So, you’ve decided to embrace your green thumb and try your hand at growing marijuana indoors. Choosing to grow marijuana is not as easy as going to the store, picking up a seedling, and tending to it the way you would other plants. Growing cannabis is a nuanced art that requires patience and practice, can be extremely rewarding.
In this article, we’ll break down the basics of how to grow marijuana indoors. Even if you have absolutely zero growing knowledge, by the end, you’ll understand where to begin and how to make all of your grower dreams come true.
Post updated: April 9th, 2020
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Choosing Your Strain and Buying the Seeds
Growing cannabis indoors requires a series of choices, and the first decision you’ll need to make is which strain you want to grow. You may already have a particular strain in mind, in which case, you’ll need to find an online seed bank that sells that strain. If you’re not committed to a specific strain, then luckily, it’s easy to browse online and find a seed that you think will work for you. When shopping online seed banks, it’s important to learn how to navigate the world of buying cannabis seeds online.
The first decision you’ll want to make is are you going to grow an indica strain, a sativa strain, or a hybrid of the two.
Once you’ve made that decision, you’ll see there’s another big decision to make when buying seeds. You’ll notice that they usually come in three options: feminized seeds, autoflower seeds, and regular seeds.
Simply put, feminized seeds are seeds that produce all female plants. Since female cannabis seeds are the ones that produce buds, buying feminized seeds takes the guesswork out of how many of your seeds will actually produce potent cannabis plants. A lot of growers prefer feminized seeds because they save a lot of time and money in the early stages of the marijuana growing process. If you’re buying your seeds from a reputable seed bank, you can almost always guarantee that your feminized seeds will flower the way that they should.
Auto-flowering seeds are easier to grow because they germinate quickly and do not require as much light as other types of seeds. They are an excellent choice for beginner growers who want to test the waters with their first harvest before committing to more complicated strategies. These seeds tend to vary in quality, depending on how they are bred. Some products have incredibly high and bountiful yields, while others might not bloom at all.
Regular seeds are seeds that you find that were shed from naturally growing cannabis plants. These seeds tend to be purer in their chemical makeup since it’s unlikely that they’ve been inbred or backcrossed with other types of seeds. They also take a slightly higher learning curve to get right the first time since you are taking a gamble at whether or not they will produce buds. Only female marijuana seeds produce buds or marijuana flowers, so when you plant regular seeds, it’s best to plant a large quantity since there’s no telling how many of them will actually flower.
When shopping for cannabis seeds online, look for sites that take secure payment options that you have available to you. Most online seed banks only accept credit or debit cards and, in some cases, certain types of cryptocurrency. It’s always risky to send cash when dealing with cannabis seeds.
For more information and recommendations of our favorite online seed banks, check out our full post on the best online seed banks that ship to the USA.
Ordering seeds online always poses the risk that your seeds will be confiscated by customs or get lost before they make it to you. Most trusted sites like ILGM will gladly replace your lost seeds if you find your seeds missing in action.
Set Up Your Grow Space
Once you order your seeds, it might take up to a month for them to arrive. In the meantime, you should start setting up your grow space. Depending on how much space you have, you can choose between various types of grow tents or grow boxes. Your grow room doesn’t need to look like what you imagine to be a typical grow room, like the ones you see on TV or in movies. Any small space, like a cabinet, closet, or spare room, will suffice. However, much space you have will determine the kind of equipment you buy, and even how many seeds you can plant.
You can also create a growing space with many different budgets. Some growers set up their grow areas for as little as $100, while others with larger budgets can end up spending thousands on their grow rooms.
If it’s your first grow, try to start small, but create a space that can grow with you. Even if you have a lot of space, it will take some trial and error before figuring out the right set up for you. That way, you won’t end up spending a ton of money when you may not entirely like the first set up you use.
To start, you don’t need the most advanced setup to be able to get good results. But when it comes to the tools you need to set up your grow space, some items are non-negotiable. Things like grow lights, a cannabis growing medium (like soil or hydroponics), and proper ventilation are absolutely necessary to make sure that your plants grow successfully.
Choosing A Grow Medium: Soil vs Hydroponics
If you ask experienced cannabis growers about their medium of choice, you might notice some polarizing debate on the pros and cons of each. The two most popular grow mediums for growing marijuana indoors come down to soil and hydroponics. While we don’t think that one is inherently better than the other to produce healthy buds, they require different levels of attention, and each has its own advantages and disadvantages.
A lot of times, when talking about hydro vs. soil, people will be referring to indoor versus outdoor growing. Outdoor growers tend to exclusively use organic soil, while the majority of indoor cannabis growers rely on hydroponics systems.
However, these aren’t rules of law that you have to follow. Some indoor growers prefer using potting soil because they find that it is more natural and bountiful. If you do choose to use soil, check out our post on the best soil for growing weed. In contrast, some outdoor growers in areas with less rain will opt to use hydroponics systems to minimize the risk of their plants overdrying.
The main differentiator between the two is that plants grown in soil tend to produce much higher yields than soilless plants grown hydroponically. For this reason, using soil indoors is not always conducive unless you have a grow space with very high ceilings.
Hydroponic systems make it much easier to manage the quality control of your plants because you can control exactly how much water and nutrients they are receiving through the hydro system. It’s much more difficult to control the soil and the outcome of your plants. To learn more about the various types of hydro systems, check out our post on the best hydroponic systems for growing cannabis.
When choosing your medium, base the decision on the amount of space you have in your grow room, whether or not you want to resort to manually watering, and whether you care enough about maintaining the natural integrity of the plant that gets lost through hydroponics systems.
Using soil will maintain the natural composition of the plant, while hydroponics makes it much easier to grow indoors and grow healthy plants with the highest cannabinoid levels.
Pick Your Grow Lights
After you decide on the growing medium, the next step is to determine which type of grow lights you want to use. Light plays a huge role in the quality of our cannabis plants, so it’s important to choose the best lights that complement your grow setup. There are dozens of types of grow lights on the market, but the most common when it comes to growing cannabis are LED lights, HID lights, and fluorescent lights.
HID grow lights
HID (high-intensity discharge) lights are commonly used because they provide a great balance of energy efficiency, light output, and value for the cost. Some HID brands cost more than standard fluorescent, but they also produce more light per unit of electricity. However, they are not as energy efficient as LED lights.
LED grow lights
LED lights are some of the most widely used and talked about grow lights, mostly because they have been around for much longer. LEDs are pretty efficient and also tend to be some of the easiest lights to set up and use for new growers. One of the main drawbacks of LEDs is that they can get costly when you start dealing with large plant quantities. Overall, LED’s tend to last longer, generate less heat, and have better designs that accommodate more types of grow spaces. You can also easily find LED grow lights online and in stores.
Fluorescent grow lights
Fluorescent lights are popular among small scale growers because they are inexpensive to set up and don’t require cooling systems because they don’t generate as much heat as the other types of lights. The main downside is that they are not very energy efficient. They produce significantly less light per watt compared to LEDs and HIDs.
A few other types of lights you might come across are HPS (high-pressure sodium) lights, and incandescent lights, which both are a bit more challenging to manage for first-time growers.
If you don’t have the time to monitor your plants vigilantly and adjust the lights manually, we recommend investing in a grow light timer. Grow light timers will help you make sure that your plants are always receiving the right amount of light in the grow room, even when you’re not paying close attention.
Set up a Ventilation System
With all of the lights generating heat in your grow room, your plants will be producing a lot of Co2. You need to create a proper ventilation system to make sure that the room stays cool enough to dissipate moisture and heat that could damage your plants. Higher humidity levels can also attract pests and other harmful pathogens. Luckily, you can quickly remedy too much heat with a ventilation system, a Co2 regulator, and a proper humidifier. The easiest and most cost-effective way to ventilate your grow room is with an inline fan.
A good rule to follow is that your fan should have the capacity to move the area’s entire volume of air every ten or so minutes. So, an exhaust fan that is installed in a 200 cubic foot grow space should be capable of moving 20 cubic feet per minute. The larger your space and the more grow lights you have, the more fans and ventilation you’ll need to protect your plants. If you’re concerned about the level of c02 in your grow room, then you can also choose to set up a carbon filter to monitor levels and filter out extra carbon dioxide.
If your space is small enough, you may be able to get away with a single fan, and just leave the door open for a few hours per day. Always remember to place your fan close to the space intake to promote better air circulation throughout your grow space.
Sometimes, if you live in a colder climate, you may face the problem of your grow room getting too cold. If the lights in your grow room aren’t enough to keep the room heated, then you should also incorporate a heater into your grow room.
Start Growing Marijuana
Once you have the grow space set up, and your seeds ready, now is the moment you’ve been waiting for. It’s time to start growing. But before you start, it’s important to know what to expect from this process.
The seedling stage is when you take a dormant seed and begin the life cycle by trying to get that seed to sprout. For the seed to sprout, you need to simulate an environment as close to the outdoors as possible. You can still sprout your seeds indoors using a controlled environment like your grow room. Once you have the seeds in your grow medium, it might take up to a week for the first seedling to sprout. To make sure that your seedling sprouts in a way that promotes future growth, we recommend starting off using a soil that has the right combination of fungi and microbes. Once the seedling is sprouted, then you can transfer them (carefully) to the grow medium that they’ll live in for the rest of the process.
Vegetative Growth Stage
Once your plants start to develop large green leaves, you’ll know that they’re entering the vegetative growth phase. During this time, the roots of the plant will begin to expand outward, and you’ll notice your seedlings growing taller.
Depending on how much light your plants receive, this stage can last anywhere from three to five weeks.
Once the vegetative stage is over, your cannabis plants will have matured long enough to produce marijuana flowers. You may start to notice your seeds blooming and even producing their own cannabis seeds that you can save and reuse.
At this point, if your grow lights have a “flowering mode,” it’s time to flip that on. If your lights don’t have different modes, then it’s time to increase the light output as much as possible. During this phase, your plants will develop faster under red spectrum lights. If you have the budget, opt for lights with specific growth phases. YOu can also just keep a separate set of lights on hand to use during this phase.
For this stage, you should use a grow light timer and place it on a 12-12 cycle. This means your cannabis plants will get 12 hours of light, followed by 12 hours of darkness daily. Also, make sure that your room is as sealed as possible during the dark hours and that no light leaks into the grow space.
You should also make sure that your plants are all receiving light equally. The lights must be high enough to evenly disperse across all of your plants evenly.
The flowering stage is by far the most critical phase of this entire process. It’s also the phase where the most can go wrong.
If your plants aren’t getting enough water, you might notice, leaves drying up or falling off, spotting or coloring. If you’re over-watering your plants and heat and not enough fresh air, you may notice mold or a foul smell is coming from the plants.
Keep a close eye on your plants at this time and adjust your lighting, fans, and ventilation as necessary. As your plants are near the end of the flowering phase, you will start to see yellowing of some leaves. This is entirely normal.
The growth stage typically lasts about two months but may vary depending on the conditions of your grow room.
Cloning and Clipping
If you plan to increase the number of plants you have, a great way to do that is to clone your current plants. After the vegetative phase, you can clip your plants and replant those sprigs, also known as cloning. If you’re confident with the seedlings you’ve grown, this is a great way to avoid the seedling phase moving forward, and grow more plants, more quickly.
To start cloning, grab some high-quality gardening scissors, choose a strong stem from your plant, and clip it at a forty-five-degree angle with a sterilized cutting blade. CLean that branch of all leaves and smaller branches before you cut it, but leave the small cluster of leaves at the top of the plant. Then, keep your cuttings under low light until you notice the plant’s roots starting to develop. This process usually takes about a week.
Nourishing your Marijuana Plants
One of the final, but most important steps in the process is to make sure that your plants are getting all of the nutrients they need. Whether you’re using soil or hydroponics, you need to invest in the right plant food that will help you get the best results as possible from your seeds.
There are dozens of nutrient solutions and fertilizers that are proven to produce bigger yields, higher terpenes more potent THC in your plants, and more aesthetically pleasing flowers Depending on what your priorities are with your plants, pick a nutrient kit that meets your needs and will help you reach your goals with your plants. If you’re a new grower, there are plenty of nutrient kits that are easy to use for beginners and come with clear instructions on how and when to use the nutrients for optimal plant growth.
Growing marijuana is a long game. Even after reading a beginner’s guide like this one, it might take some trial and error until you learn the best ways to manage your plants in the space that you have. Remember that growing marijuana indoors is a huge commitment. It doesn’t matter if you’re trying to grow indica or sativa, your plants need nurturing and care, as do any other type of plant. If you put in the effort to learn as much as possible about the growing process, your plants will reflect your efforts. And of course, this process should be fun! Try not to take it very seriously, and enjoy the journey to reap the benefits of a bountiful harvest. Happy growing!
If you’d like to see a cannabis grow from start to finish, check out our Aurora Indica Grow Journal (starting with the first week).