Growing Cannabis 101

Section 01

Choosing Your Seeds

The single most important decision you'll make is choosing the right variety for your situation. Buy the wrong genetics for your setup and no amount of skill or equipment will save you. Get it right, and the plant does most of the work.

The three main types

• Feminized — bred to produce only female plants (females produce the buds). Best for most growers. Predictable, high-yielding, wide variety available.
• Autoflowering — flower automatically after a set number of weeks regardless of light schedule. Fast (8–12 weeks from seed to harvest), forgiving, and ideal for beginners or anyone who wants a quicker turnaround.
• Regular — produce roughly 50% male and 50% female plants. Preferred by breeders and those working with heritage genetics. Requires sexing plants and removing males before they pollinate females.

Indoor vs. outdoor

Before you pick a strain, decide where you're growing. Outdoor growers need varieties suited to their climate — in the UK, look for strains with a shorter flowering period that finish before October dampness sets in. Indoor growers have more freedom but need to match strain size to their available height and space.

What to look for on a product page

• Flowering time — how long from flip (or from seed for autos) to harvest
• THC / CBD content — general potency indicator
• Indica / Sativa / Hybrid — broadly indicates growth structure and effect profile
• Yield — average output indoors (g/m²) or outdoors (g/plant)
• Difficulty — some strains are forgiving; others are finicky about nutrition and environment

Section 02

Germination

Germination is the process of waking a dormant seed. A viable seed contains a fully formed embryo — all it needs is warmth and moisture to trigger growth. The taproot (the first white root) should emerge within 12–72 hours under good conditions.

The paper towel method

This is the most reliable method for beginners and the one we recommend. You'll need two clean plates or saucers, kitchen paper, and a warm spot.

1. Dampen two sheets of kitchen paper — wet, but not dripping.
2. Place your seeds on one sheet with at least 2–3cm of space between them.
3. Cover with the second sheet and place a second saucer on top to retain moisture.
4. Keep in a warm, dark place — an airing cupboard or on top of a boiler works well.
5. Check every 12 hours. Once the taproot is 3–5mm long, transfer to your growing medium.

Direct to soil

An equally valid method. Pre-moisten your growing medium, make a small hole around 5mm deep, drop the seed in, and lightly cover. Keep the medium consistently moist (not waterlogged) and warm. Most seeds will pop through the surface within 3–7 days.

What lighting for seedlings?

Seedlings don't need intense light. Fluorescent tubes or LED grow lights kept 30–40cm above the canopy at 18 hours on / 6 hours off works well for the first two weeks. Intense light at this stage stresses young plants unnecessarily.

Section 03

The Vegetative Stage

Once the seedling has established its first true leaves, it enters the vegetative stage — the period of rapid growth where the plant builds its structure: roots, stems, and the branches that will eventually support your buds.

Indoor growing

Keep lights on for 18 hours and off for 6. Cannabis requires uninterrupted darkness during the dark period — any light leak during lights-off can confuse the plant and cause issues later. Duration of the vegetative stage is up to you: 2 weeks produces a compact plant; 4–8 weeks produces a larger one with greater yield potential. When you're ready to flower, you flip the lights to 12/12.

Outdoor growing

Outdoors, the plant stays in veg while daylight hours are above 14 per day — typically May through July in the UK. Plants put outdoors in late May will veg strongly through June and July before naturally triggering into flower as days shorten in August. The longer your plants veg, the bigger the eventual plant and yield.

Watering

Cannabis does not like sitting in wet soil. Water when the top 2–3cm of soil feels dry to the touch, or lift the pot — a light pot needs water, a heavy one doesn't. Overwatering is one of the most common beginner mistakes and causes drooping, yellowing, and root rot.

Nutrients

During veg, plants need nitrogen-heavy feeding. Most quality potting mixes contain enough nutrients for the first 3–4 weeks. After that, a balanced grow feed (higher N) at the manufacturer's recommended dose works well. Start at half-strength if in doubt — it's much easier to add nutrients than to flush excess.

Section 04

The Flowering Stage

Flowering is triggered by a change in light — either by you switching your indoor lights to 12 hours on / 12 hours off, or by shortening natural daylight outdoors. This is where your plant's energy shifts from building structure to producing buds.

Outdoor flowering

In northern Europe, most plants begin flowering naturally in August as daylight drops below 14 hours. Flowering continues through to September–October depending on the variety. For UK outdoor growers, strains that finish in 8–9 weeks of flower are a safer choice — anything requiring more than 10 weeks runs a real risk of cold weather and mould before harvest.

Autoflowering varieties

Autos bypass the light-trigger entirely. They start flowering after a set number of weeks from germination regardless of your light schedule. Running autos at 18–20 hours of light from seed to harvest gives the best results.

Sexing your plants (regular seeds only)

If you're growing regular seeds, you'll need to identify and remove male plants before they open their pollen sacs. Males develop small clusters of round pods (like a bunch of tiny grapes) at the nodes, typically appearing in the first 1–2 weeks of the flowering stage. Females develop small white hair-like pistils. Remove males immediately — once pollen is released, nearby females will be seeded.

Nutrition during flower

Switch from a grow (high-N) to a bloom feed (high P and K) as soon as you flip to 12/12. Nitrogen demand drops sharply in flower. Around 2 weeks before your expected harvest date, stop feeding entirely and water with plain pH-adjusted water — this is the nutrient flush, and it improves the final taste significantly.

Section 05

Harvesting

Harvesting at the right moment is one of the most underrated skills in cultivation. Harvest too early and you lose yield and potency. Too late and the effect profile shifts — THC degrades to CBN, producing a heavier, more sedative effect.

Reading the trichomes

The most accurate way to judge harvest time is by examining the resin glands (trichomes) under a jeweller's loupe or digital microscope. You're looking at the tiny mushroom-shaped structures on the buds and sugar leaves:

• Clear trichomes — not ready. Cannabinoid production is still underway.
• Milky white / cloudy — approaching peak THC content. Effect will be more cerebral and energetic.
• Amber trichomes — THC is degrading to CBN. Effect shifts towards relaxing and sedative. Some growers prefer 10–20% amber for this reason.

For most growers, a mix of mostly cloudy with 10–15% amber is the sweet spot.

Other harvest indicators

• Pistils (hairs) have turned mostly orange or red — typically 80–90%
• Fan leaves begin to yellow naturally — the plant is redirecting energy
• Buds feel firm and dense, not soft
• Strong, developed aroma

Harvesting

Cut the main branches at the base. Remove large fan leaves immediately — they contain little useful material. Smaller sugar leaves (the ones coated in trichomes) can be left on for now if you're wet trimming after drying, or removed before drying if you prefer a dry trim.

Section 06

Drying & Curing

Drying and curing are where a lot of otherwise excellent grows fall apart. Rush either stage and you'll end up with harsh, grassy-smelling material. Do both properly and the same genetics will be smooth, aromatic, and considerably more potent.

Drying

Hang cut branches upside down in a cool, dark, well-ventilated space. Aim for:

• Temperature: 15–21°C
• Humidity: 45–55%
• Airflow: steady, gentle — not blowing directly on buds
• Light: none — UV degrades cannabinoids

Drying typically takes 7–14 days. The buds are ready when the smaller stems snap cleanly rather than bending, and the outer surface feels dry to the touch. Don't rush this — a slower dry (cooler temperature, slightly higher humidity) preserves terpenes and produces better-smelling end product.

Curing

Curing is the process of slowly breaking down chlorophyll and allowing enzymatic processes to continue improving aroma and flavour — similar in principle to aging wine or cheese. It makes a significant and measurable difference to the final product.

1. Trim dried buds from branches and remove remaining sugar leaves.
2. Place loosely in wide-mouth glass jars — fill to around two-thirds, no more.
3. Store jars in a cool, dark place.
4. For the first two weeks, open jars for 5–10 minutes once or twice a day ("burping") to release moisture and refresh air.
5. After two weeks, burp every few days.
6. After four weeks, the cure is usable. Eight weeks or more produces noticeably better results.