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This should help you out my friend. ( KNOW THIS IS LONG) So copy and paste to your files for future reference.
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 & Video
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
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
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.”
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
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.
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?
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.
Watch our video above to see Nebula give a demonstration!
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.
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!
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.
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 straightforward
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
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