What are the Best pH Levels for Growing Cannabis?
Want healthy, productive plants? Dial in your potential hydrogen and you’ll be on your way to a thriving crop. We discuss the importance of achieving the right pH balance with a seasoned growing pro.
The pH and nutrient concentration of a cannabis plant’s medium is a lot like a transistor radio; you have to dial in the right numbers to unlock its full potential.
Whether you are growing with a soil or soilless setup, pH (potential hydrogen) measures the acidity and alkalinity of the medium, which in turn controls the nutrients the plant can absorb.
Students enrolled in the Cannabis Professional Series at Kwantlen Polytechnic University, based in Surrey, British Columbia, learn about the importance of ideal pH levels early in the course.
“It’s something that’s misunderstood, often overlooked, and it’s highly important,” says Nico Hach é , one of the program’s instructors and a horticultural consultant with Root to Shoot Solutions. “People talk about nutrient lockout, that’s generally pH related.”
Soil pH meter – Rukawajung/Shutterstock
Cannabis plants prefer a slightly acidic environment for its roots. Growers using soil as their medium should adjust their pH to a range of 6 to 6.8. For a soilless garden, pH should sit between 5.5 to 6.5.
Allowing a pH range, regardless of the medium, ensures the plant is able to absorb the variety of nutrients required for optimum growth. For example, the plant’s ability to absorb manganese increases with a more acidic medium. Numerous pH and nutrient uptake charts are available online to illustrate the ideal pH for each element needed throughout the vegetative and flowering stages of growth.
“A range allows marijuana to absorb what it likes,” says Hach é. “Your pH doesn’t change your concentration of nutrition, it changes the availability of nutrients. Even though the nutrients are there, they might not be up-taken, or they may be absorbed in excess.”
Young cannabis sativa plant in its first weeks of growing. Yellow leaves could be a sign of chlorosis or unbalanced water pH. – Moha El-Jaw/Shutterstock
While many nutrient companies add pH stabilizers to their products, Hach é recommends frequent water testing to ensure pH remains in the ideal range.
“Water is a big factor that can affect your pH. City water, pond water, or river water, whatever set-up you have, every water source is different,” he says.
Whether or not different cannabis strains thrive under distinctive pH levels is an area that has undergone little scientific scrutiny. Hach é doubts that exploring specific acidity levels based on cannabis species would produce noticeable improvements in yield or quality.
“When you’re talking about changing your acidity like that, it’s complex. Often, they’re hybrid plants, so they’re not true indicas or sativas,” he adds. “It becomes difficult to start playing with that too much.”
However, matching pH to the plant’s natural environment could help promote native characteristics, like terpene profiles.
“When you think of the regions of the world where these plants come from, they’re complete opposites. All the factors would be different,” Hach é says. “Y ou can treat them exactly the same, they’re both marijuana plants, but you could probably be a little more efficient by fine-tuning indicas or sativas.”
Unlike pH, nutrient concentration should be adjusted for different strains of cannabis. The electroconductivity (EC) or total dissolved solids (TDS) are both measurements used to determine the nutrient concentration in your medium.
“You can definitely manipulate how often and how much you feed individual strains,” Hach é said. “The fast-growing plants will be very hungry. You can afford to feed them more and keep pushing them. If you were to do the same to a shorter, slower growing plant, you might push them too much.”
Cannabis plant with tips of the leaves burned by overnutrition. – Moha El-Jaw/Shutterstock
Overfeeding a plant will likely result in nutrient burn, causing the plant’s leaf tips to turn yellow or brown. Left unchecked, nutrient burn will hinder growth and yield. Underfeeding will also affect the plant’s ability to reach its full potential.
To find out what’s right for the strains in your garden, Hach é recommends starting with a low nutrient concentration in the cloning or seed phase of growth. The EC should gradually increase as the plant matures.
“To find out how far you can go, push. It is a matter of trial and error and knowing your plants. Make sure you take notes and keep track,” he said. “There’s also early telltale signs you can see if you’re pushing too much.”
The EC should peak about halfway through the flowering stage of growth.
“With a nine-week flowering or 10-week flowering plant, I would peak around the fourth or fifth week and then begin to tone it down, so you can start your flush at the end. You slowly creep up,” says Hach é.
A gradual increase, as well as a slow decline, in EC will allow you to determine how far you are able to push your plants while avoiding possible shock caused by drastic swings in nutrient concentration.
“Never have big shifts. A change is a stressor,” says Hach é. “C onsistency is key with anything you do with plants.”
The best way to germinate cannabis seeds!
With this guide, we would like to explain to you, how to germinate a cannabis seed most successfully. There are three common methods of cannabis seeds to germinate. Properly executed, they will be successful in almost every case.
- Germinate hemp seeds directly in soil
- Activate cannabis seeds with water
- Germinate cannabis seeds in damp cloths
So that cannabis seeds can be germinated under optimal conditions, in all three breeding types, some basic rules have to be considered. Before we describe the methods exactly, we first want to talk about these basics; The first golden rule is for example, not to treat cannabis seeds with bare hands to avoid the chance of contamination with bacteria or fungus. We strongly recommend the use of clean gloves and some disinfected tweezers!
Germinate weed seeds – The quality of the water:
The water temperature should be around 20 degrees and have good quality. The quality of the water can be tested with a PH meter and an EC meter. Recommendation: Osmosis water or drinking water very debil (with little salts and mineral arm).
The ideal substrate to germinate weed seeds:
You can work with different substrates. The most common are earth (light mix), coco and rock wool. Even with the substrates, the soil and ambient temperature should be right. A light mix is specially adapted to sensitive plants such as hemp. Most mixtures contain nutrients and minerals for a few weeks, which the young plant absorbs when it needs them.
For Coco substrate, before working with it, you should test the EC content, as most Coco substrates have a very high value. To lower the value, wash the Coco once with mineral water (osmosis water).
Breeding for coco and rock wool is also referred to as hydroponic cultivation, which means that significantly more air circulation at the roots is created. But the nutrients that are then fed to his plants are more directly absorbed by them. The risk of over or under-fertilization is greater but also the expected yield. Breeding on hydroponics is what gardeners with more experience.
Required air, light, and temperature for germination:
In order not to endanger the germination capacity of the seed, it should be stored in a dark and cool place (6 ° – 10°).
Before the seed is germinated, it must not be exposed to light and the air temperature should not be below 20° C (68° F) nor exceed 30° C (86° F). Maintaining a temperature around 25°C (77° F) is ideal. For outdoor cultivation, it’s recommended to germinate indoors, letting the seedlings grow for a few weeks, and don’t set plants outside too early.
Method 1. – Germinate hemp seeds in soil
- Prepare material (fill small flowerpots with soil).
- Lightly moisten the potting soil with good water. (Too much moisture = mold and fungal danger).
- Place the seeds in a 0.5cm recess in the center of the pot. Make sure that the seed is transverse and not upright, this can affect the germination rate. Nature has not shaped the seed without reason oval. If you set the seed transverse, it will easily position itself properly in the soil after germination! When you work with jiffies it works something similar. The jiffy is only soaked in water until it swells apart, then the water is expressed again without crushing it until residual moisture is over. At Jiffy, the factory usually prepares a slight depression for the seed.
- Lightly cover the seed with soil so that no light can shine directly on the seed. Also with the jiffi one covers the seeds with a little material. Wet but not wet! Now pour no more that could flush the seed back up and the amount of water is also difficult to control.
- In case of too little moisture, we recommend wetting the plant with a spray bottle.
- Now put the plant in a safe place and depending on the variety and genetics can be expected in the next 36 to 72 hours with a first result. In some cases, it can take up to 6 days.
Method 2. Germinate cannabis seeds in a paper towel.
- For preparation, we gonna need two plates, some sheets of kitchen roll, good quality water as described above, and our seeds.
- Put two sheets of kitchen paper on one of the plates and moisten them with water.
- Put your seeds on the damp cloth and put two more kitchen towels over it.
- Moisten also the upper cloths. Runoff excess water that the wipes are only slightly saturated.
- Put the second plate on the other plate like a shell.
- Store in a dark place and check daily that do not dry out the kitchen towels and of course to see if the seedlings are already broken. Once it is germinated, a small white shoot comes from one side. Now the time has come, the seed can be placed in the substrate of your choice. Carefully remove the seeds with tweezers from the cloths and carefully place them diagonally with the small germ downwards into a prepared hole. Only so deep that the seed is slightly covered with soil (max 5mm).
7. Wait, wait, wait and then be happy.
Method 3. Germinate cannabis seeds in a cup of water
This method is particularly suitable for activating seeds that have been stored for a long time
The addition of hydrogen peroxide is suitable for softening the husk of the hemp seed. About 3 – 5 drops per 100 ml of water are sufficient.
- Prepare a cup of water at a temperature of about 12 degrees Celsius (54 degrees Fahrenheit).
- Put the seeds into the water for 12 hours.
- Prepare to plant the seed in a small flower pot. Exactly as we described in method 1, under point 3.
- After planting, cover the seed with the substrate and moisten again with water.
- After about 2 – 3 days, the germ should gradually see daylight.
Cannabis seeds do not germinate? These are the most common mistakes:
- The pH of the water is too high or too low. Regardless of the method used to germinate the cannabis seeds, the pH should always be between 5.5 and 6.5.
- The EC value of the water is too high, it should be below 0.8.
- The water temperature was ignored, it should be between 20 ° and 22 ° celsius.
- If you let the hemp seeds germinate into soil, it may be that too much water was used, the soil was fertilized too much, or that the seed was pushed too deep into the soil, or was placed upside down.
- The seeds were exposed to strong temperature differences during transport.
This information is only of interest to customers who live in a country where cultivating and cultivating cannabis seeds is not a violation of the law.
Cannabis pH and Watering your Plants
When growing cannabis, and almost any other type of plant, there are various factors that influence how they grow and the quality of the final product such as the quality of the air, water, sun and soil. Any sort of issue with the quality or presence of these parameters will generally produce poorly plants that are likely to catch more illnesses and/or be infested by insects or fungi. That’s why we’re going to be talking about pH for cannabis plants; pH is one of the most determining factors when it comes to feeding cannabis plants and having them absorb everything you give them.
What is pH?
pH is used to measure acidity and alkalinity of a liquid or dissolved solid. pH levels can range from anywhere between 0.0 and 14.0; substances with a pH lower than 7 are considered acidic, whereas those with a pH higher than 7 are considered more alkaline. If the solution is exactly 7.0, it’s pH neutral. A great example of an acidic substance is hydrochloric acid, which has a pH of 0.0, whereas caustic soda (washing soda) is highly alkaline, with a pH of 14.0. Water is the best example of neutral substances, as it tends to sit at around 7.0 pH.
The Importance of Measuring Cannabis pH Levels
When you put a lot of work and effort into growing cannabis in the hopes of obtained the best possible results. pH is an incredibly important factor when it comes to making sure that your plants are absorbing everything you give them via their roots. If your plants’ roots are not being given substances with the right pH, they won’t be able to absorb certain types of nutrients, and in a matter of time they may end up showing signs of deficiencies or excess, as certain types of minerals build up in the growing medium, creating a toxic environment for your plants’ roots while also stopping other nutrients from being absorbed.
If you manage to keep pH levels under check when watering, you still may end up with deficiencies or overwatering, although the probabilities of this happening are much lower and they’ll be much easier to fix if the pH is right.
What Should pH be for Cannabis Plants
For a cannabis plant to grow to the best of its abilities, you need to keep in mind that pH levels shouldn’t always be exactly the same; depending on the strain grown, the stage in which it is in (germination, growth, pre-flower, bloom), the growth medium and whether you’re growing organically or using minerals, the pH level of your water should vary slightly.
You can grow cannabis by keeping the pH at a constant level, although it’ll need to range between 5.5 and 7.0. This allows for decent results, although you won’t be making the most out of your seeds nor the nutrients you’re using to feed your plants. Plus, you may end up with feeding and nutritional issues further down the line.
These are the ideal pH values for growing cannabis in hydroponic and aeroponic settings including other inert substrates:
- First weeks: 5.8 – 5.9 pH
- Pre-bloom: 6.0 – 6.2 pH
- Real bloom: 6.0 – 6.3 pH
These are the ideal pH values for growing cannabis peat mixes or straight in the ground:
- First weeks: 5.5 – 6.0 pH
- Pre-bloom: 6.0 – 6.2 pH
- Real bloom: 6.2 – 6.5 pH
Adjusting pH for Cannabis Plants
Figuring out how to adjust the pH in your water isn’t that complicated at all. You need to discern between watering using nutrients and only water, and there will be a difference between using automatic watering systems and watering manually.
Using just water
Fill your tank or bottle, let the water sit for a few minutes and then measure the pH in the water using a pH meter. If needed, follow the instructions provided by the manufacturer of your pH Up or Down products. If there is no recommendation, add an extremely small amount to your water tank or bottle, dilute properly and let it sit before measuring it again. Repeat this process as many times as necessary until pH levels are as desired.
Water with nutrients
This process varies depending on the fertilizers used; some brands recommend adjusting the pH before adding their products, whereas others recommend measuring and adjusting the pH after adding them to your water. If the manufacturer has not left any specific instructions, we recommend dissolving your nutrients one by one, mixing thoroughly. Then, you’re going to need to let it sit for a few minutes in order for the pH to balance out. This way you can measure and adjust accordingly without any fluctuations.
When it comes to automatic watering systems, a large tank is usually used alongside an automatic pipe system which usually contains water and nutrients, enough to feed your plants for about one to two weeks. In order to adjust the pH and keep it balanced within the recommended pH value, we recommend using pH and temperature monitors so that you can have an eye on the pH at all times. This allows you to easily and quickly adjust the pH when needed – all you have to do is keep an eye on it and you’ll be able to fix it before anything goes wrong.
Note: in order to avoid taking too long to adjust the pH in your water, we recommend writing down the original pH of your water and then writing down how much product was needed to get it to the right value. This will save plenty of time down the line.
How to adjust the pH in Water |The Best pH for Cannabis
Adjusting the pH in your water can be so simple that it gets complicated if you don’t have the proper tools and they aren’t in decent condition. In order to do this correctly, you’ll need to use a pH meter as well as specific liquid products used to adjust pH upwards or downwards. We’re going to have a quick look at pH meters and liquids used for adjusting pH.
pH meters are measuring instruments that are quite easy to use; most of the time, all you have to do is switch it on and place the sensor end in the water in order to analyze its pH. In order to avoid bad readings and issues with the meter itself, we recommend cleaning it after every use as well as adjusting them when necessary. Also, you’ll want to keep the sensor moist using a maintenance solution.
Liquids used to reduce or increase the pH in nutrient solutions contain either acidic or alkaline ingredients, which can be organic and/or mineral. Plus, depending on the manufacturer, some pH adjusters can be specific for the growth period or for the bloom phase.
Mineral pH adjusting products are generally made using the following ingredients:
- Nitric acid: depending on the ratio, you can use this to increase or decrease pH levels, plus it’s perfect for the growth period thanks to its high Nitrogen count.
- Phosphoric acid: this is used to lower the pH and it’s ideal for the flowering period thanks to its high phosphorus content, although it can also be used in the growth period.
- Potassium hydroxide: this is used to increase the pH in water. Thanks to its high potassium content it can be used in the growth and flowering periods.
Organic pH adjusters tend to contain the following components:
- Humic acids: these acids increase the pH in your water and can be used during the entire growing period, although we recommend using it during the growth period as humic acids can actually decrease THC yield.
- Citric acid: this is used to decrease pH and it can be used during the entire growth and flowering process.
The main difference between organic and mineral pH adjusters is that the minerals tend to harm any natural life in the soil, so you need to rebuild it after every use. Organic products don’t have the same reaction, although you’ll need to use slightly more product than mineral products in order to get the desired levels.
Cannabis pH Meter Types
pH Testing Drops
This type of pH measuring kit is one of the easiest kits to use; all it contains is a vile, liquid reagent, and a color chart. In order to figure out the pH in your water, all you have to do is fill up ¾ of the vile using the water you want to analyze. Add in a couple of drops of the liquid reagent, and then place the lid on the vile straight away. Shake thoroughly for a few seconds and then text the color using the included color chart – this allows you to figure out the pH in your water.
We highly recommend keeping in mind that this type of reagent liquid can only be used in water without any nutrients or additives, as it will end up giving a false reading in such cases.
pH 600 ECO Milwaukee Meter
This is one of the most used pH meters on the market when it comes to indoor and outdoor growing rooms, as it’s the most affordable one and it provides good results. It’s a great way to get started when it comes to growing cannabis if you’re on a budget. You’ll need to calibrate it by using a calibration liquid – first, adjust it to 7.0 pH and then adjust it down to 4.0 pH. In order to adjust the pH to your calibration liquid, you need to turn the small screw that it has while checking the screen to make sure you’re adjusting it right.
The only downside to this meter is that you’re going to need to keep the sensor clean and humid/moist by using a pH meter maintenance liquid – if not, your meter will most likely start producing erroneous results when compared to other meters. You’ll also need to take into account that this device is not water-resistant, so do not let it fall into the water when using it.
ADWA pH AD-100 Meter
This pH meter is slightly more sophisticated than the previous model; as well as offering precise data, it can also adjust itself automatically when using pH 7.0 and 4-0 calibrators, which come included. It also has an automatic temperature compensation feature, which makes for much more precise measurements. This particular model is much stronger and more trustworthy as times goes on, although just like with any other meter, you’ll need to keep it humid and in good condition to avoid bad readings. The only inconvenience here is that it isn’t waterproof; all you need to do is place the tip of the sensor in the water.
ADWA pH AD-11 Meter
This AD-11 ADWA meter is a semi-professional model that, apart from precisely measuring the pH in your water thanks to automatic temperature compensation, also indicates the temperature of the water and can emerge unscathed if dropped in the water. This doesn’t mean that it’s entirely waterproof, and you still need to use the sensor part when measuring pH values. These water-resistant ADWA meters are quite prone to sensor issues, as they’re quite delicate, but you can easily get your hands on a replacement sensor. This allows you to keep one on hand just in case it breaks and your plants are at a delicate period.
In order to calibrate it, you’ll need to hold the ON/OFF button for a few seconds while it’s on until the letters CAL come up on the screen. Next, the meter itself will let you know what calibration liquid is needed – first, you have to use pH 7.00 and next you’ll need to use pH 4.00. In order to keep it in decent shape, you’ll need to clean it after every use and use maintenance solution when storing it to keep it working well and for much longer.
Guardian Bluelab Monitor
The Guardian Bluelab Monitor is, without a doubt, the most sophisticated, professional and precise pH meter found in this post; it’s a pH, EC and temperature meter that works continuously; it’s a great idea for hydroponic and aeroponic grow set-ups, as these types of grows tend to need a lot more control when it comes to the water used.
In order to use this continuous pH, EC and temperature meter correctly, all you have to do is place the monitor at head-height so that you can easily take a look at it, and then you’ll need to adjust the pH and EC in your water, depending on your plants’ needs and the period that they’re in. It also has a visual alarm system (a blinking light) that lets you know when the pH or EC in your nutrient tank aren’t at the right values, allowing you to correct almost any fluctuation instantly.
When you use any type of continuous pH monitor, you’ll end up saving loads of time when it comes to watering, allowing you to make the most of your cannabis plants’ potential. Keep in mind that the sensors can be replaced in case one of them breaks or is worn – you can easily replace them. In as far as its calibration system, it’s super easy – only the pH sensors needs to be calibrated in the exact same way as the rest of pH meters on the market. We recommend cleaning the sensors after every grow and storing them in maintenance liquid.
In order to learn more about the pH meters for growing cannabis plants in this post, you can go straight to their product page by clicking on their picture, allowing you to visualize the product better thanks to their concise, simple descriptions that make them incredibly easy to understand. Plus, we stock many more models that you can have a look at!