by Ed Rosenthal
Female flowers have no petals, but they are identifiable because of their pistils. The pistils have noticeable stigmas, two white or sometimes pastel pink or lavender antennae-like protrusions, attached to an ovary, which is an oblong pod-like structure. The stigmas pull pollen from the air and then transfer it via hollow tubes down to the ovary. In the ovary, the captured pollen from one stigma fertilizes the egg to form an embryo. The pollen from the other stigma is combined with portions of the ovary to form a food source for the embryo within the seed. The stigmas of fertilized flowers then dry up, beginning at the tips. Each fertilized flower produces a seed. Seed development starts as soon as the female flower is fertilized and is apparent by the third day. The ovary at the base of the pistil swells as the new seed grows inside of it.
Full-blown male flowers as they open to reveal five creamy yellow petals.
An hermaphrodite bud. Both male and female flowers are apparent. Sometimes hermaphrodites have just a few hidden male flowers. A single hermaphrodite plant can pollinate an entire garden and should be removed before the flowers have a chance to release their pollen.
A single male flower sometimes grows from nodes lower on the plant before flowering begins. This indicates sex.
This is not going to happen in your garden unless you are careless or planning to produce seed. Since you’ve eliminated the males, the females’ stigmas search in vain for pollen. Eventually they dry up and become part of the ripe, unfertilized bud. The females’ leaves start growing closer together as they form strong stems that will hold clusters of flowers along a branch. These branches of ripening buds are often called colas.
As flowering proceeds, closely watch any plants that have not clearly indicated their sex. Males usually indicate earlier than females, so you are less likely to encounter males starting to indicate later in the season.
Male flowers sometimes appear just as a bud is maturing. They are an indication that the bud is ripe.
HERMAPHRODITISM
Some plants that are primarily female become hermaphrodites and grow male flowers in addition to female ones. This can happen indoors and outdoors, though stress plays a role, and some varieties are more prone to hermaphroditism than others.
A hermaphrodite’s male flowers may be interspersed among its female buds; they may appear in clusters; or they may occupy one or more separate branches.
For obvious reasons, hermaphrodites are dangerous in any sinsemilla garden; even a single male flower can ruin many neighboring buds. Any plants with male flowers should be removed from the garden. This is the only safe course of action.
Older male flower: In your sinsemilla garden, these are useful to breeders.
Trying to control a hermaphroditic plant by removing just the male flowers is an extremely difficult task, and one mistake, lapse in monitoring or hidden flower can cause serious damage. Even if the plant seems like a winner, it is not worth risking the rest of the buds in the garden.
There are several reasons why a plant becomes hermaphroditic. It may have a genetic disposition to be a hermaphrodite. For instance, French hemp breeders have developed monoecious varieties; all of the plants have both male and female flowers. Female plants sometimes develop male flowers as a result of stress, including irregular light cycles and heat stress during flowering, or other drastic changes in the environment.
Some plants develop male flowers just as they ripen. This is an indicator of ripeness, and is not a danger to the garden since the plants are to be harvested shortly.
Use blue fluorescents or LEDS to induce indication flowers in vegetative plants. Give the plants 12 hours of regular light and then 12 hours of blue light. The plants will continue to grow vegetatively, but they will also produce some flowers.
FLOWER GROWTH
Within a few days of establishing a long dark period the plant’s growth pattern changes. First, its rate of growth, which might be as much as two inches (5 cm) a day during the vegetative growth cycle, slows. Under a flowering light regime, indica varieties usually grow another 20-25% taller and wider. Sativas can double in size before growth stops. Hybrids have growth patterns that vary between these two extremes. If you are intending to produce seeds and have both male and female plants growing, they begin to differentiate and become dimorphic.
The males elongate and grow new shoots that hold the flowers, or they develop flowers along their existing branches. Upon ripening, the male flower sacks, which contain copious amounts of pollen, tower above the females. This difference serves the plant well, since marijuana is normally wind-pollinated, and the pollen from a tall male plant is more likely to catch the wind for a ride and drift down into an obliging female stigma below.
Within the first week, females start to grow stockier stems with shorter nodes between the leaves. The number of fingers on new leaves decreases, and the plants no longer form leaves on opposite sides of the stem but now alternate sides. Most importantly, the first stigmas appear.
JACK HERER VARIANT SATIVA-DOMINANT—Flowering by weeks: (1) Week 1: Vegetative growth has slowed, growth is in transition. (2) Week 2: First stigmas appear. (3) Week 3: Vigorous flower growth begins. (4) Week 5: As vigorous flower growth occurs, layers of stigmas appear. This continues through week 7. (5) Week 8: New flower growth ends; stigmas start to dry and trichomes become more prominent. (6) Week 10: Stigmas have dried and changed color from clear to milky white or amber. Trichomes stand more erect as they fill with resin. The ovaries are beginning to expand. The odor is becoming more pungent. (7) Week 11: This bud is ripe! The trichomes are erect and the caps are stretched thick with resin. They fluoresce in the light and the odor has intensified.
Using specialized formulas and nutrients during the flowering cycle can help increase your crop’s yield. Home and Garden Shooting Powder is a flower booster that starts a new flowering cycle after the regular flowering phase, which creates a new layer of growth over the existing flowers and increases yield by up to 20%.
Home and Garden Bud XL can be used in conjunction with Shooting Powder, and helps direct energy to new growth in the flowers, rather than the leaves.
Flowers develop capitate trichomes all over their outer surfaces. They also develop along the small leaf parts surrounding the flower. These capitate trichomes are unlike the sessile trichomes found on the immature plant, the sun leaves and the stem. The sessile glands are small and are either directly connected to leaves or stems or rest on a one-cell stalk. Capitate trichomes have a much longer, four-celled stem with a large, bulbous cap at the end. When these trichomes first appear, the caps are small, but they swell as the resins are produced and stored. By the time they are ripe, the caps look like balloons so over-inflated that they might burst. Given any stress, such as wind, rain or touch, many of them will.
By the second week, the first stigmas are joined by a cascade of flower growth. The plant is now spending most of its energy on flower development.
The flowering pattern changes as the stigmas begin to wither, dry, and turn red, purple, or even a light brown, similar to the pattern of fertilized flowers. In the third week, a large number of stigmas form along the stem and on the tops of the branches. As long as it remains unfertilized, the plant continues to produce new flowers.
Over a period of several weeks, the clusters grow thick with unfertilized flowers forming at each leaf node along the branches and main stem. The buds fill out with fresh, moist stigmas reaching out for pollen. Just as the cluster looks like it’s finished, a new wave of flower growth appears, usually concentrated in a relatively bare spot. Successive waves of flowers may appear for weeks.
The stigma's color is a factor of genetics and temperature. Many indicas and most sativas develop a red color; however, the color may change to purple or become more pronounced, particularly if the roots are subjected to a cool environment, below 55˚ F (12˚ C).
Flower ripening starts between the fifth and eighth week. The calyxes (ovaries) start to swell. These are false seed pods; the flowers have not been fertil
ized and no seed can develop. The swollen calyx is one indication of ripeness. It begins about two weeks before maturation, so the timing depends on the variety.
Capitate trichomes, the tiny stalk-like resin glands that fill with THC, terpenes, and other cannabinoids, start to grow on the leaves surrounding the flowers. The flower areas will become totally covered with resin glands. The length of this stage of growth can last from two to five weeks, depending on the variety. Varieties that ripen in seven weeks usually spend about three weeks in this period of heavy flower growth. Late-season and long-maturing varieties linger in this stage for five weeks or more.
The trichomes become more prominent and stand more erect. The cap that tops each one swells with resin. The viscous, sticky liquid contains terpenes and cannabinoids such as THC, which are produced on the inside membrane of the trichome cap. As the resin accumulates in the cap, the flowers’ odor becomes more intense.
Many growers like to give their crop a “bloom booster,” before their final flush. Bloom boosters are nutrient formulas designed to improve the flavor, aroma and size of buds. Ginormous from Humboldt Nutrients is 100% biodegradable and can be applied foliarly during the first week of flowering.
This X-ray micrograph shows THC manufactured at the inner wall of the trichome membrane. The little dots represent THC molecules at the surface of the inner wall. The photo was taken by creating an antibody enhanced with gold that docked to the THC molecule, making it visible through an X-ray image. Photo: Professor Paul Mahlberg.
Many gardeners pick the buds before they are ripe. They miss the intense odors and flavors of ripe cannabis, not to mention the enhanced high and stronger medical properties. It’s worth the extra time to harvest ripe buds. Would you want to eat an unripe peach?
The odor reaches a peak at the same time the trichomes begin to fluoresce in the light, twinkling like little crystals. In some varieties, they are so prominent that the whole bud sparkles. Using a magnifying glass, a photographer’s loop, or a microscope, you can monitor the buds progression to the peak of ripeness by watching the resin in the gland tops. Under magnification, you can see the individual glands turn from clear to amber or a cloudy white as they mature. These colors indicate that the THC is beginning to degrade into two other cannabinoids, CBL and CBN, which are not nearly as powerful as THC. When they begin to change from clear to amber or cloudy white, the buds should be harvested. This is the peak moment.
No bud should be picked before its time. Plants and varieties differ as to maturation pattern. Some plants mature all at once, so that the whole plant can be picked. Other varieties mature from the top down, or the buds on the outside of the branch mature faster than inner buds hidden from the light. Once the outer buds are harvested, the inner branches are exposed to light and quickly ripen. It can take two weeks of choosing mature buds before the plant is totally picked. Picking the plant a little at a time ensures that every bud is at maximum potency and quality.
VARIATIONS ON LIGHT AND FLOWERING REGIMES
The flowering response to different light cycles is a graduated one. Plants that initiate flowering at a particular light to darkness ratio will flower more heavily when the length of darkness is increased. This response is more pronounced on plants such as indicas that originated at higher latitudes, where the light cycle is more pronounced. All varieties respond to a longer dark period by hastening ripening. Shortening the light regime down to 10 hours of light and 14 of darkness forces all plants, indicas as well as long-flowering sativas, to ripen faster.
Cannabinoids and terpenes are costly for the plant to produce, so they must serve a purpose, or they would never have evolved. THC and the water-soluble compounds which impart the taste and aroma to cannabis flowers protect the plant:
•By acting as anti-bacterial agents.
•Repelling or trapping insects.
•The psychoactive effects probably causes mental discomfort to birds and mammals that eat it.
•THC levels increase as UV-B exposure increases, so THC probably protects the plant from UV light. This is not an uncommon use of chemistry by plants.
•To assure that the flowers and seeds are not consumed before they mature, plants produce a powerful array of chemicals to thwart predators.
•Once the seed matures and drops out of its resin-coated pod, it is far more palatable to animals that were repelled by the resin. Small mammals and birds may eat the seeds, and some of the seeds pass through the animals’ digestive systems and remain viable. As animals excrete viable seeds on suitable ground, they spread the plant to new locations.
A consistent, uninterrupted dark period is key to good results for marijuana and other long-night flowering plants. Chrysanthemums are an example whose growth patterns and flowering behaviors have been studied extensively by the greenhouse industry. Researchers found that the largest flowers with the highest total weight are grown when the dark-cycle routine is provided each night. When the plants were in darkness only six nights a week, there was a slight diminution of flower size and total weight. With each additional lost night, flower size and weight dropped.
Without consistent dark periods of sufficient length, cannabis buds elongate and grow looser. Every time the dark period of the flowering cycle is interrupted, there is a slight loss of flower-growing time and thus of yield. A spate of light interruptions of the dark cycle may also stress the plant to the point that it becomes hermaphroditic.
Some cannabis varieties have a flowering trigger that they respond to under normal growing conditions, but when they are accustomed to an unusual light regimen, they may respond to the change in the light conditions in unusual ways. For instance, early-flowering indicas normally trigger when they receive a minimum of 10 hours of darkness, but when they are grown under continuous light, a regimen of just eight hours of darkness, they will initiate flowering.
Once indicas are triggered, the light cycle has little effect upon them. The developing flowers are not as sensitive to occasional interruption of the darkness cycle. Indica-sativa hybrids, early-flowering indicas, and South Africans react similarly. These plants don’t revert to vegetative growth as easily as some sativaindica varieties, so the plants are harder to regenerate. Some varieties, especially indicas, respond to unnatural light cycles by showing photo-period response disorders. For instance, some female plants turn hermaphroditic when exposed to long dark periods during early growth.
A bud, ready to pick. It has been held upright using a bamboo pole and a twist-tie.
A stray male flower on an older bud is often an indication of ripeness.
Cold may hasten sexual expression but not flower development of some northern varieties. Cold weather slows growth, lowers yield, and delays ripening. In autumn, gardeners often protect their northern-variety plants from bad weather, waiting for a few days of warm, sunny weather so the buds will ripen.
Males and ruderalis strains from the far north are not photosensitive at all. Both age and development play a role in determining when these plants flower. Ruderalis develops flowers under continuous light within a few weeks of germination. Males of most varieties indicate under continuous light within three to nine months. Some equatorial sativa males are exceptions and require a dark period to flower. Under 18 hours of light, males indicate sooner than under continuous light.
AUTO-FLOWERING PLANTS
This trait has been bred into several varieties that are available commercially as “auto-flowering” plants. No matter what light regime they are growing under, they will germinate, grow and flower in a predetermined pattern. Some varieties are 90-100 day plants from germination to harvest. These varieties produce small plants for the most part. They are very difficult if not impossible to treat as clones so feminized seeds are helpful when growing a garden of the auto-flowering plants.
Notice the circled areas. The glands stand completely erect since they are filled with resin (notice the circled areas).
1-2. Close-up of mature buds. The trichomes loo
k like little crystals as they fluoresce in bright light. 3. Two stigmas are attached to each female flower. Both must be pollinated. One becomes the seed and the other the endosperm, food for the embryo. 4. With rough handling the outer gland heads fall off. Be kind and gentle to your buds.
The path to ripening takes many commercial varieties only 55 to 65 days. The last quarter of the flowering period is the most exciting. At day 45 the stigmas are still fertile, searching the air for pollen. The trichomes are present but the caps have not yet filled. At day 48 the stigmas are still fertile but the trichome caps are becoming more visible. By day 53, the stigmas have turned brown and the bud has taken on purple tones, but the trichomes aren’t filled to membrane stretch. The odor intensity is increasing. Finally, at day 56 the trichome cap membrane is stretching and creating glistening crystals under the light. The odor has reached its peak intensity. Photos: Rachael Smzajda, Courtesy of Harborside Health Center
UNRIPE BUD: The caps on the trichomes have not swollen to the point where they look like they will burst. All of the glands are still clear, indicating continuing growth.
RIPE BUD: The caps are swelling and the first ones are turning translucent or milky white, an indication that THC deterioration has begun. The caps are fluorescing.