September 24, 2022

How to grow fat buds on your cannabis plant

A good, strong harvest is the grand finale of any proper grow. A harvest can represent months of planning, maintenance, and plant care. The crown jewel of a successful harvest is dense, fat buds that swell up with THC and trichomes. There is nothing worse than putting months of work into a harvest only to end up with small or loose buds with no weight to them. Fortunately, by following the correct steps, your can make sure that you grow dense buds every single time.

Why dense buds are desirable

Dense buds are heavier than loose buds, and have bigger yields. A harvest with light, airy buds may look promising at first. However, once you grind them you may be disappointed with how little there actually is to smoke.

Although some strains may naturally have lighter buds than others, very dense buds are generally a sign of a healthy plant. Big buds are a sign that a plant is getting the nutrition, lighting, and growing environment that it needs to grow strong and support its cannabis buds. Healthy plants have the energy to produce dense buds with large yields, while plants suffering from disease or improper nutrition will have much lower yields.

How to make buds swell up

There are many factors to go into a successful grow, these are the most important items to focus on to grow bigger buds:

  • Provide adequate lighting from grow lights (for indoor grows)
  • Feed your plant the correct nutrition
  • Select a strain that can grow dense buds
  • Train your plant correctly
  • Optimizing airflow to your plant
  • Maintaining correct temperature and humidity levels
  • Harvest your plant at the right time
  • Dry and cure your cannabis buds correctly

These will all be discussed in greater detail below. Of these, the most important factors to grow bigger buds are grow lights, plant nutrition, and airflow.

Use strong grow lights to grow dense buds

A good light source in your grow room is one of the most important factors to grow dense buds. Light is what gives your plant the energy it need to grow big and healthy, and to support bud production during the flowering stage.

Cannabis plants in the vegetative stage need strong lighting to grow their roots, branches, and leaves. A strong, healthy cannabis plant in the vegetative stage will provide a good base for growing bigger buds when it reaches the flowering stage.

Up to a certain point, flowering cannabis plants need as much light as they can get. The general rule of thumb is that more light equals bigger buds during flowering. It is crucial that plants get enough light while in their flowering stage. Of course, too much light can cause light stress or heat damage, so don’t overdo it.

Inadequate lighting is one of the biggest reasons for poor harvests and small buds. If you’re trying to get a big yield, lighting from a small 50W grow light or from an open window generally won’t be enough. The plant can still grow and survive at those lighting levels, but their bud yield may be underwhelming.

How strong should your grow lights be to grow dense buds?

Professional growers have a rule of thumb that 1000W per square meter of grow space is the ideal grow light intensity to for a strong harvest. While 1000W may maximize yields, such lighting isn’t always affordable for everyone. Furthermore, the 1000W recommendation was developed for HID grow lights which are less efficient than newer LED grow lights. In general, 75W-100W per plant can ensure bigger buds during flowering, especially for LED light sets.

Most indoor growers interested in big yields use either LED or HID grow lights to grow dense buds. While it’s possible to use something like CFL grow lights for a cheaper setup, they generally do not give enough light to maximize bud development.

The following are the recommended guidelines for wattage per plant:

For HID grow lights:

  • 1 plant: 110w
  • 2 plants: 260w
  • 4 plants: 410w
  • 6 plants: 610w

For LED grow lights:

  • 1 plant: 100W
  • 2 pants: 200W
  • 4 plants: 290W
  • 6 plants: 360W

How far away from your plants should your grow lights be?

To maximize your cannabis plant’s growth, grow lights should be kept an optimal distance from your cannabis plants. If the lights are too far away, they won’t provide your cannabis plant with enough light and energy to grow. If they are too close, it may lead to issues such as light or heat burn.

Since HID and LED light systems give off different levels of heat and energy per watt, they have different distance requirements.

Optimal LED light distance

  • Sub 150W: Can be kept a little less than 1 foot away
  • 150-300W: Should be kept a little less than 2 feet away
  • 300W: Keep over 2 feet away.

Optimal HID light distance

  • 150W: Can be kept a little less than 1 foot away
  • 400W: Should be kept between 1 foot and 1.5 feet away
  • 600W: Should be kept between 1.5 feet and 2 feet away
  • 1000W: Should be kept between 2.0 feet and 2.5 feet away

Adjust as necessary

The above numbers are a rough guide on distancing your grow lights. Indoor growers should adjust their light distance over time based on the observed reaction of their cannabis plants. The rule of thumb for your grow room should be to get the lights as close as possible to the plants without them getting light burn.

Use the right wavelength light to grow dense cannabis buds

Many growers may not know that their cannabis plants need different wavelength light when they are in the vegetative stage and the flowering stage. Plants in the vegetative stage absorb blue wavelength light while plants in the flowering stage absorb red wavelength light.

This distinction is very important when using HID lights, because different HID light types emit different light. When using a HID setup in your grow room, use HPS grow lights (which emit red wavelength light) for the vegetative stage and use MH grow lights (which emit blue light) for the flowering stage.

LED lights are the most convenient for growing cannabis buds because LED lights have full spectrum light. This means that they emit both blue and red wavelength light and therefore work well for all growing stages of the cannabis plant.

Give your cannabis plants the correct nutrition for dense buds

Nutrients play a huge role in the health and growth of your marijuana plant. While good nutrition alone isn’t enough for your plant to grow very dense buds, improper nutrition will almost guarantee that your plant will grow small buds.

It’s important to know what nutrients your plants require and also at what growth stage the plants requires them. This is because your plant’s nutrition requirements will change over time.

While it’s possible to grow a cannabis plant using regular soil from the store, there are many fertilizers and growth boosters out there that can improve your plant growth and help to grow dense buds. Optimizing your plant’s nutrition will also prevent problems associated with overfeeding and nutrient burn.

The big 3 macro nutrients

The three main macro nutrients that your plant requires nitrogen (N), phosphorous (P), and potassium (K). Collectively these nutrients are referred to by the acronym NPK. Nitrogen provides support for plant growth during the vegetative stage. Phosphorous is necessary for photosynthesis. Potassium helps grow buds during the flowering stage.

Cannabis plant nutrition requirements change over time

While nitrogen is very important early on in the vegetative stage, it becomes less important in the flowering stages. Conversely, Potassium becomes much more important once the plants begin to grow buds. For example, a plant may require 2-1-3 NPK ratio in the vegetative stage, but only a 1-2-3 ratio in the flowering stage. There are special cannabis growth and bloom boosters for sale that have the exact nutrients required at each stage. These can prevent nutrient deficiencies as well as overfeeding.

Avoid giving your plant too much nitrogen

When plants transition to the flowering stage, it’s easy to overfeed them with too much nitrogen as their nitrogen requirements begin to drop. This is the most common cause of nutrient burn, which can damage your plant’s leaves, leading to small buds.

It is very important to switch to bloom nutrients for healthy buds once your see buds develop on your cannabis plants. These special formulas can prevent nutrient burn while also supporting dense bud growth.

Additionally, avoid putting time-release nutrient capsules in your plant’s soil during the vegetative stage. These capsules may continue to release the wrong nutrients once your plant changes to the flowering stage. In fact, to be safe, it may be necessary to flush out the soil entirely to remove excess nutrients between growth stages.

Plant micronutrients

In addition to the big 3 macronutrients, cannabis plants also require a whole host of other nutrients in very small doses. These include, boron, copper, magnesium, and many others. Fortunately, you do no need to be individually concerned about any of these micronutrients, as they should be included in any nutrient-enriched soil or cannabis growth formula that you buy.

Correct your Ph levels

Ph levels are essential for for your plant to properly grow and develop its bud sites. Your marijuana plant requires correct soil Ph in order to absorb nutrients. The following Ph levels are recommended for growing healthy buds:

  • Soil grow medium: 6.0-7.0
  • Hydroponic grow medium: 5.5-6.5

Improper Ph levels can lead to nutrient deficiencies in your marijuana plants. Growers may misdiagnose the issue and begin overfeeding their plants. This nutrient buildup can then shock the plants once Ph levels are corrected and the plants begin absorbing nutrients again.

Grow bigger buds with supplements

There are many supplement products for sale that promise to help your plants grow dense buds. These supplement products are different from grow fertilizers because they usually don’t have much nitrogen.

Instead, many of them have extra phosphorus and potassium, which they claim will help grow bigger buds during flowering. Often times, these supplements have sugars or a variety of other chemicals that promise to help your plant develop its cannabis buds.

Right now, the truth is that there are no scientific studies that back these claims. However, there are many anecdotal claims about the effectiveness of these bloom supplements for growing bigger buds.

These supplements are by no means necessary. However, it’s important to experiment for yourself to see if they make a difference for you. If you do try one of these, make sure to use only 3/4 of the recommended amounts, as usually the recommended dosages on these boosters are very high. This will help to avoid nutrient burn.

Make sure to water your plants correctly

Improper watering can harm your marijuana plants and reduce their yield. The most common issue with watering among newer growers is overwatering. Marijuana plants roots need periods of dryness so that they can absorb oxygen. Overwatering will lead to unhappy roots which can the affect the entire plant.

Overwatering can also lead to root rot. If a plant is affected by root rot, it may be impossible to fix and the entire plant may have to be thrown out.

Choose a strain that produces dense cannabis buds

Indica vs sativa

In general, indica leaning strains tend to produce denser buds, while sativa strains tend to produce fluffy, airy buds. This difference is at the genetic level, so a well cared-for sativa plant will still have looser buds than an indica strain.

There are many good sativa strains that produce bigger buds, which produce big yields despite being less dense. When well cared for, both indica and sativa strains can produce satisfactory harvests. However, all things being equal, indica dominant strains tend to have the densest buds.

Indica genetics

Indica strains originate from parts of Northern Europe and Russia. These areas tend to have drier and colder climates, and indica plants have a compact appearance with denser buds to help protect against the colder weather. Indica plants naturally grow their bud sites closer together, which leads to denser buds.

Dense indica cannabis buds are more vulnerable to bud rot

Growers should note that the dense buds on indica strains are more vulnerable to bud rot. Mold thrives best in dense, compact areas with lack of air flow. It also thrives best in warm, humid environments.

Indica leaning strains are not native to humid environments, and therefore have less defense against diseases like bud rot. When growing an indica strain, it’s important to monitor your grow tent to keep temperature and humidity at the right levels, and to also ensure good airflow. See our article on moldy weed for more information.

Sativa genetics

Sativa plants tend to have fluffy, airy buds compared to indica plants. Although they have looser buds, they also tend to grow bigger buds than indica plants. Sativa plants have more space between their bud nodes, which gives each bud more growing space.

Sativa plants are native to the equatorial area of central America. They are used to warm, humid growing environments. They produce airy buds and have a looser, skinnier plant appearance that give them more protection against diseases like mold and bud rot.

Optimize your airflow to grow dense buds on your marijuana plants

Cannabis plants that grow dense buds tend to have great airflow and space between their buds. Fresh air is important because cannabis plants need to absorb a lot of CO2 to grow lots of vegetative growth and bigger buds.

However, more specifically, it’s important to expose the buds themselves to as much air as possible. Buds that are not exposed to air flow tend to become small popcorn buds, or sometimes stop growing all together. Dense buds and big buds always have good fresh air exposure.

Why fresh air helps grow bigger buds

To understand why extra air flow causes plants to grow dense buds, you must understand the plant’s biology. Cannabis plants are a wind pollinated plant, which means they are fertilized by pollen traveling through the air. Buds that are not exposed to air are ones that cannot absorb pollen and cannot be fertilized. Mother nature hates wasting energy, so if certain buds cannot be pollenated then the plant will not waste energy growing them.

How to ensure good airflow indoors

To ensure good airflow, your grow room should have good ventilation. This can be accomplished by using a good exhaust fan and a good intake fan. Together, they can move all the air you need through the grow space.

The second thing to look at is the airflow around the plants themselves. There should be enough space between plants so that they are not squished right next to each other. Additionally, the plants themselves can be trained to grow in a way that opens up the buds to lots of light and air. Finally, buds themselves can be pruned so that there are not too many leaves are touching the buds. Pruning is an advanced technique that should only be done for excessively leafy plants.

Train your marijuana plant correctly

Training your marijuana plant correctly can help it to grow dense buds. While many training techniques exist, the most important thing is to remove small branches and weak stems from the plant. Dense buds tend to grow on strong, well supported branches. Cutting off the weaker stems will allow your plant to focus it’s energy on the bigger branches where the big buds will be.

Additionally, techniques exist that allow growers to make the most of their grow space and really open up their plants to get as much light and air exposure as possible. These techniques are separated into two groups: low stress training and high stress training

Low stress training

Low stress training involves bending and tying plant stems when they are young to shape the way that the plant grows. This is commonly done to make the plants grow wider rather than vertical. Plant stems may be tied down, or they may be looped through something like a screen. The screen technique is known as the “screen of green” technique.

High stress training

High stress training involves cutting the branches themselves. Often, a technique called “topping” is employed to stop the plant from growing too tall. Topping involved physically cutting off the top of the plant. Pruning or removing of branches and leaves is another example of high stress training.

Set the right temperature for your cannabis plants

Raising your plants in the correct temperature conditions can help them to thrive and grow dense buds. Cannabis plants have a certain range of temperatures that they grow best in. Thankfully, this range is fairly wide at 65-85 degrees Fahrenheit.

Maintaining correct temperatures will depend on the surrounding climate conditions and growing environment. Indoor growers have a variety of tools available to help maintain correct temperatures, including air conditioners, heaters, and fans.

Both indica and sativa strains can suffer from the effects of freezing weather or excess heat. However, indica strains tend to do better in slightly colder weather while sativa strains tend to do slightly better in hotter weather. The main reason for this that indica strains come from colder areas while sativa strains grow naturally in hotter, more humid areas.

When conditions are too warm

Allowing your plants to get too much heat can trigger heat burn and naturally lead to small looser buds (also known as “popcorn buds”). Not only that, but excess heat can even stress your plants to the point where they become hermaphrodite plants. These plants can ruin entire harvests by pollenating other nearby plants and causing seedy nuggets.

When conditions are too cold

Cold conditions cause problems because they can turn branches and leaves purple. Purple leaves absorb far less light than green leaves. These plants then have less energy to grow their buds, and as previously mentioned, plants need a lot of light intensity and energy to grow dense buds.

Set the right humidity level to grow dense buds

It’s important to control your grow room humidity levels if you want to grow dense buds. Particularly, growers should drastically cut their humidity levels during the flowering stage if they want bigger buds.

While humidity levels of up to 70% are acceptable during your plant’s vegetative stage, during the flowering stage this needs to be cut down to under 55%. This lower humidity level will trigger the plant’s bud sites to grow denser buds. Additionally, low humidity levels in the flowering stage can promote extra resin and trichome production in the plant’s cannabis buds.

An added bonus is that low humidity levels also help protect the plant against diseases such as bud rot. Bud rot thrives in high humidity and can ruin an entire plant or plants, so it’s best to avoid conditions where it can grow.

Harvest your cannabis plants at the correct time

Timing is very important for deciding when to harvest your cannabis buds. The difference of waiting a couple days or a week can be the difference between harvesting small, loose buds and harvesting fully grown dense buds. Newer growers like to harvest far too early in the flowering stage. They wind up with small buds, when all they had to do to grow dense buds was wait.

Experienced growers wait for the right signs before they begin collecting cannabis buds from their plants. The most important signal that your cannabis buds are ready for picking is that their colors change. Buds are covered in while flower pistils, however on developed buds these pistils begin to turn an amber color.

Patient growers are rewarded with bigger buds. If you go through the effort to carefully grow your plant for months, make sure you give it time in the final stretch to grow the dense buds you’ve been wanting.

Dry and cure your harvest for denser buds

The drying and curing process takes place after the buds are harvested. This process is necessary because freshly harvested buds have very high water content. Curing your cannabis buds properly will “tighten them up”, and slightly increase bud density. There are other benefits as well such as better smell, taste, and bag appeal. See our article here on how to properly trim your weed.


When growing cannabis plants, big buds are the result of good growing habits. If you follow the right steps, and put the necessary time, energy, and preparation into your grow, you will be rewarded with a harvest full of dense buds.

Plant growing basics are generally the most important things that will ensure a good harvest. These include using good lighting, providing your plant with proper nutrition, and keeping good airflow in your space.

Once the basics are handled, other important factors are selecting the right strain, keeping good humidity and temperature levels, training your plant correctly, and harvesting and curing your cannabis properly.

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