Help! Seedling nutritional deficiency

rollmyegg said:

Hey growers, this is my first topic and also my first grow.

I will start with the basic info.

I'm growing a "Sweet Mango Auto" in a hydroponic system. The Seedling is now 14 days old.
It's just one plant, I decided to start slow. The nutrient mix is a Atami B'cuzz A and B Hydro all in one mix.
I read about it, and what I understood, is that this mix has actually all nutrition's you need from grow to harvest. I also bought a bottle of calmag. I prepared a solution with 1ml of the solution per 1l distilled water and also adjusted the Ph to a 5.5-6. PPM was around 600., now 300. The temperature is between 28-30 Celsius ( 82.40℉ to 86 F) . I know its a bit too high, but the plant never had issues with it until yet.
Two T8 growing lights with enough lumen and with full spectrum. Enough for the first 2-3 weeks until i put it on the balcony.
I don't use a water or oxygen pump in the humidtydome. The plant sits on a rockwool cube 1 inch deep in the nutrient solution. Do I need to add some extra calcium or is calcium oxide enough?

Now to the problem:

Since 3 days , the leaves have a slight pale green color on the outside the leaves, from the halfway from the middle to the border. I was concerned and start to read a bit, and assumed that may a lack of potassium would be responsible. I mixed a new solution, because i assumed I made a mistake with the first one and created some nutrient lockup. Because in the B'cuzz hydro is already potassium oxide (K2O) included I didn't bothered to buy normal potassium. I hope it's the same. Please advise me if I'm wrong at this. Nothing changed, so I start to dig deeper, and found a interesting article that it could be overfeeding. it makes sense because my leaves start to curl weird as well. So I flushed the nutrition solution and put normal tap water for 24 hours to give it a rest and flush out the stuff. Today I woke up and got those yellow dead spots on the leaves. Now I'm on a point where I need expert help.

Thank you all. F.

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• 300ppm, much less, 600ppm, is too high for a start that small. You should be in the 200ppm range. If you stay with dwc, dump your current "soup" (nutrient-rich water), and use straight water for a couple days. Then, introduce a little solution (around 200ppm) and increase it up to 300ppm over a week.
• I wouldn't use a 1-part nutrient solution for growing weed. I highly recommend using General Hydroponics nutrients, specifically "MaxiGro", and "MaxiBloom", both of which are cheap on Amazon and other places.
• Do not use the nutrient feed chart on the back of whatever nutrient you decide to go with. This is usually way too high for growing weed, and each plant has different needs that can't be determined at the lab. Instead, look up the nutrient charts specifically for growing cannabis in either soil or hydro (both of which have different requirements). If no online feedchart is available, rule of thumb is half-strength of what the feedchart on the label suggests.
• In general, you absolutely need an air pump with dwc. Roots need oxygen, and if they are just sitting in the water, your plant will drown. An air pump and air stone will inject dissolved oxygen into the water, that the roots can then use to breath.
• I can't tell what kind of container you're using, but it doesn't look familiar from the picture. A starter dwc usually consists of a 5-gallon bucket, a small air pump and stone, and a netpot sitting in a cut out hole in the lid. Lots of vids on YouTube for building very inexpensive"dwc bubbling buckets".
• If you're going to put the plant outside, you'd be better off just doing soil for the whole grow. Absolutely do not bring your plant back in the house after putting her outside. That's a sure way to get really nasty bugs in your grow room, if you're growing inside as well as out.
• Temps are a little high, but still in range. But you need to get a small fan moving the air around your plant to help keep it cool through perspiration. The breeze moving your plant around also helps build up strength in the stalk. But you don't want too much air blowing directly on your plant because it can cause wind burn.
• You want to add CalMag to RO water, but if going to soil, you won't need it.
• Once you get your plant on the right track, you'll want to look at the new growth to determine how your plant's doing. Damaged leaves will not repair themselves, so don't worry when they don't start looking healthy and new. Again, new growth is what you want to look at. It'll be a little light until the leaves grow larger, then they'll turn darker.

JSB99 said:

300ppm, much less, 600ppm, is too high for a start that small. You should be in the 200ppm range. If you stay with dwc, dump your current "soup" (nutrient-rich water), and use straight water for a couple days. Then, introduce a little solution (around 200ppm) and increase it up to 300ppm over a week.

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rkymtnman said:

exactly what i was thinking. good advice.

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Logan Burke said:

I shot straight to the bottom to reply when I saw 1ml calmag/1l of water....that's a high, high dose of cal-mag, I don't feed my full grown plants that much cal-mag lol....and not very many nutrients have a single formula for both veggy and flower that is effective, but rather, one bottle for veg and a different bottle for bloom, maybe that's what you meant. I know I went from two soil grows to DWC, but with that being said, my first DWC was an unmitigated disaster lol. I believe that you can do it, and with one already started I'd try it, but I'd grow one in soil along side it as a back up so you aren't relying on that for all of your medicine.
Also, I've always believed that it's best not to add something such as cal-mag unless/until you see a deficiency symptom that you think it could be of use for...try using it more as a reactionary measure verses a proactive measure..with the proper planning and people's help like JSB and RkyMtnMan, you'll be just fine for whichever kind of grow you decide to do!

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JSB99 said:

GrowWeedEasy is a great site to learn a ton about growing. I highly suggest you do lots of research there.

Good luck

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