ph fluctuation

[allhailthebud]

hey people.,

 

ive looked over the net and it seems a few of my plants have a ph fluctuation.. im guessing just keeping a steady ph from now on will clear it up ?

 

no-where on the net actually told me how to fix the problem. i havnt been using my ph meter because i need to get new batteries...

 

cheers

[Luke Skywalker]

Well, if you don't have batteries for your pH meter how do you know that it's fluctuating? Are you using an indicator liquid tester?

 

pH can swing a bit without harm, and it may actually be more beneficial to run pH over a range, say 5.5 - 6.2, with the low end to start and moving up slowly over a week or so of recirculation to the higher figure before being adjusted back down. This is because nutrients are pulled up by the plant in varying proportions at different pH levels. As the nutrients in the solution are drawn upon by the roots, the pH levels will change to reflect this. i.e. if the plant pulls out an acidic substance, (nutrient ion, although some are alkaline) it will make the solution more alkaline in exchange.

 

What makes you think you've got fluctuation, is it a deficiency you've identified or is it simply from getting swinging results of tests? Also, what kind of water are you using and how does it read straight from the source in pH and e.c.? Tap water often contains lots of impurities and salts and this can affect how the solution behaves in holding pH levels and resisting pH changes.

 

Firstly though, it's best to get some details from you regarding the system. Run to waste, recirc, media, grow room size and lighting setup, and what you've done to prepare the media. What nutrients and additives and how long the plants have been in there, temps, humidity etc etc....

 

Some media like perlite and clay will need to be flushed for a day or so in a fresh, pH adjusted solution running continuously to "set" the pH level of the media into the right range. You'll have to add acid to the tank over that day as the pH rises when it runs through the media. Media like coco-peat and similar organic soilless media will usually not require such a pH "setting" but will benefit from a quick flush with pH adjusted water to ensure the right levels are there and that it is nice and clean. Some companies make coco-buffering solutions which may be of benefit in this end.

 

So yeah, a little more info would help, and go get some batteries for your pH pen. You'd be well advised to check the calibration on the pen and have a liquid comparison test just in case anyway.

 

Hope that helps.

[allhailthebud]

luke,

 

the plants are in dirt but i plan to set up a flood and drain setup that i seen on this forums and another, the Sea of Green flood and drain setup.

 

I have about 15 clones 30cm tall just repotted tonight, the reason i thought it was ph fluctuation was because i was using the nute solution and then i started watering them with water straight from the tap.

 

 

 

i was reading on this site http://www.marijuana-seeds.net/Thanks-ThankYou.htm under over water, underneth it has a couple pictures http://www.marijuana-seeds.net/Thanks/1301.jpg and http://www.marijuana-seeds.net/Thanks/1302.jpg

 

thats what my plants currently have.^^^^only on a couple leaves on each plant

[Luke Skywalker]

They're indoors then? I wouldn't recommend potting out clones from soil (or potting mixture?, there is a difference) into a hydro system. It's messy and can lead to disease problems if you're not thorough. Not to mention the stress involved.

 

If the pots are small it may move the pH up a bit, depending on what the pH of the media, it's CEC, (ability to hold onto some nutrients,) and what the pH of the water you used was.... It could be overwatering perhaps, but really, I'm clutching at straws here...

 

I really need to know what the setup of the growroom is, and to see a photo of the actual plants to give more of a specific diagnosis. Other than that, I would look toward getting a soil pH test kit and seeing what that gives you after a representative sample from many pots. You may have to lime or acidify the soil/potting mix, depending on what it is. What rates of nutrients and what have you fed it too? If you can really give me a scary long rundown of what the setup is and as much info on the history it will help heaps...

 

Sorry to be not enough of an assistance, but a picture speaks a thousand words, nes pas?

[allhailthebud]

luke,

 

ive got about 20 plants in soil from the backyard under 400w in an area OF (in meters) 2.5L x 1.5W x 2h

 

since i noticed the yellowing i repotted them into bigger pots and started giving them a mid strength nute + gave them a dose of epsom salts for what i think was a magnesium deficiency,

 

Since i gave them the epsom salts yesterday the plants are standing up again looking healthier..

 

just wondering, how long does it take for the purpleing of the stems to f-off ?

 

and will the yellowing leaves thrive again or will they just die after it recovers from the deficiency ?

 

ALSO - does anyone know a rough guesstimate of how much PH UP/DOWN to add to how many litres ?

 

i honestly think i added 1ml to about 9L of water and it went from 7.2 to 3.8

 

i also have to go get a soil ph test kit..

 

ive been feeding them currently per 20L

 

1ml superthrive per liter

1ml amsterdam indoors per liter (A +

Edited December 14, 2007 by allhailthebud

[Tom]

ive got about 20 plants in soil from the backyard under 400w in an area OF (in meters) 2.5L x 1.5W x 2h

400w is woefully underpowered for that sort of area, 2,000w would be closer to the requirements for optimum growth.

since i noticed the yellowing i repotted them into bigger pots and started giving them a mid strength nute + gave them a dose of epsom salts for what i think was a magnesium deficiency,

Yellowing is not due to Mg deficiency, more a sign they are lacking nitrogen.

ALSO - does anyone know a rough guesstimate of how much PH UP/DOWN to add to how many litres ?

That all depends on the starting PH and the fertilisers, time to buy those batteries and calibration liquid as Luke suggested, if you can't supply photos then we are at least going to need accurate information.

They're indoors then? I wouldn't recommend potting out clones from soil (or potting mixture?, there is a difference) into a hydro system. It's messy and can lead to disease problems if you're not thorough. Not to mention the stress involved.

Ditto.