How to Grow Marijuana from Seed
If you’re in a location where cannabis (another term for marijuana; short for the plant cannabis sativa) is illegal, growing it is probably illegal too. Bringing in seeds or cuttings to your location can very well be a felony, and reputable sellers won’t ship to you.
You can probably purchase and grow hemp seeds and plants, which have a negligible amount of THC, but these plants won’t produce the psychoactive effects of plants that contain higher levels of THC. Check with your seller to be certain you’re getting what you think you’re purchasing. If you buy seeds for CBD-only hemp plants by mistake, you can end up being very disappointed post-harvest.
How to acquire seeds or cuttings
You can usually find cannabis seeds for sale at most dispensaries in areas where growing cannabis for personal use is legal. You may also find growers who sell cuttings/clones. You can expect to pay $50 to $100 for a pack of ten seeds. When shopping for seeds or cuttings, read the labels and any other information the manufacturer provides on its website or in its catalog to make sure you’re getting the right seeds or cuttings (the strain) for the plants you want to grow.
One way to get your mitts on some seeds is to collect seeds when you find them in flowers you purchased, or get some from friends if they’re collecting.
- Feminized seeds: Nearly all seeds sold by reputable companies are feminized, but make sure they are. These seeds are specially treated to grow into female plants.
- Auto-flowering or photoperiod: Auto-flowering plants are easier, because they enter the flower stage after a certain number of weeks regardless of the light/dark cycle. If you’re a beginner, seriously consider going with auto-flowering plants.
- Genetic background: If seeds are from a well-established strain, such as O.G. Kush, Bubble Gum, or a cross-breed, the genetic background should be stated.
- Blend: The blend represents the percentage of the three species — sativa, indica, and ruderalis. All auto-flower strains contain some percentage of ruderalis, which is responsible for the auto-flowering nature of the plant.
- Yield indoors: The number of grams of bud per square meter of plant when grown indoors.
- Yield outdoors: The number of grams of bud per plant (after drying) when grown outdoors.
- Plant height indoors: Shorter than when grown outdoors.
- Plant height outdoors: Taller than when grown indoors.
- Time to harvest: Approximate number of weeks after germination the flower should be ready to harvest.
- Potency: Percentages of CBD and THC.
- Effect: The type of experience you can expect when consuming product from the plant.
Know the laws about buying cannabis
- In some European countries, laws prohibit growing cannabis, but seed is legal, which is quite confusing. You’re allowed to buy and eat cannabis seeds because they’re non-psychotropic, but you can’t buy them to grow cannabis. Other countries in Europe, such as Germany, have their own seed laws.
- In Canada, where cannabis is federally legal, seeds can be shipped across provincial lines.
- In the U.S., in some states in which cannabis is legal, you can purchase seeds from some dispensaries or other locations to grow plants as long as you keep them in the state. Other states may bar selling to non-licensed growers. Shipping or transporting seeds across state or international borders is illegal, although a few reputable online seed stores ship to individuals with success.
Cuttings are typically treated in a similar manner as seeds in legalized locations. They may be available from some dispensaries or outlets for pick up or delivery with a fee. They’re prohibited from crossing U.S. state lines or international borders. You can buy individual plants and mix and match strains. Prices vary and are often determined by plant size.
Buy cuttings (clones) only from a reputable source who understands proper back-crossing of strains for stability. Back-crossing involves pollinating a plant with one of its parent plants to promote sexual stability, so that when you have a female it won’t hermaphrodite into a male during flowering.
Both seeds and clones are often able to be purchased from commercial locations already in your state.
In the U.S., transporting any part of the cannabis plant over state lines is illegal. This applies to seeds and clones and, technically, even to tissue samples.
How to germinate cannabis seeds
Germinating seeds requires a dark environment that is around 70 degrees. There are many ways to germinate seeds (in soil, in a wet paper towel, in starter plugs) You can also sow them directly into soil in a garden or container, as long as the soil is light and fluffy, so the roots can easily grow down and the stalk can break through the soil. Plant the seeds about 1/4- to 1/2-inch deep and cover them loosely with soil.
Most importantly, seeds need a moist environment; they won’t germinate if they get too dry. You can use a heat mat to increase the success of germination in colder climates.
How to transplant marijuana plants
When transplanting any plant, whether it started from seed or a clone, handle it gently, being very careful not to damage the roots. Center the plant in the pot, and plant it deep enough to cover the root ball completely in soil. If the plant is root bound, you can gently tease the roots apart to encourage outward growth.
Pack your soil or other grow medium down around the roots well enough to support the plant while new roots grow, but not so tight that the soil restricts outward root growth. Water the soil around the roots.
About This Article
This article is from the book:
About the book authors:
Kim Ronkin Casey has been a communications professional for more than 20 years and recently took a year-long leap into the world of cannabis as the communications manager for one of the leading dispensaries in North America. She now consults for companies in the industry on internal and external communications. Joe Kraynak is a professional writer who has contributed to numerous For Dummies books.
How much weed can you get from growing one plant?
As states legalize weed and the plant becomes more accepted, more people are trying out their green thumbs by growing their own weed at home. Most states with legal weed allow one person to grow six plants at their residence and an entire household to grow 12 plants. Some allow less, and some allow more.
(To see how many plants your state allows you to grow at home, check out this table).
But how much actual weed is that in dried buds that you can smoke? An ounce? A pound? Two pounds? The tricky thing is, all weed plants aren’t the same size, and many factors affect how big a plant will get and how dense its buds become.
We’ll go through those factors and talk a little bit about the harvest process to estimate how much weed you can get from one plant.
How much bud from one weed plant?
Many factors affect how big a plant gets, but generally speaking, if you are growing a healthy plant, you can expect these yields from one weed plant:
- Outdoor plant: ½ pound of buds, or about 224g
- Indoor plant: ¼ pound of buds, or about 112g
Note that these are estimates. When growing outdoors, plants can usually get massive because they aren’t restricted to space—it’s not uncommon to get closer to a pound a plant or more.
When growing indoors, you’re often limited by space—a plant can’t get as big in a grow tent as in a big, open basement. You’re also limited by how powerful your grow light is. For example, Leafly editor David Downs harvested 150g from one indoor plant with one 200W Black Dog LED light. The company said that light maxes out around a half-pound of buds, or 224g.
Also, these estimates are for healthy plants. If a plant becomes nutrient-deficient, gets bugs or mold, or doesn’t receive enough light, expect a lot less.
How long will one plant’s worth of bud last you?
However big your plant gets, you’ll likely have more flower than you know what to do with. Many people will save a certain amount of flower for smoking, and make edibles, concentrates, and other weed products with the rest of their harvest.
Consider how much weed you smoke in a day, week, or month. For reference, a gram is about two medium joints or 3-4 bowls. Do you smoke a gram a day or a week? Two grams a day or a week?
Using the above yield estimate of ¼ lb., or 112 grams, for one medium-to-large-sized indoor plant, if you smoke one gram a day, that one plant would last you 112 days, or just under four months! Two grams a day would last you just under two months, and half a gram a day—or an eighth a week—would last you eight months.
This will help give you a sense of how many plants you should grow. If you’re growing indoors, you can grow one plant at a time, harvest it, and start another, keeping a continuous cycle of growing.
If growing outdoors, you may only get one harvest a year. Remember, check out how many plants you can legally grow in your state here.
Read more of Leafly’s guide to growing
Factors that determine a weed plant’s yield
The amount of dried buds you harvest from a weed plant is called its yield, just like any crop, such as corn, wheat, fruit, etc. Ideally, when growing weed, you want high yields and high-quality buds. Getting both takes a little practice.
A weed plant will lose about 75% of its weight to moisture loss and trimming after being cut down. A considerable amount of moisture leaves the plant during the drying process, and trimming removes all the stems, branches, fan leaves, and trim from the plant.
So if you weigh a freshly cut plant at three pounds, don’t get too excited—you’ll likely get ¾ lb. of finished buds (which is still a lot of weed).
A big plant doesn’t necessarily mean big yields, as buds can be thin and wispy. A medium-sized plant with quality, dense nugs could yield more than a six-foot tree. Also, if growing multiple plants, they can grow over each other and shade one other out, reducing yields. Make sure to give plants plenty of space.
Some major factors that contribute to a weed plant’s yield include:
- Grow duration
- Soil type/amount
Certain weed strains grow big or tall or are high-yielders simply because of their genetics. Traditionally, indicas grow short and stout, and sativas grow tall and lanky. That’s not always true across the board, but it is a good rule of thumb.
For example, Lemon Skunk is famously a tall, lanky strain, so you’re likely to get high yields from it. Blue Dream and Chemdog are also known for their high yields.
Aside from its candy-like flavor, Runtz gets its name because its buds grow small, like the runt of the litter. It might be a low-yielder, but you’ll usually get high-quality buds.
How long you allow a plant to grow, or the length of time from seed germination to harvest, is one of the most significant factors determining weed yield. If you start growing seeds in March rather than May, those plants will have two extra months to get big.
When growing outdoors, the local climate is the main determining factor of when you can put seeds in the ground. Some regions are too cold to put plants outside until May, but you can start growing plants indoors with the right setup.
Some regions get rain early in the fall, so you’ll want to grow plants that are ready to harvest by the beginning of October. In tropical climates, you can practically grow weed outdoors all year round.
When growing indoors, growth duration is determined by how much space you have to work with. If you have a spacious basement or shed, you can let plants grow for months and get as big as you want before forcing them to flower. If space is tight, like in a grow tent or other small areas, you may only be able to let your plants get a few feet tall.
How much light a plant receives is highly variable. When growing outside, it all depends on where a plant is located to receive the most light throughout the entire season. Weed plants like full sun—at least six hours of direct sunlight every day. If a plant is in the shade or gets shaded as the light changes throughout the season, it can affect yields.
Indoors, it depends on how powerful your light is. A small 200W LED is great for a small grow tent, but you’ll need something bigger for a bigger space, which also means a more expensive light.
Be sure to prune your plants to remove dead leaves and buds, and branches that won’t turn into sizable buds. Clearing out plant matter will allow the quality buds to get more light.
Weed typically likes warm, temperate climates—think of Northern California’s Emerald Triangle region—but certain strains thrive in different temperatures. Traditionally, indicas like cold, dry climates and sativas like warm, humid climates.
Sudden extreme changes in temperature can affect a plant’s growth and yields, such as a sudden cold snap, which can slow a plant’s growth, or a heatwave, which can dry out a plant.
Different soils have different nutrient levels and some nutrients can promote plant growth. You can also add nutrients to soil or water to help plants grow big and strong.
Additionally, if growing in containers, the size of the container, or the amount of soil the plant’s roots have, will affect the size of a plant. Growing in too small of a pot can stunt a plant’s growth.
Check out guidelines on how big of a container you need for different sized plants here.
Growing directly in the ground will give your plant’s roots plenty of space, but you may need to add nutrients depending on the soil’s quality.
How Many Cannabis Seeds Per Pot?
If you have ever wondered how many cannabis seeds per pot, look no further. One seed is all it takes to grow one plant so even if you see plants that look like as if they were bushes it is all just one seed. Regardless of the apparent size of the plant, all growers know that only one cannabis seeds per pot is required.
So you know how many cannabis seeds per pot, but you want to know what will happen anyway?
If you use more than one or many cannabis seeds in a pot, the cannabis plants will begin to compete against each other for nutrients, so the smallest cannabis plants (which sometimes may be the best phenotypes.) will get wiped out by the bigger cannabis plants.
If you are growing from regular cannabis seeds they could also cross-pollinate resulting in buds with cannabis seeds in them. It sounds simple enough but if the buds have seeds inside them, the potency of the strain can be reduced up to 30%. Each cannabis seed is a plant and they need their own space to grow and thrive, as well as to produce bigger and better buds. Remember that more than one cannabis seed per pot is too many.
You might find our FAQ Submission How Many Marijuana Seeds To Grow A Plant? useful!