Let's be real. Most people think they can just toss a seed in some dirt, splash a little water on it, and wake up to a forest of sticky buds. It doesn't work that way. Honestly, the first time I tried it, I ended up with a sad, stretchy stick that looked more like a Charlie Brown Christmas tree than anything you’d actually want to smoke. If you're wondering how do you grow a weed plant and get actual results, you have to realize you’re managing a living, breathing biological system. It’s chemistry. It's lighting. It’s mostly just patience.
You’ve got to start with the genetics.
If you buy "bag seed" from some random eighth you bought, you’re gambling. Those seeds are often the result of stress-induced hermaphroditism. You spend four months growing a plant only to realize it's full of seeds because the genetics were garbage. Buy from a reputable seed bank. North Atlantic Seed Co. or Mephisto Genetics are solid choices because they actually stabilize their lines. You want "feminized" seeds unless you want to spend your life sexing plants and tossing out the males.
The Environment Is Your Boss
Your plant is only as good as the air it breathes. Most beginners focus on the soil, but the environment—temperature and humidity—is what actually dictates how the plant "sweats" or transpires. This is called Vapor Pressure Deficit (VPD). If it’s too humid, the plant can’t pull water up through its roots. If it's too dry, the plant closes its pores to save water and stops growing.
Keep your tent between 70°F and 85°F.
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Anything higher and you’re basically slow-cooking the terpenes (the stuff that makes it smell good) right off the plant. Humidity needs to be high in the beginning—like 70%—and then you slowly drop it as the plant gets older. By the time you’re in late flower, you want it down to 40% to prevent bud rot. Botrytis (gray mold) will ruin a six-month project in about 48 hours. It’s heartbreaking.
Lighting: Don't Cheap Out
You cannot grow top-shelf cannabis with a desk lamp. Period. You need a full-spectrum LED light. Look for brands that use Samsung LM301B or LM301H diodes. Brands like Spider Farmer or Mars Hydro are the "entry-level" standard that actually works. You’re looking for PAR (Photosynthetically Active Radiation), not just "brightness." Your eyes might think the light is bright, but the plant knows if the spectrum is missing the red and blue wavelengths it needs to build cells.
How Do You Grow a Weed Plant in Soil vs. Coco?
This is the big debate. Soil is "forgiving." It acts as a buffer. If you mess up the pH of your water, the soil can usually handle it for a bit. But it’s slow.
Coco coir, which is basically ground-up coconut husks, is hydroponics in a pot. It’s inert. It has zero nutrients in it. This means you are the god of that plant. Every single thing it eats comes from the bottle of nutrients you mix into the water. It grows twice as fast as soil, but if you forget to water it for one day, it will wilt and potentially die. Beginners usually do better in a "super soil" like FoxFarm Ocean Forest or Coast of Maine. You just add water for the first month and the soil does the heavy lifting.
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- Germination: Soak the seed in a glass of water for 24 hours. Once the "taproot" peeks out, put it in a damp paper towel or straight into a small starter cube.
- Seedling Phase: This is the most dangerous time. Don't overwater. A seedling only needs a few teaspoons of water. If the soil is soaking wet, the roots can't breathe and they rot. This is called "damping off."
- Vegetative Stage: The plant is just growing leaves and stems. Give it 18 hours of light and 6 hours of darkness. It needs nitrogen. Lots of it.
- Flowering Stage: This is the magic. For photoperiod plants, you change the light to 12 hours on and 12 hours off. This tells the plant "winter is coming," and it starts producing flowers to try and reproduce.
The Nutrients and pH Trap
The biggest mistake? Overfeeding.
People think more fertilizer equals bigger buds. It actually just equals "nutrient burn." The tips of your leaves will turn brown and crispy. It’s a chemical burn. Most nutrient companies (like General Hydroponics or Advanced Nutrients) want you to use way too much so you buy more bottles. Start at half the recommended dose.
And check your pH.
If your water is too acidic or too alkaline, the roots literally "lock out" certain minerals. Even if the food is in the soil, the plant can't see it. For soil, aim for 6.0 to 6.8. For coco or hydro, you need it tighter, between 5.5 and 6.2. Buy a decent pH pen like an Apera or BlueLab. The cheap $10 yellow ones from Amazon are notoriously inaccurate and will lie to your face while your plant dies.
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Training Your Plant
If you just let a weed plant grow, it becomes a Christmas tree shape with one big bud at the top and a bunch of tiny "larf" at the bottom. You want a flat canopy. Use "Low Stress Training" (LST). Basically, you take the main stem and gently tie it down so it's horizontal. This breaks the "apical dominance." The plant freaks out and sends growth hormones to all the side branches, turning them all into "main" buds. More surface area for the light means a way bigger harvest.
When to Actually Harvest
Stop looking at the hairs (pistils). Beginners see white hairs turn orange and think they're done. They aren't. You need a jeweler's loupe or a digital microscope. Look at the trichomes—the tiny crystals.
- Clear: Not ready. No potency.
- Cloudy: Peak THC. This is the "head high" stage.
- Amber: The THC is degrading into CBN. This gives you that "couch-lock" heavy feeling.
Most growers harvest when it's about 80% cloudy and 20% amber.
The Drying Process: Where 50% of Quality is Lost
You spent four months growing. Don't ruin it now. You have to dry the plant slowly. Chop the whole plant and hang it upside down in a dark room. 60 degrees Fahrenheit and 60% humidity is the "Golden Rule." If it dries in three days, it will taste like hay or lawn clippings. You want it to take 10 to 14 days. This allows the chlorophyll to break down properly.
Once the small stems "snap" instead of bending, put the buds in glass jars. This is the curing phase. Open the jars for 15 minutes a day (burping) for the first two weeks. This evens out the moisture and develops the flavor. A bud cured for a month tastes infinitely better than a bud dried in a week and smoked immediately.
Actionable Next Steps
- Audit your space: Measure your temperature and humidity over 24 hours before you even buy a seed. If you can't keep it under 85°F, you need an exhaust fan.
- Buy a quality light first: Skimp on the tent, skimp on the pots, but do not skimp on the LED.
- Choose your medium: If you are busy, go with a 5-gallon pot of organic soil. If you have time to tinker every day, go with coco coir and high-frequency fertigation.
- Source genetics: Look for "Auto-flowering" seeds if you want a faster harvest (usually 70-90 days from seed to finish) without worrying about light schedules.