Welcome to the Skunkology beginners guide to growing weed indoors! This guide is exactly what you need if you're thinking about attempting your first grow or you just want to get a feel for what's involved. We'll cover everything you need to know including equipment, where to get seeds, hydroponics, growth mediums and much more. Let's get started!
The advantages of growing weed indoors
- You can grow bigger buds because you have total control over the growing conditions including light, humidity, temperature and nutrients.
- You can grow more quickly because you leave your grow lights on for 24 hours a day during the vegetative growth stage.
- There's no seasons to worry about to growing indoors means you can have multiple harvests per year.
- Pests and insects are way less of a problem.
- Growing weed indoors is more stealthy (as long as you control the stink your plants produce).
The disadvantages of growing weed indoors
- Growing weed indoors is more expensive because you need electricity to run grow lights and you need to control the temperature and humidity of your grow room.
- Space for growing indoors can be hard to find.
- Some folks think that growing outdoors is more 'natural' and they value the natural process of sunlight, soil and water. Studies also show that photosynthesis works better with natural sunlight.
Check out our beginners guide to growing weed outdoors if you think that might work better for you.
How long will it take to grow weed indoors?
This is a tricky one to answer and depends a lot on the strain you're growing, the humidity and temperature of your grow room and how big you want your plants to grow.
Length of the germination and seedling stage
- Seed germination takes between 2 and 5 days but for some strains it can take up to 2 weeks.
- The seedling phase can last anywhere between 1 week and 1 month.
Length of the vegetative stage
The vegetative stage is where your plants use all their energy to grow more leaves and get bigger and bushier.
- When growing weed indoors, the vegetative stage can last between 3 weeks and several months.
Length of the flowering stage
- The flowering stage can last between 6 weeks and 5 months and depends a lot on the strain of weed you are growing. On average, most strains flower for around 8 to 14 weeks
One big advantage of growing weed indoors is that you can trigger the flowering stage and start growing buds whenever you want! In the vegetative stage, many growers leave their grow lights on for 24 hours a day to get maximum growth. The flowering stage is triggered by switching the lights to a 12 hours on and 12 hours off schedule. Speed and size is a trade off because triggering the flowering stage earlier means smaller plants and a smaller yield of buds.
If you buy your seeds online, they normally include instructions that tell you how long you should flower your plants before harvesting the buds.
Length of the drying and curing process
Once your buds have been harvested, they need to be dried and cured. The drying process takes between 3 and 7 days and curing takes a minimum of 1 month.
Soil vs Hydroponics
Before starting your first grow, the biggest decision you have to make is whether to grow in soil or use hydroponics. Many people assume hydroponics refers to complicated water bath systems but it actually refers to any type of growing system that doesn't use soil. With hydroponics, you have to provide 100% of the nutrients your plants need when you water them.
Growing your plants in pots using soil or potting mix is the easiest way to go. You still need to provide your plants with some nutrients but they get a lot of what they need from the soil.
There are lots of different types hydroponic indoor growing systems but they all fall into two main categories.
Hand watered hydroponics
Your plants are grown in pots but instead of soil you fill them with an inert growth medium (like coco coir) that contains no nutrients. Nutrients are added to the water supply when you hand water the your plants. Hydroponic growth mediums are discussed in more detail below.
Water bath hydroponic systems
Hydroponic water bath systems are a more advanced way to grow. There many systems available that use different methods of circulating water around so the plants can extract the nutrients. Popular methods include Deep Water Culture, Aeroponics and flood & drain systems.
Read our article to understand more about how hydroponics works and the different techniques in use.
We've also reviewed all the best hydroponics systems for 2017.
Advantages of hydroponics
- You have total control over the nutrients you give your plants which makes it easier to keep them healthy
- Hydroponic systems can be automated for a hands free grow
- Your plants grow much more quickly during the vegetative stage so you get your buds faster!
What equipment do I need for growing weed indoors?
Before making decisions on equipment, you’ll need to pick a space to grow your weed. The size of your space will determine how many plants you can grow. It could be a closet, an entire room, part of your garage or shed, or even an extra bathroom. As long as you have access to power for lighting and water, anywhere is fine!
Once you’ve picked your space, you’ll need the following equipment.
1. A grow tent or grow room
By far the best option for beginners growing weed indoors is to use a grow tent. Grow tents come in different sizes and we recommended you get the biggest one that will fit in your space so you have room to expand.
Read our article here on the best grow tent for growing weed.
2. A growth medium
Next you’ll need to choose what medium to grow your weed in.
Soil is needed if you're not using a hydroponic system. We recommend both FoxFarms and Roots Organics.
To learn more you can also check out our article on the best soil for growing weed where we review all the soil mix options and soil additives.
Hydroponic growth mediums
If you’re growing hydroponically either in pots or using a water bath system, you’ll need a soil free medium. There a lots to choose from and each has advantages and disadvantages. The most commonly used are:
- Coco coir
- Jiffy pellets (Peat pellets)
- Rockwool cubes
- Clay pebbles
To understand the advantages of each time and get product recommendations, read our article on hydroponic growing medium alternatives.
Note: If you’re using a hydroponic kit, the growth medium is often supplied with the kit.
3. Pots & containers
These will be needed if you're growing in soil or using a hand watered hydro system. There are lots of different size pots available and what you choose depends on what size plants you want. The bigger the pot you use, the larger your plants will grow because there's more room for them to develop a big root system. Deeper pots will also grow bigger plants.
- A 2-3 gallon container will grow a 12” plant
- A 5-8 gallon container will grow a 35” plant
- A 12 gallon container will grow a 60” plant
Terracotta pots and plastic pots are cheap and do the job well. Fabric pots and air pots breathe well and deliver more oxygen to the roots of your plants. You'll need to water your plants more often if you go with these because they dry out more quickly.
Another option is to start your seedlings in a small cup (a disposable solo cup is perfect) and then carefully transfer them to a larger pot once a few leaves have grown. Starting your plants in a smaller pot will speed up the growing process.
4. A hydroponic setup
If you decide to grow using water bath hydroponics there are lots of indoor growing systems available depending on the level of complexity and automation you want.
Read our reviews of the best hydroponic system for weed to help you choose.
5. Grow lights
You need grow lights for growing weed indoors because there's no sunlight! There are different types available and each has advantages.
LED lights are the newest type of grow light for growing weed indoors and are becoming very popular.
- Small (stealthy) panels are available that don’t produce much heat or use much electricity.
- They give reasonably good yields (probably not as good as HID).
We've reviewed the best LED grow lights for growing weed if you choose to go with LED lights.
High Intensity Discharge lights (HID)
These are still the most popular and most powerful grow lights available. The most commonly used types for growing weed are high pressure sodium (HPS) and Metal Halide (MH). HPS bulbs give a bluish light which make them idea for the flowering stage. MH bulbs give a more orange/red light and are great for the vegetative stage. Many HID lighting kits allow you to switch bulbs and use both types during different stages of the growth cycle.
- They give the best yields due to their power and natural light.
- They’re easy to use and pretty much all work the same way.
- They’re reasonably cheap.
HID lights produce a lot of heat and can use a lot or power for big grow spaces. You'll need to exhaust the extra heat out of your grow space when using bigger HID lights.
We've reviewed the best HID lights for growing weed if HID lights work for you.
Fluorescent lights are popular with growers who don’t have much space or don’t care about big yields. The most popular type of fluorescent lights used for growing are T5 grow lights.
- They’re super cheap and don’t produce much heat or use much electricity.
- They produce bushy, short plants when used throughout the entire growth cycle which is fine for growers with small spaces.
The yield for fluorescent lights is a lot less and growers often just use them during the vegetative stage and switch to HIDs or LEDs for the flowering stage.
Check out our article where we review the best T5 grow lights you can buy.
Stale air can encourage mold growth and insects if you don't circulated it out of your grow tent. Fresh air circulating into your growing area will also produce faster growing plants and bigger yields.
The combination of a fan, a charcoal filter and some ducting to a nearby window is a great way to keep fresh air circulating through your grow tent. The charcoal filter removes the stink of your buds from the outgoing air to keep your grow stealthy.
7. Nutrients and fertilizers
The nutrients your plants need depends on whether you’re growing in soil or hydroponically. When growing hydroponically you need to provide all your plant’s nutrients. Plants grown in soil get many of their nutrients from the soil.
Plants need 3 important nutrients to grow. Nitrogen (N), Phosphorous (P) and Potassium (K), known as the N-P-K scale.
Your plants need different levels of N-P-K at different points in the growth cycle.
- During the vegetative stage, they need higher levels of nitrogen (N) and potassium (K)
- When your plants shift to the flowering stage phosphorous (P) and potassium (K) become more important.
Nutrient kits always show the ratio of N-P-K on the bottle and have detailed instructions how to use them. Never over fertilize your plants as this can damage or even kill them!
Wikipedia has a good article on plant nutrition of you'd like to learn more.
Soil nutrients for weed
We recommend the Fox Farm Liquid Nutrient Trio Soil Formula when growing in soil or potting mix.
Hydroponic nutrients for weed
We've reviewed the best hydroponic nutrients for growing weed if you decide to go with a hydro setup.
In addition to N-P-K, your hydro weed plants will need lots of other micro-nutrients that are normally present in the soil. These include magnesium, calcium, iron, sulfur and zinc. Hydroponic nutrient kits contain all these extra nutrients and include detailed feeding schedules.
We think the General Hydroponics Flora series is the best hydroponic nutrient system.
8. Controlling temperature and humidity
When your plants are in the vegetative stage, they prefer a temperature between 70 - 85 degrees Fahrenheit (20-30 degrees Celsius) and humidity between 40% and 70%.
In the flowering stage, they prefer a slightly cooler temperature of between 65 - 80 degrees Fahrenheit (10 - 26 degrees Celsius) and humidity between 40% and 50%. This mimics the cooler weather that plants grown outdoors would experience towards the end of the growth cycle.
Any temperature above 80 degrees Fahrenheit will really slow down the growth of your plants and make your buds much less potent. Any temperature below 60 degrees Fahrenheit can also slow down grown and encourage mold to form.
Use a humidifier to increase the moisture content of the air in your grow space if it’s too low and a dehumidifier to remove moisture. A good ventilation system will also reduce humidity significantly.
If the temperature is too high in your grow space:
- Increase the ventilation
- Add a portable air conditioner with a thermostat to regulate the temperature. Keep in mind that air conditioners can also affect the humidity in your grow space!
If the temperature is too low in your grow space:
- Increase the power of your grow lights
- Use a heat map under your plants
- Use a portable heater with a thermostat to control the temperature
Temperature and humidity controllers are available that allow you to automatically control switching devices on and off to maintain a set humidity and temperature.
Our article on the best humidity controller for weed has an in-depth discussion achieving the correct humidity and temperature for your plants.
Choosing a strain of marijuana seeds for growing weed indoors
Almost any strain of weed will perform well when you’re growing weed indoors because you can manipulate the conditions to suit the particular strain.
Read our article here to understand the different types of weed strains.
Things to keep in mind when you’re selecting a strain are:
- Length of the flowering phase
- Type of high the strain gives
- Flavor & taste
- The size of the plants
Growers often favor indica dominant strains when growing weed indoors because they produce a shorter, bushier plant that doesn’t waste as much room by growing tall.
Wikileaf maintains an awesome database of hundreds of different weed strains.
Where can I buy seeds online?
Where to get weed seeds is a questions we're often asked. There are many places online where you can purchase quality seeds. Pick a strain to suit your climate, whether you're growing in pots or in the ground and what kind of high you’re looking for.
Some reputable online sites that sell seeds and ship worldwide include:
Germinating your seeds
Read our article to learn more about how to germinate weed seeds.
Germinate your seeds using your preferred method. Your seeds should germinate in around 2 - 5 days but some strains can take as long as 2 weeks. If you’re germinating seeds outside of the growth medium be careful when transporting for planting because they are easily damaged. Using a pair of tweezers is a good tip.
The techniques for seed germination are identical regardless of whether you’re growing in soil or hydroponically in coco or another hydroponic medium.
Planting your seeds
Planting in soil
- Make a small hole in your container about 3 times as deep as the size of the germinated seed and carefully drop it in with tweezers. The seed will naturally orient itself correctly over time so don't worry which way you drop it in.
2. Cover with soil and thoroughly moisten with water.
Here is a video demonstration of how to do this:
Planting in a hydroponic growth medium
The technique for planting in most hand watered hydroponic growth mediums is basically the same as planting in soil. Example videos are listed below that demonstrate planting in a variety of common growth mediums.
Growers often get their seeds to the seedling stage before transplanting into hydroponic growth mediums. Here’s an example of this transfer process:
The growth stages of your indoor weed plants
As your weed plant develops, it passes through several stages of growth on the way to producing smokable buds.
- The seedling stage
- The vegetative stage
- The flowering stage (buds!)
1. The seedling stage
The seedling stage lasts from 1 week to 1 month. During this time your plant develops a tiny root system and will sprout tiny round ‘seedling leaves’ that look different to the leaves of the mature plant (called ‘true leaves’).
Your plants are officially in the vegetative stage when they've grown 7 sets of true leaves.
2. The vegetative stage
The vegetative stage is when your plants use all their energy to grow stems, leaves and roots.
The main advantage of growing weed indoors is that you have complete control over how long your plants stay in the vegetative growth stage. This can drastically shorten the growth cycle and get you smoking sooner!
During the vegetative stage your plants will use as much light as they can get to grow bigger. You can even leave your grow lights on for 24 hours a day. Keep your plants in the vegetative stage for as little as 2 weeks if you only want small plants or up to 2 months or longer to grow huge plants!
If you’re growing bigger plants, pruning them during the vegetative stage can help control size, shape and yield. Pruning dry, yellow or damaged leaves will ensure the plant's energy goes into growing healthy stems and leaves. Pruning the main stem (by cutting off the top of the plant) will force the lower branches to become thicker and stronger.
You can safely prune your plants from a few weeks into the vegetative stage all the way through to the start of the flowering stage.
Your plants also benefit from high levels of potassium (K) and nitrogen (N) during this stage and your nutrient kit should be providing this mix.
Towards the end of the vegetative stage, the sex of your plants will be revealed. Hopefully, if you’ve bought good seeds or grown from a female clone, all your plants will be female.
- Read our article about the difference between male and female weed plants.
- Understand everything you need to know about growing cloned weed.
You should remove all the male plants at this stage to prevent pollination, unless you're intentionally trying to pollinate your female plants so they produce seed. When female plants are pollinated, they direct much of the energy they get from nutrients and sunlight into producing seeds instead of growing big buds!
3. The flowering stage
The flowering stage is where your female plants direct their energy into growing buds. In nature, as the seasons move towards winter the days get shorter and the nights get longer. Plants have evolved over thousands of years to detect this change and enter the flowering phase when the amount of darkness and sunlight they receive is roughly equal.
When growing weed indoors, you can trick your plants into entering the flowering stage by changing the amount of light your plants receive.
To trigger the flowering stage, simply use a timer on your grow lights to switch from 18-24 hours of sunlight to an even cycle of 12 hours light followed by 12 hours of darkness.
The length of time your plants will need to spend in the flowering stage depends on the strain of weed you’re growing. It can vary from between 6-8 weeks all the way up to 3 or 4 months.
For example, northern lights (indica) flowers for only 6 - 8 weeks and most haze strains (sativa) flower for several months.
After around 6 weeks of flowering, you’ll be able to smell your delicious buds. The ones on the outside of the plant will get bigger and more ripe first because the are receiving more sunlight. You can remove these and start the drying process but leave the less mature buds to continue to ripen.
Harvesting your weed plants
If you’re growing weed indoors from seeds you bought online, the instructions should tell you how long the flowering stage should continue before you harvest. However, you can also look at your plants and easily tell when it’s time:
- Crystals will be visible around the buds and they’ll be sticky to the touch
- The pistils on the flowers (the tiny hairs on your buds) will turn from white into a brown or red color
- Your plants are diverting all their energy into growing flowers which can make the leaves look wilted or yellow
To harvest, simply cut each branch separately using secateurs in preparation for drying.
Trimming your buds
Trimming your buds is an important step because:
- It will give your weed better flavor
- Make your buds look more appealing and professional
- You weed will be stronger because the leaves contain much less THC and CBD and leaving them on means you are diluting the strength
There is a lot of debate around whether it's best to 'wet trim' (before drying) or 'dry trim' (after drying). There are advantages and disadvantages to both techniques.
Read our article to learn more about trimming your buds as well as what is the best bud trimming machine for weed.
Curing and drying your weed
Dry your buds by hanging the cut branches by their stems in a dark cupboard between 60 and 70 degrees Fahrenheit (16 to 21 degrees Celsius) at around 50% humidity. If you live in very humid area it’s a good idea to trim all the buds away from the branches and dry on a rack. If you live in an area with very low humidity, leaving leaves on the stems along with your buds as they hang will slow down the drying process and ensure your buds don’t dry too quickly.
Use a humidifier or a dehumidifier to make your drying environment perfect. You can measure the humidity of your drying space with a hydrometer.
Your buds should dry in around 3 to 7 days. You can tell they’re dry enough when the outside of the buds feel dry and the stems snap cleanly in half when you break them.
If your buds dry to quickly, you’ll end up with weed that is very harsh to smoke and won’t taste as good.
If your buds take too long to dry, you run the risk of mold developing on the buds.
During the drying phase your buds will seriously stink! If you’re growing in an area where you need to be stealthy keep this in mind. You can quickly become used to the smell because you smell it so often.
Once your buds are dry, cure them by placing them in sealed jars for 1 month. Curing will massively improve the taste of your weed and will also allow you to keep your weed for longer without any loss in strength. You can keep cured weed in sealed containers in a dark place for 2 years or more.
It’s important that your buds are dry when the curing process starts because mold or bacteria can easily form inside the jars if they are too moist. While your weed is curing, open the jars every couple of days to replenish and replace the oxygen.
If you want to remove all the guesswork, you can use a hydrometer to accurately measure the relative humidity inside your curing jars. Aim to keep the buds at between 60% - 65% relative humidity.
Another awesome option is to use humidity control pouches. Just place one in each jar and they will ensure your weed stays at the correct humidity level.
There is much debate around the curing process and some growers choose not to cure their weed at all. We believe that curing your weed will turn good weed into awesome weed with just a little more patience. After all, you’ve come this far right?
You're done, congratulations! We hope you found this step by step guide to growing weed indoors useful. Time to smoke a bowl 🙂