Why can’t I grow dense buds?

Published Feb 09, 2020

by Nebula Haze

Bud density isn’t everything… but it sure is nice! If your buds keep coming out light and fluffy and you’re not sure why, this article will break it down for you. Learn exactly how to get the densest cannabis buds possible.

Example of dense buds

A dense marijuana bud like this needs to be ground up before you can use it!Learn how to prevent airy “popcorn” buds!

Fluffy, larfy, airy popcorn cannabis bud that never really filled out or got dense because it didn't get enough light during the flowering stage

Here are the 5 most common reasons your buds aren’t as compact as they could be.

1. ) Genetics

You can’t overcome a plant’s genes. Some plants will only grow small and airy buds, even in perfect conditions. If the genetics don’t support bud density, it’s not your fault if buds come out fluffy, and there’s not much you can do. That being said, some of my absolute favorite strains have buds that tend to come out with a lower density. Low density doesn’t necessarily mean buds are bad. It’s common with sativa and haze-leaning strains, as well as certain hybrids.

Once you’re smoking the buds, you don’t notice the difference!

I personally love Durban Poison for the captivating bud effects and excellent yields, but the buds aren’t necessarily the most dense.

Same thing with Liberty Haze, another favorite of mine. High yields and potency, but a somewhat looser bud structure.

Choosing a strain that’s known to grow dense will considerably increase the chance of producing dense buds. Indica-leaning strains tend to develop the densest buds, though these days, just about every strain is a hybrid.

Aurora Indica is a hardy strain that stays short and tends to grow solid buds even in poor conditions (plus the yields and effects are fantastic)

These are the rock-hard buds from that Aurora Indica plant

The Aurora Indica buds at harvest. 5.3 ounces from one plant!Bubblelicious is another popular strain that produces dense buds with splendid effects

It's normal for leaves to start yellowing as harvest approaches

Here are more dense strain recommendations:

  • Original Amnesia – The effects more than live up to the name (you won’t remember what you’re doing). I’ve grown this strain a few times, and buds alway come out dense and tight!
  • Bubba Kush – One of the densest versions of the classic strain, and outstanding effects!
  • L.A. Sorbet – A lovely cross with the effects of L.A. Confidential but sweeter flavors and even denser nugs.
  • Critical Purple Kush – Purple strain with strong body effects. Buds leave you relaxed and happy.
  • Somango – Although the buds have strong, psychoactive Sativa-like effects, the plant grows dense buds and has a relatively short flowering period just like an Indica.
  • Wonder Woman – Not only does this strain produce rock-hard buds, but it’s also one of the highest yielding strains I’ve ever grown. It always yields more than any other plant in the tent.
  • Pink Kush – Beautiful dense buds with exceptional effects. Superb bag appeal.
  • Black Sugar – Stays short, high yields, and dense sparkly buds!
  • Power Africa x MK Ultra FAST – Great for outdoors, mold-resistant, and ready to harvest earlier than most strains.
  • Cinderella Jack auto – Most dense (and potent) autoflowering strain I’ve grown so far!

What’s your favorite dense strain? Let us know!

 

2.) Poor Nutrition in the Flowering Stage

Cannabis plants tend to be relatively forgiving in the vegetative stage, and the exact nutrients provided don’t matter much as long as plants are growing green and healthy. Yet once you’re in the flowering stage and buds are forming, nutrients begin to have a direct effect on your bud quality, density, and yields.

Don’t Let Plants Run Out of Nutrients While Buds Form

Don’t rely on regular potting soil for nutrients in the flowering stage. Plants that are grown in the same soil from seed to harvest often use up the nutrients by the time buds start forming. Proper nutrition is crucial for a plant to produce the biggest, densest buds.

Don’t rely on regular potting soil to provide nutrients while buds are forming. Plants need plenty of P&K in the flowering stage.

Example of a beautiful cannabis canopy full of buds - these plants were just the right height at harvest

If you’re already adding cannabis-friendly nutrients in the water, this likely doesn’t apply to you.

However, if you’re not using nutrients, It’s a good idea to supplement your plant with flowering stage nutrients (high in P and K). The exception is when you’re either regularly transplanting into fresh soil, or using a composted, amended soil (which slowly releases organic nutrients throughout the plant’s life). The specific brand of nutrients isn’t nearly as critical as making sure you’re giving the plant what it needs. Learn more about the best cannabis nutrients.

Get quality nutrients to make sure your plants get enough nutrients in the flowering stage

Avoid Too Much Nitrogen in the Flowering Stage

On the flip side, you can give plants too high levels of nutrients. Providing high levels of nutrients overall causes nutrient burn, which is cosmetic and doesn’t have a massive effect on bud density. However, if you’re giving plants too high levels of nitrogen (N) in the flowering stage, it can inhibit bud development.

Too much nitrogen (N) causes dark green leaves. Sometimes they appear almost shiny

A nitrogen toxicity sometimes causes the tips of leaves to claw down

Luckily it’s effortless to tell if your plant has too much nitrogen. The main symptom of a nitrogen toxicity is dark green leaves, and possibly also clawed tips.

Too much nitrogen in the flowering stage can suppress bud development

A Nitrogen toxicity can also cause certain leaves to turn yellow, but other than that it looks nothing like a cannabis nitrogen deficiency

A nitrogen toxicity is super easy to fix. Just reduce the amount of nitrogen your plants are getting. Don’t stop giving nitrogen altogether though, pull it back.

If you’re using all-purpose or vegetative nutrients (which are high in nitrogen), you need to find different nutrients. Suitable nutrients for the flowering stage are typically labeled as “Bloom” nutrients and contain low levels of Nitrogen. If you’re using nutrients with multiple bottles that you combine according to a nutrient schedule (like the General Hydroponics Flora trio or the Fox Farm trio), you don’t need to worry. The schedule will automatically decrease the amount of Nitrogen during the flowering stage.

Buds don’t develop as well as they could when a plant is getting too much nitrogen

What if you’re using Bloom nutrients with low nitrogen, but plants still look dark?

In this case, reduce the nutrient levels overall. Don’t change the ratio. You can use fractions to figure out how much nutrients to add (for example trying to cut the nutrients by a 1/3), but I don’t like doing fractions. It’s too easy for me to mess up! Instead, I add extra water after mixing nutrients to dilute the overall levels without messing with the proportions.

When treating a Nitrogen Toxicity, make sure that you give enough water to get some runoff. Runoff water helps flush out any nutrient buildup in the grow medium.

Learn more about nitrogen toxicities

Don’t Ignore Nutrient Deficiencies

Now you know that flowering cannabis plants need plenty of Phosphorus and Potassium (P&K), but not much Nitrogen (N). The next most common nutrient challenge in the flowering stage is the appearance of nutrient deficiencies. If you’re not adding nutrients in the water, there’s a chance that the plant needs higher levels of nutrients overall, and supplementing with a suitable Bloom nutrient will solve the problem.

Not sure which bloom nutrient to get? Dyna-Gro Bloom is an affordable and effective bloom nutrient for cannabis in any grow medium that will provide your plant with complete flowering stage nutrition in any grow medium. An easy way to prevent flowering stage deficiencies!

However, if you’re already using nutrients and still see a nutrient deficiency, it’s likely caused by incorrect pH at the roots.

Don’t ignore nutrient problems like this potassium deficiency! Keep plant leaves as healthy as possible in the flowering stage for the best bud development.

Why should you care about nutrient deficiencies?

Although P&K are most important to bud development, your plants need a variety of nutrients to complete normal plant processes. Any time you ignore a plant that’s getting sick, you’re lowering the overall growth rates and potentially reducing bud size and density.

Diagnose my nutrient deficiency!

What About Supplements?

What about plant supplements? How important are they to bud density?

The truth is, you can achieve incredible bud quality and density using just base nutrients. They contain everything your plant needs for healthy growth, and so you don’t need any supplements to grow great buds. When I first started growing, I felt confused because it seemed like you need supplements to produce brag-worthy buds and yields. I’ve learned over the years that nutrient companies want you to believe that because that helps them sell more bottles. I’m not saying that supplements don’t provide benefits, I just want to assure you that they’re not necessary. They can sometimes make things more complicated by interacting with your nutrients or each other. Many supplements can be useful in small doses but may kill your plants at higher doses, so give sparingly at first to see what effect they have.

Some supplements claim to increase the density of buds, but it’s hard to pin down exactly which ones work. Unfortunately, there are not many side-by-side experiments showing the difference that each supplement makes. Here are some popular choices.

These supplements claim to increase yields and density with extra Phosphorus (P) & Potassium (K)

Get Liquid KoolBloom on Amazon.com Get HydroPlex on Amazon.com Get Beastie Bloomz on Amazon.com

Tips for using supplements in the flowering stage

  • Only add one new supplement at a time. You’re most likely to have unexpected results if you add several new things at once.
  • Adding just one supplement at a time also helps you pinpoint which supplement is causing the effects you see.
  • Always use supplements made by the same company as your base nutrients. Sticking with one company reduces the chance of unwanted interactions. Each company designs its nutrients and supplements to be used together.
  • Use any supplement sparingly. A little usually goes a long way! Too much of certain supplements can harm plants, burn the leaves, or stunt bud growth. Always start at the lowest recommended dose (or less) and only increase if plants seem to be responding well.

We all want magic in a bottle, but it’s important to remember that the environment and overall plant care are much more critical to achieving excellent bud quality and yields than any particular supplement. You can’t overcome a bad growing environment no matter what you give your plants (more on that next).

Learn more about cannabis plant supplements

 

3.) Wrong grow light

Unfortunately, some grow lights struggle to grow dense buds no matter what you do.

Grow lights that excel at producing excellent bud density:

Fluorescent lights like CFLs and T5s can produce dense buds when you keep the lights close. However, the lower buds on plants grown under fluorescents are typically on the fluffier side because the light doesn’t penetrate far into the plant. Fluorescent lights produce high bud quality and potency (I’ with CFLs), but if density is most important to you, fluorescent lights may not be the best choice.

CFLs and T5s must be kept extremely close to achieve high bud density. Only the buds close to the light will get dense.

Notice how all the colas go down almost to the base of the marijuana plant - this is the best way to train your plant to get the biggest buds

Specific LEDs (especially the no-name ones) have low penetration down into the plant and buds simply don’t harden up.

Low-quality LEDs often produce airy buds. These buds were grown under cheap LEDs. They stayed small and larfy even though plants looked happy and healthy.

Cannabis plants growing under LED grow lights - you can see the natural green color of the leaves only in the front, since a little bit of natural light is hitting them from outside the tent. The rest of the leaves look purple!

If density is the most crucial factor for you, generally, you’ll get the best results with HID lights like HPS in the flowering stage. However, the technology for LEDs has improved dramatically in the last few years, and there are many modern models of LEDs that consistently produce long, dense buds.

High-quality LEDs tend to cost a bit more, but the results can be worth it. For example, you can achieve impressive density and yields from LED models like the HLG Quantum Boards (HLG 100 3000k version, HLG 300 V2 R-spec, HLG 550 V2 R-Spec, etc.). Learn more about the best LED grow lights for cannabis.

Certain LEDs produce high density. The HLG 100 (3000k version) uses only 100W and made these extremely dense buds for me. I’m currently flowering several plants under an HLG 300, and so far, I’m even more impressed!

HPS grow lights consistently produce dense buds as long as plants are healthy and the environment is right

Cannabis plants growing under the yellow light of an HPS - HPS grow lights give the best yields of all grow lights!This bud was grown under HPS

This marijuana cola is ready for harvest - all the pistils have darkened and curled in

Buds become solid even with low-wattage models like this 150W HPS.

Use Scrog for better yields - this example of ScrOG by LBH from Rollitup.org

LEC/CMH grow lights also tend to produce dense buds (though often not as dense as HPS). One of my favorite aspects of growing with an LEC is buds come out extremely sparkly and stinky compared to other grow lights.

These sticky, dense buds were grown under a 315 LEC.

A view of flowering cannabis plants in a grow tent under a 315 LEC grow light - chunky and getting close to harvest!

 

4.) Vegetative Stage Mistakes

During the vegetative stage, you have total control over a plant’s final shape and size. You can use this to your advantage. Set your plants up correctly so they can support dense buds later.

Too Many Bud Sites

You can increase your overall yields by training your plant in the vegetative stage (with techniques like LST or manifolding), so it grows multiple primary buds instead of one.

Plant training increases yields by forcing plants to grow multiple main buds instead of just one

This cannabis plant was topped and then bent with low stress training (LST) to grow multiple colas, increasing yields dramatically!

However, if you grow a plant with tons and tons of buds sites, it may not be able to fatten them all up before harvest. This is most likely to happen on smaller plants, younger plants, and when using smaller grow lights. If you’ve got a relatively small plant, try to force the plant to focus on just a few main buds instead of dozens. A general rule of thumb is that plants under 2 feet tall should have 4-10 primary buds. Big or wide plants can support more.

Don’t spread the plant’s energy too thin or you may end up with tons of baby “popcorn” buds.

This plant has too many bud sites for its size. Although it may get good yields, none of the buds will grow particularly big or dense.

Bigger plants, older plants, and manifolded plants can support more big, dense buds. Especially when combined with a powerful grow light!

Don’t Switch to Flowering Stage Too Early

This is sort of related to the last point. Bigger plants can support bigger buds, and switching to 12/12 early means that your plant might not get big enough to make dense, thick colas/buds.

Try to switch to the flowering stage when your plant has reached about half the final desired size. Since plants about double in size after they start getting 12/12, this should give you the biggest plants possible for your grow space.

Switch to 12/12 when plants are half the final desired height. This helps ensure they’re big enough to support dense buds

Change to a 12/12 light schedule when your plants reach about half the final desired height

5.) Flowering Stage Mistakes

A common cause of airy buds is poor care in the flowering stage. Here are several factors that can prevent you from getting the best density. This stage is the most essential part of your plant’s life when it comes to bud quality, density, and yields!

Ultra-leafy plants

When plants are so leafy that air and light can’t get through the plant, the buds don’t get as dense as they could.

These plants are too leafy for the flowering stage. Buds won’t fatten far into the plant, and won’t be as dense as they could be.

White Powdery mold most often attacks big leafy plants in small spacesAir and light should be able to travel through the plant in the flowering stage. For some plants, you won’t have to do anything. But with some plants, you may need to remove leaves to achieve the optimal amount of leafiness.

You may need to remove leaves if plants get too leafy

Not sure if your plants are too leafy?

This 3-step defoliation tutorial ensures your plants have the perfect amount of leaves.

Don’t ignore pests or disease

I mentioned nutrient deficiencies already, but it’s also vital that you react immediately to any other issues that may come up. Don’t ignore a problem until it gets out of control.

Typically a plant is simple to treat when it’s just starting to experience problems, but the longer it goes on, the worse it gets. An unhealthy plant won’t grow buds as well as a healthy one, so stay on top of your plant’s health.

Don’t ignore problems like pests or disease

Example of a pink, red, blue, purple and yellow leafhopper - this color of leafhopper is pretty common in the USA

Extreme temperatures (especially heat)

A lot of growers ignore issues with the plant’s flowering stage environment. Growers often don’t realize how much this can hurt their results. It’s easy to ignore environmental problems like heat because typically, your plants and buds will still be growing.

If plants look okay, the heat should be fine, right? Unfortunately, no.

When the air is too warm (above 80°F/26°C) in the flowering stage, buds tend to grow more light and airy. Sometimes buds even grow unsightly foxtails as a result of heat.

Optimal temperature range for the cannabis flowering stage

Buds get less dense when it’s too hot. Look at the loose structure of this bud grown in extreme heat.

New white pistils and lots of sugar leaves growing in strange shapes is a sign of heat or light stress

Too-cold air can also cause buds to grow small, airy, and loose

Lot of space between cannabis nodes - no buds can form on the spaces, so try to choose main colas that have lots of closely spaced nodes

Another thing about temperature: cannabis plants in the flowering stage like it to be a little warm in the day, but cool at night. Warm nights are also associated with airy buds. Try to keep the temperature between 65-80F (18-27C) for the best bud development in the flowering stage.

Check out our complete temperature tutorial.

High Humidity

Humidity in the flowering stage is another factor that’s often ignored. Each plant leaf is constantly adding moisture in the air, which means that the humidity tends to rise in the grow space as plants get bigger. That’s ironic because plants like high humidity when they’re young/small, but it causes problems in the flowering stage.

High humidity can trigger bud rot and powdery white mildew, which is plenty enough reason to control humidity. But there’s more. Buds don’t get as sparkly as they could in high humidity, and buds overall tend to grow more loose and airy.

Keep humidity under 50% RH while buds are forming for the best results!

Check out our full humidity tutorial.

Keep humidity under 50% RH while buds are forming, or they may not get as dense as they could

Example of Sativa plants that have been trained to grow wide and flat, so that many big colas can be kept close to the light

Poor Airflow

Buds seem to fatten the best when they get plenty of light and fresh air. You’ve already taken care of light, but you should also ensure your plants get excellent airflow. Air circulation helps control humidity, prevent wet spots, and moves air through the plant and around the buds.

Air-Circulation and Exhaust Tutorial

Make sure plants get fresh air and good airflow

Great air circulation and overall airflow makes cannabis plants happy!

Any other major stress

If your plant doesn’t “look good” or seems sickly in the flowering stage, that’s the first thing you should focus on to improve the density.

If plants look generally unhealthy, focus on fixing that before trying anything else. These plants are suffering from heat stress. Look how loose the buds are.

Example of dry, crispy leaves with lots of brown spots and yellowing - caused by too much light and heat!

Buds tend to stay small and fluffy on an unhealthy plant.

The leaf edges and tips turn bright yellow during a cannabis copper deficiency

Cannabis copper deficiency caused by incorrect pH

 

6.) Harvest Mistakes

Don’t harvest too early

Buds gain a lot of size, weight, and density during the last few weeks before harvest time. That means if you harvest your plants a few weeks early, they will be significantly smaller and less dense than they could be. Early-harvested buds also aren’t as potent and may give some people a headache. There are lots of great reasons to harvest your plants at the right time.

Learn the exact right time to harvest your plants

Don’t harvest until plants are ready. These Original Amnesia buds are dense and ready to harvest!

Start with great genetics to get great results!

Not drying and curing

Drying and curing buds makes them smoke better, smell better, feel more potent. Don’t skip this step!

As a bonus, drying and curing can help tighten buds up for that “California dispensary” look.

How to dry and cure your buds

Buds tend to look more “tight” and feel denser after being dried and cured

I’ve found that waiting to trim buds until after drying can also help them feel and appear more dense (compared to trimming before drying)

 

If you avoid these mistakes, you will produce cannabis buds as dense as you’ve always dreamed!

 

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