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 Does One Plant Produce?
“How can I grow as much weed as possible?” You know that’s what’s on your mind when you ask or wonder about plant yield. Old and new marijuana growers (and scientists and politicians ) alike want to know how to get the highest yield per plant and per grow. Planning and practice can make a huge difference– especially when you are only growing one plant!
But, ultimately let’s not forget that the cannabis plant is a sentient being. She’s alive! Her growth is dependent on many factors and the same plant can produce a pound in one situation and a couple grams in another. Below we will detail the known factors that impact yield and potency, discuss where things can go wrong, and where things can grow right.
What is yield? (wet vs. dry yield)
Yield is the amount of weed you get when you harvest your marijuana plants. This is only the buds themselves, removed from the stems. This is most often measured once your marijuana buds are dried and trimmed. This is generally measured in grams, ounces, and pounds. The “lid” is not a used measurement anymore.
One of the most know measurements currently is an 1/8th (of an ounce) which is 3.5 grams. This is commonly found in dispensaries as well as something one might purchase from their friendly neighborhood weed guy. In this picture below, only two perfectly grown and cured buds were needed to reach this weight!
Wet and dry cannabis does not weigh the same.
Immediately upon harvesting, your buds will be quite heavy. That’s because, like humans, freshly harvested cannabis flowers are 75 – 80% water by weight. Once dried and cured, the actual harvest you get is about ¼ of the wet weight. So, if your harvest weighs out at an ounce at first cut, when it’s all said and done, you will have a quarter ounce of homegrown weed to smoke.
To estimate your dry yield from your wet yield, just multiply the wet yield by 0.25 to get an idea of what you’ll have to share with your friends (or stash away for yourself)!
This varies slightly depending on if you grew a sativa-dominant or an indica-dominant strain. Sativas are notoriously more airy so if you weigh your sativa harvest wet, you will get 20 – 22% dry. Indicas tend to be a bit chunkier so if you weigh your indica harvest wet, you will get 22 – 25% dry.
Yield vs. Potency
Yield is an important factor to consider because cannabis is an annual crop; there’s only one harvest per plant. After harvest, the plant is dead and returns to compost. Yield is the weight of the buds that you harvest. Yield should not be confused with the potency of these hefty green nuggets. Potency is the strength of the cannabinoids found in the trichomes on your cannabis buds.
In other words, you can have a high yield of low potency buds. Or you can have a low yield of high potency buds. In a perfect world, you’d get a high yield of high potency buds and we are going to discuss how to make that happen!
What to do to increase your weed plant’s yield?
Let’s get the most out of your homegrown medical (and recreational) marijuana. Best plant performance and yield are the result of growing the right strains under the right conditions. The most important factors being: light, plant density, fertilizer, temperature, duration of the flowering growth stage, and plant variety. In sum, the TLDR version is:
blast as much light as you can afford, grow less plants to fill your space appropriately, feed your plants just enough but not too much, keep the space not too hot and not too cold, don’t harvest early, and don’t buy shit genetics
(bag seed gamblers are included!)
Light to Increase Weed Plant High Yield
The yield from an indoor-grown cannabis plant largely depends on the light the plant receives. Cannabis plants, being photosynthesizers, receive all their energy to function from light.
The type, quality, and amount of light you provide your marijuana plant directly influences yield and should not be taken lightly (see what we did there?)
Sunlight is the most powerful light us earthlings have access to, so if you are able to give your plant direct sunlight, do it! Sunshine is also free, and that is a big plus. The only downside is that we cannot control cloudy or rainy days and winter makes it challenging to grow with the limited amount of sunlight (the freezing temperatures also don’t help).
Moving to an indoor grow environment, w hen it comes to lighting fixtures, it does not benefit you to get the cheaper option. And we know how challenging it is to pick the right light- – there’s so many options out there! (incandescent, CFL, HPS, LEDs)
We do not encourage growers to use incandescent light bulbs when growing indoors. To get enough energy for your plant, the bulb would put off too much heat and not be fun to see on your electric bill. CFL bulbs are equally useless. Stick to new technology to protect your plants and your wallet.
While HPS light fixtures are historically the choice for those who want to maximize their indoor cannabis crop harvest, they are slowly fading out from commonplace. An experienced grower can expect to harvest a gram of weed from each watt of HPS light provided to the plant. This means that if the light is a 400-watt HPS bulb, then 400 grams of weed could potentially be harvested. However, LED light technology is getting more advanced. LEDs are: 1) cheaper to run than HPS and 2) run cooler than HPS which also lowers the cost of air conditioning and 3) reduces the likelihood of burning your plants with too much light.
When choosing an LED light fixture for your weed plants you are up against a surplus of options and information.
The most important metrics to look for in a lighting fixture are PPF, PPFD, and energy usage/efficacy . If none of these are present, you may want to look at a different fixture.
PPF, PPFD, and photon efficiency are measurements related to PAR. PAR is photosynthetic active radiation. PAR is not a unit of measurement but instead defines the type of light needed to support photosynthesis.
PPF is how much PAR a lighting system produces each second. This is not often listed as it does not show how much of the measured light actually lands on your plants but is a useful metric to calculate how capable a light fixture is at creating PAR.
PPFD (photosynthetic photon flux density) is the measurement of how much PAR actually arrives at your plant. This is a spot measurement and is typically highest at the center point beneath the light and decreases as light ripples outwardly. This changes with the distance away from the plant. Ideally, the higher the better but a single measurement won’t tell you much– you want the average taken from many measurements throughout the coverage area.
Photon efficacy is a way of defining how good a lighting fixture is at converting the electrical energy into PAR light that your plant can actually consume. This is not often listed in the spec sheet for most lights. Instead, most light manufacturers list the wattage, either total electrical watts or watts per square foot. Knowing the wattage is good to budget the main cost of your indoor cannabis grow. But the wattage doesn’t give the best information about the quality of light as watts are a measurement of the energy coming into the light fixture (from your electric bill) where photon efficacy is how good the light is at giving your plant energy.
We suggest paying attention to whether or not the company you want to buy a light from lists the actual wattage or the watt equivalent. (Hint: if they are only disclosing the watt equivalent, the light is most likely not strong enough for cannabis.)
LED wattage and incandescent wattage aren’t the same.
Many LEDs are marketed with their “incandescent equivalent” wattage, referring to the brightness of the LED. For example, a 10 watt LED may say “75 watts” on the package and in fine print say that the brightness is equivalent to a 75 watt incandescent. But for growing cannabis, you’re going to want an actual real 75 watts (or higher!) from your LED lamp .
Can I give my weed plant too much light?
The answer in fancy, science talk:
Effectively, within the range of practical indoor PPFD levels—the more light that is provided, the proportionally higher the increase in yield will be. Therefore, the question of the optimum LI [light intensity] may be reduced to more practical functions of economics and infrastructure limitations: basically, how much lighting capacity can a grower afford to install and run? – Victoria Rodriguez-Morrison, David Llewellyn , and Youbin Zheng
In plain English:
No, not really! For a vegging photoperiod cannabis plant, you will want to give her a minimum of 18 hours of light a day– some give 20 hours or even keep the lights on 24/7. We know that a lot of good growth happens during the dark period when the cannabis plant has time to rest so we suggest either a 18/6 or 20/4 light cycle for photoperiod cannabis in the vegetative stage.
Same goes with autoflowering cannabis, with an autoflower seed indoors, you’ll want to give it 20 hours light / 4 hours darkness each day.
When it comes to using light to maximize yield, maximize the light intensity to meet your budget.
Grow Less Cannabis Plants to Get More Weed
In some ways you may think that if you pop more marijuana seeds or get more clones that you will get a bigger harvest in the end. This is not always true.
Each cannabis plant wants her own space. Planting more than one seed in a pot leads to competition between plants for the shared nutrients and reduced yields. As seen in this photo below where two seedlings starved each other and both ended up dwarfed:
The size of the container that you grow your pot in matters, too. Outdoor plants have the potential of reaching extreme oak tree size when planted directly in good soil (which can be hard to find) and allowed to flourish in an open, sunny space. Indoor cannabis plants, become much like a goldfish in either a fishbowl or an aquarium or an ocean, you will grow a different size plant from the Mini Complete Pot Grow Kit (1/2 Gallon) to the Medium Complete Pot Grow Kit (5 gallon) or the Large Complete Pot Grow Kit (35 gallon) . The bigger pot, the bigger plant (and the more pot).
Growing in a grow tent, consider the total space as well as the size of your containers. It may sound like a good idea to pack a small 24’’ x 48’’ x 60’’ tent with as many pots as possible but this will limit the canopy space for your plants to fill. Best to give each pot space for the plant to fill out.
Growing less plants means:
- A longer vegetative stage. This means bigger plants. Bigger plants have bigger harvests and higher yield. When growing photoperiod cannabis indoors, it is time to transition your tent to flower when the tips of the leaves of each plant begin to touch. More plants touch each other faster.
- Less plants to manage! You know each one personally and can tell when even the slightest thing is off which means you can catch pests and diseases before they become a major problem. This also means that you will have more time for defoliation and advanced pruning techniques to maximize your yield!
In the same space with a 600 watt HPS lamp, you can either get 37.5 grams from 16 plants, 150 grams from four plants, or a pound from one single plant! Don’t compromise on plant density; the more space you give a single plant, the more she can blossom.
Best Grow Mediums to Maximize Harvest
Yield can also vary based on the particular grow medium you use. It has been clearly documented that using hydroponics to grow marijuana can result in 20 percent more yield compared to using soil indoors.
Hydroponics increases yield because it is the most efficient way to feed plants. The grower supplies all the nutrients that the plant would naturally need to find for herself in the soil.
But, hydroponic systems are also 1) more expensive to set up and run, 2) can take time (like several runs) to dial in a nutrient feeding schedule and 3) can go wrong if your plants are fed too much.
At the simplest level, fertilizers come in varying NPK (Nitrogen, Phosphorous, and Potassium) formulations. Fertilizers that are richer in nitrogen are ideal for the vegetative phase, and those richer in potassium are better suited to the flowering phase. Growing hydroponically you need to know which nutrients your cannabis plants need during their different stages of growth and have that ready.
Whether you opt for organic, inorganic, or a mixture of the two is more of a personal decision. The important thing is that your marijuana plants receive enough nutrients to give you a higher yield per plant, but never too much. Unlike light intensity, there is a sweet spot for nutrients when it comes to growing marijuana. Too much of a good thing can negatively impact your plants. Unfortunately, finding the right balance between enough nutrients and excess nutrition usually comes with experience.
Soil grown marijuana can pull down some epic yields as well. But not all soils are created equal. For example, one person growing marijuana in loam soil may have a richer harvest since loam soil is easy for the roots to penetrate. On the other hand, clay soil could lead to a dismal yield since it doesn’t easily drain and can be quite compact, making it difficult for cannabis roots to grow.
That’s why a Pot for Pot specially formulated our Superb Soil to contain just the right amount of nutrients to maximize cannabis growth. With a Pot for Pot kits, there’s no need to add additional fertilizer because their soil has everything your plant needs from seed to harvest . It isn’t just easy to use, it’s optimized for marijuana growth.
Our complete grow kits include everything you need to go from seed to your very own supply of high grade medical cannabis.