EP 47▶ 5:35Genetics & breeding
How Much THC Is in a Cannabis Seed? (Less Than You Think)
Hardly any THC hides in a cannabis seed, and that's exactly the problem.
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Seed Science
The genetics, germination and breeding of cannabis seeds, explained with the research. Every episode is a short video and a full article, with its sources.
Latest · Episode 47Genetics & breeding
How Much THC Is in a Cannabis Seed? (Less Than You Think)
Hardly any THC hides in a cannabis seed, and that's exactly the problem. Even seeds from drug-type plants test far under the 0.3% hemp line, so from 11 December the US judges a seed by its parents.
Read and watchEP 47▶ 5:35
EP 46▶ 6:23Growing
Do HPS Lamps Really Grow Bigger Buds? (LED vs HPS)
For decades indoor growers flowered under the orange glow of a sodium lamp, and plenty still swear it grows bigger buds.
EP 45▶ 5:59Germination & seedlings
7 Germination Myths Debunked (What the Science Says)
Sandpaper the shell.
EP 44▶ 4:31Germination & seedlings
Seedling Stuck in Its Shell? Here's Why (and What to Do)
Your seedling came up with its seed leaves still locked inside the shell.
EP 43▶ 5:36Growing
What Size LED Do You Actually Need for Your Tent?
Grow lights are sold by the number on the box.
EP 42▶ 6:11Genetics & breeding
Hemp or Marijuana? It's One Number (And It Was Arbitrary)
Hemp and the plant in your tent are one species, split by one number: 0.3% THC.
EP 41▶ 4:18Growing
Silver Streaks and Black Dots? It's Thrips
Silver streaks on your leaves, with tiny black dots?
EP 40▶ 5:56Germination & seedlings
How Much Light Do Seedlings Really Need?
Your seedlings need less light than a flowering plant, but probably more than you're giving them.
EP 39▶ 4:34Growing
What Size Grow Tent Do You Actually Need?
Grow tents come in every size, from a 60 cm cube to rooms you can walk into.
EP 38▶ 5:46Growing
How a Trichome Works: What That Frost on Your Plant Really Is
That frost on your flowers isn't frost.
EP 37▶ 4:35Genetics & breeding
How Many Seeds Do You Need to Find a Keeper?
Breeders grow hundreds of plants to keep one.
EP 36▶ 6:18Autoflowers
7 Autoflower Myths Debunked (What the Research Says)
Autos need 24 hours of light.
EP 35▶ 5:30Germination & seedlings
Why Your Seedling Suddenly Fell Over (Damping-Off)
Fine yesterday, lying flat today.
EP 34▶ 8:07Genetics & breeding
How Feminised Seeds Are Really Made (The Full Process)
Every feminised seed starts with a female plant that has been tricked into making pollen.
EP 33▶ 4:13Growing
If You Can See the Webs, You're Already Late (Spider Mites)
Webbing means a heavy infestation.
EP 32▶ 2:55Autoflowers
Best Light Schedule for Autoflowers: 18/6 vs 20/4 vs 24/0
18, 20 or 24 hours of light for your autos?
EP 31▶ 3:31Growing
Is 12/12 Really the Magic Number? The Science of Dark Periods
Your plant doesn't count the hours of light.
EP 30▶ 4:10Genetics & breeding
Regular vs Feminised Seeds: Which Should You Grow?
Regular or feminised?
EP 29▶ 3:47Germination & seedlings
5 Seedling Mistakes, Explained by Science
Most seedlings don't die from neglect.
EP 28▶ 4:20Germination & seedlings
Why Didn't Your Seeds Sprout? (6 Reasons)
You planted five seeds and only two came up.
EP 27▶ 3:56Genetics & breeding
Why Does So Much Weed Taste the Same Now?
Thousands of strain names, so why does so much of it taste the same?
EP 26▶ 4:34Growing
Why Your Plant Shoots Up After 12/12 (The Science)
You switch the lights to flower and your plant shoots up.
EP 25▶ 3:13Germination & seedlings
Do Bigger Seeds Grow Bigger Plants? (What the Research Shows)
Every pack has big seeds and small ones, and plenty of growers plant the biggest first.
EP 24▶ 3:08Autoflowers
Why Is My Autoflower So Small? (The First 4 Weeks Decide It)
An autoflower doesn't wait until it is big enough.
EP 23▶ 3:36Autoflowers
Does Pot Size Matter for Autoflowers? (What the Research Says)
Does a bigger pot really mean a bigger harvest?
EP 22▶ 3:33Growing
Does Purple Mean More Potent? What the Research Shows
Your plant is turning purple.
EP 21▶ 3:28Germination & seedlings
The Best Way to Germinate Seeds? What the Lab Studies Show
Paper towel, soil, or a glass of water?
EP 20▶ 4:34Genetics & breeding
Are Triploid Seeds Worth It? (What the Research Shows)
Triploid seeds promise flowers that stay seedless even when stray pollen blows in.
EP 19▶ 5:16Germination & seedlings
Why Your Seedlings Stretch (And the Free Fix That Stops It)
Long, pale, floppy stems are one of the commonest problems in a young grow.
EP 18▶ 4:42Growing
Do Mycorrhizal Fungi Actually Help Your Plants? (What the Science Says)
Under every healthy plant there is a second root system, and it isn't a plant.
EP 17▶ 4:54Germination & seedlings
7 Seed Myths You Still Believe (What the Science Says)
Almost everything you can see on a seed belongs to its mother, not the plant inside it.
EP 16▶ 4:24Genetics & breeding
How a New Cannabis Strain Is Made (Step by Step)
Every strain began with two parents and a wish list.
EP 15▶ 4:19Autoflowers
Every Autoflower Has the Same Typo in Its DNA
Regular cannabis waits for long nights before it flowers.
EP 14▶ 4:26Genetics & breeding
Indica vs Sativa: What the DNA Actually Says
For decades we have called them sativa and indica.
EP 13▶ 4:14Genetics & breeding
Why "Feminised" Plants Still Make Pollen (The Science of Hermaphrodites)
You bought feminised seeds, then in week five of flowering you find pollen.
EP 12▶ 3:59Genetics & breeding
Afghani: The Landrace Behind Almost Every Strain
Short, stocky, fast to finish and covered in resin: the plants we now call indica trace back to one corner of Central Asia.
EP 11▶ 2:35Autoflowers
5 Autoflower Mistakes Every Grower Makes (Explained by Genetics)
Autoflowers are sold as the easy option, so why do so many end up tiny and stunted?
EP 08▶ 3:15Genetics & breeding
Same Strain, Different Smell: The Genetics of Cannabis Aroma
Two plants, same strain, same seed pack.
EP 07▶ 3:18Genetics & breeding
Landraces: Where Cannabis Seeds Really Came From
Long before strain names and seed banks there were places: mountain valleys and tropical fields where cannabis was grown, saved and replanted for centuries.
EP 06▶ 3:25Genetics & breeding
Phenotypes: Why Seeds From the Same Pack Grow Differently
Plant ten seeds from the same pack: one grows tall, one stays short, one turns purple, one smells completely different.
EP 05▶ 3:55Germination & seedlings
How Long Do Cannabis Seeds Really Last? What the Science Says About Storing Seed
In one long-running study, cannabis seeds kept warm and slightly damp were all dead within 18 months, while cool, dry seeds were still germinating years later.
EP 04▶ 3:24Germination & seedlings
Germination: What Really Happens Inside a Sprouting Seed?
A cannabis seed can sit in a drawer for years, barely breathing.
EP 03▶ 3:52Autoflowers
Autoflowers: The Plant That Ignores the Sun (Science & History)
Most cannabis waits for long nights before it flowers.
EP 02▶ 3:04Genetics & breeding
F1, S1, BX: What Your Seed Pack Is Really Telling You
F1, F2, IBL, S1, BX3: the codes on a seed pack are not marketing fluff.
EP 01▶ 3:33Genetics & breeding
How Feminised Seeds Are Made (The Science, Explained)
Plant ten regular seeds and about half grow up male.