# Ph issues help!

Discussion in 'Growing Marijuana Indoors' started by rockstar99, Nov 28, 2011.

1. Ok guys i need a little help i checked my PH run off and it showed 5.4 average that explains why some of my plants are a little yellowish green ... how can i adjust this and what should a run off ph usually be at?

2. ph should be 6.3-6.8 for soil, get some ph up and down by gen hydro or a few other manufactures, you need to water with a higher ph and test runoff untill it evens out and raises up to about 6.4

3. ok you think if i used a 8.0 ph in the water and gave them to the plants that it would equal it out because im giving them a mid 6 and its giving me a 5.5 ph so if i raise it to about 8.0 ph it will give me a 6.5. also i have heard doing this method is bad unless you flush the soil is that true. and if i were to flush it how many gallons of water would you say i should use to flush the 5 gallon bucket of soil.

4. ya know i think thats about how it works, yo try and even out the soil ph by the input, cos apparently the runoff is the ph of the soil. and shoot what ive heard about flushing is use 3X the amount of water...but 15 gallons sounds insane, lets get some more experienced blades in here and help out.

5. toss in the gardenlime

• Like x 1
6. You have the right idea -- input a higher pH to get a resulting higher runoff pH -- but the math doesn't necessarily work exactly the way you are thinking. No one can say for sure if using 8.0 water will get you in range, your runoff pH is the result of many factors interacting with each other. You'll have to experiment and see what input pH will get you the runoff pH you need as a result of the interactions of your water, nutes, soil, additives, etc.

Getting your pH in line does not create the need for flushing -- if anything, flush when you are unable to get your pH in line. Flushing is to cleanse the soil of excess ferts, salts and waste byproducts. And yes rule of thumb is to run 3x the pot volume through, so 15 gallons of water to properly flush a 5-gallon pot. You should only need to flush 1-2x per grow unless you are having substantial problems.

7. #8
Last edited by a moderator: Nov 30, 2011
Yep, what toast said. If you are doing 6.5 now and comming out with 5.5 I personally would try 7.5 next time and see where that gives you, and go from there. Dont over water or anything, just wait till they need water and gradually adjust. Unless they are looking terrible then maybe flush. And yea 3x the volume of your container, and yea flushing sucks. Also, lime is probably not a bad idea. I have never used it my self but a quick search can tell you all you need to know. I think you add t tbs per gallon of soil. Not sure though so dont quote me. You can work it into the soil or even put it in water and water it in. I am considering going that route myself.

8. Depending on how you grow, there are a number of ways to adjust your pH.

When growing hydroponic marijuana the pH of the nutrient solution should be between 5.5 and 6.8. In most cases optimal pH is about 5.8 to 6.3 but this may vary slightly depending on the particular marijuana strain and the growing conditions you provide.

Some growers report good results with pH as low as 5.0. You can experiment to see what works best for your particular plants but always keep the pH between 5.0 and 7.0.

Measure the pH right after you add the nutrient solution to the reservoir (mix well first) because the nutrients will change the pH level of the water. Check the pH level about once a week.

pH-up and pH-down solutions are used to adjust the pH level of hydroponic nutrient solution and hydroponic media when the pH is out of range. pH-up (also called pH increase) is used to raise the pH level and pH-down (also called pH decrease) is used to reduce the pH level. A pH-up or pH-down solution for hydroponic or aquarium use is recommended.

For hydroponic applications, nitric, phosphoric or citric acids (even vinegar) can be used to lower pH, while potassium hydroxide can be used to raise pH. If you understand what you are doing, you can use them instead of buying pH-up and pH-down solutions (contributed by james and jorge).

However, if you aren't sure of the correct amount of acid or base that is needed to adjust the pH to optimum values, it is best to buy a solution specifically made to raise or lower the pH and carefully follow the manufacturers instructions.

Unless directed to do so by the manufacturer, don't try to adjust your pH by more than 0.2 per day. Make drastic changes over a number of days. If your pH is 7.0 and you would like it at 6.5, try lowering it by 0.1 a day for 5 days (or do it even more gradually). Overcompensating can spell disaster for your garden.

"pH And Marijuana Growing In Soil"

When growing marijuana in soil the pH of the soil should be between 6.5 and 7.0. When growing in containers, a single pH reading for each container is recommended. When growing outdoors in a garden, it is best to take two or three pH measurements from different areas of the garden.

If you have a large garden, you may have to adjust the pH in various parts of your garden to different levels. Check the pH once every one-two weeks.

Unlike hydroponics where the nutrient solution is in a single reservoir and only needs to be checked once, a soil garden will get its nutrients from the soil it is growing in. Even a small garden that contains a few plants may have soil that varies in pH from one area to another.

Most fertilizers cause a pH change in the soil. Adding fertilizer to the soil almost always results in a more acidic (lower) pH. As time goes on, the amount of salts produced by the breakdown of fertilizers in the soil causes the soil to become increasingly acidic and eventually the concentration of these salts in the soil will stunt the plant and cause browning out of the foliage.

Also, as the plant gets older its roots become less effective in bringing food to the leaves. To avoid the accumulation of these salts in your soil and to ensure that your plant is getting all of the food it needs, you can begin leaf feeding your plant at the age of about 1.5 months.

Dissolve the fertilizer in water (worm castings mixed with water will work well for leaf feeding) and spray the mixture directly onto the foliage. The leaves absorb the fertilizer into their veins. If you want to continue to put fertilizer into the soil as well as leaf feeding, be sure not to overdose your plants.

"Adjusting pH of Marijuana Grown In Soil"

A good way to stabilize soil is to use dolomite lime (calcium-magnesium carbonate). Dolomitic lime acts slowly and continuously, so soil will remain pH stable for a few months.

Using fine size dolomite lime is important, coarser grades can take a year or longer to work. You can find fine size dolomite lime at any well stocked garden supply center.

Dolomite lime has been used by gardeners as a pH stabilizer for many years. It has a pH that is neutral (7.0). When added to soil in the correct proportions, it will stabilize soil at a pH near 7.0.

When growing in containers, add one cup of fine dolomite lime to each cubic foot of soil. Mix the dry soil thoroughly with the dolomite lime, then lightly water it. After watering, re-mix it and wait for a day or two before checking the pH. When growing in an outdoor garden, follow the dolomite lime manufacturers instructions.

Lowering soil pH: small amounts of composted leaves, cottonseed meal, or peat moss will lower the pH of soil.

Raising soil pH: small amounts of hardwood ashes or crushed oyster/egg shells will help to raise the soil pH. Hydrated lime can also be used to raise the pH of soil. In containers, use no more than 1/8 cup of hydrated lime per cubic foot of soil (per application). Mix it into warm water, then apply the water to the soil. When growing in an outdoor garden, follow the manufacturers instructions.

Wait at least a day or two before checking the pH level of soil after attempting to raise, lower or stabilize it. If adjustments still have to be made, use small amounts of whatever material you are using. Don't try to adjust the pH more than 0.1 every two days.

I've found that many people using pH Perfect nutrients from AN have an easier time controlling their pH. But these tips will help too, if you're not using the lineup.

9. #10
Last edited by a moderator: Dec 3, 2011
Nice and Kind.

10. #11
Last edited by a moderator: Dec 3, 2011
For those of you that don't know, a neutralisation reaction is one between an acid an a base (an alkali is a soluble base). Acids have a pH lower that 7 and alkalis higher, 7 being neutral, you all know this. Acidity is caused by dissociated (free) hydrogen nuclei (the H+ from HCl - hydrochloric acid), the higher concentration of these the stronger the acid (as a general rule)(i.e. pH1 lots of [H+]). Bases dissociate hydroxide groups (OH-) and the same principle applies stronger base = higher conc of OH-. H+ and OH- react to form H2O. and the remain components of the acid form a salt.

e.g.

Hydrochloric acid + potassium hydroxide = water + potassium chloride

HCl + KOH = H2O + KCl

So basically to help you understand you have to add a basic solution (an alkali - potassium hydroxide for example) of pH greater than 7 to neutralise the acid. Adding anything less than pH 7 is just adding more [H+], essentially more acid. You need to get the alkali in there to neutralise that shit.

soz for the jib