Cannabis Seed Development

Understanding the plant’s needs during these 8 growth stages will help growers get the best performance from their crops. Cannabis seed germination is an important process for growers and researchers alike. Many biotechnological applications require a reliable sterile method for seed germination. This protocol outlines a seed germination procedure for <i>Cannabis sativa</i> using a hydrogen peroxide (H<sub>2</sub>O … SEED Initiatives is the first U.S. government program to fund equity-centered community investment grants from local cannabis tax revenue.

The 8 Growth Stages of Your Cannabis Plant

Cannabis transitions through several developmental stages, just like we do.

Cannabis requires different inputs and climate conditions during different growth stages.

This plant will grow like a weed when these requirements are met, but success is not guaranteed. Understanding the plant’s needs during these 8 growth stages will help you get the best performance from your plants.

Cannabis Developmental Stages:

1) Seed Storage (Dormancy)

2) Seed Germination Stage

3) Seedling Stage

4) Vegetative Growth

5) Sexual Maturity

6) Early-Flower (Stretch)

7) Mid Flower Stage

8) Late Flower (Senescence)

1) Seed Storage (Dormancy)

A seed is a storehouse of genetic potential.

When cannabis seeds are properly stored, they can remain viable for 10-15 years.

The three key conditions for long term storage are Cool, Dry, and Dark. Seeds are best stored in tinted jars, containing desiccant packs, in the fridge.

When you take them out, let the jar come to room temperature before opening to avoid condensation.

When cannabis seeds are first harvested, they have a high level of dormancy, or resistance to sprouting.

This dormancy is a response to natural seasonal conditions.

If the seeds did not have some level of dormancy, they could all sprout soon after they fell from the plant, only to be killed by the coming winter.

A seed will slowly lose this dormancy over a period of a few months.

One way to increase the germination (sprouting) percentage of cannabis seeds is to store them in the refrigerator for a few weeks.

This technique is referred to as cold stratification and imitates winter conditions to help seeds lose their dormancy faster.

Most reputable breeders will cold stratify their seeds after harvest, so that they are ready to sprout when you receive them.

2) Seed Germination Stage

If a seed is viable, it will germinate when environmental conditions are favorable for growth.

A temperature of 70-80 F (21-27 C) and the presence of water and oxygen are required for germination.

Cannabis seeds can have a germination success rate of over 95% the first season, with a slow decline in viability over time.

Cannabis seeds are protected by a durable seed coat.

This seed coat is softened by the presence of water.

In most cases scarification, or roughening of the seed coat, will help water to penetrate and begin the process of germination.

Penetration of water and oxygen into the seed begins a metabolic reaction which fuels initial plant growth.

A taproot, or radicle will emerge from the base of the seed and begin growing down into the soil.

This root radicle will orient its growth toward the earth’s center through a process known as gravitropism.

As the root becomes anchored in the soil, the shoot will push up through the soil surface.

The seed coat will usually stay attached to the top of the shoot until it is pushed off by the growth of the first set of leaves.

The first set of leaves to emerge are very simple in form, and known as seed leaves, or cotyledons.

As soon as the cotyledons emerge, they begin to photosynthesize, or convert light energy into fuel for further growth. This marks the beginning of the seedling stage.

3) Seedling Stage

As soon as the first true leaf set has emerged, the plant will require sufficient light to avoid elongation, or stretching for the light.

The seedling growth stage usually lasts for 15 to 20 days as the young plant becomes more established.

See also  Autoflower Cannabis Seeds Usa

The second set of leaves to emerge are also single-bladed, but have serrate edges, and look like cannabis leaves. This is the first true leaf set.

Subsequent leaf sets occur in pairs, on opposite sides of the stem and leaf blades will typically increase to 3, 5, and then 7 blades as the plant matures.

The intersection of each leaf stem (petiole) with the main stem is known as a node. A new shoot will emerge from each node as the plant matures.

Seedlings are usually either germinated in small 4” cups or germinated in root plugs before being transplanted into small cups or pots up to 1 gallon in size.

Autoflower seeds are usually germinated in plugs and transplanted directly into their final pot. Autos have a very fast lifecycle and are not tolerant of multiple transplants.

4) Vegetative Growth

Once a cannabis plant has a well-established root system, and 4-6 nodes of growth it enters the vegetative growth stage. The ideal relative humidity at this stage is 65-70%. The plant will continue to elongate and develop mature 5 to 7 blade leaf sets.

Seedlings are usually potted up into a 1-gallon pot, or directly into their final pot for the vegetative growth stage. This allows for root expansion to support continued growth of foliage. As cannabis plants mature, secondary shoots at each node of growth will begin to develop leaf sets of increasing complexity.

If conditions are favorable, your cannabis plants will grow like a weed during the vegetative stage. When plants are well rooted, and growing vigorously, training and pruning techniques will help shape the plant for future production without compromising growth.

Several training techniques are commonly applied to cannabis plants to increase the number of colas, or top flowers, while decreasing overall height of the plant. These techniques include low stress bending, and high stress interventions like topping.

5) Sexual Maturity

Most Cannabis plants will become developmentally mature when they reach 14”-20” in height, or 8 to 10 nodes of growth. At this stage the leaves and shoots at each node will begin to alternate, rather than occurring opposite each other. Plants may begin to pre-flower, developing reproductive organs that allow determination of their sex.

Cannabis plants are dioecious, meaning that male and female reproductive organs occur on different plants. This is fortunate for us, as it allows us to select the desirable female plants, while eliminating male plants before they can seed our crop.

Feminized Seed

There are a few reliable ways to ensure that our plants are all female.

Hi quality feminized, or all female, seeds are now widely available for purchase. These seeds can save a lot of time and resources for cultivators regardless of size of their garden.

When sourced from a reputable breeder, the plants grown from feminized seed will be over 99% female, with a very small percentage of hermaphrodite or intersex plants.

Genetic testing

There are also genetic tests available to determine if a plant is male or female.

These cost about 10 dollars per test and can very accurately identify plant sex through genetic analysis.

For home growers, facing strict plant counts, it is very helpful to quickly determine the sex of your plants, and be assured of complete accuracy.

The process usually involves removing a cotyledon from a seedling, compressing it with blotter paper, and mailing the sample to a lab.

The resulting sample is legal to mail anywhere in the world, as no cannabinoids are present. In most cases, genetic testing costs less than growing plants until they are mature enough for visual identification.

Visual Identification

The traditional way to separate male plants from female is through visual identification during the pre-flower stage. These pre-flowers will form next to the stipule at the base of each node.

Visual identification is straightforward, but with some strains the pre-flowers may not be evident until after flowering has been induced. This is inconvenient and can result in gaps in flowering canopies, and accidental seeding if growers are not attentive.

See also  Plant Cannabis Seeds Point Down

6) Early Flower (Stretch)

Cannabis plants are either autoflower or photoperiod plants.

Autoflowering plants will enter the early-flower stage after 10-20 days of vegetative growth.

Photoperiod plants will begin to flower when they receive more than 10-11 hours of uninterrupted darkness during each 24-hour period.

Plants begin to elongate, or stretch about 5 days after entering flower, and stop growing taller after about 3 weeks.

The early flowering stage is really a hyper vegetative period.

At this point the plant has been trained and a trellis is usually installed to support the large cannabis flowers that are just beginning to form.

Lots of organic Nitrogen, and plentiful water is necessary to sustain vigorous growth.

Ideal climate conditions for this stage of growth include 55%-70% relative humidity and temperatures of 72-84 F (22-29C).

For indoor gardens, light intensity is slowly increased to make up for the reduction in light hours to a 12hour photoperiod.

As flowering progresses, the plant will stop vertical growth, and begin to form much simpler leaf sets. The reproductive organs, or pistils, will multiply, and cluster into small round buds.

There should be a strong focus on pest management during the early flower period. Reduction in pest populations to an absolute minimum during early flower will help to preserve crop quality during later flowering stages when pest pressures are higher, and treatments are more limited.

7) Mid Flower Stage

Plants will stop growing vertically and making new leaves about 20 days after flowering begins. The plant’s development will shift to flower expansion during the mid-flower stage. Flower expansion will continue until about 35 days after initiation. Relative humidity should be reduced to 50-60% to limit the risk of fungal disease.

At this stage, plants are at the peak of their reproductive potential.

Pistils have congregated to form large flower sets, or colas.

Each pistil is a reproductive organ. Their collective sexual frustration, due to lack of pollen fertilization, results in the profuse formation of psychoactive cannabinoids.

These cannabinoids are synthesized within glandular trichomes.

Other substances, including flavonoids, esters, and terpenoids are also synthesized by the plant during the peak flowering phase.

The presence of some of these compounds, particularly monoterpenes, is very evident during this period due to the smell of success that emanates from the crop.

As the flowers expand, some of the older leaves will start to yellow, and fall off. These should be removed as soon as possible. Some of the fungal diseases that affect cannabis are saprophytes and will infect dying plant material.

During early and mid flower, it is often helpful to selectively remove fan leaves.

Fan leaves are removed to allow light to penetrate the canopy and directly illuminate flower sites, and to enable air to flow through the canopy.

Airflow is important for climate equalization, to prevent disease, and promote plant health.

8) Late Flower Stage

The late flowering stage is when the bulk of psychoactive cannabinoids are synthesized. Between 20 and 30 percent of the dried flower weight is added during the final ripening phase. Humidity should be reduced to 50-60% to prevent bud rot from establishing in the large flowers. Temperatures should be reduced to a maximum of 80 degrees Fahrenheit (27 C)

Nighttime temperatures are also often reduced during this growth stage. The reduction in temperature during late flower serves several purposes.

When the humidity has been reduced, lowering the temperature helps the plant to transpire more efficiently due to a reduction in the Vapour Pressure Deficit (VPD).

Lower temperature can also help to manage the reproductive cycle of pests, including the three spotted spider mite, which thrives in hot-dry conditions.

See also  How To Germinate Cannabis Seeds In Peat Pellets

Lower nighttime temperatures can also increase the purple coloration in cannabis flowers. Cannabis plants, like many other plants, will produce a purple pigment known as anthocyanin when exposed to temperature extremes.

This pigment absorbs light energy as heat and helps to protect plants against both hot and cold temperatures.

Cannabis flowers change appearance as the white hairs or stigmas emerging from the pistils dry up and lose their ability to become pollinated and form seed. This final stage of plant life is also known as senescence. Many leaves will begin to yellow and die at this stage, and the plant is at its most vulnerable to pest attack.

Development and Standardization of Rapid and Efficient Seed Germination Protocol for Cannabis sativa

Cannabis seed germination is an important process for growers and researchers alike. Many biotechnological applications require a reliable sterile method for seed germination. This protocol outlines a seed germination procedure for Cannabis sativa using a hydrogen peroxide (H2O2) solution as liquid germination media. In this protocol, all three steps including seed sterilization, germination, and seedlings development were carried out in an H2O2 solution of different concentrations; 1% H2O2 solution showed the fastest and the most efficient germination. This protocol also exhibited high germination efficiency for very old cannabis seeds with lower viability. Overall, this protocol demonstrates superior germination compared to water control and reduces the risk of contamination, making it suitable for tissue culture and other sensitive applications.

Keywords: Cannabis sativa; Hydrogen peroxide; Rapid germination; Seed sterilization; Seedling development.

Copyright © 2021 The Authors; exclusive licensee Bio-protocol LLC.

Conflict of interest statement

Competing interestsThe authors declare that they have no competing interests.

SEED Initiatives

SEED Initiatives is the first U.S. government program to fund equity-centered community investment grants from local cannabis tax revenue.

The New Vision

Social Equity & Education Development (SEED) Initiatives is supported by an ongoing $1 million in cannabis tax revenue allocation and a vehicle for single-source monitoring, measuring, and reporting on the city’s cannabis tax revenue.

Portland City Council’s decision to allocate ongoing funding to the SEED Initiatives is one small step toward rectifying past racially-biased cannabis policies and disparate cannabis-related arrests. This commitment has the potential to begin to repair the lasting legal, social, economic, and inter-generational consequences past cannabis prohibition has had on Black and brown communities.

The History

In November 2016, Portland voters approved Ballot Measure 26-180 to impose a 3% local tax on adult-use cannabis retail sales. Since then, over $14 million in cannabis tax revenue has been allocated across various City of Portland bureaus to support street infrastructure improvements; DUII training; drug rehabilitation; criminal justice, expungement and re-entry services; and small business owners from communities disproportionately impacted by cannabis prohibition.

For more detailed information about the history of Portland’s local cannabis tax, please review these additional resources:

    , prepared by City Budget Office (2020) , prepared by the Cannabis Program (2019)

SEED Grant Fund

In alignment with the Ballot Measure 26-180 passed in 2016, the SEED Grant Fund prioritizes Black, Indigenous, and people of color (BIPOC) and women led/owned small business initiatives and/or projects, programs or services that support economic and educational development of Black and brown communities, which were most impacted by cannabis prohibition.

The SEED Grant Fund supports nonprofit and for-profit entities of any size, including community-based organizations, individuals, firms, teams or consultants. Newly-formed groups or initiatives with fiscal sponsorship from a nonprofit entity are also eligible. Multi-entity collaborations, coalitions and/or consortium efforts are encouraged to apply.

The SEED Grant Fund distributes funding across a range of projects, programs and services within the following designated priority areas, but are not limited to:

  • Education development
  • Entrepreneurship and economic development
  • Social justice

In the 5 cycles of the grant program, the SEED Grant Fund (formerly Cannabis Social Equity Grant) has awarded $4,379,415 through 42 grants.