Medpot Minstrel: Hydroponics Medical Marijuana

Friday, April 20, 2007

Role of Potassium, Connoisseur Harvest Approaching

Potassium is a macronutrient. It’s the K in NPK. This chemical is used in each stage of a plant’s life. Soils that are high in Potassium increase a plant’s resistance not only to bacteria, but also to mold and mildew.

K is involved in the manufacture of carbohydrates—both sugars and starches. It is also a major player in cell division. It boosts chlorophyll in plant foilage and stimulates and regulates the opening of the stomata. Leaves store and move carbs with the help of Potassium.

Last week I discussed how the polyamino alcohols in Connoisseur increase the elasticity of cannabis cell walls, thus allowing more carbohydrate accumulation in the marijuana leaves. Then when bud formation requires the extra energy, these carbs are transferred to the bud sites.

Potassium plays a primary role in this process. I also mentioned that certain growers got good results reducing the ppm of their base nutrient (i.e. Connoisseur) by 2 or 300 ppm, then doubling up on the Bud Blood during the first week of flower formation.

I called the Advanced Nutrients Medical tech guys, since I was concerned that such high Phosphorus and Potassium levels might hurt some plants. They confirmed my suspicions. You should only try this with well-established plants—ones that have been vegging for some time.

If the plant had only 2-3 weeks of vegging and is only a foot and a half high, doubling the Bud Blood is not a good idea. Also, it’s a new method, unproven in scientifically conducted trials. With anything new, you should leave a large percentage of your crop using your tried and true procedures, and pick one or two “sacrificial lambs,” as the tech guy called them, in order to try the new regimen.

This way you’ll be protecting the bulk of your crop from possible failure, but also providing a scientific comparison to see if your trial method worked or not. Are there any other compatible ingredients with Connoisseur—such as Bud Blood—that we should know about?

The AN tech guy said that if I check the Nutrient Calculator, the suggested ingredients are all compatible with Connoisseur, and are basically the same ones as with Sensi-2. “The interaction with the supplements as far as the feed rate and the time is basically the same,” said Tech Mike.

“Does Connoisseur need extra Calcium, or anything?” I asked. “Not unless you’re growing in coco fiber. If you were growing with Connoisseur in coco, then you would need the Sensi Cal. Otherwise, you would use Monkey Juice for coco.”

I asked about a discrepancy between the Nutrient Calculator and the Advancedpedia. The latter states that Bud Blood, which is very high in Phosphorus and Potassium, should be used during the first two weeks of flowering. The Nutrient Calculator suggests to use Bud Blood for only one week.

Tech Mike explained that it’s hard to be as accurate and up-to-date with published material as with the Nutrient Calculator. The Calculator is updated quarterly, so it more accurately reflects the latest Research and Development conclusions. But the Advancedpedia will be corrected in due time.

Then the talk turned to my reservoir. I have a six-bucket ebb and flow system with a 72-Liter extra deep reservoir. That’s 12-Liters per bucket. I just wanted to make sure that I was doing things right, since I was using this new, super powerful base fertilizer, Connoisseur.

I pre-mix my nutrient solution the night before, making sure that hard-to-dissolve ingredients, like Barricade, are well blended into the mix. I take pH readings every half-hour, until my solution has settled between 5.6 and 5.8 pH. If you get two consecutive identical readings in a row you can be pretty certain that your solution has stabilized.

I have my timer set for three floodings per day, each for a 20-minute duration. My medium is baked clay pebbles, and I flush my system between changes. Tech Mike suggested that I mark the top level when I first pour in the mix, then top up my res up to the mark line with water only, never with food.

Taking evaporation into account, my plants consume about 20 percent of the content of the reservoir, per day. By topping up with water only, I am changing the pH of the mix. “Don’t worry about the pH, it will fluctuate,” I am told. “Worry more about the temperature of the nutrient solution. Don’t ever let it go above 80º F. Better to keep it at 70 or even 60º F. Your roots can cook at anything higher than 85º F.”

I remembered last summer at the height of the heat wave when I had to put ice cubes in my reservoir to bring the temp down. Then Tech Mike reminded me that I should always check my airstones. “Make sure that the air is bubbling through the water. Your roots need to breathe, even when they’re submerged.”

I remember a previous session on the phone, when he explained that your roots can be divided into three sections. The bottom third is okay with sucking up water, the middle third can either suck water or breathe air. The top third of your roots prefers to breathe air.

This is week six of flowering, and I’m still adding Connoisseur A and Connoisseur B in reduced quantities, after that tip burn episode. Instead of 130 mL of each, I’m only adding 110 mL of each. I’m reducing each ingredient in the mix, across the board, by ten to twenty percent.

Instead of 86 mL of Humic and Fulvic Acid and Mother Earth Super Tea Bloom, I’ve added only 72 mL. Instead of 259 mL of B-52, I’ve poured in only 245 mL. Of Carbo Load Powder I measure only 20 grams. Barricade got reduced to 7 mL. Sensi Zym to 380 mL and Overdrive to 150 mL.

The total ppm for week 6 is 1000, instead of the suggested 1400 ppm for bloom-medium feeding. Next week I’ll add nothing but 180 mL of Final Phase, and then I’ll flush the system and harvest. My buds are looking gigantic already—I don’t know if I can wait that long!

I understand that Connoisseur will be available in all markets by next month. The tech guys say that feedback is very good on it—all growers who are testing it are satisfied with the results. I am very satisfied. My ladies never had it so good!

posted by Wes @ 6:06 PM

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