The Cannabis Encyclopedia, Chapter 5: Seeds and Seedlings

Excerpt from Jorge’s Upcoming Book:

The Cannabis Encyclopedia: Indoor, Outdoor and Greenhouse Cultivation, Concentrates and Cooking Medical Marijuana

Cannabis Encyclopedia

Chapter 5: Seeds and Seedlings



Seed varieties developed in California are often crossed by European breeders and sold to cannabis gardeners around the world.

Exponential growth of seed selection and legal seed sales in the Netherlands, the United Kingdom, Canada, France, Switzerland, Spain, medical cannabis states in the USA, and many other countries,is making cannabis genetics more accessible than ever before. Most of the seeds (genetics) are available worldwide via Internet purveyors. Cannabis seeds are sold in every country on earth—some of which are illegal. Google “buy marijuana seeds” for an eye-opening example. See “Finding Seeds” below for more information.


This cannabis sativa plant grown in 1976 originated in Colombia.


This Afghani from 1979 is classified as cannabis indica.


Cannabis Ruderalis from the Joint Doctor

There are thousands of varieties of cannabis. Most popular varieties include a combination of two or more of the following: Cannabis sativa,Cannabis indica,and Cannabis ruderalis. There are fewer pure indica, sativa, or ruderalis seeds available. The majority of seeds are bred to grow best indoors. Often indoor varieties are easy to acclimate to greenhouse climates. Fewer tried-and-true varieties are available for outdoors, but their number continues to grow.

Cannabis seeds available today are one of four basic types:

1. Natural – produce separate male and female plants, Mother Nature’s original seeds.  Natural or “regular” seeds require 11–12 hours of light and 11–12 hours of darkness daily to flower.
See chapter 08, Flowering for more information on indica and sativa varieties.


Regular cannabis plants are NOT feminized. Regular or naturally occurring cannabis plants are dioecious, having male plants and female plants.

2. Feminized – produce 99+ percent female plants. No male plants; male flowers occasionally occur. Female-only plants were first developed in India in 1982.* Feminized seeds require 12 hours of light and 12 hours of darkness daily to flower. All regular seeds can be feminized.
*Study by H. Y. Mohan Ram and R. Sett, Department of Botany, University of Delhi, Delhi (India) – “Induction of Fertile Male Flowers in Genetically Female Cannabis sativa, Plants by Silver Nitrate and Silver Thiosulphate Anionic Complex”


Feminized Power Plant

3. Autoflowering – ready for harvest 70–80 days after germination
Seeds contain C. ruderalis genes mixed with indica and/or sativa genes.
Autoflowering seeds flower regardless of light regimen. Autoflowering feminized seeds have been very popular in Europe since 2008, with the introduction of ‘Lowryder II’ genetics. Before that they were considered a novelty.

New autoflowering varieties are growing 3–4 feet (91–122 cm) tall.

Super autoflowering varieties are growing 6–7 feet (183–213 cm) tall.


Autoflowering feminized Diesel x Low Ryder

4. Autoflowering Feminized – produce 99+ percent female plants that flower and are ready for harvest 70–110 days after seed germination
Seeds contain C. ruderalis genes mixed with indica and sativa genes.
Autoflowering feminized varieties flower after 3–4 weeks of growth, regardless of light regimen.
Super autoflowering-feminized varieties flower after 4–5 weeks of growth. They grow longer and bigger.


Ruderalis cross


This beautiful room full of F1 hybrid Bubblicious plants are from Resin Seeds.

F1 hybrid seeds have “hybrid vigor.” F1 hybrids grow faster and bigger than seeds of non-F1 hybrids. See chapter 25, Breeding for more information on F1 hybrid plants.



This seed contains the complete instructions (genetic codes) to grow a Jack Herer plant.

A seed contains all the genetic characteristics of a plant. The genetic code contained within a plant dictates whether it is regular, feminized, autoflowering, or autofloweringfeminized. Seeds are the result of sexual propagation and contain genes from each parent, male and female.* Some (intersex) plants, known as hermaphrodites, bear both male and female flowers on the same plant. The genes within a seed also dictate a plant’s size; disease- and pest resistance; root, stem, leaf, and flower production; cannabinoid levels; and many other traits. The genetic makeup of a seed is the single most important factor dictating how well a plant will grow under artificial light or natural sunlight and the levels of cannabinoids it will produce.’
*>See chapter 25, Breeding for deviations from this rule (i.e., where intersex plants are bred).

The genetic makeup of a seed is the single most important factor dictating how well a plant will grow under natural or artificial sunlight and the levels of cannabinoids it will produce.

All seeds have the same basic requirements for germination and seedling growth. Strong healthy parents, proper breeding practices, and excellent care will yield strong seeds that germinate well. Strong seeds produce healthy plants and heavy harvests. Seeds stored under adverse conditions (hot, cold,or humid) or stored too long will germinate slowly and have a high rate of failure. Vigorous seeds initiate growth within a day or two. Some seeds take longer to germinate. Seeds that take longer than a month to germinate could always be slow and less productive.


The outer shell of Skunk #1 seeds break away when germinating.

The cask, or outer protective shell, on some seeds never properly seals, which allows moisture and air to penetrate. It also causes hormone concentrations to dissipate and make seeds less viable. Permeable seeds invite diseases and pests to move in. Such seeds are immature, white, fragile, and crush easily with slight pressure between finger and thumb. These are weak seeds and do not have enough strength to germinate and grow well.

chapter 5 image
The cutaway drawing in the center shows how the seed will develop into different plant parts.

A simple view of a seed exposes an embryo containing genes and a supply of food wrapped in a protective outer coating. Seeds range in size from small dark ones from tropical climates to huge seeds bred for hemp oil extraction. Mature seeds that are hard, beige to dark brown, and spotted or mottled have the highest germination rate. Soft, pale, or green seeds are usually immature and should be avoided. Immature seeds germinate poorly and often produce sickly plants. Healthy, fresh, dry, mature seeds less than a year old sprout quickly and grow robust plants.


Regular Seeds


F1 hybrid vigor
No diseases
Easy transport
Genetic expression
Not F1 hybrids – less vigor
Slow to start
Easy to lose
Must cull males



Feminized Seeds


F1 hybrid vigor
All female
Use less space
Use less light
Not F1 hybrids – less vigor
Possible intersex qualities


Autoflowering Seeds


F1 hybrid vigor
Flower in 70+ days
Flower in summer
Not F1 hybrids – less vigor
Could produce poorly
Must remove males
Difficult to clone effectively





 See chapter 25 Breeding for “Advantages/Disadvantages” between seeds and clones.

Seedlings are less work to grow outdoors because branches are usually farther apart at first. Clones grow too densely from the bottom and require more pruning work.

To read more, click here to purchase The Cannabis Encyclopedia: Indoor, Outdoor and Greenhouse Cultivation, Concentrates and Cooking Medical Marijuana

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The Cannabis Encyclopedia, Chapter 6: Vegetative Growth

Excerpt from Jorge’s Upcoming Book:

The Cannabis Encyclopedia: Indoor, Outdoor and Greenhouse Cultivation, Concentrates and Cooking Medical Marijuana

Cannabis Encyclopedia


Chapter 6: Vegetative Growth




Strong vegetative growth is essential to a healthy harvest.

The cannabis seedling growth stage lasts for about two to three weeks, from seed germination to (strong) root set. Once a strong root system is established, foliage growth increases rapidly and seedlings enter the vegetative growth stage. When chlorophyll production is full speed ahead, a vegetative plant will produce as much green leafy foliage and root growth as is physically and genetically possible. Of course, growing conditions—CO2, soil oxygen levels, nutrients, water, and so on—must not be limited and must be in the proper balance to be available for rapid uptake. Properly maintained, some varieties of medical cannabis will grow from half an inch to two inches per day. A plant stunted for any reason could take weeks to resume normal growth. A severely stunted plant may never fully recover.


Growing large plants in relatively small containers, in this case a five-gallon (19 L) pot, requires daily irrigation with a complete nutrient solution. A layer of mulch would keep roots from being exposed.

A strong, unrestricted root system in a perfect rhizosphere (root zone) that is able to take in all necessary available nutrients is essential to robust growth. Unrestricted vegetative growth is the key to a healthy harvest. A plant’s nutrient and water intake changes during vegetative growth. High levels of nitrogen are needed. Potassium, phosphorus, calcium, magnesium, sulfur, and trace elements are used at much faster rates. Transpiration is carried on at a more rapid rate, requiring more water. The larger a plant gets and the bigger its root system, the faster the soil will dry out. The key to strong vegetative growth and a heavy harvest is supplying plants with the perfect environment both above ground and below ground.


These plants will spend a short time in vegetative growth and will be subject to fewer problems.

During vegetative growth, plants need water and often need supplemental fertilizer too. Outdoor and greenhouse organic gardeners are able to build organic soil with bulk nutrients and amendments. Indoor gardeners most often need to add supplemental fertilizer. The garden will also need adequate air circulation and ventilation both day and night. Nutrient deficiencies that start in the first or second week of growth indoors usually show outward signs by the third to fifth week of growth. Nutrient deficiencies that start during the fourth or fifth week of growth outdoors and in greenhouses show visible outward symptoms during the sixth to eighth week of growth. But low-level nutrient imbalances take longer to manifest, if ever.

Infestations of diseases and pests often flare as nutrient deficiencies progress. Many times new clones from another garden are already infested with spider mite eggs, powdery mildew, or root disease, with few outwardly visible signs. Always quarantine and dip new clones and seedlings in an organic fungicide/insecticide/miticide before introducing them to the garden.


Multiple nutrient deficiencies, excesses, pests, and diseases become apparent during vegetative growth.

After one to three months of vegetative growth, nutrients have had a chance to build up to toxic levels, and plants may show outward signs of deficiencies or excesses. Leaching containers will wash away water-soluble toxic nutrients, See “Leaching” in chapter 21, Nutrients, for more information. Other problems—overwatering, underwatering, air circulation and ventilation, etc.—also occur now. See “Common Nutrient Problems” in chapter 21 for more information.


Vegetative growth in cannabis is maintained indoors, outdoors, and in greenhouses with 16 to 24 hours of light daily. Autoflowering (feminized) cannabis will flower according to chronological growth and is not affected by photoperiod.

Cannabis will continue vegetative growth for a year or longer under an 18-hour photoperiod and a temperate climate. But sooner or later a genetic maximum is reached causing cannabis to degenerate. Indica and indica-dominant varieties suffering stress from cold wintry conditions tend to flower regardless of hours of light, often producing more resin on stunted plants.


Cannabis flowers when given long nights and short days.

Indoors and in greenhouses, growth stages can be controlled with the light-and-dark cycle (photoperiod). It is the main stimulus to induce flowering. Give plants a 12/12-hour day/night light schedule to induce flowering. Give plants 0 to 8 hours of darkness and 16 to 24 hours of light to retain vegetative growth. Controlling the photoperiod allows indoor and greenhouse horticulturists to control vegetative and flowering cycles. See chapter 17, Light, Lamps, and Electricity, for more information on photoperiod control. Outdoor gardeners work with Mother Nature and harvest after long nights and short days in spring and autumn.


Mother plants and clones all grow under long 18-hour days with short 6-hour nights.

Once a plant’s sex is determined, it can become a mother, clone, or breeding male and can be harvested or even rejuvenated (see “Rejuvenation” in chapter 5).
Note: Plants show early male or female “pre-flowers” about the fourth week of vegetative growth. See “Pre-flowering” in Chapter 8, Flowering.

Transplanting, pruning, bending, and trellising are all initiated when plants are in the vegetative growth stage. Information on these subjects follows.




Clones are ready to transplant once new, green growth starts.

09-SS-2014-Jorge-Ch-06-Clone -MG-4906

Good strong roots must grow before cones are ready to transplant.

When plants have outgrown their containers, they must be transplanted in order to continue rapid growth. Inhibited, cramped root systems grow sickly, stunted plants. Signs of root bound plants include slow, weak growth. Severely rootbound plants tend to grow straight up with branches that painstakingly stretch beyond the sides of the pot. By the time you see these symptoms, the plant is rootbound. To check roots, remove a plant from its pot to see if roots are deeply matted on the bottom or circling the sides of the pot.


The clones in this perfect Trichome Technologies garden are easy to care for.

When growing short plants that can be watered daily and reach full maturity in 70 to 90 days from clones or seedlings, there is little need for containers larger than approximately three to five gallons (11.4–19 L). Larger plants and mother plants will need a large pot if they are kept for more than three months.


A long vegetative growth stage lets plants get big enough to grow an abundant crop of flower buds.

Outdoors and in greenhouses, plants can grow much larger than indoors. Containers should be as big as possible to accommodate a large root mass. Big plants that produce ten pounds (4.5 kg) of medical cannabis buds can be grown in 200- to 500-gallon (757–1893 L) containers.

To read more, click here to purchase The Cannabis Encyclopedia: Indoor, Outdoor and Greenhouse Cultivation, Concentrates and Cooking Medical Marijuana

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