HELP! Yellowing seedlings in coco!

This is my first real proper grow and though all three of my fem Mango seeds sprouted, they are showing yellowing in their first leaves.

Soil is coco with some perlite and dry amendments similar to the proportions the popular youtuber mr. Canuks grow uses.

Light is a yahsense "1500 watt" (265 true watts) blurple led. Only the veg switch is turned on so it's even less than that. Water is tap left to sit for over 24 hours and PH'd to around 6.6. I sprayed thoroughly with a mister maybe several times a day at first so maybe overwatering? Letting the medium dry for a day or so now.

Spouted in their final containers (5gal fabric pots) any thoughts greatly appreciated. It appears the yellowing originates at the center goes outward

Sophon said:

This is my first real proper grow and though all three of my fem Mango seeds sprouted, they are showing yellowing in their first leaves.

Soil is coco with some perlite and dry amendments similar to the proportions the popular youtuber mr. Canuks grow uses.

Light is a yahsense "1500 watt" (265 true watts) blurple led. Only the veg switch is turned on so it's even less than that. Water is tap left to sit for over 24 hours and PH'd to around 6.6. I sprayed thoroughly with a mister maybe several times a day at first so maybe overwatering? Letting the medium dry for a day or so now.

Spouted in their final containers (5gal fabric pots) any thoughts greatly appreciated. It appears the yellowing originates at the center goes outward

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• Must Provide Nutrients from the Beginning – Coco coir is an inert growing medium with no inherent nutritional value
• You Need a Cal-Mag Supplement – Cannabis plants grown in coco coir tends to need more calcium compared to other growing mediums, so usually a standard “Cal-Mag” supplement is needed to make sure plants get all the calcium they need. These contain calcium as well as magnesium (which is needed for your plant to be able to use the calcium properly). Two great Cal-Mag supplements for cannabis are CaliMagic by Botanicare.

Some yellowing or sometimes brownish color on plants that young is normal, they grow out of it. As said above, if your using coco you need to buy some nutrients for when its old enough in about 2 weeks. Also 5 gallons is to big for a plant that size, also if you want you can turn the bloom and veg switch both on, lots of good LED lights like MarsHydro don't have switchs so its a constant blurple plants do just fine with it. But again up to you, update us in about a week if the yellowing gets worse.

Thank you so much! I'm such a noob

Little update; gave a light dose of cal mag in a watering and they are looking much happier a few days later!

Your dry amendments need to break down some before they're available to your plant. The CalMag you gave them has a small amount of N in it, which is why you saw the improvement. As your amendments break down your plant will move forward in its growth. Good luck.

6.6 pH is high for coco.

The perfect temperature and humidity for your plants are found between 75°-85°F and 50% - 70% humidity, with plenty of airflow to replenish CO2. PH is 6-6.5. You may add more calcium and magnesium than normally needed, but less water n nutrients.