By Steven Voser Reviewed by: Silvia Maroto


The calyx is the first part of the flower that is formed when a young plant enters its flowering stage, if it is indeed a plant that is capable of flowering of course. In a perfect spiraling Fibonacci sequence the plant quickly and in the most efficient way forms a protective platform comprising of small leaves, which are called the sepals. This protective platform for the flower in its entirity is called the calyx.

The calyx is designed to protect the plants reproductive organs in between the sepals and provide the flower with a base of stability. Even though all flowering male and female plants have calyxes, it is when looking at cannabis plants specifically, that only the calyxes of the female plants are of interest to the aspiring cannabis grower.

When cultivating cannabis, the objective is to harvest nice big colas of which the calyxes are a part. Not just any ordinary part, but the most important part, because the calyxes are where you find the reproductive organs of the plant, called the pistils, and the trichomes.

The pistils are where you see the long hairs coming from; these hairs are called stigmas. The stigmas will start out white when the plant is still in its early flowering stage, but will turn amber or yellow, and ultimately brown, as the plant progresses through its flowering stage. The trichomes are the resin glands where the cannabinoids are formed, including the psychoactive and more familiar THC.

calyx cannabis plant female reproductive organs of the plant


The pistils are also the best tool a grower to spot the difference between the male and the female plants. It is important to recognize the male plants early on so they can be removed and any risk of pollination can be minimized or even excluded. Female plants can be recognized by their long white hairs, that will begin to form early in the flowering stages of forming the buds or colas. The male plants will have pollen sacks, that will start to dangle in a downward fashion and eventually will burst open to pollinate the female calyxes.

The stigmas or long hairs can help a grower identify when a plant is ready to be harvested. In the first weeks a female cannabis flower or bud is formed, it will have long white hairs coming out if it. After 4 to 5 weeks the stigmas will start to turn yellowish. When about 50 to 80 percent of your plants' buds have stigmas, that have turned yellow or amber, they are ready to be harvested. If you harvest later, the stigmas will turn brown and dry out; do not wait this long to harvest your cannabis plants, as it will have your buds lose potency and taste.

In fact most of the cannabinoids are formed in the pistils and the calyxes of the cannabis plant. This is the flower part of the plant, that will eventually be harvested, dried and cured and ultimately will be ready for consumption.

The consumption part is why you do not want your female plants to be pollinated; they would start to form seeds, which are a real hassle to remove and leave a horrible taste and crackling sound when smoked. Also most of the female plants energy will be diverted into making the seeds, not swelling up the buds and forming cannabinoids.

If you intentionally aim to make your own strain of cannabis by crossing two breeds or strains, watch the calyxes of your developing plants to identify the males and females you want to use for your experiment.

What Does The Calyx Tell An Experienced Grower


When harvesting your cannabis plants, you will have to trim off the leaves to expose the buds, which then in turn can be properly dried and cured.

The big leaves, that grow lower on the plant and in between the budding areas, but not in the buds or cola’s themselves, are called fan leaves; these are basically the solar panels of the plant. These leaves provide the plant with the energy it needs to grow and form buds. The few fan leaves that remain after pruning during the flowering stage can be easily trimmed away at harvest when growing indoors. When growing outdoors, most fan leaves will still be attached to the plant at the end of the flowering stage but these can be easily removed at the time of harvesting.

There are also leaves sticking out of the buds themselves; these are called sugar leaves, because they are coated with trichomes, that look sugary white, and these are a lot harder to trim, because the high level of resin makes them very sticky. Sugar leaves are a specific type of leaf on the cannabis plant that grow between the flowers and around the buds. The calyx-to-leaf ratio is all about how much of a hassle it is going to be to trim the plant of sugar leaves when harvested. Plants with a high calyx-to-leaf ratio have fewer sugar leaves, making the buds or colas easier to trim.

Sugar leaves aren’t all bad though; they can be very well used to make edibles or cannabutter, tinctures, extractions, topicals or even hashish. They can even be smoked, but because of the higher combustion temperature of the leaves the taste may be affected.

sugar leaves bud cannabis plant resin colas

The top 5 strains with a high calyx-to-leaf ratio are:


Skunk XL is a balanced hybrid cultivar featuring 50% indica genetics and 50% sativa. Her large buds are dense with calyxes and appear snow-capped with glandular trichomes. The strain has a rich ancestry, descending from Colombian, Mexican, and Afghan landraces. She produces a stimulating effect that gradually becomes more stoning and sedating. On average, indoor plants yield 22 oz/m², whereas outdoor plants produce up to 23.8 oz.

Skunk XL


OG Kush is known far and wide for her stoning indica high and tantalising tastes of fruit and pine. She’s arguably the world’s most popular cultivar. Originating on the West Coast of the US, OG Kush is the progeny of parent strains Chemdawg, Lemon Thai, and Pakistani Kush. She produces large, narrow colas coated in sticky resin and loaded with calyxes. She’s a productive variety that delivers around 15.9 oz/m² indoors and 18.5 oz outdoors.

OG Kush


Northern Light is another legendary cultivar that sits firmly upon the pantheon of classics. The award-winning strain possesses 100% indica genetics and provides a deeply stoning effect that immediately renders the body at ease. Her tapered, calyx-loaded colas produce a THC content of 18% and medium levels of CBD. They offer sweet, fruity, and spicy tastes. Indoors, Northern Light will yield around 18.5 oz/m². Outdoor plants are capable of pumping out 22 oz/plant.

Northern Light


Lemon Shining Silver Haze is a stimulating and motivating sativa-dominant strain. Her energising and creative effects make her a popular choice in the coffeeshops of Amsterdam. She was created using parent strains Lemon Skunk and Shining Silver Haze. Her short and compact buds display an abundance of calyxes and emit a strong citrus aroma. She’s a productive variety, producing up to 16.8 oz/m² indoors. Outdoor plants offer a maximum harvest of 17.6 oz.

Lemon Shining Silver Haze


Critical Kush was born by crossbreeding legendary strains Critical and OG Kush. The indica-dominant beast boasts a THC level of 20% and exerts a fast-acting body high that stimulates the appetite and promotes restful sleep. Her flowers are small and bulbous, and feature an outrageous calyx-to-leaf ratio. Indoors, Critical Kush yields approximately 18.5 oz/m². Outdoors, individual plants can produce up to 19.4 oz.

Critical Kush

Critical Kush
23_genetic background_1 Critical x OG Kush
33_Yield indoors_1 18 to 19 oz/m²
31_plant height outdoor_1 2 to 3 feet
25_flowering time_1 8 - 10 weeks
29_THC_1 THC: 20%
28_Type Blend_1 Sativa 20% Indica 80%
34_yield outdoor_1 18 to 19 oz/plant
32_plant height outdoors_1 3 to 5 feet
27_harvest period_1 Late September
22_Effect_1 Long Lasting , Physically Relaxing, Powerful

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