[The information in this article has under no circumstances been created for – or is intended to be used for – illegal purposes. Growing/cultivating cannabis is illegal in many U.S. states. We, therefore, advise that all readers become familiar with current laws and regulations in their region before they learn how to grow cannabis indoors].
As a potential first-time grower, getting started is the biggest roadblock you’ll likely face. First, you have to find the right place to cultivate and obtain the proper growing equipment. Then, you need to buy cannabis seeds and spend a lot of time checking and maintaining your crop.
You must also operate within the boundaries of the law before getting started. Growing marijuana remains illegal in many U.S. states. Make sure home cultivation is allowed where you live before proceeding. Assuming you are legally able to continue, keep reading our detailed guide to growing cannabis indoors.
Step 1: Choose the Perfect Cannabis Grow Room
You don’t need a particularly large growing/cultivating space. A typical grow room for a small-scale grower is a small tent, cabinet, or designated area in a spare room, even an unused corner of the house is sufficient! Here are a few helpful tips to get started.
1 – Begin Growing from a Small Plot & Adjust as Necessary
By “small,” I mean nothing more than a few plants at most. You can start with just one or two plants. There’s an inevitable learning curve involved with growing weed indoors and you’re bound to make some mistakes.
It shouldn’t take long to get the hang of things and start producing some beautiful, flowering cannabis plants, but you’ll need to make room as your plants grow. From the first signs of flowering, you can expect a plant to double or even triple in size by harvest time.
Make sure that you have enough space to work in!
2 – A Clean Space is One of the Most Important Things to Remember
Make sure your cultivating space is sanitized and clean. There’s an inherent risk posed by pests and contaminants. A messy space invites pathogens, harmful bacteria, and mold. A good idea is to plan a bi-weekly cleaning routine and stick to it.
Marijuana plants are “bioaccumulators,” which means they “suck up” everything around them (both in the air and the soil). Make sure the area surrounding the plants is clean enough to keep potential contaminants out.
3 – Keep Your Grow Space as “Light-Sealed” as Possible
Light is essential for the growing process. Your plants receive direct light the majority of the time. Be direct here: eg. plants need 12 hours of continuous, uninterrupted darkness to flower and eventually produce buds.
Like most living things, cannabis plants need their “rest time.” If light from a surrounding source is seeping in during dark hours, the (bud-producing) females could get confused and develop hermaphroditic characteristics.
A hermaphrodite cannabis plant will produce flower that’s full of seeds, ruining your chances of a decent yield of smokable buds.
4 – Successful Indoor Growing Requires the Following Features
- Choose a secure place safe away from animal and human invaders, somewhere you can monitor them regularly.
- Temperature and humidity need to be carefully and conscientiously managed.
- Make sure your spot is safe and easily accessible at any time, day or night.
Step 2: Choose (and Use) Your Cannabis Grow Lights
The light source you use in your grow room plays a significant role in determining the quality of the plants. I recommend spending a large portion of your budget on a good lighting setup. It is worth it in the end, particularly if you plan on growing long term.
Here’s a basic rundown of the most popular types of cannabis grow lights used today.
LED grow lights
If cost isn’t a consideration, LED (light-emitting diode) lighting is the preferred option for most marijuana growers. These are highly efficient light fixtures for indoor growing. They use less energy and create very little heat. LEDs produce wavelengths across the light spectrum, so they can be used for both the vegetative and flowering cycles.
The drawback is they can cost 3-5 times more than a decent HID setup! If you’re serious about getting into growing and have money to spend, however, give serious consideration to LEDs. But do your homework to avoid ‘scam’ LEDs online.
Induction grow lights
Induction lamps are an odd choice for indoor growers. However, some companies have recently adapted them for the cannabis industry. They can potentially represent decent value in terms of cost and efficiency.
Nikola Tesla invented the process of generating heat from magnetic induction in the 19th century. These types of lamps produce bright light with little heat compared to HID setups.
HID grow lights
The most commonly used lights for DIY-style growing are probably HID (high-intensity discharge) grow lights. They typically represent the best overall value in terms of cost, efficiency, and ease-of-operation.
The main drawback is that they require numerous accessories to run correctly. As a consequence, the overall cost can ramp up pretty quickly, depending on how much you’re willing to splurge.
For example, most growers use one of two main types of HID lamps/bulbs depending on the developmental stage. Metal halide (MH) bulbs are best during vegetative growth. High-Pressure Sodium (HPS) is the preferred option for the mature flowering stage. If you can only afford one, choose HPS as they are much better for flowering and are more efficient on a ‘watt-to-light’ scale.
HID lights produce a substantial amount of heat. Therefore, proper use of air circulation and conditioning becomes vital. Some growers choose air-cooled fixtures to mechanically remove heat.
Fluorescent grow lights
Fluorescent lights are generally much cheaper and easier to use than the other options. They represent an excellent option for propagation of young plants or those with extremely low yield expectation. And remember: watts = grams. Low wattage will not prevent you from growing potent little flowers. They also don’t require a connection to an external ventilation system. Fluorescent lights are far less powerful than the other options. However, for novice DIY growers with a single plant or two and little space, they might be your best bet.
Step 3: Fresh Air is the Lifeblood of Healthy Cannabis Plants
Make sure you have consistent airflow across your entire plot. Depending on the size of your grow room, you can achieve this easily. Utilize several types of fans, including oscillating wall mount, stand fans, and box fans. Place them strategically to create good air flow throughout the space.
Since warmer air rises, mount your exhaust fan(s) high so they can suck out hot, stagnant air. On the flip side, your intake fan should be mounted low so it can provide a good supply of cool, CO2-filled fresh air. This technique allows for a constant supply of fresh air for your plants. It also helps keep temperatures to a manageable level.
Most cannabis strains prefer an upper-temperature range between 75- and 85-degrees Fahrenheit. When the lights are off, keep room temperature between 55 and 75 degrees. Indica strains tend to prefer the cooler end of the range.
Step 4: Develop a Control System and Monitor the Growing Process
The next step is a self-monitoring system to control it all. We assume you can’t spend 24 hours a day in your grow space! You need a 24-hour timer and an adjustable thermostat. The latter allows you to set your exhaust fan to switch on once temperatures go above a certain degree. The result is a relatively stable temperature range and humidity level while saving energy and money.
The 24-hour timer is just as important. When the marijuana plants are in vegetative growth, you need the light supply on for around 16-24 hours per day. Once they mature and reach the flowering stage, your plants need 12 hours light and 12 hours dark.
We also recommend investing in a pH meter to check on the quality of your water and soil regularly. If you’re growing in soil, try to keep the pH between 6 and 7, with the sweet spot being 6.2-6.5. If you’re growing hydroponically, 5.5 to 6.5 is an appropriate range with the sweet spot of 5.8-6.0.
Homegrown CannabisCo are the masters when it comes to seeds. Offering a massive variety of cannabis seeds that are well categorized, not only does this company create a resource for superb quality options including feminized seeds, it also provides extensive growing information for those looking for some support along their journey.
Step 5: Be an Artist! [And Choose a Cannabis “Grow Medium”…]
When cultivating cannabis indoors, there are two viable options: Growing in traditional soil or a hydroponic tray. Soil is typically recommended if you’re growing indoors for the first time. It’s cheaper, more straightforward, and more forgiving than an advanced hydroponic system. Let’s take a closer look at each of the two options.
Soil vs. Soilless Growing
Soil is less expensive, easier, and offers a higher margin of error. However, you need to carefully select the soil you use because quality can vary enormously.
General potting soil doesn’t work very well. You want a high-grade horticultural potting mix, which is light and airy. Some mixes come “charged” with a small amount of nutrients to get you through the first few weeks. However, these will need regular fertilizing later.
Other mixes are “neutral,” without any nutrients present. These mixes need appropriate amounts of fertilizer right from the start. Amendments to soil ingredients include compost teas and mycorrhizae bacteria, as well as other organic compost nutrients.
Another idea is “all-in-one” automated hydroponic setups, which may help you experience faster growth and more abundant yields. This is only the case if everything is done correctly – all the time, every time (unlike soil which has natural buffers to give you some wiggle room).
A hydroponic system delivers all necessary mineral salt nutrients to plants in water. If you want to choose hydroponic over traditional soil, there are several types which are straightforward and fairly easy to understand. These include Ebb and Flow, Flood and drain and DWC or Deep Water Culture.
Step 6: Choose a “Canna-tainer” (Container) to Grow Your Cannabis In
It’s very important to grow your cannabis plants to a size suitable to your space and likewise to the container you choose. You will need to transplant every time your plants double to triple their size. Small cups or 4-6” pots are good for starts.
Think about how big you ultimately want to grow your plants when deciding on pot size for their final home. I suggest one-gallon of soil for every foot tall you intend to grow them. Regardless, plants don’t like waterlogged conditions so perforate the bottom of the bucket so the water can drain as needed.
There are some outstanding pre-filled soil kits specially designed for increased airflow. Keep these in mind when deciding what to grow your first cannabis plants in.
Step 7: Show Your Cannabis Plants Some Love (By Giving Them Lots of Nutrients)
Ensuring your plants get the right nutrients is probably second only to lighting in terms of importance. Proper nutrient selection and application are among the most critical factors in growing premium-grade cannabis. While weed is resilient, growing it in sub-optimal conditions means you will miss out on yield and potency.
Whether you’re using an organic soil mix or growing hydroponically, your cannabis plants need the “super seven” macronutrients. In no particular order, these are:
- Nitrogen (N)
- Phosphorous (P)
- Potassium (K)
- Calcium (Ca
- Magnesium (Mg)
- Iron (Fe)
- Copper (Cu)
You can get these macronutrients pre-packaged in liquid or powder form (if you’re using an un-supplemented soil mix). However, a lot of organic “super soils” already contain them in sufficient amounts.
Lastly, some strains indeed require more calcium than others to produce robust, healthy nugs. Perform a little research on the particular strain you are growing. This process enables you to become more familiar with the kind of “food” it needs and prefers the most.
Step 8: Cannabis Plants LOVE Water!
A common assumption amongst rookie plant growers is that the more you water, the better.
While this is true to an extent, there is such a thing as “too much water.” Overwatering your indoor cannabis plants can prove detrimental to their productivity, and potentially stunt or kill them!
The frequency of watering and the amount you give is determined by a few obvious things. These include the size of the plant, the stage of development, and the rate of photosynthesis (how fast it’s growing). However, there’s no exact science when deciding how much water to give and how often.
Make sure there are holes drilled into your growing container so the water can drain out. When watering, try, and only moisten the soil rather than saturating it. This allows you to fully saturate the pot without overwatering. Try not to water until they’re almost dry. This is called cycling.
Lastly, consider using an RO filter as excess levels of chlorine and unfiltered minerals could harm the plants. You may want to choose a distilled option or at least filter it before adding it to your soil. Mineral-laden tap water can cause unwanted build-up in the cannabis root systems, which can lead to detrimental root disease.
Step 9: Set Time to Care For Your Plant (Every Single Day!)
DIY indoor growers are unable to perform a 24/7 watch over their plants. However, you can provide adequate care by setting aside a few minutes a day. Routine checks, such as ensuring things like temperature, humidity, pH, and water levels are correct, are essential.
Also, watch out for male plants in your crop. If you wish to grow high-THC buds, the only thing you want in your crop is female plants. If you have a male in your crop, REMOVE IT. Once it reaches maturity and its pollen sacs burst, it fertilizes the females. At this point, they’ll start developing seeds rather than growing buds. While the plants won’t die, their ability to yield buds is ruined.
If you don’t know how to tell a male cannabis plant from a female, we’ve got a great article on the topic.
If you’re growing from seed, you need to wait until the flowering stage. After a week of nighttime photoperiod, the plants will start reaching maturity and will develop reproductive parts at the nodes.
This is when you can extract the male plants and eliminate them. Male plants will have what look like little clusters of bananas; these are the pollen sacs. Female plants will have sharper early-stage calyxes with white hairs (pistils). Those growing from female clones or pre-purchased feminized seeds should have no concerns about male plants.
Step 10: Cut Your Cannabis Plants Down — Carefully!
The final step involves harvesting your plants. Once you get used to the process, you’ll find it more enjoyable than tedious.
The first step is to cut off the big water leaves, otherwise known as the fan leaves. They have minimal THC in them and are generally removed. You’ll notice a visible difference between the long, green fan leaves and the smaller sugar leaves. The latter is covered in resinous glands (trichomes).
Some people like to grind the sugar leaves and use them. However, it is all about the clean, leafless nugs if the goal is to fully enjoy an intoxicating high. You can use the sugar leaves to make cannabutter, however. After trimming, you should hang the buds up to dry. After 7-10 days, you can place them in airtight containers to cure. The more patient you are, the better the buds will taste. They are also more potent!
Final Thoughts on Growing Cannabis Indoors
Harvesting hemp and cannabis is a lovely experience. It is one we recommend to any weed lover who has a passion for all aspects of the plant. You learn so much about cannabis and botany/biology in general. Most growers believe they learn something new with every harvest.
There’s no doubt a bit of a learning curve involved. You’ll make your fair share of mistakes. However, trust us when we say it’s all worth it in the end.
Enjoy, and more than anything else; remember to HAVE FUN!