How to identify indica and sativa plants
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- Is there really a difference between indica and sativa?
- Identifying sativa vs indica plants
- Preference of indica vs sativa
- Sativa vs. Indica Cultivation Considerations
For those who regularly use cannabis for therapeutic or recreational purposes, the notion of cultivating plants for personal use may be appealing. Growing cannabis can be straightforward, but as with most crops, yield and quality can be improved with awareness of the plant’s life cycle and growth requirements. When it comes to growing cannabis, the first decision is to determine whether to cultivate indica or sativa plants.
Is there really a difference between indica and sativa?
Up until recently, the cannabis plant was classified as sativa, indica, ruderalis, or the elusive afghanica, which originated in or near Afghanistan. The usefulness of this cannabis taxonomy for contemporary consumers has been questioned by experts, including Dr. Ethan Russo , who has recommended abandoning this classification system. Due to human intervention, very few modern cannabis plants are purely indica or purely sativa. Russo argues that it’s more helpful to identify biochemical compound content, such as cannabinoids and terpenes .
However, differentiating indica from sativa remains very useful for cannabis cultivators. Using morphology, or phenotype, is the most common way to classify cannabis cultivars . Indica and sativa, the most commonly recognized cultivars, have distinctive physical features and growth traits. Understanding their respective growth cycles and how to tend each plant type will help ensure optimal growth and bud output.
Hybrid strains are also commonplace, with many growers opting for plants that blend the most desirable properties of both sativa and indica. Hybrids may be indica- or sativa-dominant, like Sour Diesel. White Widow exemplifies a balanced hybrid cultivar.
Identifying sativa vs indica plants
Identifying Sativa Plants
Sativa cannabis plants originated close to the equator, thriving in temperate regions with mild winters and long summers. Sativa strains can reach up to 10 feet tall and are characterized by sparse foliage and light-green, thin-fingered, delicate leaves. They boast a long flowering period as there is no climatic impetus to reproduce rapidly and disseminate seeds. The extended flowering period is somewhat offset by a reduced vegetative period, in which no flowers are present. Sativa is known for generally lower yields than their indica counterparts.
Sativa cultivars are not ideal for home growers hoping to cultivate indoors, or within a restricted space. These plants generally require balmy temperatures and relatively high humidity where they thrive when given have space to grow.
Identifying Indica Plants
Cannabis indica cultivars are smaller in height than their sativa counterparts with broad, dark-green leaves and a bushier appearance. Indica plants are popular among home growers due to their high yields and shorter flowering periods. They typically mature faster than sativa cultivars under similar conditions, producing flowers in as few as eight weeks.
The rapid flowering period occurs due to the biological need to reproduce and spread their genes before the arrival of harsh winter conditions. These cultivars also tend to have a different smell, perhaps reflecting a different terpene profile .
Indica plants were originally found in unforgiving dry and colder Asian climates, which resulted in their robust and more compact physical profile. Their short stature makes them ideal for indoor cultivation.
Sativa strains have light-green, thin-fingered, delicate leaves. Cannabis indica cultivars have broad, dark-green leaves. Photo by: Gina Coleman/Weedmaps
Preference of indica vs sativa
If you’re contemplating growing cannabis and wondering whether to grow indica or sativa, your choice will likely be guided by the kinds of effects you’re looking to experience. It’s important to note that effects have more to do with the cannabinoid and terpene makeup of the plant and less to do with its morphology. Here’s the lowdown on the differences between growing indica and sativa.
Sativa vs. Indica Cultivation Considerations
The growth cycle of any plant can be divided into the four distinct stages of germination, seedlings, vegetation, and flowering. While harvest doesn’t represent a formal phase, it does constitute a significant phase for the grower.
Some home growers elect to grow cannabis from feminized seeds, which produce exclusively female plants. This ensures none of the female flowers are pollinated by male flowers, which would cause them to produce seed, reducing the cannabinoid yield. Seeds can be easily germinated within paper towels dampened (not wet) with distilled water.
If you’re growing sativa strains from seed, aim for an optimal temperature of 75 F (24 C) to encourage germination within three to seven days. Lower temperatures will delay the emergence of the radicle (the part of the plant that develops into the root).
If you’re growing indica plants from seed, expect a slightly shorter germination period. Like sativa seeds, indica seeds require a warm temperature to germinate (approximately 71 to 75F or 22 to 25C).
When the beginnings of the tap root and a leaf or two appear, the seedling can be carefully transplanted. Both indica and sativa plants require special care and benefit from proper soil composition, climate control, and lighting as they are establishing root systems. The seedling stage lasts from 1-3 weeks.
The vegetative phase is characterized by the growth of the stem and leaves. The length of time a sativa or indica plant remains in the vegetative state depends entirely on its exposure to light. Sativa and indica plants move into the vegetative state after three to six weeks.
The vegetative phase is characterized by the growth of the stem and leaves. Photo by: Gina Coleman/Weedmaps
The sativa vegetative period starts slowly, with the stem elongating more rapidly later in the vegetative cycle. The stem of the sativa plant is fibrous rather than woody, and the leaves develop as narrow fingers. Throughout the duration of the vegetative cycle, seven to twelve leaf pairs form in a certain pattern . The first leaf pair comprises a single leaflet. The second pair has three leaflets. The third pair has five leaflets, and so on. Sativa uses less chlorophyll during the vegetative cycle than indica, resulting in light-green leaves.
Indica strains do not undergo the same stem elongation as the plant focuses on developing a thick, woody trunk to support the weight of future buds. Perhaps the most distinguishing characteristic of cannabis indica plants is their leaves. Indica’s unmistakeable fat, forest-green fingers help to soak up light and accelerate growth. Outdoors, indica plants are unlikely to grow taller than six feet (two meters), and indoor plants usually grow three feet (one meter) or less. Indica strains tend to spread out wide like a bush, with vigorous branching.
In both strains, pre-flowers can be easily mistaken for new branches. If you haven’t used feminized seeds, the pre-flowering period is the time to separate male plants from female plants. Males must be removed immediately to avoid pollinating females unless the intention is to produce seeds. The first male pre-flowers appear as a small sac, while female plants produce a structure called a cola that looks similar to a hair and will later become a flower or bud.
Flowering occurs when the days shorten, or when the plant receives 12 hours or less of continuous daily light. Photo by: Gina Coleman/Weedmaps
Flowering occurs when the days shorten, or when the plant receives 12 hours or less of continuous daily light. You can force flowering by reducing the hours of light exposure or photoperiod, signaling to the plant that the nights are becoming longer.
Sativa strains can take 10 to 12 weeks before the flowers are ready to harvest. These plants continue to grow tall and fast throughout their life cycle and can double in height even after they’ve entered the flowering period. The overall life cycle for sativa can last up to six months, resulting in a more extended growth-period than that of indica.
Indica strains flower more rapidly than sativa, forming flowers after seven to nine weeks on average. They continue flowering for up to twelve weeks. Many indica slow their upward growth as they begin flowering, and instead become bushier, with branches and leaves fanning out. Their life span is three to four months.
Sativa buds are ready to harvest when the majority of the trichomes, or resinous glands on the buds, appear milky-white with only an occasional clear trichome in the mix. Sativa bud structure is frequently elongated and thin, with an appearance similar to spears. However, the flower buds of sativa can also form foxtails, when the calyxes, or nug groupings, of the female buds stack up on each other.
Indica buds are tightly packed and tend to grow in a more chunky formation than those of sativa. Indica trichomes that are ready to harvest can take on a milky-translucence as well, but often appear more amber in color.
Sativa buds are ready to harvest when the majority of the trichomes appear milky-white with only an occasional clear trichome in the mix. Indica trichomes that are ready to harvest can take on a milky-translucence as well, but often appear more amber in color. Photo by: Gina Coleman/Weedmaps
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Understanding, Identifying and Using Cannabis Leaves
The leaves are the most recognisable and well-known part of the cannabis plant. Despite the great degree of variation found naturally in local populations of cannabis, the leaves do not alter greatly in appearance between varieties. Here is the story behind the leaves of three main strains, how to identify them and some ideas on how you can use these leaves.
The leaves of a cannabis plant play a big role in supporting its growth and the overall health of the plant. The stomata on the bottom of the leaves, which are tiny little holes that open and close, take in carbon dioxide and release water and oxygen. This is required for photosynthesis, which would be near impossible without the leaves. They also provide a way for the plant to absorb nutrients (foliar feeding).
Cannabis leaf phyllotaxy
According to the standard phyllotaxy (the arrangement of leaves on a plant stem), cannabis leaves are compound (with multiple leaflets, as opposed to simple, where a single leaf grows from the stem) and opposite decussate rather than alternate.
Opposite leaves emerge in pairs, one each side of the stem, with a clear vertical space between the leaf pairs. Decussate leaves are opposite, but each new leaf pair is at a right-angle to the last pair. Alternate leaves emerge from the stem singly, swapping sides as the vertical height increases.
Although cannabis leaves are usually decussate, as the plant prepares to flower the leaves may begin to emerge in an alternate pattern. Interestingly, rejuvenated cannabis plants demonstrate alternate phyllotaxy.
Experiments with hemp showed that early-planted specimens, which flowered in low light conditions but did not die, began to put out new alternate leaf growth when hours of sunlight increased. The initial new growth was simple rather than compound, and as new growth continued, the number of leaflets gradually increased.
There is some evidence that this phenomenon leads to vegetative growth of greatly increased vigour, although the genetic processes responsible are not fully understood. It is thought that the evolution of opposite-decussate phyllotaxy occurred comparatively recently, from an alternate-leaved ancestor, and that the genes controlling the decussate phyllotaxy ‘switch off’ around the time of inflorescence.
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The leaves can help identify common growing mishaps
The leaves of cannabis plants can be very telling. Here are some tell-tale signs of a mishap in the making that can be seen by merely inspecting the leaves:
- Blistered, twisted, shiny “wet” looking leaves – This may be an indication of mites, which are too small to see with the naked eye. If this is the case, new leaves may grow in twisted, top leaves can droop.
- Spotted leaves – Spotty leaves may indicate a deficiency (likely a calcium deficiency). This normally affects new leaves or parts that are actively growing.
- Edge of leaves fading to pale yellow – This is likely a sign of magnesium deficiency.
- Edge of leaves change to white or bright yellow – If this is seen along with the inner main part of the leaves turning purplish or dark blue, then there’s probably a copper deficiency. They may also appear shiny or start to turn under. This most often affects leaves directly in the light.
- Curling, folding, miscolouring leaves – If leaves are too close to light or heat, they can start undergoing heat stress. This can lead to them folding up, curling down under and turning yellow or even plainly getting a burnt look to the edges.
- New leaves grow in bright yellow – If new leaves are growing in from the get-go with a bright yellow colour, the plant may have an iron deficiency.
Leaf differences between the three main subspecies
Putting aside the eccentricities of cannabis leaf growth for a moment, let us take a look at the differences between the three pure main subspecies of cannabis, which are:
- C. sativa
- C. indica
- C. ruderalis
C. sativa leaves are long and slender, often with pronounced serrations, giving the leaves a jagged, almost spiky appearance. The colour of sativa leaves ranges from bright, lime green to blackish-green at the darkest. The largest leaves can often have up to thirteen leaflets.
C. indica leaves are much wider. The largest leaves usually have fewer leaflets than the largest sativa leaves, with seven to nine leaflets. Indica leaves are commonly deep olive-green; very light green leaves are rare and often a sign of deficiency.
C. ruderalis leaves are generally smaller than the other subspecies’, as the mature plant is much smaller overall. The largest leaves may contain anything from five to thirteen leaflets. Ruderalis leaves are usually closer to the indica in terms of width, although they can be much narrower than any indica leaf would normally be.
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Mutated patterns seen in cannabis leaves
The incredible variation in cannabis morphology throughout the world has led to some very unusual leaf patterns occasionally occurring. Many of these traits are seen as highly desirable due to their visual dissimilarity to “normal” cannabis, as they can serve to disguise a crop from the unwelcome attention of law enforcement in areas where cultivation is illegal.
Webbed leaves are a common mutation, and one which various breeders have attempted to stabilise. Such efforts have unfortunately not prevailed to the point where webbed varieties are now commercially available, though. In the past, however, it was possible to source webbed varieties such as Ducksfoot in seed form.
Whorled phyllotaxy is another common mutation, although this is less desirable as a concealment trait as the plants still definitely resemble cannabis.
However, many growers find the trait desirable for cosmetic purposes, Some believe that such plants yield flowers of higher potency, although this has not been demonstrably proven.
Australian Bastard Cannabis is perhaps the most striking mutation yet seen in cannabis. It is believed that this mutation was first seen in escaped populations around Sydney. Breeders have also attempted to stabilise this trait … again, without commercial success.
This mutation takes the form of hairless, succulent leaflets, usually with no more than five leaflets to a leaf. The individual leaflets usually do not exceed a few centimetres in length.
Despite the allure of cannabis that does not resemble cannabis, most attempts to breed viable strains using these genetics have ended in failure.
Not unsurprisingly, the best results will usually be gained from healthy plants that exhibit normal characteristics. However, the success of breeding ruderalis genetics (which are poor in cannabinoids) with higher-potency varieties indicates that further research may yield improved results.
Cannabis leaves are so recognizable, they’re basically iconic. But what do you know about them? Learn to identify the leaves and what you can do with them.