Found this PH chart and thought it was pretty useful! Good visual explanation of the PH levels. So I thought I would post it for anyone that maybe interested.
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I like it,
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So there’s kind of a fine line in there for Phosphorous huh?
PH is very important to maintain in a range or you will see symptoms of lockout very quickly. Not only P. I like to maintain my hydro between 5.5 and 6.2. With Coco/peat you just adjust to your specified target.
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I veg at 5.8 and flower closer to 6-6.2
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Some people intentionally vary their pH throughout the grow to allow the plants full access to nutrients.
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Charts are awesome, But knowing how it works is even better.
This post is in 2 parts copy and paste both into your files for future reference.
PART 1 OF 2
How to Check pH & Stop Cannabis Nutrient Deficiencies
If you’re already using quality cannabis-friendly nutrients, the most
common reason growers see nutrient deficiencies in their plants is because
the pH at the roots is not right!
Adjusting your pH only takes a few minutes, and your cannabis garden will
thank you!
Adjusting pH takes less than 5 minutes, and your plants will reward you.
Think of it like a supplement to make your cannabis grow faster and healthier!
Table of Contents
Introduction: How Does pH Prevent Nutrient Deficiencies?
What’s the Correct pH?
Soil pH Chart (6.0 – 7.0 pH)
Hydro/Soilless/Coco pH Chart (5.5 – 6.5 pH)
How to Test and Adjust pH – Step-by-Step Instructions on
How Much PH Up/Down Do I Use?
Digital PH Pen vs Drops / Strips
Common Questions & Problems
Summary: 8 Things You Must Remember About pH
Intro: How Does pH Stop Cannabis Nutrient Deficiencies?
Get one on Amazon.com!
PH is the measure of how “acidic” or “alkaline” something is, on a 1-14 scale.
A pH of “7” is considered neutral, for example pure water has a pH of about 7.
The measurements of pH has to do with the concentration of hydrogen in the sample.
A cannabis grower can measure the pH of a water sample using special pH tester
drops or a digital pH pen, like the one shown here on the right.
Okay, so why is pH important to cannabis growers?
Cannabis naturally likes a slightly acidic environment at the roots. Soil with
a slightly acidic pH is what causes cannabis plants to thrive in the wild. Proper
pH at the roots helps plants get access to the nutrients they need. If the pH at
the roots is too high or low, the plant can’t properly absorb nutrients and you
end up with cannabis nutrient deficiencies!
Paying Attention to pH Gives You Healthy Leaves!
Achieve healthy cannabis leaves by maintaining pH
Some growers get lucky and grow cannabis successfully without having to
worry about pH. Perhaps they had just the right soil, and happened to have
just the right water to create the perfect pH environment for the plant roots.
If your plant is growing perfectly, without any signs of nutrient deficiencies,
than managing the pH might not be something you’re concerned about.
Unfortunately, many growers aren’t so lucky and their setup naturally has a
pH that is too high or too low for optimum cannabis growth. While there are
ways of getting around testing pH for your cannabis grow, nearly all growers
will do better by paying attention to pH.
What’s Are the Benefits of Managing pH?
By maintaining pH…
plants are less likely to suffer leaf problems or nutrient deficiencies
without nutrient problems, cannabis plants can grow faster and produce
bigger yields
occasionally growers are alerted to possible issues before they become a
problem, for example if you determine the pH is too high or too low, you
can fix it before your leaves start suffering from deficiencies
The main thing to remember is that maintaining the right pH at the cannabis
roots helps the plant absorb nutrients. Why is that?
Nutrients take different forms (on a chemical level) depending on the pH
around them. Some forms are easier for the roots to absorb than others.
When the pH is too high or too low, the plant can show signs of a nutrient
deficiency even when the nutrients are physically there at the roots.
With pH, you’re helping plants get access to all the nutrients all the time.
While pH is important for all grows, it is most important for growers using
cannabis nutrients. The way that liquid nutrients are formulated, they are
highly available to plant roots, but only in the right pH range.
What’s the Right pH?
Soil – 6.0-7.0 pH
Hydro/Soilless/Coco – 5.5-6.5 pH
As a result of the pH being too high or too low, cannabis plants may
start showing signs of nutrient deficiencies even if the nutrients are
available in the growing medium.
Once you get the hang of maintaining the pH, it’s a breeze and will
take you only seconds. And after you have your grow dialed in, you may
not even need to check pH as often because you know what to expect.
What’s the Best pH for Growing Cannabis?
The following charts show you how easy it is for the plant to absorb
each nutrient at different pH levels. This can give you something to
aim for when you notice a specific nutrient deficiency.
Soil ~ 6.0 – 7.0 pH
In the wild, cannabis prefers a slightly acidic soil environment.
For soil an optimum root zone pH for cannabis is between 6.0 and 7.0,
with the most time spent with a pH between 6.2 – 6.9. It’s a good idea
to let the pH cover a range instead of always adjusting to the exact
same pH number.
See which nutrients are best absorbed at which pH levels
Growing marijuana in soil pH Chart
In a soil environment that doesn’t use liquid nutrients, pH isn’t as
important. When using liquid nutrients in soil, you will almost always
need to manage pH to prevent problems and get the best harvest.
Hydroponics, Soilless or Coco ~ 5.5 – 6.5 pH
For hydroponic growing setups (as well as soilless growing mediums
like coco coir) an optimum root zone pH is between 5.5 and 6.5. This
is slightly more acidic than the optimal root pH for growing in soil.
It’s a good idea to let the pH cover a range instead of always
adjusting to the exact same pH number.
See which nutrients are best absorbed at which pH levels
Growing marijuana in hydroponics pH Chart (including soilless mixes
that include coco coir, vermiculite, perlite etc)
With hydroponics, it’s especially important to allow the pH to range
slightly, as you can see above, some nutrients can only be absorbed
at higher or lower pH’s.
In a hydroponic setup, you will almost always be using liquid or
powder nutrients, so save yourself a ton of trouble by watching and
adjusting the pH as needed! The pH will naturally change over time,
and you only need to correct it when it starts going out of the 5.5-6.5
range.
What about soilless mediums like coco coir?
Most soilless growing mediums are completely inert, which means they
don’t contribute any nutrients to the plant. Instead they act more as
a support system for your roots while you provide all the nutrients through
the water. When the plant is getting all it’s nutrients in the water, it’s
considered a “hydroponic” growing setup.
However, some soilless growing mediums with a lot of organic matter may
need a slightly higher pH to thrive. For example if you heavily amended
your growing medium with worm castings (worm poop), you will want to aim
for a pH between soil and hydroponic ranges since you’ve added “soil-like”
components.
No Need to Be Exact – Let pH Range Up & Down
The thing to remember with pH is that you don’t need to be exact. What
you do need to be is consistent in keeping the pH from creeping too high
or too low in your plant root zone.
As long as you stick within the recommended pH ranges above, you will
prevent the majority of all nutrient problems caused by too-high or too-low pH.
Why is it a good idea to let the pH cover a range instead of always
adjusting to the exact same pH number? Some nutrients are better absorbed
at slightly higher pH readings, while others are absorbed better at lower
pH readings. Not having to try to pinpoint an exact number also saves a lot
of unnecessary frustration.
If your marijuana plant roots are experiencing the wrong pH, it’s recommended
you react as soon as you notice, and not wait until you actually notice problems
with the leaves. It can be tempting to ignore a pH problem, but you’ll often get
the best results by acting before your plant displays a problem. That being said,
if your plant is growing green, vibrant and healthy, sometimes the old saying
applies, “if it ain’t broke, don’t fix it.”
Tips
Be consistent in making sure pH stays in the range
You don’t need to be exact, just keep an eye on things and react if you notice
the pH is getting too high or too low
Add all of your nutrients to your water first before checking and adjusting the pH.
Your nutrients will affect the pH of your water so it’s important they get added
before making any adjustments.
How to Test and Adjust pH for Cannabis
Supplies: What Do I Need to Test & Adjust pH?
Get one on Amazon.com!
? PH Tester
Digital pH Pen or
pH Measurement Kit with drops or strips
These are the two most common methods for measuring water pH when growing cannabis.
Learn more about the pros and cons between a Digital pH Pen or a pH Measurement Kit.
? PH Adjuster
A bottle of “PH Up” and a bottle of “PH Down”
A bottle of PH Up & PH Down gives you one of the best ways to adjust pH in soil or hydro.
They each come in a bottle that lets you easily measure how much to add to your water.
General Hydroponics makes the most common version of products like this, but there are
other brands such as Mad Farmer which make similar products that are just as good.
There are other methods of adjusting pH, but using pH Up and pH Down is the best method
I’ve tried – I know these products work great for growing cannabis, and they keep the
pH more stable than natural alternatives like vinegar or baking soda.
? Water
For many growers, tap water works just fine for growing cannabis. Do you need special water?
I use a container that was originally made for drinking water to mix up my nutrients,
but many different types of containers will work. Most importantly, avoid anything
fragile, especially glass (which can break your instruments or shatter).
? Nutrients (If You’re Using Nutrients)
Learn more about cannabis nutrients – do you need them for your setup?
How to Adjust pH For Your Cannabis Plants
1.Add Any Nutrients or Supplements to Your Water – always do this first
because nutrients can change the pH of your water
2.Gently Shake or Stir Your Water
3.Test pH – this is done using a pH Pen, drops, or strips. Which one works best?
4.Adjust pH by adding “PH Up” or “PH Down” solution. Your goal is to get
your water in the right pH range for your growing medium. If your pH is too
low, you need to add “PH Up,” and if your pH is too high, you need to add
“PH Down” in order to correct the pH.
5.Re-test to make sure pH is in proper range.
6.Water plants with pH’ed nutrient solution or add water to hydroponic reservoir
7.Check – Soil or soilless growers who handwater their plants should check the pH
or their runoff water to make sure it’s in the right range – try to test the earliest
runoff if possible. Hydroponic growers can check the pH of their water by testing a
small sample from their water reservoir a few minutes later. How do I correct a bad pH?
That’s it!
How much pH Up/Down do I add?
The amount of pH Up or Down you add will vary a lot depending on your water. If
you’re using very soft water than you will need just a tiny amount of fluid to
adjust the water’s pH since there’s not much “stuff” in the water to buffer the pH.
However, if you’re using hard water than you’ll need to add more.
For PH Down – 1 mL/gallon of water will generally reduce your pH about 1 point.
That’s just a very rough estimate, but gives you a starting point. In imperial
measurements, that’s 0.2 tsp/gallon (1 tsp/5 gallons) will reduce the pH by 1 point.
If you’re regularly measuring PH Down I highly recommend using a blunt-tip syringe
with mL measurements, it’s much simpler because imperial measurements don’t have
precise enough measurements for the small amounts needed with PH Down!
Note: If you are starting with RO (reverse osmosis) or soft water, you likely need
less PH Down than the specified amount; if you have very hard water you may need more!
For PH UP – PH Up is not potent stuff! It actually has a very weak effect. Compared
to PH Down you will need to add much more PH Up to adjust the pH by the same amount.
With PH Up, depending on how hard your water is you need to add 2-4mL/gallon of water
to raise the pH 1 point. In imperial measurements that’s 0.4-0.8tsp/gallon.
The first time you’re adjusting, you don’t know what pH your water is, how “hard”
it is, and how your particular nutrients and supplements are going to affect the pH.
Initially, you’ll have to add just a little bit at a time and keep testing until you
get an idea of exactly how much you’ll need with your tap water, and the nutrients
you’re using. After 1-2 times this step will only take seconds!
It can be helpful to make a note of the total amount of pH up/down added. The total
amount of used pH up/down will be about the same each time. Remember that number and
write it down! It will make pH’ing easier in the future! The amount will change a
little depending on which nutrients your plant is getting for its current stage of
life, but having a ballpark figure is really helpful.
Unfortunately there’s no exact formula to adjusting pH, because factors such as the
source of water, growing medium, nutrients, drainage and growing setup all have an
effect on pH.
You will need to use trial and error to figure out what amount of pH Up or Down
works for you in your setup with your nutrients.
If you’re new to adjusting pH, start small with pH Up and Down, and only work
your way up to bigger amounts after you’ve gained some experience. Most growers
will be able to figure out their personal measurements within 1-2 waterings.
The very first time you pH your water, it will take a little trial and error to
figure out how much PH Up or PH Down to add to get to the right number, since
everyone’s water is a little different. The general idea is to start with a
little bit, maybe a few drops, then retest and add more if needed. Continue
this until you get the water in the proper range. PH Down is much stronger
than PH Up, so be extra careful with PH Down! After the first time, it will
be much easier to measure out how much you need.
Tips for Cannabis Nutrient & pH Management:
Don’t Go Overboard: With liquid nutrients, it’s usually better to give too
little than too much. You can always add more, but it’s harder to take nutrients
back. A good rule of thumb is to start out at half the recommended dose, and only
raise nutrient levels if the plant needs it.
Never Mix Nutrients or Supplements Directly With Each other: Always add nutrients
directly to your water. It’s bad to mix nutrients together. They can react with
each other in a way that can make nutrients less available to your plants. Most
nutrient bottles or pH adjusters will come with a clear warning that says the
same thing. Always add any additives directly to the water – your plants will
thank you for it.
Add “Micro” to Water First – If you’re using a 3-part nutrient series with a
bottle for “Micro,” you should always add that to the water first. It will also
say so on the bottle and on the nutrient schedule, but just something to be aware of.
Tap Water Can Be Easier to pH Than RO or Highly Filtered Water: Tap water or
mineral water has an extra buffer of extra minerals and other “stuff” in the
water. This helps prevent the pH from swinging up too high or too low quickly
and can make pHing easier. RO water has very little buffer (it’s basically pure water)
and tends to swing up and down in pH easily with just a little pH Up or Down.
Do you need special water or is your tap water good enough?
Shaking Water Changes the pH: When checking and adjusting pH, some growers like
to shake their water container to make sure everything is evenly mixed. This works
well, and roots love the extra dissolved oxygen, but it’s important to understand
that after shaking the nutrient water for a long time, the additional dissolved
oxygen will raise the pH of the water. Don’t worry about this – don’t retest then
readjust the pH. If you’re going to hand-water to your plant, you want to make
sure you go by the pH of the water before it was shaken up. In hydro, the water
is going to be oxygenated anyway, so shaking it before testing is ok. If water
is allowed to sit for a while, it’s normal for the pH to change a bit. When it
comes to mixing, make sure you mix water gently so nutrients and pH Up or Down
are evenly distributed, but avoid vigorous shaking until after you’ve already
adjusted the pH.
pH Drift is Normal. Try to keep pH in the suggested range and you’ll be fine,
even if it’s on the higher or lower end of the scale.
How Do I Correct a Bad pH?
Summary of Steps
1.Get Current Root pH
2.Adjust pH – Instructions
3.Checking & Maintenance
1.) First get a ballpark figure of the current root pH
Soil or Soilless Mediums
Next time you water the growing medium, test the pH of the water going in
Test the pH of the water that runs out of the bottom (runoff water)
If the pH of the runoff is in the right range, even if it’s not the same as the
pH you put in, you’re good. If the pH of the runoff water coming out is too high
or too low for your range, you know that you’ll need to correct the pH.
Hydroponics
Test the pH of the reservoir by taking a small sample of water and use it to test the pH.
If the pH is outside the 5.5-6.5 pH range, you know you’ll need to correct the pH.
2.) If pH at Root Zone is Off, Adjust the pH
Let’s break down exactly what you need to do!
Hand-Watered Plants
Soil
Soilless
Hydroponics (roots in water)
Tips For hand-watered plants… (soil or soilless)
Think about the pH of the water that you watered your plants with. You made
sure it was in the right range. So if the pH that comes out the bottom is
outside the range, that means you need to either raise or lower the pH to
get it back where it should be.
Flushing – pH problems are sometimes caused by over-fertilizing (the plant
was given too many nutrients or supplements, which builds up salts in the growing medium).
If you believe this is the case, flush the growing medium to remove salt buildup. This
should only be done when the regular method isn’t working for you, and/or you have no
other choice. Flushing means giving your plants 1-3 times the volume of its container
with plain, pHed water. The flush leaches out extra nutrients and salts. After the flush,
water plants with a light nutrient solution. It’s normal for plants to droop when they’ve
been flushed (showing signs of being overwatered), but the drooping will go away as soon
as the medium begins to dry out. After the top inch of growing medium has dried out,
water the plant as normal and test the runoff water to see if the pH has corrected itself.
Soil
Water going in should be 6-7 pH
If runoff pH is…
6-7 pH – in the right range, no changes needed.
Less than 6 – provide next watering at pH 7
More than 7 – provide next watering at pH 6
Continue this formula with each watering.
Soilless (like Coco Coir)
Water going in should be 5.5-6.5 pH
If runoff pH is…
5.5-6.5 pH – in the right range, no changes needed.
Less than 5.5 – provide next watering at pH 6.5
More than 6.5 – provide next watering at pH 5.5
Continue this formula with each watering.
Hydroponics (roots in water)
Maintaining pH is especially important in hydroponics. Luckily it’s really straight
forward since you only have to worry about the water in your reservoir. However,
if the pH is off in between reservoir changes, you can make adjustments.
If pH is too high, add a tiny amount of “PH Down” solution to your reservoir
(a little bit goes a long way with PH Down). Return to reservoir and check pH
again in a few minutes.
If pH is too low, add a small amount of “PH Up” solution to your reservoir.
Return to reservoir and check pH again in a few minutes.
Tips for Hydroponics Growers
The pH of the water tends to go up when the water is oxygenated
(for example by adding bubbles or shaking water) – this is normal.
The pH also changes as plants use up nutrients in the water
It’s a good idea to completely change your reservoir at least once every
1-2 weeks, especially in the flowering stage when plants are more picky.
This constant renewal helps prevent a lot of pH problems as well as nutrient
buildup in the reservoir.
Test reservoir water regularly so you spot any pH problems before they damage your plants
3.)Keep Testing! Learn if you need any more adjustments.
If you’ve recently adjusted the pH of your growing medium or hydroponic setup,
or made any other major changes, it’s important to keep testing pH regularly!
Digital PH Pen vs Drops or Strips
The most common way to test for the pH of water is probably using drops or strips.
These work by taking a water sample, and you compare the color produced to a chart.
These give you a rough idea of the pH.
Digital pH pens look a bit like a thermometer. Basically you dip the end into your
water and a digital readout on the screen will tell you the pH.
They each have their pros and cons, so it’s important to figure out which one
works better for you.
PH Strips or Drops
Pros
Cheap
Cons
Not as exact as a PH Pen
Some people don’t like using a color chart (learn some tricks)
It can be hard to read the color in different colored lighting
Harder to use if you have dark nutrients that stain your water
Digital PH Pen
Pros
Get an exact reading of the pH on a digital screen – no comparing to charts
or other guesswork
Very quick and easy to test – just dip the pen into the water for a few
seconds and the pH will show up on the screen
Cons
Can be easy to break – always put the cap back on after use!
Needs to be stored properly – always put a few drops of storage liquid in the
cap before putting your pen away or it will stop working
Needs to be calibrated every grow or so just to make sure it’s staying accurate
Expensive compared to drops/strips – Requires purchase of not just the PH Pen
(which can be pricey) but also 3-4 separate fluids for storage and calibration.
That being said, once you’ve purchased everything you’re set for many grows.
PH Kit with Drops or Strips
This type of pH Test Kit works by using drops or strips that turn a color to
reveal the pH of your water, using a color chart. Basically you take a small
sample of water in an included test tube, add a few drops of the pH solution
or dip the strip, and then match the resulting color to figure out the pH.
Many pH Control Kits come with pH Up & pH Down included. Even though they’re
often sold by “General Hydroponics,” these kits work great for soil in addition
to hydroponic applications.
Directions
Find the pH – watch the video
1.Take small water sample in included test tube
2.Add a few drops of pH fluid (or dip strip)
3.Match the color to find the pH (compare to chart)
Adjust the pH:
1.Add a small amount of PH Up to bring it up
2.Add a small amount of PH Down to bring it down
3.Re-test
How much should I use?
Digital pH Testers
How Do Digital pH Testers Work For Growing Cannabis?
Digital pH Pens offer a precise way to measure the pH of your water. No need to
squint at a color chart with a pH Pen, you simply look at the number printed out
on your screen.
All testers come with step-by-step directions that tell you exactly what you
need to do to make sure you pH tester is accurate for years to come!
Don’t get a “TDS” or “PPM” meter by accident! It’s different from a pH pen!
Get one on Amazon.com!PH Tester PH-009 Digital pH Meter – With 2 Pack of
Calibration Solution Mixture Included – Cheap!
You just can’t beat the price! This is one of the cheapest pH pens I’ve seen.
Actually comes with a 2-pack sample of calibration fluid, so you don’t need
to buy those just to get started the first time (though you will need to get more soon).
You still need to get storage solution.
It may not have all the bells and whistles, but it will get the job done on a budget!
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PART 2 OF 2
The HI98128 digital pH tester by Hanna is top-of-the-line
Hanna Instruments HI 98128 pH Tester – this high-end ($$$) tester has all the
bells and whistles you could possibly want from a digital pH Tester, but may
be overkill for new growers.
About the HI98128 pH Tester Model:
All the bells & whistles
You’ll need to get calibration solution (like every pH tester)
Follow the directions, including use and storage – it’s pretty straightforward
All pH tester pens come with step-by-step directions that tell you exactly what
you need to do to get a quick, easy and accurate reading every time! In order
to make sure your pH pen stays accurate, you need to get a few extra bottles.
Calibration, Storage and Cleaning Solution for pH Pens
Calibration and Storage Fluid for pH Pens
Get calibration fluid for your PH Pen on Amazon.com!Calibration fluid –
You get a “4.01” & “7.0” bottle together as a kit, and you need both of them
to be able to calibrate your pH pen
Storage Solution – Not 100% necessary, but it dramatically extends the life
of the pen. You put a little bit of this liquid in the cap before you put your
pH pen away each time. Storage solution can also be used as cleaning solution
in a pinch, so if you’re just going to get one, get storage solution over cleaning solution.
Cleaning Solution – Not 100% necessary, but it extends the life of the pen
If you don’t get all these extra items, you won’t be able to take the best
care of your digital pH tester and it won’t give you accurate pH readings
and they won’t last nearly as long.
There are many other digital pH testers besides the ones listed above, and
many of them will work great. Just be sure you don’t actually buy a “TDS” or “PPM”
meter by accident, which is different and does not actually test pH. If you want a
TDS meter, that’s great, but many growers accidentally buy one and don’t realize
what it’s actually for. Learn more about TDS & PPM.
What to Do After You Test the pH
Get a bottle of PH Up and Down from Amazon.com
After using your pH pen, you use a bottle of PH Down & PH Down to adjust the
pH to where it should be, if needed.
How to Adjust the pH
1.Add a small amount of PH Up to bring it up
2.Add a small amount of PH Down to bring it down
3.Re-test
How much should I use?
Common pH Problems & Questions
Common pH Problems
I Can’t Tell the Color When Using a Liquid pH Test Kit
My pH Pen Isn’t Working
My pH Keep Changing While I’m Testing
My Runoff Water is Too High / Too Low
Common Questions About pH
My Plants Look Great, Should I Still Test for pH?
Why Should I Adjust pH Before Adding Nutrients?
How Do I Adjust pH of Outdoor Soil?
How Do I Learn About My Local Water?
Can I Get Out of Managing pH?
I’m using pH drops and I can’t tell which color it’s turning.
Try addition more drops of indicator fluid, as well as using fewer drops.
When there’s not enough, or two much of the indicator fluid in your vial,
it makes it really hard to tell what color the water is turning.
My pH pen isn’t working
Take a look at the pH pen itself. Is the electrode broken? It looks like
a glass bulb on the end of the pen.
Next, was it stored properly? What that means is, was it stored with storage
fluid in the cap. If it was stored dry, it can break the pen even if everything looks okay.
Ok, you’re pretty sure the pen itself is okay, so the next question is
whether it’s been calibrated properly. Have you recently calibrated it
with the 4.0 and 7.0 calibration fluid? An uncalibrated pH pen can give
you a wildly inaccurate readings.
Lastly, is the battery ok? These batteries last a really long time but
it’s still something to check.
My pH keeps changing when I’m testing
Something to keep in mind is shaking your water actually temporarily raises
the pH. So if you keep shaking the water and testing again, you’re going to
notice that the pH reading is different.
If you’re using pH fluid or strips, make sure you’re following the directions
closely. Adding too much or too little fluid will make it impossible to track the pH.
If you’re using a pH pen, make sure pH tester is working by testing it on
4.0 and 7.0 calibration fluid.
My runoff pH is too high/low, what do I do?
If the pH is really far off, or if plant is suffering from toxicity or
severe nutrient burn, it may be a good idea to flush the growing medium
first. What that means is that you give the plant enough water to get lots
of runoff. This helps “flush” out any extra nutrients or salt buildup in the
soil. Only flush if you absolutely need to, though! Flushing can temporarily
slow down the growth of your plant, so it should only be used in an emergency.
If the runoff is only off by a little bit, you can correct the pH by changing
the amount of pH Down or pH Up you provide the plant when watering.
Here’s the full instructions with step-by-step help on how to fix an incorrect pH.
Other Questions About pH
Everything is fine, should I worry about pH?
PH is certainly something to be aware of in order to prevent the plant from
showing nutrient deficiencies, but honestly “if it ain’t broke don’t fix it!”
If your plant is growing fast and all the leaves look green and healthy, there’s
really no reason to change anything. That being said, if you start noticing
nutrient deficiencies in your leaves, the very first thing to check is the root pH.
Do I pH the water before or after adding nutrients?
Add nutrients first, then pH the water.
You should test the pH after you add nutrients to the water (if adding nutrients).
The nutrients will often change the pH of the water, and you’re concerned with
making sure the pH of the water is right, as experienced by the roots.
If not using any nutrients for this feeding, simply adjust the pH of the plain water.
How Easy is it to Use Liquid Nutrients and Maintain pH?
Liquid nutrients for plants are simple to use (usually consisting of 1-3 bottles
for all stages of life) and don’t take up much space. These nutrient systems can
be used to provide exactly the right nutrients for your cannabis plant at each
stage of life.
Learn about nutrients & get customized nutrient schedules for growing cannabis
Many growers use liquid nutrients made for soil to supplement their soil grow.
There are also nutrients which are made to be used in hydroponic setups to provide
all the nutrients the plant needs throughout its life, even without soil.
Whether made for soil or hydroponics, all liquid nutrients are used in a similar way.
The Hydroponics vs Soil debate continues to rage on, but no matter what your
choice, the nutrients available today have exactly what’s needed by a cannabis
plant to thrive at all stages of life, coasting perfectly to harvest time.
For soil growers, being aware of pH is important, especially those using liquid
nutrients. For soilless and hydroponic growers, liquid nutrients and pH management
are required tools that give growers a greater ability to affect plant growth –
for better or worse.
Note: Some soil growers will add a handful of dolomite lime as they’re mixing their
soil. Dolomite lime can help buffer pH and keep it from getting too low, while also
adding a source of calcium and magnesium. But lime should be added before you start
your grow so it has enough time to break down, so this method is not recommended
unless you’re mixing up your own soil. Learn how to mix up your own soil for growing cannabis.
Is it Hard to Maintain pH?
No way, maintaining pH for your cannabis grow can be easy and intuitive!
Learn all about how to check and adjust your pH for cannabis
Measuring and adjusting the pH is as simple a process as mixing up the nutrients
them selves. The pHing process can take less than a minute, and the results you’ll
get in better growth and bigger colas are worth the few minutes it takes to pH.
Basically you take a small sample of your water and test to find out the pH.
You can use a pH Control kit or a digital pH tester. The pH control kit has you
add a few drops of a special solution to your small water sample and match the
resulting color to find the pH. A digital pH tester can be stuck directly in the
water to get the pH printed on a small screen, but requires regular calibration
and proper storage with storage solution to stay accurate.
Whether you’re using a pH control kit or a digital tester, basically you use
your water sample to learn the pH. You have “pH Up” or “pH Down” solution to
adjust if it’s too high or too low.
How to bring pH up or down outdoors
Great for outdoors, these options for adjusting pH are not recommended for
indoor growers unless you know what you’re doing ??
Note: There are other methods of natural pH management besides the ones that
follow, but these are the ones we know will definitely work. They are intended
for growers who are growing on larger patches of land and need to change the
pH of a lot of soil.
Bring Up pH
Lime is one of the most proven ways to bring up the pH of soil outdoors.
Use agricultural or garden lime in soil to bring up pH (the smaller the particles
of lime, the sooner they will become available). This type of lime (agricultural
or garden lime) adds pleny of Calcium, too, but not a lot of Magnesium.
Dolomite lime will add plenty of Magnesium in addition to Calcium. Many cannabis
growers like to add handful of dolomite to their soil when mixing it up to buffer
the pH and provide a steady source of calcium and magnesium.
Mix lime thoroughly with the soil, and keep it relatively moist to “activate”
the lime. The finer the limestone source, the quicker it will be absorbed – powdered
lime works much more quickly than larger sources of lime, which take time to break down.
Liming to bring up pH and enrich with Calcium/Magnesium should be used at the
beginning of the grow before plants are placed in the soil. Cannabis likes
slightly acidic soil, so it’s important not to go overboard and bring the pH
too high (soil for cannabis should be pH 6.0-7.0, so pH 7.0 and above is too high).
Don’t use lime unless you follow the directions closely, you don’t want to
cause a bigger problem than the one you’re trying to fix.
Adding lime in the middle of a grow can cause or mask a bigger problem with
the nutrients and salt buildups in the soil. You’ll get the best results if
you add the lime to moist soil 2-3 months before growing, so the lime has
time to break down in the soil and adjust the soil pH.
However, some cannabis growers do add lime to their flowering cannabis plants
grown in soil to help buffer the pH and keep the pH from dropping. When adding
lime in the middle of a grow (after you’ve established that there’s too-low ph in the soil)
do not add more than 1 teaspoon (5 ml) per gallon of soil.
Bring Down pH
There are a few common way to bring down the pH of soil:
Aluminum sulfate – works more quickly
Elemental sulfur – tends to take longer
Alkaline soil needs to have the pH lowered to grow cannabis. Cannabis needs a soil
pH of 6.0-7.0, and alkaline soil has a pH above 7.
Just like lime, using aluminum sulfate or elemental sulfur to bring down pH can be
tough to get just right. Don’t use lime unless you follow the directions closely,
you don’t want to cause a bigger problem than the one you’re trying to fix.
While aluminum sulfate is effective at lowering the pH in a relatively short
amount of time, elemental sulfur should only be used at the beginning of the
grow. You’ll get the best results if you add the elemental sulfur to moist soil
2-3 months before growing, so the sulfur has time to break down in the soil and
adjust the pH. Depending on where you live, Sulfur (or “Sulphur”) is also known
as “soil sulfur,” “powdered sulfur” or “flowers of sulfur.”
How Do I Learn More About My Local Water?
Check with your water company to learn more about your tap water. They will be
able to provide you with lots of important info.
You can also do some testing on your own such as…
pH (discussed in this article)
PPM: What It Is and How to Track It
Special Water Won’t Help Your Grow Unless You Need It!
Many growers don’t need special water. Some growers think that special water
will somehow give them better results when it comes to cannabis growth and
harvest. The truth is, special water is not going to help your grow unless
you actually need it.
What options do you have if your water is not good for growing cannabis?
1.RO (Reverse Osmosis Water) – RO gives you nearly pure H2O. Everything has
been taken out of the water, including minerals. With RO, you have a blank
slate to start with, so you have 100% control over the water in your grow.
However, with RO water, there’s less buffer to help prevent pH fluctuations.
PH tends to swing up and down more easily in RO water. RO also tends to be
associated with calcium and magnesium deficiencies (since these minerals are
normally found in water), so adding a Cal-Mag supplement is usually beneficial
for RO growers.
2.Filtered or Store-bought drinking water (treat similarly to tap water)
3.Rain water (treat similarly to tap water – some rain water isn’t good)
How Can I Get Out of Managing pH?
Growers who rely on using properly amended and/or composted soil are the least
likely to be hit by nutrient deficiencies caused by pH problems. The more organic
matter in the soil, generally the less the soil pH matters as far as nutrient absorption.
The natural process of soil breaking down helps make nutrients more available to the roots.
But cannabis needs very specific nutrient requirements to get the best results.
Growing in Soil? You may not need to worry about pH
If you want to grow cannabis without worrying about pH, you’ll likely want to
grow using amended, composted soil. Read about composting your own soil for
growing cannabis. However when it comes to composting soil, it generally takes
a bit of time, space and mixing before your soil is ready to use.
Mixing Super Soil with Jinxproof and Mr. Spliff - two famous organic marijuana
growers and teachers
No Time to Compost Your Own Soil? Liquid Nutrients are Easy, Cheap & Effective
A lot of growers don’t have the time or space to mix up their own soil, which
may involve amending, understanding how micro-organisms in the soil affect nutrient
absorption, maintaining a compost pile, etc. Because growing in soil can involve a
lot of prep work (or for those who live in a city where there’s not enough room for
an organic, composted soil grow), there are hundreds of liquid nutrients which can
be much more convenient for cannabis gardeners.
Liquid nutrients provide plants with everything they need at all stages of life. By
following a simple nutrient schedule, growers are able to use the perfect amount of
nutrients at the right time to power the growth of the plant, leaves and buds.
Whether you’re growing in soil or hydroponics, you can use cannabis nutrients to make
sure your plants have all nutrients needed, without having to mix up any soil yourself.
Just follow the basic instructions for the nutrients, and your cannabis will thrive.
For many growers, liquid nutrients make growing cannabis more simple, straightforward
and satisfying.
Learn About Liquid Nutrients for Cannabis:
Learn more about cannabis nutrients here!
Who Should pH? Everyone Who Uses Liquid Nutrients
Paying attention to pH is pretty much required for any cannabis growers using liquid
nutrients. Even soil growers using liquid nutrients should pay attention, though soil
growers tend to get more of a buffer from all the organic matter, especially those
starting with great composted soil that has been made for a plant like cannabis.
Unless you’re willing to learn about soil for cannabis and mix up your own soil, there’s
often no way you can get out of pH management – if you refuse to manage pH, your only
option is to just try it your way to see what happens.
Some growers get lucky winging it, and if you’ve successfully grown a plant like tomatoes
or corn, you’ll probably be able to provide for your plants using what you already know.
But if you’re just thinking about buying standard potting soil from the local garden store,
or using soil you found around your house, you’re probably going to need liquid nutrients
to supplement your cannabis grow for the best results and yields. Maintaining pH is one of
the best tools you have to get the most from your nutrients.
This colorful nug is here partly because the grower chose to check and adjust pH
Summary: What You Need to Remember About pH & Growing Cannabis
1.) Always test the pH of water you give your plants (it takes under 5 minutes).
Testing – you can use digital pens or a pH Test Kit with drops or strips
Get a bottle of pH Up & pH Down – these magical bottles of fluid give you a way to adjust
the pH up or down quickly and with precision
2.) If you are using nutrients and still seeing nutrient deficiencies, the first thing to
do is check is the pH, since the wrong pH can prevent plants from absorbing nutrients effectively
3.) You may need to flush plants with extra water if the pH is way out of whack
4.) Add all your nutrients and supplements before testing/adjusting pH. Many nutrients/supplements
can change the pH of your water. Make sure to add everything to your water before you attempt to
test or adjust the pH.
5.) It’s okay/good to let pH drift up & down as long as it stays in the right range – Soil pH
should be between 6.0 – 7.0. Hydroponics pH should be between 5.5 – 6.5
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Danggggg, I know his hand is cramping from writing all that.
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Wow, what an incredible work of art! I’m in PH prison right now and have to learn every word of this before I get out! In the middle of my first grow and I have three beautiful plants and they just got viciously sick and I was asked by one of the pros on these forums something about PH, and I was like “huh??,well I bought all those meters but I’ve never used them yet on anything” lol. Yes sir you heard it right, I’ve never checked pH on any water I’ve used or any batches of nutrients or any soil testing etc nothing nada, lol, and I have a beautiful super skunk Auto almost ready for harvest with a foot-long cola and two beautiful super skunk photos one I just flipped to 12/12 and the other is still in veg and all three were absolutely beautiful until they all got very very sick and now I am doing a crash course starting in the morning on pH and pot flushing and PPM and a bunch of other things I don’t even know what they mean lol, these two posts will glide me on through :-), however I still need just one more thing I never bought, pH up and pH down, could somebody please tell me the correct brand name of those I should buy from Amazon? Thank you very much,
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Oops, just saw 2 years later, lol, well I guess later is better than never. If somebody happens to read this, I would appreciate a brand name of ph up and down if possible:)
@Claybo I am new here and don’t want to guide you wring, but with my inground pool I am testing and adjusting PH all the time.
Pool chemicals are highly overpriced and if you read the labels they are nothing special. PH up is EXACTLY the same as arm and hammer baking soda. PH down is muriatic acid. I use these 2 things to regulate my pool (22000 gallons, a bit different I’m sure)
My well water maintains a perfect PH for my plants so I don’t adjust. Not sure if this information will be helpful but it’s possibly a starting point to research.
If I am wrong one of the pros here will probably explain better.
Good luck 
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@Gjgkeb
Thanks for the reply, Very interesting. That is sometimes the same for a lot of rebranded and relabeled ingredients.
Funny story: Yrs ago I contracted to paint the interior of huge house and it had mold everywhere, ceiling, walls closets, green everywhere. The paint store sold us a product that came in 16 ounce spray containers with some fancy mold remover name on it, we bought a couple and it worked incredibly well, just spray it and wash it down with water and presto it was gone, worked beautifully and it cost $6.95 per bottle, but it didn’t go far, one wall would use one bottle. About 100 walls and ceilings to go, so we ended up buying about 11 cases over the span of a couple weeks,12 bottles per case, yeah big bucks! It was like $600 or something total by the end of the job, well one day I was reading the back of it and saw the ingredients and noticed the ingredients were the exact same ingredients word for word that was on the back of a gal bleach bottle. We still had all these empty bottles still in their case boxes, we went to the supermarket and bought a dozen or two gallon bottles of bleach (at that time a no name brand of a gallon of bleach was $.99) and filled up all the empty 16 ounce bottles. We cleaned all the bottles up and they looked brand new and we put them back in the case boxes and returned them to the paint store and got all of our 5/$600 back lol.
Hey I’ll check about using what you mentioned, thanks much for your reply, and yeah this forum has some awesome people not only who participate on it but who run it. I’m a newbie here but learning fast from the Bros n Gals here.
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