil are you using? Sounds like nute burn from hot soil. Also next time fill the cups full with soil!!! you should be able to get about 3-4 weeks of growing in them cups before you transplant, u just cut your time in half by less soil! Also check your pH
nute burn you need perlite in the soil too also CFLs should be 1-2 inch from the plants. It won't burn them unless they are touching the lamps. Check the temps in the room though. Also have fans on them 24/7 here's an easy soil mix for seedlings 30% perlite 50% peat moss dolomite lime (1 cup for 20 gallons of peat moss about) 20% worm castings (baby food for plants) OR promix+20%worm castings
I am using just miracle gro, which seemed like a bad idea buuut I went with it anyway. If it is a nute burn how can I drain the soil of excess and change the pH? And is it too late to introduce an entirely new soil mix?
No, I would take them out of there gently, rince water on the soil so it comes off and then try getting a less strong soil mix. MG is ok for bigger plants not seedlings!
Gotcha Thanks! What kind of risk would I run if I continued to us MG through the remainder of the seedling stage? And if I was to use that soil mix, should I then use MG when I move them outside or continue to use that mix?
the risk is to burn them more and stunt them for life (runts) take them out of there asap, imo, without damaging esp. the main tap root (the central root), shake off the soil gently with fingers, mist the roots to get most but not all of soil out, then place in a non agressive mix (peat-perlite-castings-lime) or promix perlite castings. After a month, move up to a bigger pot with some composted horse manure and kelp at bottom (and still the same mix). Later repot with flower nutes at bottom (high p bat guano, kelp). You can also use blood and bone meal later (instead of horse manure and guano). Alwys add kelp or greensand for K though. Good luck.