Hojas amarillentas

Happy growing, everyone!

I’m reaching out to the community because I’m having a problem: the leaves are turning a yellowish color and yellow spots are starting to appear (I’m attaching sample photos). To give some context: they are XXL autoflowers from BSF Seeds, 22 days since germination. I am cultivating them indoors, with a Quantum Board Q300 light from GrowTech, at a distance of 55cm and with the power set to 45-50%. I usually have a relative humidity of approximately 50-70% and somewhat high temperatures (25-30 degrees Celsius), since here in Argentina it’s mid-summer. At first I thought the problem was the light, that maybe it was too close and burning the leaves. Then I did some research and saw it could be a lack of Magnesium or pH lockout.

Does anyone have an idea what these symptoms could mean?

Thanks in advance and good luck with your grows!

I think 22 days is a bit early to get CalMag problems. What kind of soil do you have? Is it pre-fertilized, and if so, how heavily? How much and how often do you water the plants?

Hello, personally I’m leaning towards a possible nitrogen deficiency? I think you’re growing in soil or coco coir?

I would start by doing a light watering with pH calibrated with a nitrogen supplement and take a reading of the water flowing from your pots to get more information on if your pH is ok and the EC and there you will have proof if your pH is in the right acidity and if the EC is too low you should give them and if it is too high it is blocked.

Welcome! We need more information. We need to know your watering and feed schedules, ph, EC or ppm, medium used, and environmental factors like temp and humidity. Without that you’ll get educated guesses based on a photo.

I am using GrowMix’s MultiPro substrate; it comes pre-fertilized, but I don’t know exactly how much fertilizer it contains. I am watering every 3-4 days, with 500ml (I’m gradually increasing) of carbon-filtered water. I adjust the pH to 6.1-6.3.

My last watering was with vegetative fertilizer but in a very low dose. I am growing in the pre-fertilized substrate

Thanks! I’m going to measure the pH and calibrate. The last watering I did, I already incorporated vegetative fertilizer to give it nitrogen.

Thanks! I’ve been watering approximately every 3-4 days. The last watering I did, I gave them vegetative fertilizer (Top Veg), in a very low dose, 1.5ml per 1.5l of water, and currently I’m giving each plant 500-600ml. I was adjusting the pH to 6.1-6.3 and my water’s EC is very low (150-200ppm).

I apologize for my post. I should have paid attention better when I read your post. I think 30 degrees is a little high but not horrible. I don’t know anything about your medium so I can’t help there. Find out what your medium is made from, is it a soil or coco based medium. It matters when it comes to the correct ph range. If it’s soil based your ph is a little low and could be causing your deficiency. I think it looks like a classic magnesium deficiency or it could be the start of lockout.