Cal mag def spots at the top of the plant.

Ive got 8 Blue dreams sitting in 5 gallon pots of promix under a 600w super hps bulb the correct hight above the plants.There going to be starting week 5 soon Ive been feeding them 10ml of bio thrive bloom, 5ml of cal/mag, 5ml of bio fish(not the name but its the fish sup in the g.o line), 8ml of big bud and 5ml of silica blast. Ive been ph'ing at 6.4 with room temp water. I fed yesterday a noticed what looks like the beginning of cal/mag def but its at the top of the plant? anybody know why that might be? i know that it should be going after the bottom leaves first of its a deficiency but i didn't think that 6.4 was a bad enough ph range to cause a lock out. I could use some help, thanks

Test the soil PH.

PHing the water won't do a thing. The cut off for calcium is a soil ph of 6.5. Ph'ed water isn't strong enough to change the PH of the medium. If the PH is off. It'll take a larger dose of either a base or acid to change it. The amount base/acid to ph water is a microdose to soil.

Younger plants can take low PH..until they hit flower. If the soil PH isn't close to the 6.5-7.0. The plant will express lock out problems.

SouthCross said:

Test the soil PH.

PHing the water won't do a thing. The cut off for calcium is a soil ph of 6.5. Ph'ed water isn't strong enough to change the PH of the medium. If the PH is off. It'll take a larger dose of either a base or acid to change it. The amount base/acid to ph water is a microdose to soil.

Younger plants can take low PH..until they hit flower. If the soil PH isn't close to the 6.5-7.0. The plant will express lock out problems.

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How do i check the soil ph? ive never had to do that before this problem has only happend in the last two harvest and only to my blue dream cuts. thanks

jswett1100 said:

How do i check the soil ph? ive never had to do that before this problem has only happend in the last two harvest and only to my blue dream cuts. thanks

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Get a tall shot glass or a small clear drinking glass. Tablespoon. Scoop up about 2 tablespoon samples of soil out the pot. Two different spots. Try to get it as deep as you can without hurting the plant. 1"-3"

Put the dirt in the glass container. Don't pack it down tight. Leave it kinda fluffy. Add the same water you've been using on the plants. Cover it with about an 1" of water. Let sit for at least 15-20mins. You can also let sit overnight to get the clearest sample.

Test the PH of that water.

SouthCross said:

Get a tall shot glass or a small clear drinking glass. Tablespoon. Scoop up about 2 tablespoon samples of soil out the pot. Two different spots. Try to get it as deep as you can without hurting the plant. 1"-3"

Put the dirt in the glass container. Don't pack it down tight. Leave it kinda fluffy. Add the same water you've been using on the plants. Cover it with about an 1" of water. Let sit for at least 15-20mins. You can also let sit overnight to get the clearest sample.

Test the PH of that water.

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So i put soil in a cup then i put water in it and let it sit. so how do i get the water out after? or do i just put the ph pen directly in the soil/water cup? Also i always ph so should i set the water to my regular ph and use that or just my regular tap which is around 8.0 ph?

jswett1100 said:

So i put soil in a cup then i put water in it and let it sit. so how do i get the water out after? or do i just put the ph pen directly in the soil/water cup? Also i always ph so should i set the water to my regular ph and use that or just my regular tap which is around 8.0 ph?

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I use a syringe from the feed store. An eye dropper would work. Stick a plastic straw in it. Cover one end with a finger and pull it bit by bit.

The water will be kinda murky but you can still see the red, yellow, or green of the test.

SouthCross said:

I use a syringe from the feed store. An eye dropper would work. Stick a plastic straw in it. Cover one end with a finger and pull it bit by bit.

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Oh okay that could work. I can use the same syringe I use to measure my nutes. Thanks for the help il let you know what my soil ph is and il get back to you.

SouthCross said:

I use a syringe from the feed store. An eye dropper would work. Stick a plastic straw in it. Cover one end with a finger and pull it bit by bit.

The water will be kinda murky but you can still see red, yellow, or green.

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But should i ph the water i put in the soil or just use my tap?

Tap. Nothing added. If that's the source water you're using.

SouthCross said:

Tap. Nothing added. If that's the source water you're using.

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Yes i use my tap water but i always ph when I water. to around 6.5 I just used my tap water when I did what you told me.

You don't want any extra alkaline or acid in the test water. It'll give better a baseline to what ph the soil is running.

SouthCross said:

You don't want any extra alkaline or acid in the test water. It'll give better a baseline to what ph the soil is running.

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okay sweet il let you know il do two tests of the soil.

The stuff that floats. Most of it doesn't sink. There will a middle layer that'd be the clearest. Between what floats and the dirt. Take the sample from there.

jswett1100 said:

okay sweet il let you know il do two tests of the soil.

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Hook it up. You can buy $200 worth of a soil ph meter. Then find out the dirt in a cup method is the same testing procedure with the $$$$ meter. Im cheap.

SouthCross said:

Hook it up. You can buy $200 worth of a soil ph meter. Then find out the dirt in a cup method is the same testing procedure with the $$$$ meter. Im cheap.

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I already forked out that much for my ph tester i dont need another exspensive toy to test dirt haha ive let both test sit for 10 minutes im about to go into the room and post my results

SouthCross said:

The stuff that floats. Most of it doesn't sink. There will a middle layer that'd be the clearest. Between what floats and the dirt. Take the sample from there.

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Okay so ive got two results the first soil sample ph out at 7.4 and the next sample ph at 7.0, what can we get from those results?

jswett1100 said:

Okay so ive got two results the first soil sample ph out at 7.4 and the next sample ph at 7.0, what can we get from those results?

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Let it continue to sit for a couple hours. Retest. If it's the same.

It's alkaline. Calcium is absorbed at ~6.5. Next test is the ph of the run off from the soil in the pot. It doesn't have happen until the plants need water again.

Adjust the ph of the water down to a level the run off coming out the pot is 6.5. It might take adjusting the water to 4.5-5.0. Or lower. Think of the ingredients of PH Down being used as a soil additive. Like sulfur but faster and on a much smaller scale.

A half point PH swing is tiny. Much lower ph water should correct it. Compost Teas will help keep it low.

SouthCross said:

Let it continue to sit for a couple hours. Retest. If it's the same.

It's alkaline. Calcium is absorbed at ~6.5. Next test is the ph of the run off from the soil in the pot. It doesn't have happen until the plants need water again.

Adjust the ph of the water down to a level the run off coming out the pot is 6.5. It might take adjusting the water to 4.5-5.0. Or lower. Think of the ingredients of PH being used as a soil additive. Like lsulfur but on a much smaller scale.

A half point PH swing is tiny. Much lower ph water should correct it. Compost Teas will help keep it lower.

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Okay will do. IITs gonna be a while until they need to be watered again they were watered yesterday. Generally this strain ive always givin 10ml of cal/mag but they seemed to be enjoying just the 5. Its very well possible they do just need to be given more cal mag im not sure but It shouldnt hurt them to give them more especially if they arnt already getting an abundance. Thanks for the help il test once i water. only one of the plants really is showing signs of any deficiency at all and its only a few spots on a couple leaves but i wanted to catch it in the beggining before it got bad. Thanks for the help again

jswett1100 said:

Okay will do. IITs gonna be a while until they need to be watered again they were watered yesterday. Generally this strain ive always givin 10ml of cal/mag but they seemed to be enjoying just the 5. Its very well possible they do just need to be given more cal mag im not sure but It shouldnt hurt them to give them more especially if they arnt already getting an abundance. Thanks for the help il test once i water. only one of the plants really is showing signs of any deficiency at all and its only a few spots on a couple leaves but i wanted to catch it in the beggining before it got bad. Thanks for the help again

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How did things turn out? your pH readings?