water and ph

[pronetorock]

Am noticing the slightest bit of burn on the tips of two of my babies, 6 days old now and no nutes as to yet, and no pics sorry i know they do help. Promix soil under cool white 4100 k cfl's 4 inches away with good ventilation and temps are 76/78, which left me to wonder the problem is water. Used the test strips and came out to 7.0 without nutes and between 5.8 and 6.0 with nutes. Is this water okay to use, would a feeding now help matters? Also there is no food in the soil, if the water is the problem just guessing here. Any advice welcomed thx.

 

[inflorescence]

Some promixes come with a fert "charge" which is a one time release of nutes.
Promix says this will be washed away (leached out of the soil) after one watering but if you don't leach the promix first and instead just plant directly into the promix then this charge could be too much for a seedling. Pretty stupid of promix to do this, but since they sell a seedling mix with a lower or no nute charge, they pretty much assume all their other mixes will be used for more mature plants. Also, promix is hideously low in pH unless you add ~2 TBS lime to it first and let it raise the pH to a more stable ~6.5.

 

[inuyasha]

For soil grow the ph is 6,5 to 7,0. bellow 6,5 e above 7,0, I always get problems for my experience,to make a housemade ph downer you can add some acetic acid to the water( vinegar) to put it down, as a ph up backing soda, when I am using nutes I usually don't use much the ph downer, and without nute after letting the water ( I use tap water as a ro system here is more then a 1000 dollars )sit for a while to let the chlorine evaporates my water ph is usually ok if I want to use it plain on my plants.
To test you soil ph you have to test the ph in the water run off, put water at 7.0 and see how it comes, it can not come bellow 6.5, it that happens add some dolomite lime, put some dolomite and mix with water and water you plants with that, be carefull to not add much, as it has a slow release.

 

[sproutco]

Also, promix is hideously low in pH unless you add ~2 TBS lime to it first and let it raise the pH to a more stable ~6.5.

Optimum ph in promix is 5.6 to 6.2 so you would be liming too high. Great post. Promix has a starter charge = liquid ferts sprayed onto the soilless mix to get plants started.

 

[inflorescence]

sproutco, maybe I should have said 2 TBS to MY promix because based on the charts I posted my HP comes in at 4.75 and raises to 4.9 after 7 days, which IMO is WAY to low so I need to add the 2 TBS to get mine even up to like 6.0-6.5. Anything below 6 is too low IMO and it's funny because the HP data sheets promix sends out says their pH is 5.2-6.2 which is just too low IMO and MY promix doesn't even reach their low end of 5.2 so either my methods are off or promix just doesn't want to admit their mixes are to low in pH, EVEN with the lime THEY add.

Also, my measurement of initial ppm of HP, without it being leach at least once, shows an initial ppm of 890 which is too high for a seedling IMO. Not only that but part of that 890 is N which can burn a seedling also, which is what I think is what's happening with the posters plants.

 

[sproutco]

Your methods may be off. Retest according to my post in your thread using at least 2 cups soil mix. I bet people use this stuff by the dumptruck, literally 10 tons, without added lime.

You might be right about the ec being high. I think .5 to .9 for seedlings so 800 divided by 700 conversion = more than 1 ec. See my thread for exact numbers in test your own ph. You should use lots of water at planting to reduce the starter charge when planting seeds. These mixes are not intended for seeds but for moving a mature plant to a larger pot. The starter charge can be handy if you "pot up" 100,000 plants and are moving them into the greenhouse. You have to get a sense for conveinence in the greenhouse industry or even the simple home owner.

Doing great inflorescence!

 

[inflorescence]

I tested using distilled water from the store. It said it had 0 ppm, but the pH was jumpy. I never could get a stable pH reading of just the water before I added it to the mix so I'm gonna try a differnt "brand" of distilled water from the store. It's amazing how different brand distilled waters can vary, I assume from the amount of kH in each.

 

[sproutco]

Ph in distilled water will be 7 because there is nothing in it.

 

[pronetorock]

Hey,thank you for responding! How exactly does one check for runoff? Do i let the water drain from the bottom of the cup with the plant or with another cup just with the soil? Tried test without the plant and it came back same way as before running through soil 7.0 Am afraid would overwater doing runoff they are still so tiny, and never water that much at one time, also on the promix wrapping it says there is lime added, but still should add more? I asked dude that very question at store and said the buffer in it was enough and i didnt want to have to much in it. Never have heard of this fert charge but dont think that was the kind of promix i bought. This whole ph thing is new to me ,so i just add few drops of vinegar with plain water take ph to 6.0/6.5 and leave out vinegar when adding nutes if it is also at 6.5 is this correct?

 

[sproutco]

Very dilutely add ferts to your water that has npk plus 6 micronutrients: iron, manganese, zinc, copper, boron, molybdenum to your water. You would do this when true leaves form not the first unserrated leaves or codyledons that appear. Adjust ph to 6. You can use vinegar but there are better things to use. See how to make my own ph up and down in my signature. You might need to go up or down depending on your water's buffer to change. If your promix or ferts do not contain sulfur, you might add 1/4 teaspoon epsom salts per gallon of water along with your regular ferts. Do this once. See me later for more tips and hints.

Be sure to check out the links in my signature below.

 

[pronetorock]

Will give them 1/4 dose of veg ferts 5-5-1 but will check all what is in it. Thing is tried promix b4 with different water source unter 40 watt tubes and they were super healthy, why am so headstrong believing it is the water ph but ph is brand new for me and would be paranoid of overwatering doing runoff to check that. If i just continued to water at 7.0 would the burning if is the case would the plants stablize at 7.0 waterings or continue to burn?

 

[inflorescence]

What kind of water are you using, distilled or tap? If your nutes drop your waters pH that means your water doesn't have much of a buffer in it, so when you water with just water, the water will take on the pH of the soil it is going into. If the soil is acidic,the water going into your soil will become acidic.
But burn doesn't happen becasue of pH, it's from too much ppm or the the right ppm with the wrong ratios or the right ratios but the wrong constituents for your plant at that phase, so if your water has high ppm this could be burning your tips.

 

[inflorescence]

Ph in distilled water will be 7 because there is nothing in it.

Theoretically yes, but I've read 0 ppm water is constantly dissociating it's H's from it's OH's and rebonding. Also, distilled water may have 0 ppm but when I swirl around my pH probe in it the pH drops dramtically, I assume because of either the CO2 from the air entering the water and forming carbonic acid or from the CO2 dissolving from the water.

I mean distilled water has 0 ppm, but has some dissolved 02 in it yet that 02 isn't showing up on the meter because it doesn't conduct ec well, so there may be some carbonates in the water also yet still show a 0 ppm because I'm not sure how well carbonates and bicarbonates conduct ec.

All I know is when I drop my probe in my distilled water, it reads 8 then slowy drops and if I swirl it it will drop to like 5.5.
This is on a calibrated meter so I can't figure it out.
Thanks for all your help though. You definately know your shit.

 

[pronetorock]

That is what is happening am getting tiny brown dots on leaves,now on those leaves with the brown dots the leaves are twisting and color is changing to a burnt shade of green and also others have burned tips. Using rainwater now which though was okay to use, is that why my nutes dropped ph? and before was using dehumidifier water without any problems, would that be close to what distilled is? They were nice and healthy but under flo tubes at that time also, so am left to guess my cfl's to strong for the babies or crappy water, just wanna know why my leaves are burning off to nothing

 

[mace_ecam]

you can have distilled water
you can have RO water
but it is almost impossible to get pure H2O

for seedlings i prefer seedlings raising mix or germination soil, don't know why, but it's like perfect for seedlings...