Onset of Mag. deficiency?

[elsamurai]

Just finished my first run off test, I think I got the gist of things. My normal irrigation water was sitting at 6.5. I saturated the soil as per the instructions, waited and hour, then ran the distilled water through the plants. The run off read at 6.1-6.0. That leaves my soil PH sitting at roughly 5.8. How do I rectify and neutralize the acidity content? Just correct by using less acidic waterings?

that's what I do. water in at 7-7.5

 

[Waira]

Musky- for us soil growers, nothing beats an actual in-soil pH reading! The Accurate 8 soil pH probe is a good unit for the money-- this icon shows it, the long probe one- hsoil: ...works on the same principle as the other cheapie skinny probes (useless!) you see at garden centers all over, but it's much more robustly built and accurate,... has a built in moisture meter too! A TDS or EC meter is also very handy, though not needed all the time, but what it tells you can be critical to dealing with pH issues,... TDS and EC are measuring the same thing, but reporting it in a different way- ppm is a conversion from EC,... anyway, for pH issues, and water, it's all about the hardness of the water, how much dissolved minerals are in it, namely CaCO3 (to a lesser degree, MgCO3 too, amounts vary),... it's the CO3-- that becomes HCO3- that does the buffering of H+ in solutions,... some hardness is good for this reason; too much can cause problems with build-up of minerals, and too little makes it difficult to stably pH adjust; in RO/DI water, those buffering minerals have been stripped away, so that even small inputs cause wild pH swings... for soil growers, RO/DI isn't necessary, but knowing how hard the water is important,... some folks blend it with tap water if the ppm's are high,... if you have native 6.5 water, it sounds pretty soft-- low ppm's, which is generally good! You can add Ca-Mg supplements to it, which will raise the pH some, and give the plant the extra Ca and Mg they tend to really need,... lots of choices, and formulations,... I'd stay with one that has all carbonate sourced Ca and Mg,... General Organics CaMg+ is one,... mind some of the others, as they use nitrate sourced Ca/Mg, not that that's a bad thing, but as such has reduced carbonates in it,... So, like El Sam' said, for now, don't adjust your water, if anything, use a pH up or Ca-Mg product to raise it, and water as usual,.. and keep your feed soln. pH above 6.5 too,... the soil is a bit too acidic, but not enough to warrant more drastic measures,... next grow round, pre-test the soil pH, and look into getting some garden lime, dolomite lime, or the like, and mixing some in,......easier to prevent than fix!

 

[Muskellunge218]

Dam, thanks for the write up, Waira-botinast extraordinaire! The CalMg plus product by General Organics has been ordered and is on it's way. I knew that was an impending reality with me running under a LED. Last two waterings, yesterday mid-day and this morning, were at 7.1 PH. The light green is fading and the plants are still noticeably growing. Ill post pics if anyone is interested. How much longer should I run these basic waterings, and the million dollar question, what is the butter zone PH that one should water at, or at leas an average? Also, for reference sakes, my tap water that I have been using for irrigation, after resting for 24 hours, sits at 7.6. Also, the city maintains the water to an extent, my home does not possess a water softener. A digital PPM reader is another impending purchase as well. Thanks again W.