a lot of biomass - could be low on Nitrogen? always load up on Nitrogen before going into transition and stretch- it takes a lot of energy to Stretch. (Nitrogen=growth energy) Transition/Stretch is still in Veg cycle - Dont switch to bloom ferts till after stretch (or 2 wks after 12/12)

Newbie24 said:

Hey team, I’m new to the game and could do with some advise, I’ve got 3 x super skunks in veg stage in 15l auto pots for about 5 weeks now, and I think I’m having some magnesium deficiency? What do you guys think? I’ve given it come cal mag for the last couple of feeds but hasn’t seemed to do too much.

Ph has been about 6.4 in the tank and about 6.7 in the base of the pots

Any advise would be much appreciated

Cheers

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What are you growing in ?

HeadHunterpipes said:

What are you growing in ?

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A 50/50 potting mix and perlite ( nothing flash, just a standard potting mix)

Choppr said:

a lot of biomass - could be low on Nitrogen? always load up on Nitrogen before going into transition and stretch- it takes a lot of energy to Stretch. (Nitrogen=growth energy) Transition/Stretch is still in Veg cycle - Dont switch to bloom ferts till after stretch (or 2 wks after 12/12)

Click to expand...

Maybe I’ll up my nitrogen and see what happens, maybe even foliage spray also?

Def nitro, and 1 plant a lil bitchier than the ithers.
Foliar sprays don’t really help anything man
Up your nitro a little bit,

The two gentlemen above know the damn deal best of luck

better transplant those soon,..

GNick55 said:

better transplant those soon,..

Click to expand...

Do you think they are out growing the 15l pots?

Newbie24 said:

Do you think they are out growing the 15l pots?

Click to expand...

yep,.. slide one out when dry,.

Thanks for the advise team, I’ve upped the nitrogen and will transfer into 25l pot in the next day or so and cross my fingers and toes they come back healthy then they will be going into flower

you could take a plant and place the bottom of the pot on your knee to push up on to loosen the plant than set it down and pull it up out of the pot by the trunk,.

When you transplant, I would check the yellowing plant closely to see how wet she is. The beginning of root rot could look like this. If it’s too wet, let it dry out for a while. H202 might be a thought for the root zone.

I would also do a magnesium foliar spray. One tablespoon/gal every 3 days for 3-4 applications. They love it.

Phil

Just saying, building your soil.
I am a big fan of adding in top soil which is 50% silica and 5 % nutrients those nutrients are part the micro nutrients family your plant needs.
The plant in the back that is lighter green color I think it might need zinc and iron too.

Kind of a balance you need the micro nutrients so the plant can uptake the macro nutrients.

Suggest you go through the needed nutrient charts and add the nutrients that are not in your organic soil.

Cannabis Nutrients: A Complete Guide​

HomeCannabis Nutrients: A Complete Guide

​

Growing cannabis is an art and a science. From selecting the right strain to managing your grow environment, every step contributes to the success of your cultivation journey. However, one aspect often overlooked by beginners yet essential for every grower is understanding cannabis nutrients. These nutrients are the lifeblood of your plants, fueling their growth and enabling them to produce those luscious, resin-coated buds every grower dreams of.

In this guide, we’ll dive deep into everything you need to know about cannabis nutrients, including what they are, how they work, and how to use them effectively. Whether you’re a seasoned grower or a complete novice, this comprehensive guide will equip you with the knowledge to maximize your plant’s potential.

​

What Are Cannabis Nutrients?​

Cannabis nutrients are the essential minerals and compounds that cannabis plants require to grow, develop, and thrive. These nutrients fall into three main categories:

​

1. Macronutrients​

These are the primary building blocks for cannabis plants and are required in large amounts:

• Nitrogen (N): Vital for vegetative growth, nitrogen helps in leaf and stem development and is a key component of chlorophyll.
• Phosphorus (P): Essential for root development, flowering, and energy transfer within the plant.
• Potassium (K): Plays a crucial role in water regulation, nutrient uptake, and overall plant health.

2. Secondary Nutrients​

While not as prominent as macronutrients, secondary nutrients are still crucial:

• Calcium (Ca): Strengthens cell walls and aids in root development.
• Magnesium (Mg): Central to chlorophyll production and photosynthesis.
• Sulfur (S): Supports protein synthesis and enzyme function.

3. Micronutrients​

Required in trace amounts, these nutrients support various biochemical processes:

• Iron (Fe), Zinc (Zn), Manganese (Mn), Copper (Cu), Boron (B), Molybdenum (Mo), and Chlorine (Cl).

How Cannabis Plants Absorb Nutrients​

Cannabis plants absorb nutrients through their roots, where they’re dissolved in water and transported throughout the plant via the vascular system. This process is influenced by factors such as pH levels, soil composition, and water quality. Ensuring the correct pH range (6.0-7.0 for soil and 5.5-6.5 for hydroponics) is critical for optimal nutrient uptake.

The Role of pH in Nutrient Uptake​

Even if you provide all the essential nutrients, your plants can still suffer deficiencies if the pH isn’t within the optimal range. Here’s why:

• High pH: Can lock out micronutrients like iron, manganese, and zinc.
• Low pH: Can inhibit the absorption of calcium, magnesium, and phosphorus.

To avoid nutrient lockout, regularly test and adjust your pH levels using pH meters and buffers.

Types of Nutrients for Cannabis​

There are several types of nutrient products available for cannabis growers. Each has its advantages and disadvantages, depending on your growing method and goals.

​

1. Organic Nutrients​

Derived from natural sources such as compost, bone meal, and fish emulsion, organic nutrients improve soil health and promote sustainable growing practices.

Pros:

• Enhances soil microbiology.
• Environmentally friendly.
• Produces flavorful buds.

Cons:

• Slower nutrient release.
• Harder to control precise nutrient levels.

​

2. Synthetic Nutrients​

These are man-made fertilizers formulated for immediate absorption by plants. They’re ideal for hydroponic systems and growers seeking precise control.

Pros:

• Fast-acting.
• Highly customizable.
• Consistent results.

Cons:

• Can harm soil microbiology over time.
• Higher risk of nutrient burn.

​

3. Pre-Mixed Nutrients vs. Custom Blends​

• Pre-Mixed Nutrients: Convenient and easy to use, suitable for beginners.
• Custom Blends: Allow advanced growers to tailor nutrient mixes to specific strains and growth stages.

Feeding Schedules and Growth Stages​

Understanding your plant’s nutritional needs during each stage of growth is crucial for a successful harvest. Here’s a breakdown:

1. Seedling Stage​

• Nutrient Needs: Minimal nutrients, primarily water.
• Recommended Feeding: Use a diluted solution with high nitrogen and low phosphorus.

2. Vegetative Stage​

• Nutrient Needs: High nitrogen, moderate phosphorus, and potassium.
• Recommended Feeding: Increase nutrient strength gradually as plants grow larger.

3. Flowering Stage​

• Nutrient Needs: High phosphorus and potassium, lower nitrogen.
• Recommended Feeding: Transition to a bloom nutrient formula rich in phosphorus.

4. Flush Stage​

• Nutrient Needs: None.
• Recommended Feeding: Flush plants with plain water to remove residual nutrients before harvest.

Common Nutrient Deficiencies and Toxicities​

Recognizing the signs of nutrient imbalances is key to addressing issues early. Here’s how to identify and remedy common problems:

Nitrogen Deficiency​

• Symptoms: Yellowing leaves starting at the bottom.
• Solution: Increase nitrogen supply.

Phosphorus Deficiency​

• Symptoms: Purple or dark spots on leaves.
• Solution: Adjust pH and add phosphorus-rich fertilizers.

Potassium Deficiency​

• Symptoms: Brown edges on leaves and weak stems.
• Solution: Add potassium supplements.

Nutrient Burn​

• Symptoms: Leaf tips turn brown and curl.
• Solution: Flush plants with water and reduce nutrient strength.

Nutrient Delivery Methods​

Cannabis nutrients can be delivered in various ways, each suited to different growing environments:

1. Soil Feeding​

• Nutrients are mixed into the soil or applied as a liquid solution.

2. Foliar Feeding​

• Nutrients are sprayed directly onto the leaves for rapid absorption.

3. Hydroponic Feeding​

• Nutrients are dissolved in water and delivered directly to the roots.

Best Practices for Using Cannabis Nutrients​

1. Start Low and Go Slow: Begin with a low nutrient concentration and increase gradually.
2. Monitor Plant Health: Regularly inspect your plants for signs of deficiencies or toxicities.
3. Adjust for Environment: Factors like light intensity and temperature affect nutrient requirements.
4. Flush Periodically: Flush your plants to prevent salt buildup in the growing medium.
5. Keep a Grow Journal: Record feeding schedules and observations for future reference.

Top Nutrient Brands for Cannabis​

The market is filled with nutrient products, but here are some trusted brands favored by growers:

• FoxFarm: Known for organic-based nutrients.
• General Hydroponics: Popular among hydroponic growers.
• Advanced Nutrients: Offers pH-perfect formulas.
• Botanicare: Focused on sustainability and quality.
• Canna: Tailored for professional growers.

DIY Cannabis Nutrient Recipes​

For growers who prefer a hands-on approach, creating your own nutrient mix can be rewarding:

Vegetative Stage Recipe​

• 1 cup of worm castings.
• 2 tablespoons of fish emulsion.
• 1 gallon of water.

Flowering Stage Recipe​

• 1 cup of bat guano.
• 1 tablespoon of molasses.
• 1 gallon of water.

Mix ingredients thoroughly and apply to plants as needed.

Conclusion​

Mastering cannabis nutrients is a cornerstone of successful cultivation. By understanding the essential nutrients, recognizing plant needs at each growth stage, and fine-tuning your feeding strategy, you can unlock the full potential of your cannabis plants. Whether you choose organic or synthetic nutrients, soil or hydroponics, the key is to observe, adapt, and enjoy the process.
Happy growing!


Hope this helps.

Thanks guys! I think they were definitely root bound, may explain why it wasn’t taking on much nutrients.. they are in bigger pots now so I’ll give them a couple days to come right then flower time

Newbie24​

Indoors I am hydroponic grower,, I have tried 5 gallon buckets, the plants roots grow around the air stones and kind of want lift the air stones up toward the base of the plant but other issue is the bucket is full of roots .
I am a big fan of large pots or containers for the plants root system.

The fastest grow system is aeroponics,,, because the plants roots are being misted with water and the hanging roots are in oxygen too.

Roots being in stagnate water NO OXYGEN makes the root rot in every grow system known to man .
My point is design your grow medium to allow good drainage and where the root system is getting oxygenated water .
I copy info and paste allot because of my writing skills .
But allot of info in here about how to grow healthy cannabis plants in natural to hydroponic grow systems.
Hope you learn from this info .. best of luck.






Written by Editorial Team
Updated on: May 21, 2024
7 minread
0
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The short answer is ‘yes,’ of course, but there is a lot more to it than that! It is easy to dismiss the importance of oxygen when growing cannabis. After all, dry air contains approximately 20.95% of it, so your plants are okay, right? Even at 100% relative humidity, the atmosphere consists of 20.4% oxygen. However, if you don’t allow for excellent air circulation in the grow room, your plants could suffer.

Cannabis & Respiration​

Respiration is the act of breathing. Like every other living organism, plants respire. While their needs are less complex than those of humans, they still require a well-ventilated growing area to thrive. Your cannabis plants use their roots, stems, and leaves for aerobic respiration. They use oxygen as an oxidizer. Dark respiration does not depend on light, whereas photorespiration does.
It is a 24/7 process but is more intense at night because of the cessation of photosynthesis. In case you wanted a quick recap, here is what photosynthesis looks like:

• The plant draws water through its roots.
• The leaves take in carbon dioxide (CO2) from the air and trap energy from the sunlight.
• Next, the plant uses the sun’s energy to turn water and carbon dioxide into sugars and oxygen.
• The plant releases the oxygen into the air and uses the sugars to grow.

Without photosynthesis, the depletion of oxygen in the atmosphere would occur within a few millennia. As you can ascertain from the information above, photosynthesis involves several processes. This is why plants have a higher respiration capacity at night and why every marijuana growing guide you have read tells you to keep the nighttime temperature lower than during the day.
Another reason cannabis plants need air is the CO2 levels they provide. Today, the level of carbon dioxide in the atmosphere is over 400 parts per million (ppm). For the record, it is the highest level in the last 800,000 years! Elevated CO2 is not suitable for humans, but plants thrive on it. Ideally, your grow room will contain a carbon dioxide level of between 1,000 and 1,400 ppm.

Other Important Components of Respiration​

It is also essential that you keep the substrate and roots well-oxygenated. Growers who use organic soil need an even higher level of oxygenation because the microorganisms in the earth also require oxygen. The porosity of your substrate also impacts the respiration capacity of the soil. Improve matters by adding perlite or coco coir to your soil mixture.
Your marijuana plants contain a myriad of tiny pores called stomas. Think of these as the plant’s ‘nostrils,’ which they use to absorb CO2 and release oxygen. If you find most of the stomas on the underside of the leaves, spray both sides with water twice a day. The ideal temperature of the water is between 65 and 70 degrees Fahrenheit. Stomas are minuscule and get clogged easily, so regular cleaning is required. Outdoor growers don’t have this problem, as rainfall does the work for them.
During photosynthesis, your crop absorbs CO2 and releases O2. At night, it absorbs O2 and releases CO2. If you grow your plants outdoors, you have automatic air circulation. Indoor growers, on the other hand, need to invest in well-placed fans or a ventilation system. An intake fan is also necessary to bring in fresh air, and an exhaust fan to remove stale air.

Why Air Circulation Is Crucial​

Constant air exchange is the key to a successful indoor grow. The three things to worry about are:

• Clean stomas
• Good air circulation
• Consistent air exchange

Remember that even distribution throughout the entire room is a prerequisite. Otherwise, you will end up with areas featuring stagnant air. It is a balancing act because you must ensure the air is neither too moist nor too dry. We recommend avoiding air layers because hot air gathers in higher areas, while cooler air usually flows downward. The result is a slower-growing crop that is more susceptible to insect infestation and mold growth.

Useful Air Circulation & Exchange Equipment​

The following is not an exhaustive list, and you do not need to buy all of it. Your needs depend on the size of your grow room. If you have a small grow tent, for example, there is no need to buy half a dozen items from this list!

• Intake Fan: Brings oxygen-rich air to the growing space.
• Exhaust Fan: Removes air that is low in oxygen.
• Active Carbon Filter: A necessary purchase if you grow stinky weed and don’t want to attract attention!
• Ventilation Ducts: You can purchase ducts to remove stale air and others to allow fresh air in.
• Acoustic Box: Reduces the noise caused by the fans.
• Ceiling Fan: As the name suggests, you suspend this fan to your grow room’s ceiling, ideally between the lamp and the tops of your plants. A ceiling fan helps cool down the layer of hot air that accumulates in that region.
• Clip Fan: A smaller fan that is ideal for small tents.
• Oscillating Stand Fan: Allows for even air distribution.
• Floor Fan: Helps recirculate the area near the floor. In general, only those with a large growing area need this device.
• Dehumidifier: Helps reduce the humidity in a room.
• Humidifier: Increases the level of humidity in a room.
• Thermohydrometer: Measures a room’s temperature and humidity.

Boost Yield with Dissolved Oxygen​

Dissolved oxygen (DO) relates to the level of oxygen saturation in the water. The more O2 in water, the better off your marijuana plants’ roots are. The process of a plant exhaling water vapor, oxygen, and nutrients via the stomata is known as transpiration. It enables your plants to cool down, alters osmotic pressure in cells, and ensures a steady flow of water and nutrients up from the root system.
When your weed’s roots are in an environment with lots of oxygen, they are more efficient at absorbing nutrients. O2 helps provide the metabolic energy needed for nutrient uptake. When you expose cannabis roots to high levels of oxygen, you benefit from greater root mass and healthier root tips.
A lack of oxygen in the root system reduces the rate of water and nutrient uptake. This results in a reduction in plant growth and occasional wilting due to heat stress. Throw in a lower level of photosynthesis and decreased glucose transfer abilities, and your crop has a lot of problems!
We haven’t even mentioned the enhanced production of ethylene. This flammable hydrocarbon gas could cause cell collapse and increase the risk of disease. If that isn’t enough, you also have a calcium shortage to contend with. In a nutshell: Less oxygen = lower transpiration = bad news!

How Much Do You Need?​

First and foremost, the only way to measure dissolved oxygen is to purchase a special DO meter. Most growers know how vital pH and EC are and have no issue buying a device to measure those readings. However, you can purchase a pH or EC meter for no more than $30. In contrast, a DO meter can cost up to $300! It is also much harder to use and often requires watching videos to know what the hell is going on.
Water in a low-pressure boiler typically has a dissolved oxygen rate of no more than 2.0 ppm. However, boiler plant operators try to keep it below 0.01 ppm. In tap water (at room temperature), the DO level rises to perhaps 5-9 ppm. According to most experts in the field, you only notice a difference at a rate of 12+ ppm. Research by the University of Wisconsin and the University of Minnesota suggests that plants utilize nutrients effectively when the DO in water is 10 – 12 ppm.
Charlie Hayes has a biochemistry degree and owns Advanced Treatment Technologies, a company that specializes in providing water treatment solutions. During his research, he found that marijuana’s health and production benefits reach a plateau at a DO rate of 40 – 45 ppm in the root zone. However, to deliver the right amount to the roots, you need to begin with a far higher concentration in a treatment system.

Increasing the Water’s Dissolved Oxygen Level​

There are several methods of increasing DO levels in the water. Aeration of water through the use of a bubbler is the most popular way. The process involves injecting air into the water. However, you must pay attention to Henry’s Law. It states that the solubility of gas is controlled by concentration, temperature, and pressure. For instance, CO2 is 20 times more soluble than oxygen.
Hayes asserts that the use of ozone is the most effective method of getting DO into the water, as it is 12.5 times more soluble than oxygen. You need a treatment system capable of handling a high concentration of ozone before you use an ozone generator. The system must also have the ability to mix the molecule properly and hold it in the solution. As Hayes states, ozone is unstable, with a half-life of as little as 3-5 minutes when converted to DO.
If you use a hydroponics system, another option is to place a stirring pump at the bottom of the reservoir, attached to minimal tubing. It mixes the solution on a timed cycle or continuously. The process is akin to how the water in the oceans keeps moving due to the work of currents. When you mix or move water, you enable the already dissolved oxygen to remain stable. You also see an increase in DO because the water mixes with air on the reservoir’s surface.
Growers also use hydrogen peroxide, but this could cause toxicity that ultimately harms plants.

Don’t Forget the Water’s Temperature!​

When exposed to temperatures below 60 degrees, the roots of your marijuana plant will decrease metabolic activity. The so-called sweet spot is between 62 and 66 degrees. Don’t allow the temperature of the root zone to go above 75 degrees, or else you risk root rot.
Fully oxygenated water at 68 degrees could hold a DO level of up to 9 ppm. The same water at 86 degrees has a DO level of just 7.5 ppm. Therefore, it makes sense to use room-temperature water when feeding your plants.

Final Thoughts on Marijuana Plants & Oxygen Levels​

Ultimately, your crop should grow just fine without the need for increased dissolved oxygen levels in the water. However, advanced growers know that increasing the DO in the water they provide to their plants is a difference-maker.
While it may not make sense to spend heavily on dissolved oxygen increasing equipment or a meter to read the level, it is a worthwhile investment if you intend to grow commercially. When your roots receive water with a heavy dose of DO, your plants will feel refreshed and energized. The result is faster growing and healthier weed, along with an increased yield.

Do you guys think they are Still abit yellow to switch into flower or do you guys think they will recover if I keep feeding nitrogen and cal mag in the first couple weeks of flower?

Newbie24 said:

Do you guys think they are Still abit yellow to switch into flower or do you guys think they will recover if I keep feeding nitrogen and cal mag in the first couple weeks of flower?

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Well…since your original post last Thursday, another of the plants yellowed noticeably. So we need to figure this out. They look overwatered to me. I would dry them out good, reduce your light intensity to half what it is now, I might also do a foliar spray with 1tbl Epsom salts/gal water two or three times and give them water only for a few waterings. (Or in the reservoir)

Taking the pressure off the plant can help.

As far as going into flower, personally I would wait a while. I went back n forth a few times on this.

my guess u overdid with P mb Mg too