Question: My first bottom leaves have died and the tips on 3 of my 12 plants have started turning yellow. This is my first grow.
Here's a picture showing the damage on one of the marijuana plants:
They were sprouted in Jiffey 7 starter cubes but I plan on switching to hydrophonic during flowering.
I'm also using a germination station. The plants are on a 24 hr light cycle.
I just STARTED USING THESE NUTRIENTS YESTERDAY. Plants are 2 weeks and 2 days old. HELP!
Answer: This appears to be a slight nutrient deficiency, which is often caused by an incorrect pH at the roots.
They don't look too bad yet, but it's important you react quickly to prevent the problem from spreading.
Have you been checking and adjusting the pH of your water?
I ask because having a too-high or too-low pH is the most common reason that marijuana plants show nutrient deficiencies, especially when they're young like this. Usually the nutrients are "there" in the growing medium, but because the pH is making the soil to acidic or basic, the plant roots can't access the nutrients. The fact that you fed your plant nutrients yesterday makes it seem unlikely that the problem is lack of nutrients, and points to the fake that an incorrect pH is probably causing this problem.
Here's info on how to manage the pH during your grow: https://www.growweedeasy.com/how-do-i-check-the-pH-of-my-water
If you're still having trouble, I recommend going through this 6-step checklist for plant problems: https://www.growweedeasy.com/growing-marijuana-plant-problem-deficiency