How to Grow Fatter Cannabis Buds?

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Added 21 August 2022

Growing a cannabis plant is easy, but it’s challenging to grow fatter buds.  

Beginners have no problems growing cannabis plants, but they get stuck when it comes to cultivating thick, dense nugs. 

If you are just starting with cannabis cultivation, you might be heading in the same direction, but you can avoid it with a few small steps. 

If you didn’t know it already, It takes surprisingly little effort to grow high-quality, big buds. 

In this article, learn all about growing fatter buds.

Why Do You Need Fatter Cannabis Buds?

fat cannabis bud

Fatter buds are not just about aesthetics — there are many reasons why users prefer bigger buds and, consequently, why growers want to grow fatter buds. Here are a few reasons.

Optimal Potency and Performance

Maybe you have got a high-THC strain to grow, but if the flowers are not big, you may not get as high as you would expect. This is because the flowers’ size is proportional to their potency and performance.

So, to maximize the buds’ potency and performance, you need to grow fat buds, i.e., like they were intended to grow.

Delicious Texture and Flavor Profile

Similarly, a smaller flower may not have the best terpene profile, which ends up affecting its overall taste and aroma. You don’t want that, and neither does your customer if you’re into commercial cultivation. 

Additionally, a poor terpene profile may even lead to a bad taste or aroma that can completely ruin the experience of consuming cannabis. So, it is advised to grow bigger buds with a rich terpene profile so that you and your friends can enjoy all that your cannabis has to offer.

Long Shelf Life

Fatter buds are healthier, so they contain enough nourishment to last long in storage. On the other hand, if the buds are small, they may wilt in storage within a few weeks. If you want to store your buds for long, you should aim for bigger buds. 

Get Your Time’s Worth

Lastly, what’s the point of spending months growing a plant, pouring your energy, time, and money into it, only to end up with buds that are small, less potent, and bitter? So, at the most basic level, it’s better to grow fatter buds to get your time and money’s worth at the end of the harvest. 

How to Grow Big, Fat Cannabis Buds?

big bud

The buds’ size depends on two things — genetics and the growth environment. Of course, you can’t change the genetics of your plant. If you have chosen a strain that tends to grow smaller buds, you can’t do anything about it.

However, for all cannabis plants, you can maximize the size of the buds by tweaking the growth environment. And there are many ways to do that: by optimizing the lights, setting the right temperature, or giving your plant a carbon dioxide boost. Learn about these techniques below.

1. Fix the Lighting

fix the lighting

The first thing you need to do is fix the lighting. You need to ensure that your grow lights offer adequate light intensity in the right spectrum to ensure your plant grows big buds. This is because your plant uses light the most during the vegetative and flowering stages to grow.

You need to focus on four things in regards to the grow lights:

  • Light’s distance from your plant
  • The intensity of the light
  • The color spectrum of the light
  • And the light cycle 

Let’s take a look at these lighting factors in detail.

Light Distance

The light source’s distance from the plant is crucial for your plant’s photosynthesis and growth. If the light is too far, your plant may experience a light deficiency, and if it is too close, your plant may experience a light burn — both of which are bad for the plant and eventually lead to smaller buds. 

The ideal distance of the lights from your plant depends on your lights, but as a basic guideline, here is a chart showcasing the ideal distances for HID lamps based on their wattage:

  • 400W: 12 inches
  • 600W: 16 inches
  • 1000W: 21 inches

This is a guideline for HID lights and does not apply to LED lights. The parameters for using LED lights are completely different and not based on wattage. 

Light Intensity

The second comes the intensity of light, i.e., how much light your plant gets. This is crucial because your plant’s growth (and bud size) depend on the light intensity. If your plant does not get the adequate intensity of light, it may grow larfs (low-quality buds), since the plant fails to produce enough energy. 

Here, you should avoid relying on the light’s wattage because it does not give you a clear picture. For example, a 100W LED does not produce the same intensity of light as a 100W CFL or HID lamp. Wattage refers to the device’s energy consumption, not light output. 

Instead, you need to look at the light in terms of lumens (or lux). Here is the optimal range of lux for the best cannabis growth:

  • Vegetative stage: 40,000 lux
  • Flowering stage: 60,000 lux

It is recommended that you invest in an accurate light meter to measure how many lumens your light source emits and to identify if you need to add more lights. 

Light Spectrum

Did you know that the color of the light also influences your plant’s growth and bud production? Each color of light has a unique wavelength, for example, purple has a wavelength of 400 nm. And the color or wavelength impacts your plant’s growth

Additionally, light panels also have a dominant color. For instance, MH lights are often blue-dominant. 

So, for the best growth, you need to choose a light source that emits the light spectrum that is right for your plant’s growth. 

Here are the best color spectrums for cannabis based on its growth stage:

  • During seedling stage: blue dominant light
  • During the vegetative stage: blue dominant light
  • During flowering stage: red to far-red light

Here, we recommend using LED lights since their color spectrum can be customized easily. On the other hand, MH, CFL, or HPS lights cannot change their color spectrum at all. Plus, some high-end LED lights emit UVB rays, which further benefit your plant in terms of growth. 

But if you don’t want to spend a lot of money on expensive LED panels, you can use MH lights during the seedling and vegetative stage and shift to HPS lights during the flowering stage. 

Light Cycle

The light cycle refers to the amount of time your plant gets light within 24 hours. It allows you to control your photoperiod plant’s growth stage. Here are the ideal lighting schedules for each growth stage:

  • During the seedling stage: 24/0 (24 hours of light and 0 hours of darkness)
  • During the veggie stage: 18/6
  • During the flowering stage: 12/12

This schedule works well for a cannabis plant for various reasons. The seedling benefits from a full day of light as it can grow bigger stems and roots, kickstarting its growth.

When the plant reaches the vegetative stage, at least 18 hours of light allows it to generate energy and grow big. And when it reaches bloom, a 12/12 light cycle disrupts the plant’s genetic clock, triggering it to grow buds. Plus, longer dark hours during bloom are crucial for big buds.

2. Set the Right Temperatures

set the right temperatures

Another factor that is crucial for growing high-quality, fatter buds is the temperature of the grow room. Throughout the plant’s growth cycle, if the temperatures are right, it will grow high-quality buds. 

During the vegetative stage, cannabis grows best between 69°F to 85°F (20.5°C to 29°C), and during bloom, between 64°F to 78°F (17.778°C to 25.5°C). So, you should aim for these ranges when growing cannabis.

Also, you need to pay attention to temperature fluctuations between the light and night cycles. The fluctuation should not be more than 40°F.

If the temperatures are too high during the flowering stage, the terpenes on the buds may evaporate, compromising their flavor and potency. So, even if you grow fatter buds, they won't be as potent or flavorful if the temperatures are too high. 

And if the temperatures are too low during the flowering stage, the plant may experience stunted growth and lowered rate of photosynthesis. 

If your grow room is too hot, follow these tips to calibrate the temperature:

  • Use an air conditioner to cool down the room
  • Or you can use a swamp cooler if your room is also dry since this cooler raises humidity
  • If temperature spikes occur due to lights, you can switch to LED lights with heat sinks that prevent them from getting too hot 
  • You can even switch the light cycle and time it in such a way that the lights are out during the hottest part of the day
  • And improve air circulation with oscillating and exhaust fans

If the temperatures are too low, you can use the following techniques:

  • Install a heater in your grow room. Ensure that it does not blow hot air directly on the plant
  • Switch to HPS or MH lights that generate heat
  • Use heating mats or cables underneath the plant
  • Insulate your grow room
  • Or build a polytunnel or greenhouse if you are growing outdoors

It is recommended that you invest in temperature and humidity meters to monitor your grow room's environment. It's a small investment that can make a big difference to your plant's health.

3. Administer Some Carbon Dioxide to Your Plant

Administer CO2

Carbon dioxide is essential for cannabis for the photosynthesis process, where the plant converts this gas into energy. And studies have shown that the higher the carbon dioxide, the better a plant grows with bigger yields. 

According to one study, plants experience continually increased growth until the carbon dioxide levels in the growing environment reach 10,000 ppm! But you don’t have to pump 10,000 ppm of carbon dioxide into your grow room — that would be dangerous for you. 

Instead, you should aim to increase the carbon dioxide concentration in the grow room to 1,200 to 2,000 ppm to increase your yield by up to 20%.

Adding more carbon dioxide to your grow room can get really expensive, so this technique may not be suitable for many growers. But if you want to use this method, you can employ various methods to introduce more carbon dioxide into your grow room, such as the following.

Use a Carbon Dioxide Generator

A carbon dioxide generator resembles a patio heater and uses either natural gas or propane to produce carbon dioxide. If you use this generator, choose natural gas or propane from a reliable, high-quality vendor. 

For a propane-based generator, choose propane gas with HD 5 Grade, and for a natural gas-based generator, choose the one with less than 1 grain (64.86 per 100 cubic feet) of sulfuric acid. 

Also, you have to tweak the growing environment further for using such a generator. You need to increase the temperature of your grow room by 5°F and relative humidity by 7%.

If you install a carbon dioxide generator, be wary of sulfur leaks. When sulfur mixes with the air, it turns into sulfuric acid, which can cause burn spots on your plants even in minuscule quantities.

Use Compressed Liquid Carbon Dioxide

Another method is using compressed carbon dioxide, which you can purchase from your local home brewing or hydroponic stores. This method allows you to administer carbon dioxide in a controlled manner with the help of emitter devices that can control the flow rate. 

Another benefit of this is that it does not produce any heat, humidity, or sulfur.

To administer carbon dioxide in this method, you would need the following things:

  • Liquid carbon dioxide cylinders
  • Plastic tubing of ¼ to ½ inch with evenly spaced holes 
  • A pressure regulator to control the tank pressure to 5 psi
  • A flow meter 
  • A solenoid valve with a timer to automate the flow

Depending on the equipment you use, you need to follow the right instructions to rig the system. Once you do that, it will gradually release carbon dioxide into the atmosphere and you won't have to worry about it.

Dry Ice

While the above-mentioned methods are expensive, there are two methods that are relatively cheaper. One of them is using dry ice. This is also the easiest method to introduce more carbon dioxide into your grow room since all you need to do is place a brick of dry ice in your grow room.

The dry ice slowly releases carbon dioxide into the grow room, increasing the overall CO2 ppm.

Or Use a Compost Bag

The second affordable method is using compost to introduce more carbon dioxide into your grow room. Here, you simply have to place a compost bag near your cannabis culture and it will gradually release CO2 into the air. 

A single compost bag can last you for two to three months, which is a great benefit, but on the flip side, you can’t adjust the flow rate, you have to let nature do its work. 

4. Feed Bone Meal to Your Plant

bone meal

Bone meal is one of the best substrate amendments that you can use to fatten up your flowers. It is essentially a mixture of ground-up animal bones. 

Bone meal is a terrific source of calcium and phosphorus, which helps the plant growth during the vegetative stage. Here, calcium encourages the formation of plant cells and phosphorus allows your plant to grow big, both of which lead to better, bigger flowers eventually.

Plus, phosphorus is one of the two essential macronutrients that cannabis requires the most during the flowering stage as it encourages bud development. 

Bone meal releases the nutrients slowly, so a single bag of it should last for the entire plant’s growth cycle. And unlike other chemical fertilizers, bone meal does not leave a chemical aftertaste on the buds. 

However, if you are a vegan, using bone meal is not suitable for you. Instead, you can use kelp meal — it offers the same benefit but is made of brown seaweed, not animal bones. 

You can purchase bone meal from your local gardening or hydroponics store. And the process of application varies from product to product, so read the instruction label carefully and follow that. 

Ideally, the best time to add bone meal to improve flowering is just when the flowers start to appear. But you can add it even during the early vegetative stage. 

5. Remove Dead Leaves on the Plant During Bloom

flowering stage

When your plant enters the flowering stage, you need to remove any dying leaves on the plant. Dying leaves are a lost cause — they consume the plant’s resources that can otherwise be used for growing bigger flowers. Typically, you can spot dying leaves as they are usually yellow. Or, they could be brown with a few spots on them. 

6. Harvest at the Right Time

harvest at the right time

Flowers tend to grow until the end, but that doesn’t mean you have to wait until the very end. You need to harvest at the right time, which can be a bit confusing for new growers. 

Harvesting at the right time will determine the effects of the buds. And the right time to harvest depends on factors like training methods used, grow medium, strain genetics, and desired yield. 

So, your plant can either be ready to harvest in six weeks or 16 weeks after germination. But most cannabis plants are ready for harvest between 9 to 12 weeks from germination. 

Understand the Strain Genetics

The first thing you need to do is to understand the strain genetics — how soon is your cannabis strain likely to be ready to harvest? You can find this information on the seed bank’s product page or in local forums. 

Look at the Trichomes

Next, you need to look at the trichomes, the small resin glands on the buds, as they are the most reliable way to determine buds’ maturity. 

Use a magnifying glass to look at these glands. If half of the terpenes appear cloudy or milky and the rest appear amber, your plant is ready for harvest. If the trichomes are clear, you need to wait for a while. 

Look at the Stigma Curling and Turning Orange

The stigma is the hair-like strands on the flowers — if they appear orange and curled up, the buds are ready for harvest. 

Leaves Curling Up

Another sign of a mature plant is the curling of leaves. This occurs due to a decrease in the plant’s water consumption, which leaves the leaves curled up. You can harvest the buds once you notice the leaves curling up. 

Do remember that the curling of leaves can also be a sign of water or nutrient deficiencies. 

You can use these methods to check your plant’s maturity and harvest accordingly. Ensure you do not harvest too early because the buds would not have grown enough and you will end up with smaller buds.

But also, do not wait too long to harvest. The flowers will grow big, but they may not be as potent or flavorful. 

Summary: How to Grow Fatter Cannabis Buds?

Growing fatter buds is something everyone wants from their cannabis plants, but it does not happen automatically. You need to work for it. So, if you want to yield bigger buds, use this guide and follow the methods to encourage your plant to grow fatter buds.

Also, you don’t need to use all the methods mentioned above. Some may be too expensive or time-consuming, and you may not prefer the others. Choose methods that work best for you and follow them accordingly. 

As long as you take good care of your plant and finetune the grow room’s environment, using even one method from the guide will lead to better results. 

Lastly, always harvest at the right time. Harvesting too early will counter all your efforts during the growing season as the flowers would not have grown to their full potential. But that does not mean you let the flowers grow wild — if they mature too much, they may not be as fun to consume. 


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I would use PPFD vs Lux for calculating light intensity. aka umol/m2/s. better offering of how well they work, granted I have used blue light from start to finish on led's in 6400K and the buds turned out great. It is also good to note unless your grow room is sealed up the added C02 is useless if its venting out. Indoor C02 is at higher levels though, I think this is because of us living in the spaces as well. Plus they are somewhat sealed but not as tight as a glass box. This is at least my understanding of it. Regarding the vegan part though, most things that vegans eat survive by eating animal by products be it their poop or bones. waste not, want not IMO.
@m0use, antibiotics mostly use gelatin derived from pigs, which makes me chuckle.
@m0use, Vent high humidity rises as does heat, co2 should be sucked in as close to the floor as you can nice n slow but constant, I personally use a 6inch 15w intake almost scraping the basement floor and it keeps 1200+ off lungpower alone. Co2 is heavier than o2. Just imagine if you had used 2300k they would have been even better buds!