Cannabis Seeds & Seedlings – Chapter 3


Cannabis seeds hold the genetic key to cannabinoid and terpene production. You hold the key to cannabinoid and terpene yield. Selecting the perfect seeds for your garden combined with keen cultivation techniques are rewarded with a heavy harvest.

Close inspection of these two groups of cannabis seeds reveals a spotty, mottled surface with numerous vein-like formations on the outer shell (testa).

A seed contains all the genetic material for growing a cannabis plant. The genes within a seed dictate a plant’s size, disease and pest resistance, root, stem, leaf and flower production, cannabinoid levels and many other traits. Seeds are the result of sexual propagation and contain genes from each parent, male and female.

Mottled dark brown lines distinguish these StinkBud seeds.

The genetic makeup of a seed is the single most important factor dictating how well a plant will grow in different climates and under artificial light, sunlight and light available inside a greenhouse. Genetic characteristics also control the maximum amounts of cannabinoids a plant is able to produce. However, growth conditions also affect cannabinoid levels. A poorly grown plant produces lower levels of cannabinoids than a healthy well-grown plant.

Chapter One, Cannabis Botany, defines the following categories of seeds: (1) regular seeds (2) feminized seeds (3) auto-flowering regular seeds and (4) autoflowering feminized seeds. Regular seeds are becoming less common in many parts of the world and numerous seeds companies offer only feminized seeds. Feminized seeds are very popular because they grow into female plants that have a high cannabinoid content. However, unstable feminized plants may occasionally develop male flowers.

Regular, Feminized & Auto-flowering Cannabis

THC CannabisMaleFemaleSeedsFemale CloneDays to Mature
Auto-flower FemOXXO70-90
CBD CannabisMaleFemaleSeedsFemale CloneDays to Mature
Auto-flower FemOXXO70-90
Industrial Fiber HempXXXX70-90

Strong viable seeds are produced by healthy parents that receive proper care. Seeds that have been stored properly germinate quickly and grow into healthy plants that produce heavy harvests. Seeds stored too long will germinate slowly and have a higher rate of failure. Vigorous seeds germinate within 48-72 hours and sprout aboveground within seven days. Seeds that take more than a week to germinate may grow slowly and produce less. However, some varieties take longer to germinate even under the best conditions.  

Cannabis seeds – THC-rich CBD-rich, etc. – can be large or small. Check out the difference in size of these seeds that were supplied by my friend Jerry from

Avoid weak seeds. If the outer protective shell does not properly seal, a little moisture and air penetrate and try to activate growth. Seed and seeds become progressively less viable. Moisture-permeable seeds signal diseases and pests to move in. Weak seeds are immature, light-colored, fragile and crush easily with slight pressure between finger and thumb. Weak seeds do not have enough stored food to germinate and grow properly.

A seed consists of an embryo containing genes and a supply of food bundled in a protective outer coating. Mature viable seeds 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. Viable, fresh, dry, mature seeds one or two years-old sprout quickly and grow robust plants.  

Buy seeds in packages of 1, 3, 5, 10 and more. Selling very small quantities of seeds started with feminized seeds that are guaranteed to be female. But if a seed does not sprout or the seedling is weak and sickly, there is no backup sibling to take its place. I advise to start with at least three feminized or auto-flowering seeds and 5-10 regular seeds from each variety. If you have room and the budget, start 10 seeds of each variety. To help ensure a crop, start more seeds than you plan to harvest.

If you start with ten regular seeds from a reputable supplier and germinate them all at once, about half will be male. If you start with five feminized seeds, one or two could grow slowly or be less cannabinoid potent. Two, maybe four seeds will grow into strong, potent females. Of these females, one will be more robust and potent than her siblings. Select this “super” female to be the mother of your clones.

Cannabis Seed Germination

Cannabis seeds need only water, heat and air to germinate. At germination, moisture causes the outside protective shell of the seed to split. Moisture continues to wick in to trigger the dormant hormones that activate the small white radicle. The radicle penetrates the soil transforming into the tap root and green growth emerges above ground. Cotyledon, or seed leaves, emerge from within the shell as they push upward in search of light. A constant stream of moisture is essential to transport water, nutrients, and hormones for rapid growth. If seedlings suffer water stress now, they will take weeks to recover. Auto-flowering seeds and seedlings are extremely susceptible to moisture, heat, and oxygen stress. See below for several cannabis seed germination techniques.

Seeds do not need extra hormones or fertilizer to germinate. Once seeds emerge and a set of cotyledon leaves develop, a mild nutrient solution is necessary in inert substrates – coco coir, perlite, rockwool, etc. – that contain no nutrients of their own.

Timeline to germinate strong viable seeds and grow into grow into seedlings

Seeds absorb water in the presence of air to initiate germination

At 48-72 hours the white root tip (radicle) is visible
At 4-7 days roots grow, seed sprouts aboveground
At 5-8 days cotyledon leaves open
At 6-9 days true leaves are visible
At 6-21 days roots develop, little foliage grows
At 21-25 days root system matures and true leaves grow
At 25-30 days seedlings are ready to start vegetative growth

Once seeds grow a specialized root system, cell growth accelerates; stem, foliage and roots develop quickly. Promote this natural growth and harvest heavily. Seeds that do not root and start strong growth, often grow slowly later.

Seeds need air to germinate. Moist, soggy growing mediums will cut off oxygen supplies; seeds will literally drown if totally submerged for more than 20 minutes after germination. Planting seeds too deeply also causes poor germination. Seedlings do not have enough stored energy to force through too much soil before sprouting. One rule of thumb is to plant seeds twice as deep as the width of the seed. For example, plant a 0.125-inch (0.3 mm) seed, 0.25-inch (6 mm) deep. I like to explain it as putting a very small dab of soil on top of the seed and keeping it evenly moist. I like to set a moist paper towel on top of the soil until the seed emerges, see below.

Household water often contains enough dissolved solids (nutrients) to nourish seeds through their first few weeks of life. But household water may cause problems. Seeds are very sensitive to excessive salts in water that disrupt internal chemistry. I prefer to use deionized, RO, distilled, demineralised, rainwater, filtered – water. Watering seeds with a nutrient solution can inhibit germination.

Seeds need heat to germinate. Seeds sprout without light in a wide range of temperatures. Properly nurtured seeds germinate in two to seven days, in temperatures from 70- 80°F (21-26.6°C). Temperatures above 86°F (30°C) impair germination and could lead to rot. Temperatures below 70°F (21ºC) slow germination. Below 60ºF (15.5 ºC) speeds stagnate and if the environment is too wet, disease could become a problem. Super hard seeds may need to be scarified (see below) to help initiate germination.

Seeds need total darkness to germinate. The rootlet or radical is the first to emerge. It needs darkness so that it can anchor the plant that will emerge aboveground. Bright light shining on a tender little rootlet can stunt growth and in extreme cases result in failed germination.

Viable seeds germinate quickly. If you have a few cannabis seeds to germinate, placing them in moist paper towels is very easy and efficient. The seeds in the moist paper towels can be placed inside a partially plastic bag to retain moisture or set on a saucer that retains moisture. Set the germinating seeds in a warm, dark location.

Three Easy Steps to Germinate Cannabis Seeds

Step 1
Soak seeds overnight in a glass of (in order of best to least) deionized, RO, distilled, demineralised, rainwater, filtered – water. Make sure seeds get good and wet to activate growth. At first seeds float. Seeds sink to the bottom as moisture penetrates the outer shell. Do not let seeds soak for more than 24 hours or they suffer oxygen deprivation and drown. Once soaked carefully place seeds in between moist paper towels on a saucer or plate.

Seeds float before the water tension is broken and moisture penetrates the outer. Growth is initiated once water enters the inner seed. Seeds sink as more and more water soaks into the interior.

Here is a selection of germinating seeds from Spain. All of the germinating seeds were given away free with Cáñamo magazine.

Step 2
In a warm location (70-85°F, [21-29°C]), place seeds in several layers of moist paper towels on a saucer or plate. You may need to add a little water to the plate daily. Be vigilant of warm nights that cause paper towels to dry. Let excess water drain away freely. The paper towels will retain enough moisture for the seed to germinate within a few days. The seed contains an adequate food supply for germination. Prevent fungal attacks by watering with a mild organic surface fungistat solution. Remove germinated seeds when the little white rootlet grows from 0.25-0.5 inches (0,6-1.25 cm) and plant in substrate with the rootlet pointed downward.

When water penetrates the outer protective shell to induce germination, plant growth is activated. A constant stream of moisture is essential to transport nutrients, hormones, and water to carry on life processes. Letting germinated seed suffer moisture stress now will stunt, even stop growth. Once the tip shrivels from lack of moisture, the plant is stunted and may take weeks to recover.

Rockwool rooting cubes retain structural integrity when moved into Deep Water Culture (DWC) gardens and other types of hydroponic gardens. Rockwool must be hydrated and conditioned by adjusting the pH to 5.5-5.8 and adding nutrient solution.

In rockwool seeds can “heave” (crawl out of the rockwool) during germination. Planting sprouted seeds with a longer white radical (0.5 inch (1.5 cm)) in rockwool avoids heaving. Take care not to expose the tender rootlet to prolonged intense light or air. Keep the growing medium evenly moist. Once the taproot sprouts, small fuzzy feeder roots will grow in a few days.

Soggy growing mediums keep seeds to stay too wet. Planting seeds too deeply causes poor germination. Seedlings do not have enough stored energy to force through a heavy layer of soil before sprouting. Plant seeds twice as deep as the width of the seed. For example, plant an 1/8 inch (3 mm) seed 1/4 inch (6 mm) deep.

Once the radicle starts to grow, the seed is ready to plant into the substrate. When planted, gravity will direct root growth downward and light aboveground will provide energy to start photosynthesis. First a set of rounded cotyledon or seed leaves appear. Next, a pair of classic serrated cannabis leaves grow on the internode above cotyledons.

Step 3
Transplant sprouted seeds when the white sprout is visible. I like to move the sprouted seed into a seedling block or mix soon after the white radicle becomes visible. The little white tap root, when long, is more difficult to keep evenly moist. Dangling rootlets are easy to damage and should not be exposed to air and light.

Transplant Sprouted Seeds into Growing Medium

Place germinated seed in a shallow planter, small seed pot, peat pellet, rooting cube or soilless mix. When starting more than a few seeds, use plug trays and fill with starter plugs, cubes, Sunshine® mix, Promix® or similar substrate. Plant germinated seeds in a heated or warm room to minimize any type of temperature stress.

Step 1
Pre-moisten the fine planting mix, seed plugs and cubes. Fill plug trays with pre-moistened substrate. Plug trays are available in many sizes. Many different plug trays are available with numbers of contiguous planting cells. Larger plug “flats” can be cut down containing 6-12 cells.

Step 2
Use a pencil eraser to make a shallow hole 0.375-0.5- inch (1-2.5 cm) in the center of the mix of each cell of the plug tray.

Small growers can take the time to plant individual germinated seeds with tweezers. Avoid touching the little white rootlet with your dirty, rough hands. It is super delicate now and easy to damage.

Step 3
Avoid touching, squeezing, scraping, fondling, etc. delicate rootlets with filthy hands to avoid injury. Move seeds with tweezers or shuffle them out of the paper towels into the planting hole to avoid disturbing rootlets. Or you can carefully pick up the fragile sprouted seeds with your clean fingers and plant them in a pre-drilled shallow hole in the soilless mix, small seed pot, peat pellet, rockwool rooting cube with the white root tip pointing down. Cover the germinated seed with a very light, 0.25–0.5-inch (1-2 cm) of moist soilless mix, peat or other substrate.

Lightly press down on the substrate to ensure it is in firm contact with the seed.

Step 4
Cover planted containers, flats, and trays with a double layer of paper towels. Check under towels daily. Spray or sprinkle with water to keep the substrate surface moist if necessary. Remove the wet paper towel covering when the seedlings start to emerge. Some gardeners prefer to wait until half (50%) of the seedlings have emerged, especially if growing hundreds of seedlings.

Step 5
Apply a very light dose of organic fertilizer once the cotyledons open. The small root system needs only water now. You may want to add a small dose of liquid kelp too. Keep the planting medium evenly moist until roots are established.

Step 6
A small spoon works well to scoop regular and feminized seedlings out of plastic cell packs when the root system is small. Do not use this method for auto-flower seedlings because it will disturb roots and provoke flowering in most varieties. Peat pellets, root cubes and other seed plugs may be transplanted in two to three weeks or when the roots can be seen through the sides.

Heat from grow lights warms the substrate surface and below. Keep an eye on soil moisture. Heat from the lamp can dry soil. More frequent watering may be required. A slight increase in substrate temperature speeds root growth.

A shallow flat or planter with a heat pad or heating cables underneath seedlings may require daily watering, while a deep, one-gallon (3 L) pot will need surface watering every few days. A properly watered flat of rockwool cubes needs water every 3-5 days when sprouting seeds. When the surface is dry (0.25- inch [7 mm] deep) it is time to water. Remember, there are few roots to absorb the water early in life and they are very delicate.

Place germinating seeds on a warm base – warm refrigerator, cable box, or soil heat pad and heating cables to keep temperature a little higher than the ambient air temperature. Bottom heat also helps avoid sudden fluctuations in temperature and moisture that shock seeds and slow germination.

Place a heat pad or soil heating cables below growing medium to speed germination. Cannabis seeds germinate and sprout quickest when the soil temperature is between 78-80°F (24-27.5°C) and the air temperature is 72-75°F (22-24°C). But stems will stretch between internodes if temperatures exceed 85°F (29°C) for several hours.

Semi-direct Seed Outdoors

Auto-flowering varieties grow well when sown semidirectly in soil. Roots have the chance to penetrate the soil and grow naturally. Sow auto-flowering varieties when the soil warms. Sow seeds up to a month earlier in raised beds and raised beds that warm sooner.

The root systems of auto-flowering varieties are very sensitive. Any time the root system is disrupted by movement or when the roots start to circle a container, the plant will start to flower. Undesirable untimely flowering adds up to puny plants that produce poorly.

These are the steps that Steve Rogers makes to plant auto-flowering cannabis seeds. First, he starts seeds in pots or plug trays. Once seedlings are strong and healthy, he transplants them outdoors.

Step 1
Cover the plug tray soil with fine potting soil or soilless mix to fill all cells. Moisten the growing medium.

Step 2
Make shallow planting holes with the end of a small stick about the size of a pencil eraser.

Step 3
Drop a single seed in each hole.

Step 4
Cover the planted growing medium with a very light fine layer of soilless mix. Smooth out the 0.25-inch (cm) layer of growing medium and lightly tamp it down.

Step 5
Water the growing medium with a fine spray so that it is evenly moist.

Step 6
Cover the planted growing medium with a layer of cardboard. Anchor the cardboard down so that it does not shift on the ground. Sprinkle the cardboard covering very lightly with water to add a little weight. Seeds should germinate and a sprout should pop through the soil after about three days.

Step 7
Wait until half (50%) of the seeds have sprouted before removing the cardboard.

Step 8
Once the seedlings start to sprout, keep them evenly moist and protected from slugs, snails, birds, and insects. Snail bait and a spun fiber covering will protect the tender seedlings until they grow tougher.

Step 9
Feed with a dilute, quarter-strength organic fertilizer solution.

Planting Auto-flowering Cannabis Seedlings

Commercial grower, Steve Rogers (Singing Pig Farm, Inc.) loves growing auto-flowering cannabis. Rogers turned his green thumb into heavy harvests, “There is a persistent myth in the cannabis community that auto-flowers should not be transplanted. I use the transplant technique because it produces better and faster growth.” Rogers is right, he has been transplanting auto-flowering seeds with almost 100% success. He continues “It’s important to grow autoflower plants quickly. If they begin to flower, there is no time to recover”.

Steve Rogers’ son, Ben, is sowing auto-flowering Blackberry Gum seeds in 1.75-inch (44 mm) Jiffy pellets that are set into 4-inch (10 cm) pots of seedling mix. The extra precaution with auto-flower seeds lets Ben transplant seedlings that have not fully developed root balls inside the Jiffy pellets. The extra 4-inch (10 cm) pot ensures that the roots that grow out the sides of the Jiffy pellet are disturbed as little as possible.

Auto-flowering varieties need to be babied during the first 4 weeks of life. Stress can cause plants to grow slowly and produce much less. Stressed autos develop less foliage, smaller flowers and low yields.

Minimize stress when transplanting. Keeping consistent levels of light, temperature, humidity, water, nutrients and growing medium chemistry will keep cannabis roots growing as fast and dense as possible. This is not possible when moving plants outdoors from an indoor garden. You can minimize the stress on cannabis plants by gradually introducing them to the new garden space. Both soil temperature and air temperature must be similar to an outdoor environment. If this is not possible, construct a makeshift greenhouse over the transplants and transplant them into raised beds.

If you are a new auto-flower grower, you may want to start auto-flowering sprouted seeds in a 5-gallon (20-L) root-pruning pot. The root-pruning container will hold the auto-flowering cannabis plant until harvest. Transplanting auto-flowering plants into their final container avoids extra work but diminishes container harvests. Outdoor crops benefit immensely using this transplanting technique.

This little plant was started from an auto-flowering seed.

Start auto-flowering plants in a Jiffy-pot, rockwool cubes, Ellepot, Rapid Rooter Plugs, Flora Root Plugs, etc. to transplant outdoors or to a larger container. The container must be rigid so that the root ball remains intact. Transplant autos as soon as cotyledon leaves start to emerge, or a day before they emerge. This will help guard against roots poking through the sides of the rigid container. I´m always amazed at how a little root movement will decrease yield.

Starting seeds directly in the soil outdoors and in a greenhouse is preferred by some growers. Planting seeds directly in Mother Earth allows the seed to become acclimated to soil life immediately. Directseeded cannabis develops a strong healthy tap root that penetrates much deeper into the soil than seeds started in containers indoors.

Start auto-flowering seeds in a plug such as an Ellepot” – a little paper tube filled with standard peat germination mix. Many different companies make similar paper-sleeve plugs. These plugs work great if you are planting 10-100s of seedlings. Many insert plugs will fit into a 1020 nursery flat that is easy to handle. Do not use Styrofoam or hard plastic trays. Autoflower roots suffer stress as soon tips hit the sides of the container or grow out the bottom of cells.

For best results, select a growing medium that is the same or almost identical to the one you plan to use in the next transplant phase. Keep the same substrate for all phases of growth and transplanting.

Optimize Auto-flower Cannabis Production

1 Grow super-autos.
2 Start seeds under lights indoors.
3 Start super-autos in small cube, plug orcontainer.
4 Give seedlings 20 hours light and 4 hours darkness.
5 Use low EC (<50 ppm) or clean Reverse Osmosis (RO) water.
6 Water with 5:2 ratio of (5) humic acid to (2) kelp.
7 Apply mycorrhizae fungi when planting and transplanting.
8 Carefully transplant to 3-5-gallon (11-20 L) air-pruning containers.
9 Fast-draining substrate.
10 Trellis train plants to receive more light.
11 Water and fertilize as needed.
12 Harvest top flowers, wait 1-2 weeks harvest ripe lower flowers.

Cannabis Seedlings

The vibrant white roots on this seedling

These healthy seedlings have outgrown their small containers and must be transplanted.

These Colombian Jack from Kannabia Seeds are at the end of the seedling stage. Take a close look at the stem above and the cotyledon leaves and see how the stem “fattens up”.

When a seed sprouts, the white taproot emerges and plows into the soil in search of nutrients. Soon afterward, the stem pushes out of the soil and cotyledons, also known as seed or seedling leaves, appear. The seed leaves spread out as the stem elongates.

The first true leaves appear within a few days and the little plantlet is now a seedling. The seedling growth stage lasts for three to six weeks. During seedling growth, a root system grows rapidly while green aboveground growth is slow. Water and heat are critical at this point of development. The new, fragile root system is very small and requires a small but constant supply of water and warmth. A fast-draining substrate that holds ample air is essential. Too much water will drown roots, often leading to root rot and damping-off. Lack of water will cause the infant root system to dry up. As the seedlings mature, some will grow faster, stronger and appear healthy in general. Once germinated, move seedlings to a slightly cooler growing area and increase light levels.

Some seeds sprout slowly and are weak and leggy. If possible, cull sickly, weak plants and focus attention on the remaining strong survivors. Seedlings should be big enough to thin out after 4-6 weeks of growth. If thinning out seedlings is too traumatic, you can continue to nurse the little seedlings along. In fact, Dr. Gary Yates advises, “I’ve found these often are the best cannabinoid producers! Don’t cull the runts if you are growing for yourself and yield is not important.”

Over-watering and under-watering are the biggest obstacles most growers face when germinating seeds and growing seedlings. Keep the soil uniformly moist, not water-logged. Do not let the growing medium surface dry for long. Keep it evenly moist. Set root cubes and planting flats up on a grate to improve drainage.

The end of the seedling stage is over when rapid foliage growth starts. Rapid growth aboveground signals the beginning of the vegetative growth stage. Plants need more room to grow; transplanting into a larger container hastens development.

Photoperiods for Cannabis Seedlings

4/20 – 4 hours dark / 20 hours light.
Less intense light illuminates plants for more hours so that plants receive the total Daily Light Integral (DLI) they need to grow to maximum potential. This photoperiod works well for seedlings and vegetative growth stages for regular and feminized cannabis. Auto-flowering cannabis can be given this 4/20 photoperiod from seed to harvest.

6/18 – 6 hours dark / 18 hours light.
This is the standard photoperiod that indoor growers have found successful to promote vegetative growth in regular and feminized cannabis plants. Many growers use this photoperiod for auto-flowering cannabis too.

12/12 – 12 hours dark / 12 hours light.
Induce seedlings to flower when they are about 21 days from seed emergence with this photoperiod. Cannabis seedlings go directly into flowering. Grow a fast 90-day crop from regular seeds with this light schedule. Cannabis plants produce fewer and smaller flowers overall because of their short lifespan. Breeders use this technique to produce male pollen in less time.

0/24 – 0 dark / 24 hours light.
This schedule allows no rest for any plant processes.

Cannabis Needs Light, Air, Water, Nutrients & Soil (LAWNS)

Light Intensity for Seedlings

Seedlings need at least 16 hours of low-intensity light daily. They grow well under fluorescent tubes and LEDs for the first two to three weeks. Fluorescent, CFL and HID grow lights can also be used. The compact fluorescent should be 12-18 inches (30-45 cm) and the HID 3-4 feet (90-120 cm) above seedlings for best growth.

Tender young seedlings need the low levels of light supplied by low-wattage fluorescent, CFL or LEDs. Fixtures typically supply 7,500-20,000 lux, the perfect intensity of light for seedlings.

Set the light fixture 4-5 inches (10-13) above the emerging seedlings. Once cotyledon and the first set of “true” cannabis leaves emerge, experiment by gradually moving the fixture as close as 2 inches (5 cm) from the top of seedlings. Each variety may react differently to light intensity. Move the light closer to increase intensity if stems start to stretch, a sure sign of light starvation. Back the light away to decrease light intensity if signs of light burn appear. Light burn causes tender leaves to contort somewhat and if intense may scar and discolor foliage. Too much light slows growth.

Many inexpensive bluetooth and WiFi-based environmental sensors (Temperature, humidity, moisture, etc.) that relay data to your mobile phone. The data is easy to analyze in real time in the chart and text readout on your mobile phone. The collected data can be used as a complete grow room history.

Keep a very close eye on the temperature and humidity. I like to set a maximum/minimum thermometer/hygrometer at seedling level. This gives me the most accurate readings.


Avoid rapid changes in temperatures and humidity, especially with low light levels. The seedling temperature range 68-78ºF (20-25.5ºC) with an ideal at 75ºF (24ºC). Ideal seedling humidity range 60-70%.

Air (oxygen) content in substrates is essential. Do not let roots get too wet and cut off air.

Temperature range for seedlings.

Humidity range for seedlings.

Ideal temperature for seedlings.


Seedlings need a constant supply of moisture. Seedling rooting plugs and cubes hold moisture for several days depending on conditions. A dilute nutrient solution is necessary for seedlings grown in inert substrates.


Start feeding after seedlings develop cotyledon leaves. Apply a very dilute quarter-strength nutrient solution. Organic soil may not need additional nutrients. If yellowing appears, give seedlings less water and less nutrients.. Be sparing with fertilizer when few roots exist. Increase the dosage as plants grow.

A nutrient solution must be added to inert substrates – coco coir, perlite, soilless mix, rockwool, expanded clay pellets, rooting plugs, etc. these inert substrates contain no nutrients of their own.

The first mild nutrient solution should be in the 6.2-6.4 pH range. Nutrient solution is acidic which will lower the pH. Keep the EC at or near 400 PPM. As seedlings grow bigger in 10-14 days increase the EC according to fertilizer manufacturer’s instructions.

A dilute solution of humic acid (HA) and kelp in a 5:2 ratio is all that is needed in organic soil to really kickstart root growth according to Steve Rogers (Singing Pig Farm, Inc.). He uses this combination of HA and kelp in a 5:2 ratio which has shown to give a 50% increase in root mass over using either product alone. Rogers also adds a light dose of fish hydrolysate. He advises using a diluted solution more often rather than giving tender seedlings a big jolt.


Soilless mixes and potting soils are often fortified with nutrients. This is especially true of seedling mixes. Instructions on the potting soil bag or manufacturer´s internet site will list the ingredients and instructions on use. If there are no instructions on the bag or internet site, think twice about purchasing the potting soil.

A little substrate heat now will help nurture small root systems to a strong start. The guidelines for substrate heat and ambient air temperatura are the same as with seeds above. Remember, to keep an eye on the substrate moisture level. It tends to dry faster when warmer than ambient air.

How to Select Cannabis Seeds

Select seeds from mother plants that show the desirable traits you want. Grow clones of the super mothers to grow and harvest a garden like this.

Grow seedlings indoors under lights and move them into the greenhouse. Once cannabis seedlings acclimate to the slightly harsher greenhouse climate, strong bushy plants can be moved outdoors when weather warms.

Cannabis Seed / Clone Selection Criteria

Budget – ($ total cost) / seeds) = ($ cost each seed)
Genetic type – regular, feminized, auto-flower
Genetic background – male parent, female parent, 3-way cross, 4-way cross
Site – indoor, greenhouse, outdoor
Days to harvest – date from seed company – Actual date you harvest
Potency – (% CBD), (% THC) (% CBG)
Flavor/taste –sweet, earthy, citrus, vanilla, pine, berry, grape, etc.
Feeling/effect – happy, euphoric, alert, relaxed, sleepy, munchies
Plant height – plant height inches/centimeters
Purpose – flowers, concentrates, vape cartridges, topical
Easy to cultivate – easy, medium, difficult
Easy to clone – easy, medium, difficult
Score – plant score (1-10)
Foto – Seeds labeled
Foto – Seedlings

Here is a link to a seed selection guide.

The seeds in this seeded female are literally popping out of the seed bracts.

Seeds found in flowers often have an unknown male parent with a sordid history. The seeds may grow into plants with similar flowers but few are identical. The inconsistent growth pattern is accompanied by different cannabinoid profiles. There is a good possibility that intersex (hermaphrodite) tendencies will crop up. A few small male “bananas” (see foto above) on a female plant could pass on the intersex trait.

Acclimated cannabis seed performs best because it has been grown in the same area for several years. This is a good reason to produce and save seeds. Localized cannabis seed typically grows well when it is acclimated to a specific climate. You have probably seen huge 10-15-foot-tall 3-4.5 m) plants in photos from Humboldt county in Northern California. These plants have been grown in the same microclimate for at least five years and they are acclimated to their environment. Of course, they are nurtured with great organic soil, expert gardening skills, and agreeable weather.

To find varieties that fit your needs, decide which qualities you like – aroma, taste, effect, medicinal value. What is your criteria for seed selection? Do you base your selection on aroma and taste? Do you want a soaring high or a mellow relaxing effect? Do you want medicinal properties that will stimulate appetite, relieve pain and anxiety? Do you plan to make concentrates? Or do you want a combination of the above qualities? Many internet sites explain the qualities of different varieties.

Check out this “Seedfinder”

Decide if you want to grow CBD-rich, THC-rich or CBG-rich seeds that are regular, feminized, autoflowering regular, auto-flowering feminized. See “Regular, Feminized & Auto-flowering Cannabis” chart above to help you make decisions.

Growing plants that grow well in your climate and that are acclimated to local growing conditions pays off with 5-10+ (2.25-5.5 kg) harvests of dried flowers.

Select varieties that grow well in your climate. Note that you can compensate for inclimate hot and cold weather by choosing the proper planting location. Extend the growing seasons by growing in raised beds and overcome harsh weather by growing in a greenhouse. Grow plants indoors and move containers outdoors when the weather permits and set up a small season-extending greenhouse. Remember to hardenoff plants when moving outdoors.

Outdoor growers in cool alpine and northern climates will need to concentrate on varieties that ripen in the geographically demanding conditions brought on by a short cold growing season. Sativa lovers will need to choose varieties that are crossed with short-season indicas and autoflowering cultivars. Cannabis plants that grow well outdoors in harsh desert conditions are few and far between. The image above was taken in Switzerland.

The Super Lemon Mango cannabis plants and other sativadominant varieties are being acclimated to the tropical climate in Thailand. According to the grower, Ryan Doran, “in my experience the indica-dominant, northern latitude, strains do excellent in northern Thailand and there is no reason to use acclimated strains in the winter. I have had great success with a wide variety of seeds that are typically bred in northern climates such as; Grand Daddy Purple, White Widow, Money Maker, OG Kush, Orange Punch, Critical OG, and Blue Dream.”

Ryan continues, “Due to the short light cycles here in Thailand, with the longest day being 13.5 hours this (17- 18º) northern latitude, indica, plants will flower anytime under natural sunlight, so they require supplemental lights for the veg stage. The quality of the flowers grown with these genetics outdoors is on par with the best flowers from California.”

Climates with temperatures above 50ºF (10ºC) both day and night from April-September offer the widest latitude of possibilities. Such climates give you the opportunity to grow all kinds of cultivars. In fact, if you start plants indoors and move them out when they are two-feet-tall (60 cm) you can grow a couple of crops.

This grow tent image was taken 17 years ago. You can see why grow tents have become so popular!

Indoor growers can cultivate seed varieties that mature into plants from 3-4 feet tall (90-120 cm). Artificial light will not penetrate foliage of tall plants. Lower branches do not receive enough light and grow wispy small flowers. Indoor growers generally cultivate low profile pure indica, indica-sativa crosses or autoflowering plants.

Auto-flower growers can move seedlings outdoors when nighttime temperatures are a minimum of 50ºF (10ºC). A small plastic greenhouse to protect autos at night will spur growth. Warmer soil in raised beds extends the outdoor season too. Autos need at least 6 hours of direct sunlight to yield a decent harvest. See “Planting Auto-flowering Cannabis” below for more information about growing autos.

Ordering Cannabis Seeds

Cannabis seed companies advertise on the internet and in magazines. Read their seed catalogs carefully and follow the guidelines they recommend for varieties to grow indoors, in greenhouses and outdoors.

Call the seed company to ask questions based on the description of the seeds. Speak to a qualified representative who will provide good answers to your questions. Companies with an e-mail address and web site are usually okay to order from, but make sure they answer your emails promptly. Do not be afraid to call several companies and ask them specific questions about the varieties (AKA strains) they sell.

No regulatory agency exists to uphold genetic standards in the cannabis seed industry. A variety that is produced by “seed company A ”will not be the same as the same variety as from “seed company B”. If you find a specific variety you like, take clones and keep it. Share the clones with friends so that you do not lose the variety.

Growers buy seeds every year for several reasons. Growing feminized and auto-flower (feminized) plants produces a consumable harvest. Starting seeds saves you from having to make clones and you can grow the newest varieties. Regular seeds are more popular in the USA and other parts of the world than they are in Western Europe and surrounding countries.

Recessive genes do not appear until the F2 if you are saving seeds. This is another reason growers plant clones or purchase new seeds.

Air (oxygen), moisture and light are the three enemies of stored seeds. Quality seeds are packaged in airtight, impermeable, dark packets. I attempted to germinate 6-year-old improperly stored seeds from 12 different companies. The one company that packages their seeds in an airtight, impermeable dark envelope had a germination rate of 30%. None of the other seeds germinated.

Storing Cannabis Seeds

Store seeds in a dark, airtight container along with moistureabsorbent silica crystals. Remove seed every month and set silica crystals in a warm sunny location to dry out. Always label containers!

If storing seeds for a year or two, no need to employ a special “low humidity” refrigerator. If you require long-term storage, a low humidity refrigerator helps guarantee seeds remain viable.

Store seeds in a dry, cool, dark place. Make sure to label containers. Fresh seeds that you have grown and harvested will remain viable for up to five years or longer when stored properly using basic techniques. Low temperatures slow internal seed activity and are essential to preserve seeds. Low humidity is essential. Keep seeds in a low humidity environment. Keeping seeds in a refrigerator

When 50% of the stored seeds do not germinate, the average storage life is over. Old seeds often take longer to sprout and have a lower rate of germination.

Seeds with a hard outer cask are the most likely to sprout and grow well. Seeds with a thin, outer protective shell never truly go dormant, because moisture and air are always present within. This moisture and air cause hormone levels to slowly dissipate. Such seeds do not store well.

Seed hormones – ABA, cytokinins and gibberellins– are prompted into action when moisture signals germination to initiate.. Prevent moisture from signaling seeds to germinate by keeping them dry. Small amounts of condensed moisture can give seeds a false start on germination and cause them to expend all their stored energy too early. The seed will have no more stored energy to germinate properly. Avoid moisture levels above 5% if possible to help ensure viable seed long term, 5 years or more. Moisture levels above 5% will cause germination levels over time. Seal seed in an airtight container and place silica crystal packages in the container to absorb excess moisture. Keep seeds preserved longer and viable by vacuumpacking to remove oxygen.

Low-humidity refrigerators are expensive and beyond the needs of most gardeners. Saving seeds with conventional means should prove adequate and certainly more economical.

Seeds were germinated and nurtered properly to produce these strong seedlings. A perfect growing environment is created with LEDs.

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