The biggest variability in how long a marijuana plant takes to grow will happen in the vegetative stage—after the seedling phase and before flower.
But the benefits are great: LEDs last much longer, use far less electricity, create less heat, and the best designs generate a fuller spectrum of light, which can get bigger yields and better quality.
For example, it takes less time to grow 3′ weed plants than 5′ plants; in the span of a year, you can maybe grow four harvests of 3′ plants, or two harvests of 5′ plants.
Although it’s more resource-intensive than growing outdoors and you will likely have to spend more money on utilities to power equipment, you can control every aspect of your grow environment and what you put in your plant, allowing you to dial in your setup to grow some primo weed.
Growing weed indoors is great because you can grow it any time of year and you’ll have complete control over the plant and what you put into it. Live in an apartment or a small house? Don’t worry, you can grow weed practically anywhere, even if you don’t have a backyard or a lot of extra space.
Indoor marijuana grow timeline.
For most first-time gardeners, we recommend buying a quality potting soil that will provide your plants with enough nutrients to get them through most of their growth cycle without having to add many amendments or liquid nutrients. This pre-fertilized soil—often referred to as “super-soil”—that can grow cannabis plants from start to finish without any added nutrients if used correctly.
For the most part, weed prefers these temps at each growth stage for optimal health:
You can make this yourself by combining worm castings, bat guano, and other components with a good soil and letting it sit for a few weeks, or it can be purchased pre-made from a local nursery or grow shop.
For a root system to develop and thrive, they will need the following:
Weed plants need different amounts of light during their vegetative and flowering stages. You don’t have to worry about this in an outdoor setting—the sun and the season dictate this—but when growing indoors, you will be controlling it.
If you’re growing in a cold, wet basement, you might have to run a dehumidifier or heater to stabilize the environment. Conversely, if your space is too hot, you might need to add extra fans or an AC to cool the plants down.
Controlling temperature in your indoor grow room or cannabis garden can be achieved by manipulating these factors:
Check out our Guide on nutrients for more info.
The two main types of HID lamp used for growing are:
A lot of people these days buy grow tents for their weed, but they aren’t necessary. You can grow in a closet, tent, cabinet, spare room, or a corner in an unfinished basement. Just keep in mind that you’ll need to tailor your equipment (and plants) to fit the space.
Fluorescent grow lights.
There should be a comfortable airflow both above and below the canopy, and fans shouldn’t blow air directly onto plants—this can cause wind burn, which makes leaves recede into a claw-like deformation.
Generally speaking, it takes anywhere from 10-32 weeks, or about 3-8 months, to smoke what you’ve grown. (It’ll be quicker if you start with a clone or an autoflower seed.)
The first step in odor control is making sure temperature and humidity are under control in your grow space—high temperature and humidity will perpetuate odors.
Terra cotta pots offer a unique set of benefits to growers in hot climates.
Humidity is the amount of water vapor in the air. Here are some ways to control it in your marijuana grow room:
Even in legal states, you may want to conceal your crop from judgmental neighbors and definitely from potential thieves. Growing indoors allows you to grow discreetly behind a locked door.
Many growers will start plants in a one-gallon pot and then transplant up to a bigger pot as plants get bigger. A lot of growers will transplant once, from a one-gallon to a five-gallon pot, and harvest from there. If your plants get bigger, they may need a seven- or ten-gallon pot.
Daily maintenance checklist for your indoor marijuana grow.
Plants need 18 hours of light a day when in the vegetative stage and 12 hours a day when flowering. The reduction in light from 18 to 12 hours a day is what triggers the flowering cycle—when weed plants start to grow buds.
Unlike outdoor growing, you aren’t tied to the sun and the seasons. You will be providing the entire environment the plants need to grow, including the grow medium—soil, rockwool, etc.—and regulating the amount of water and nutrients they receive, as well as controlling temperature, humidity, and more for them.
You can let your plants get as big as you want, and can control when they flower and when you harvest, and you can start another batch right away or whenever you want. You can grow any time of year, even straight through winter or summer, and you’ll get consistent crops each time.
Carbon filters usually work best when positioned at the highest point in your grow space, where the most heat accumulates.
Proper air circulation will help maintain temperature and humidity, and also bring down odor. Ideally, air needs to move through a garden every few minutes, and you should create a vent to the outside. Oscillating fans, and intake and exhaust fans can move air through your garden quickly, taking odors out with them.
Getting the right climate for your plants can be a delicate balance involving multiple pieces of equipment and also lots of electricity. This is part of what makes growing weed indoors more expensive than growing outdoors.
If your space is too humid, you may need to invest in a dehumidifier—also known as “dehueys.” However, keep in mind that while dehueys will reduce humidity, they typically increase temperature—you may need more fans or an AC when adding a dehumidifier.
Fans should be positioned to provide direct, even airflow throughout the garden. This typically involves using multiple fans that work together or fans that have oscillation capabilities.
If you use organic soil, all you’ll really need to do is add water, Johnson says — but don’t overdo it. The number one mistake he sees new growers make is watering their plants too often. In general, “watering every day is too much. The rule is, if you pick up your plant, and the pot is heavy, then it has a enough water. If it’s light, it’s dry, then you need to water.” You could also stick your finger knuckle-deep into the soil; if it feels dry, add water.
Since clones come from plants that have been grown indoors, let yours chill in a shaded area for a week before exposing them to full sun, Johnson says. “The clone hasn’t tasted sun like that, and the transplant itself will be stressful.”
Cannabis plants can be either male or female. Female plants yield the plump flowers, a.k.a., “buds,” that we know and love, brimming with psychoactive compounds like tetrahydrocannabinol (THC, which gets you high), Modern Farmer explains. Male plants yield much smaller flowers, which people typically don’t consume. In other words, if you want to actually indulge in your crop, you’ll want female plants.
Cannabis cultivation laws vary widely state-by-state. Also, we can’t stress this enough: Growing cannabis is illegal in a lot of places, and the penalties — which include steep fines and prison time — can be much worse than possession, since growing can imply an intent to distribute. Black and brown folx need to be especially scrupulous about heeding these rules, since law enforcement targets us way more than white people for weed-related charges, even if we consume it at similar rates.
Your cannabis will be ready to harvest at around October. You’ll know they’re ready when the buds “start to get really, really swollen and packed pretty tight,” Johnson says. But it can be hard to tell if you’re a beginner. Many growers say that if you think your plant is ready to harvest, wait two weeks, since many newbies tend to harvest too early. Or, you could share a photo of your crop on a forum and ask more experienced growers to weigh in.
Whatever you do, don’t plant your clones in the ground. They’ll run rampant, and “you’ll have pounds of weed in your house,” Johnson says, recalling the trays of weed atop his kitchen table when his crop grew wild. “You don’t need the stress of plants getting out of control, growing over your fence.” If your neighbors can see them, they might complain about them, and having too many plants could get you arrested.
While you can absolutely grow cannabis indoors, outdoor cultivation is much simpler and cheaper, says Ron Johnson, author of How to Grow Organic Cannabis: A Step-by-Step Guide for Growing Marijuana Outdoors , who also runs the website The Cannabis Gardener. “The sun is free,” he tells Mic. “You don’t have to pay hundreds of dollars a month in electrical bills.” An outdoor garden probably won’t allow you to turn over product fast enough, but it’ll suffice if you just want to grow weed for yourself. Plus, it’s gentler on the planet.
When the pandemic hit, many of us turned to quaint pastimes to soothe our existential dread, whether it was baking sourdough, knitting, or doing jigsaw puzzles. If you want to expand your repertoire of distraction methods with an activity that still has that quiet, homey vibe, but with a bit more of an edge, consider growing your own weed.
Don’t go overboard, though, he warns. Start with growing three plants in five-gallon pots. This way, if one dies, you’ll still have two plants, and the pots will limit their growth. A general rule of thumb is that they’ll grow one foot for every gallon of soil. He recommends mixing your own organic soil, which he explains how to do on his website and will save you the headache of adding nutrients or pH testing. “The soil is what we call alive,” he says. “It’s always breaking things down to replenish nutrients that are missing.” But if you can’t mix your own soil, or don’t feel like it, you could buy organic Pro-Mix soil, which Johnson says many outdoor growers use.
There are different harvesting methods, but Johnson cuts the whole plant at the base and hangs it upside down with some twine in a dark room at a temperature of around 70 degrees Fahrenheit. Add a fan for airflow — you definitely don’t want the room to be humid, which will cause mold to grow, rendering your crop unusable. It’ll probably take around a week to dry.
Do your homework and read up on the laws in your state. Some states prohibit growing cannabis, while others, like my home state of California, permits anyone over age 21 to grow cannabis, but only up to a certain number of plants. NORML has a pretty in-depth guide to the laws in each state. Colorado, Oregon, Nevada, Vermont, and Maine also allow cultivation, but again, the specifics depend on the state. Definitely clarify what your rights are before you start the glorious path to at-home bud gardening.
If you buy seeds from a seed bank, look for those labeled “feminized” to ensure they give rise to female plants, Johnson says. But if you’re a total newbie, he suggests buying clones, which are cuttings from a “mother” female plant, available at some dispensaries, as well as at nurseries. Not only are they easier to obtain, “they’re easier to grow. You get a clone, and you transplant it to some soil.”
Johnson notes that the outdoor grow season lasts from around April to October, meaning if you plant seeds now, they’d still yield flower, but not much. Since it’s late in the season, he suggests buying a large clone, which will have more branches and therefore yield more flower.
That said, when your plants are fully flowering, you might find yourself watering them daily, based on these indicators. When you do water them, keep going until you see water running off the soil, to ensure the water reaches all of the soil in the pot.
To check if your cannabis is ready for trimming, perform a break test on each branch. If it bends so much it nearly breaks, then it’s ready, and if it breaks right away, it might be overly dry, but still totally usable. Trim off the buds and seal them inside a mason jar for curing, opening it periodically over the course of about four weeks to let moisture escape. Johnson outlines a detailed schedule on his website, including instructions on how to look for mold.
Once you’ve cured your cannabis, sprinkle some bud in a bowl, or whatever your preferred method of imbibing might be, and savor your hard-earned crop.
Before you get started.
The health of your garden is completely dependent upon the environment you create and the equipment you select. It is easy to buy a new line of nutrients, but much more difficult to replace an undersized air conditioner. Careful planning prior to your grow will go a long way in saving you from expensive mishaps.
AC systems maintain temperature and also dehumidify rooms. Fluctuations in humidity can affect plant health and should be controlled using a dehumidifier or humidifier, depending on conditions.
Indoor cannabis cultivation is a rewarding endeavor that basically can be done in any climate. Growing pot takes attention to detail and the right equipment, time, and money, but the benefits reaped from growing your own weed are more than worth the time and expense. Not only is the practice of gardening itself therapeutic, it also lends a connection to the plants that cannot be experienced outside of a hands-on approach. Having trained and grown out a favorite cultivar to fruition is one of life’s great joys for a marijuana enthusiast.
With lighting, AC, and other environmental controls in place, indoor cannabis plants will require large amounts of fertilizer or nutrients throughout their lifespans. Hydroponic systems lack the base nutrients that occur within soil; that leaves it up to you, the grower, to feed their plants with nutrient concentrations — the exact formula of which depends upon plant variety and phase of cultivation. With hydroponics, salt-based nutrients typically come in the form of a concentrated liquid or dry soluble powder that can be mixed with water.
When it comes to cultivating cannabis indoors, you need to be sure to provide your plant with the optimal temperature, humidity, air circulation, CO2, and nutrients.
Tips for success.
Light-emitting diode (LED) lights are another form of high-intensity lighting that have been growing in popularity as their technology has advanced. LED lights produce a spectrum suited for all phases of plant life. They typically cost more than other grow lights, but they last much longer, are more energy efficient, and give off a lot less heat than HID lighting.
The first step in creating a proper indoor growing environment is to decide on the medium and irrigation methods you’ll be using to supply your plants with the proper nutrients throughout their growth cycle. The medium is a shelter for your plants’ roots that retains moisture. The irrigation method is the way you deliver nutrients to the plants.
Correct lighting is crucial, as it drives photosynthesis. In other words, your plants will not grow properly without proper lighting. Photo by: Gina Coleman/Weedmaps.
A recirculating system collects the nutrients and water that are used, replenishes them, but with a smaller amount of fresh nutrients, then reapplies the solution to the plants the next time the plant is fed. A grower will check the solution’s pH before and after adjusting the nutrients.
Soil is a great choice for beginners. It can be much more forgiving and requires less precision when watering and feeding plants. Less-frequent watering and a stable pH foundation can drastically increase the likelihood of a successful first harvest. Soil also contains beneficial microbes and nutrients that help keep plants healthy, though it also creates favorable conditions for pests, mold, and mildew to spread. Working with soil and hand-watering plants can also be messy, but it will allow you to get familiar with the pace in which your plants consume water and nutrients.
Ultimately, the costs of equipment and recurring utility bills are more expensive than in outdoor and greenhouse settings. However, specialized indoor cultivation equipment allows cultivators to achieve multiple harvests per year and a more reproducible product. If you’re detail-oriented and technologically inclined, indoor gardening is a fun and rewarding pastime, or could even be a full-time job.
Aeroponics are hydroponic systems in which the roots are suspended in air and lightly misted with a nutrient solution on regularly timed intervals. This method can achieve faster growth rates while using less water and nutrients than other hydroponic systems, though this is considered of the most advanced methods of growing hydroponically.
Ebb and flow systems, also known as flood and drain systems, are a popular type of recirculating system that uses a pump to bring water and nutrients from a reservoir into a flood tray where the plants are positioned in their grow medium. The nutrient solution floods the tray and gets absorbed by the roots and medium before slowly draining back into the reservoir. This process repeats itself on a timer to ensure that plants are properly hydrated.
Soil can be much more forgiving and requires less precision when watering and feeding plants additional nutrients. Photo by: Gina Coleman/Weedmaps.
Other common soilless mediums used by hydroponic growers include perlite, vermiculite, coarse sand, and gravel. Advanced growers frequently mix these media in custom quantities to create blends that suit their specific growing style and environment.
Temperature and Humidity.
Unlike outdoor cultivation — where you almost always use soil to grow your plants — growing indoors offers several different options for growing systems and media. Some media are easier to work with than others, while some are a little trickier, but offer more control over the finer details. Different media retain moisture at different rates, which in turn determines how often plants need to be watered. Some media harbor beneficial microbes that can help roots absorb nutrients better.
Coco Coir is the fibrous material found on and in coconut shells. As a byproduct of the coconut industry, it is favored by growers as a sustainable and renewable medium. Coco coir is an inert medium with a neutral pH that does not provide or maintain any nutrients. These qualities are great for growers who know how to appropriately adjust pH, allowing for quick pH and nutrient changes. There may be a learning curve, but if you’re numerically inclined, it’s not too hard to get a grip on the process. Coco coir can be used either by itself or added to soil or hydroton for improved drainage and growth capability.
Whether you are growing two or 30 plants in your house, grow equipment requires a significant amount of electricity, primarily from your lighting and air conditioning units. Make sure that all electrical equipment is installed by a trained professional to reduce the likelihood of an electrical fire. You don’t need to be an electrician to design an indoor grow, but having a basic understanding of watts, volts, and amps is essential. The equation below can be used to determine whether your property has the minimum amount of power for an indoor garden:
Maintaining a grow journal and logging all major aspects of your grow is one of the cheapest, easiest things you can do to become a better grower. Logging daily temperatures along with water and feeding amounts will help you pinpoint problems, and may give you something to show other growers who can help you resolve issues, increase your yields, and save a troubled crop.
Nutrient Film Technique (NFT) is another recirculating system in which plants are suspended by net baskets or neoprene collars that run along a trough. A thin film of water and nutrients continually circulates through the bottom of the trough, providing food to the tips of the roots, while leaving a majority of the root mass exposed to air.
Hydroponics is a blanket term for the growing of plants in a nutrient solution, with or without an inert medium to provide physical root support. Media such as fused basalt rock and chalk (known as rockwool), coconut fiber (coco coir), and clay pellets (hydroton) can drastically improve nutrient delivery. With a plant’s roots system exposed, hydroponically grown cannabis can grow faster and more efficiently, requiring less water and fewer nutrients but also requiring monitoring systems to ensure a stable pH.
Cleanliness in an indoor garden cannot be overstated. Clean your entire grow room before your first grow cycle and after every harvest. The walls, floors, trays, irrigation lines, reservoirs, lights, and fans should be cleaned using a three to five percent (3%-5%) hydrogen peroxide solution, an efficient sterilizing agent that leaves no dangerous or toxic residues behind. Be careful what you bring into your grow room. Pets, dirty clothes, and contaminated clones can introduce unwanted pests and diseases.
How to start growing weed.
Air movement is the least expensive component of creating an ideal environment for your plants. Even a gentle breeze can help keep pests and microbes from landing on your plants, move oxygen and carbon dioxide around the leaves, and create a uniform environment throughout your room. One of the easiest ways to maintain sufficient air circulation is by hanging oscillating fans on the walls or ceiling/grow tent corners and placing a small box fan on the floor. The goal with air circulation should be to mimic a light breeze and avoid powerful gusts that may harm your plants.
Planning, designing, and implementing an indoor garden can seem daunting, but having a firm understanding of the basics goes a long way in helping a new indoor grower get started on the path to a healthy and bountiful harvest.
Most local jurisdictions require you mitigate the odor from your plants to avoid disturbing your neighbors. Activated charcoal filters absorb plant odor in your grow area. Adding a charcoal filter to your HVAC system or placing one within your grow space is a great way to drastically reduce the odor. The size of the filter is largely dependent on the size of your grow. Make sure filters are sized and installed correctly. Keep track of the life of the filter, as their effectiveness diminishes over time.
Choosing the right horticultural lighting for your indoor grow can mean the difference between success and failure. Correct lighting is crucial, as it drives photosynthesis. In other words, your plants will not grow properly without proper lighting. The duration of your lighting controls the photoperiod, or the times in which a grow is exposed to light. During the vegetative growth phase, plants need a minimum of 16 hours of light. The most common schedule during this phase is 18 hours of light and six hours of darkness. To initiate flowering, plants need a shorter day, with 12 hours of light and 12 hours of darkness.
Water quality is another key aspect of indoor gardening. It’s important to determine water acidity and general mineral content prior to planting. Checking the pH, the acidity or alkalinity of the water, is easy to do with a handheld water quality meter. The same device can be used to check the total mineral or chemical content of your water as well. Knowing these things will help you determine the correct amount of nutrients to feed your plants or if fresh water needs to be introduced.
Controlling the amount of available carbon dioxide (CO2) in your garden is another aspect of growing marijuana at home . During photosynthesis, CO2 converts into sugar, which the plant uses as energy for growing its vegetation and, ultimately, its seeds or flowers. Adding CO2 to your indoor garden can drastically improve your yields. While the atmosphere naturally has an average CO2 concentration of around 400 parts per million (PPM), most indoor growers try to maintain a range of 800 to 2,000 PPM, depending on the plants’ growth stage. Levels above 2,000 PPM can damage plants, and anything above 3,000 PPM can be dangerous to humans.
To set up an indoor garden, you will need equipment to help create a stable environment that mimics the necessary periods of light and darkness to grow plants through the flowering stage. This includes horticultural lighting, fans to recreate a gentle breeze, dehumidifiers to maintain the proper humidity, HVAC (heating, ventilation, and air conditioning), and all the basic supplies that a plant needs to survive, from water to grow media to nutrients.
Before you purchase any equipment, it is important to understand the possible limitations of an indoor garden. Consider the height of the ceiling, how much insulation your space offers, and your ease of access to electricity and water. Some local jurisdictions may also ask that indoor gardens mitigate odors during the flowering phase.