Growing Cannabis Indoors in South Africa:
A Comprehensive Beginner's Guide
While growing outdoor cannabis is a rewarding and economical option (Read Here), Indoor growing provides unparalleled control over your plants’ environment.
By carefully tailoring factors like light, temperature, humidity, and nutrients, indoor growers can achieve consistent, high-quality harvests year-round regardless of the sun cycle.
In this guide, we’ll walk you through the essentials of setting up and maintaining a thriving indoor cannabis garden at home.
Why Grow Indoors?
Control: Better control over temperature, humidity, pests and light cycles. Indoor cultivation puts you in the driver’s seat. You can fine-tune every aspect of your grow room to create optimal conditions for your plants, leading to bigger yields and better quality buds.
Consistency: Plants love consistency – Indoor environments are not subject to the whims of outdoor weather. You can dial in your desired conditions and maintain them consistently, ensuring reliable growth and flowering cycles.
Stealth: Growing indoors allows for greater discretion from your neighbors and tsotsis
Multiple Harvests: With indoor setups, you can grow and harvest cannabis throughout the year, rather than being limited to a single outdoor growing season.
Let's Get Started:
The Very Basics You’ll Need:
- A Pot & Tray
- Good Soil
- Artificial Light
- Ventilation
- Water & Nutrients
- Good Seeds
Step 1: Choose Your Grow Space
The first step in setting up an indoor grow is selecting an appropriate space. This could be a spare room, garage, closet, or ideally a grow tent. Consider the following factors when choosing your grow space:
Size:
Ensure your chosen space can accommodate your target number of plants, as well as necessary equipment like lights, fans, and ventilation systems. 1m x 1m x 1.8m should be the minimum size for 3 – 4 plants. As your plants get bigger it becomes more and more difficult to water and maintain them when there is not enough space to move around. Space between plants also helps with ventilation, promoting growth and making it easier to control pest infestations.
Tip: Cover your walls with a reflective material like Mylar or white paint to maximize light efficiency. Go to your local fabric shop and get some white or silver reflective material if you don’t want to paint.
Airflow:
Unless your growing autoflowers, your grow space should be sealed to prevent light leaks from the outside – especially during flowering. A sealed space means you can maintain precise control over temperature, humidity, and even CO2 levels, but it also means heat from your lights and humidity from the moisture of your plant will build up. You need to install ventilation measures in order to extract the air and replace it with fresh air.
Tip: Beware of choosing places like garages with zinc roofs, store rooms or humid spaces with poor ventilation or little sunshine. Zinc roofs can heat up and cool down a lot during the seasons amplifying the outside conditions. Poor ventilated systems will overheat easily and be troubled by humidity problems.
Access:
Your grow space needs to be easily accessible for waterings, have sufficient space between the fans, plants and lights. It needs to be as dark as possible inside the grow space when all the lights are turned off. When plants start the flowering process they can double in size so be sure to always plan ahead and leave enough room for fully mature plants being bigger than expected.
Step 2: Get The Equipment Needed
A successful indoor grow relies on a range of equipment to create an optimal environment for your plants. Key components include:
Grow Medium:
Choosing a well-draining, nutrient-rich grow medium or soil is essential for growing indoor cannabis. Cannabis plants can be grown without soil (hydroponically) or in a growing medium (soil). Most indoor growers prefer to grow in coco peat with amendments like worm castings and perlite as a substitute for native soil.
Pots:
Whether you are starting from seed or from a clone, you will need various sized containers to optimise the growth of your plant during each stage of its development. Smaller pots give you more control over the plant’s moisture levels and root development, but too small of a pot can constrict plant growth and cause root problems. For seeds or clones, a small pot of about 100 ml should be fine, whereas a mature plant might require something that is as large as 30 liters or more. Consider using fabric pots, which allow for better air pruning of roots and prevent root lock.
Grow Lights:
Grow lights are crucial for growing indoor cannabis or adding supplemental light in greenhouses. Options include LED, HID or HPS and CFL bulbs. LED fixtures are expensive but popular for their energy efficiency and low heat output. LED flood lights or CFL bulbs are probably the cheapest way to go, and even though they don’t cover the full light spectrum you can still grow more than decent plants with these if you have enough. HPS and HID bulbs aren’t as expensive as LED lights but they produce a lot of heat as well as suck up a lot of electricity. For South Africans HPS lights were always the go to standard but with the rising cost of electricity this is quickly changing.
Ventilation & Fans:
Proper ventilation and airflow is essential to maintain healthy plants and prevent mold and pests running rampant. For sealed rooms you need to extract the heat and moisture that builds up from your grow room using an extraction fan. Fresh cool air should be sucked in naturally from bottom vents due to the negative pressure created by the main extractor fan.
Temperature & Humidity Control:
Temperature and humidity meters are vital for indoor grows. These simple and cheap meters are an essential starting point for any grower as they provide the feedback needed to understand and control your growing environment. Consider turning off your extractors during extreme cold fronts or purchasing an aircon and/or dehumidifier to maintain ideal conditions in summer.
Timers:
Manual or analog timers for your lights are crucial when growing photoperiodic plants and sticking to a strict light cycle. For vegetative plants you will need to provide 12 or more hours of light daily – most growers prefer 18 – 20 hours. For the flowering phase you need to provide a constant and uninterrupted 12 hours of light and darkness. Timers that switch your lights on or off are therefore necessary. Autoflowers will enter the flowering phase regardless of the light cycle but timers are still needed in order to provide consistency.
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Step 3: Master Environmental Control
One of the key advantages of indoor growing is the ability to precisely control your plants’ environment. Here are the main factors to manage:
Temperature:
Cannabis plants thrive between 20-30°C. Use a thermometer to monitor temperatures and adjust your ventilation and climate control equipment as needed.
Humidity:
Ideal relative humidity ranges from 40-70% depending on the growth stage. Use a hygrometer to track the levels and watch your weather patterns closely.
Air Quality:
Proper ventilation is crucial for maintaining healthy plants and preventing mold and pests. Ensure your grow space has adequate air circulation by using fans and exhaust systems. Fresh air helps replenish CO2 levels, which is essential for plant growth.
All plants turn carbon dioxide or CO2 into sugar and oxygen, and CO2 is a crucial component of photosynthesis. Increasing CO2 levels in your grow room can significantly boost growth and yields. The ideal CO2 level for cannabis plants is between 1200-1500 ppm (parts per million), compared to the atmospheric level of around 400 ppm. Note however that without the proper balancing of CO2 production and fresh air intake in a sealed environment you will likely waste your time trying to increase CO2 levels in a ventilated room.
Light Schedules:
Indoor growers typically provide 18-24 hours of light during the vegetative stage, then switch to a 12/12 – light/dark cycle to induce flowering in photoperiodic plants. Load Shedding schedules might complicate things so it may be beneficial to consider growing autoflowers.
Step 4: Choosing Your Genetics
Selecting high-quality cannabis genetics is crucial for a successful indoor grow and unlocking the full potential of any plant. When choosing your starting genetics there are several factors to consider:
Strains:
Different strains have unique growth characteristics, flavour profiles, and effects. Sativas grow tall and prefer hot climates as opposed to indicas who grow short and deal with colder climates better. Research the various available strains that align with your preferences and growing climate before starting.
Plant Types:
Sex:
Cannabis plants or seeds can be either male or female – male cannabis plants do not produce flowers that turn into buds so they have no value to home growers. Female cannabis plants however produce the flowers you are trying to cultivate. If the female flowers remain unpollinated from a male plant they will not produce seeds. Unpollinated female plants have proven to produce higher levels of THC and CBD.
Choosing high-quality seeds is essential for a successful crop and there are various options when it comes to seeds you can purchase from breeders.
Regular Seeds:
In theory regular seeds are 50% male and 50% female. Regular seeds tend to be stronger and naturally more resilient than other seeds, but there is always the risk of investing 2 months or more into a plant only to find out it is a male and that it has no use to you. If you want to try pheno hunting (*) your own cannabis varieties then regular seeds are the way to go. Just make sure you destroy the male plants before they produce any pollen. Pollen from a single male plant can travel insanely far outdoors and pollinate hundreds of plants ruining it for any of your neighbour’s crops.
Feminised Seeds:
Whether photoperiodic or autoflowering, all feminised seeds are produced by forcing a known female plant to produce chemically induced pollen like a male plant, and then to either pollinate itself or another known female plant to eventually produce seeds that are only female in sex when grown to maturity.
Feminised seeds streamline the growing process for growers by ensuring all the plants end up being bud-producing females. This takes nature’s guesswork and your potential loss of time and effort out of the equation.
Autoflowering Seeds:
Autoflowering cannabis seeds have been crossed with an arctic strain of cannabis known as cannabis ruderalis. This variety of cannabis evolved automatic flowering capabilities due to the prolonged light and dark periods of their native regions. These strains of cannabis begin flowering based on their age rather than their light cycle, allowing for faster flowering times and more discreet grows with multiple harvests per year. Autoflowering cannabis plants begin to flower after 4 – 5 weeks of growth regardless of their light cycle. You can give these plants 24 hours of light a day and they will still enter the flowering phase automatically.
Here at Seed and Soil SA we pride ourselves in providing world class autoflowering strains to South African home growers. They are not only load shedding proof and easier to grow in urban areas, they have numerous advantages over regular or feminised photoperiodic plants when it comes to growing for personal use at home. What they lack in size they make up for in speed and ease of growing.
Climate-Appropriate Strains:
There is an enormous amount of cannabis strains out there , each of which performs best under certain environmental conditions. No two strains grow the same way. Do some research on which cannabis strains are well-suited to your regional climate. Sativa dominant strains tend to tolerate heat and humidity well, while indicas are generally more resistant to drier cold air and even pests. Hybrid strains are a mixture of both and are generally great all rounders. At Seed and Soil we have tried to make the process easier by hand picking a selection of tried and tested strains to not only guarantee success but to also provide the most bang for your buck.
Sources: Always purchase seeds from a reputable seed banks like Seed and Soil SA to ensure quality and genetic integrity. Seed and Soil offers a curated selection of premium indoor-friendly strains. Read more Here
Step 5: The Growing Process:
Unless you are growing autoflowering cannabis, your plant’s growing phase is determined by the amount of light it receives each day. There are essentially 4 main phases of growth to any cannabis plant:
The germination stage:
This is essentially the first 48 – 72 hours after a seed has been in contact with water.
The sprouting stage:
Once germination has been successful and the seeds shell has cracked open, a root begins to appear and grow. This is the best time to transplant your seed to a pot
The vegetative stage:
After sprouting, all plants will start their first 2 -3 weeks off in the vegetative stage regardless of light hours. If they receive more than 13+ hours of light per day they will stay in this vegetative state and grow bigger without creating flowers for as long as one can maintain those amounts of light hours.
The Flowering stage:
The flowering stage is triggered when the amount of light the plant receives drops below 12 hours per day. The nodes of the plant (where branches grow from the stem) should develop small white hairs after about 2 weeks indicating the sex of the plant to be female. If round sacks that look like balls or seeds start to form you likely have a male plant on your hands.
Tip: Always wait a bit longer just to be sure, but make sure you don’t push it too far (3+ weeks) and accidentally pollinate other plants when the sacks burst open with pollen.
After 2 weeks the branch ends of the plant will start growing tighter and tighter forming pistils or flowers. Over time these bud sites will grow larger and fatten up. All cannabis flowers mature at different rates and Sativa strains are known to take a lot longer to mature than Indicas.
Harvest:
If all goes well, after about 9 – 12 weeks your cannabis plants will have fattened up and be fully mature, ready for harvesting and drying.
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Step 6: Dial in Nutrients and Watering
Nutrition:
A proper nutrition and watering schedule is essential for healthy, high yielding cannabis plants. Nutrients are not just meant for hydroponic growers. Even with good soil, home growers often add various forms of organic nutrients or microbes to the water in order to supplement their plant and soil health.
If you are using store bought nutrients, always stay on the safe side. Start with half of the dosage first to see how your plant reacts. Overdoing it on nutrients or fertilisers can have serious consequences.
Watering:
Water your plants gradually and evenly so that the water gets absorbed by your soil deeply, and not just penetrating the air pockets and running out. Maintain a pH range of 6.0-6.8 for soil setups to ensure optimal nutrient uptake.
Do not over water your plants as this is very difficult to recover from. Instead, lift up your pots regularly in order to judge its weight which should give you a good indication of whether or not it is time to water. Ensure proper drainage and space for roots to avoid root rot or root lock.
Step 7: Implement Some Training Techniques
The natural shape of a cannabis plant is similar to that of a Christmas tree. The main stem will grow the tallest and receive the most light/sun. Plant training techniques can be implemented to manipulate this natural growth structure allowing lower branches to receive more light and equal energy. Implementing these techniques early before the flowering phase commences can greatly improve your overall yield. Training techniques allow indoor growers to maximize yields and optimize limited grow space.
Popular methods include:
Topping: Removing the main growth tip to encourage lateral branching and to create a bushier plant.
LST (Low-Stress Training): Gently bend and tie down branches to create an even canopy and expose more bud sites to light.
SCROG (Screen of Green): Using a trellis net or screen to train plants into an even canopy, maximizing light exposure and yield.
Read more on plant training techniques Here
Step 8: Maintaining Plant Health
Proactively monitoring and addressing your plant health is crucial for a successful indoor harvest. Key areas to focus on include:
Pruning:
Regularly remove dead or yellowing leaves as well as leaves blocking bud sites to promote air circulation and redirect energy for healthier growth.
Pest Control:
Inspect your plants and soil regularly for signs of pests like gnats, spider mites, thrips, and aphids. Always address any signs of infestations early with organic pesticides or beneficial insects first before taking more drastic measures. If you are in the flowering phase of growth you should always make sure you read up on all the pesticides you are considering in order to be sure it is safe for consumption afterwards – most are not so beware!
Read more Here
Supports:
Support the weight of your plants branches once the heavier buds start to form in order to prevent branches from bending under the weight or even breaking.
Step 9: Harvest, Dry, and Trim
After several months of hard work, the final (and most exciting) phase of cannabis cultivation is here – the harvest. Here’s a quick guide to finishing your indoor crop:
When to Harvest:
The exact timing will vary by strain and original planting date. We always make a calendar note the moment we flip the lights and count forward 7-8 weeks to monitor it from there.
Signs of Ripeness:
Keep an eye out for these traits that signal your buds are ready for harvesting:
- All growth has stopped
- The buds are swollen and resin-coated
- 70% or more of the pistils darkened to a red/brown colour
- Fan leaves are yellowing and dying
- Trichomes are turning milky or amber under magnification
Basic Harvesting Tips:
- Cut your plants at the base and remove the large fan leaves.
- Hang whole sections of the plant or individual branches to dry upside down like biltong.
- Maintain 18-24°C temperatures and 45-55% humidity while drying.
- Hang the plants in a dark space that is well ventilated using fans for gentle air circulation.
- When the plants are dry enough to trim and cure the stems will snap instead of bend
- The drying process can take anywhere from 7 – 14+ days depending on the drying conditions
Trimming:
The flowers are what we consume and the leaves are bad tasting and what we are trying to get rid of. Trim off the small leaves surrounding the buds either before drying while the plants are still fresh (“wet trimming”) or after hanging and drying for a tighter final product (“dry trimming”).
Use trimming scissors for an easier and more accurate trim and remove as much leaf material as possible. If you have plenty of large buds, cut the buds into smaller more manageable sized nuggets. This will lower the risk of mold and increase the curing rate. After trimming all your buds, place them into a glass jar for curing. Do not overfill the jar. Aim for 60% – 70%.
Step 10: Curing bud for the Best Flavor:
Place your trimmed dried buds in sealed glass jars and keep them in a cool dark place. Open the jars once daily for the first week or two to release the moisture, then once weekly for 2-4 more weeks. Roll the jar around for a few times each time before opening to separate and rotate the buds. Placing a 2-way humidity pack inside the jars will guarantee freshness.
Summary:
Indoor cannabis cultivation offers unmatched control and consistency for South African growers. By carefully selecting your grow space, equipment, and genetics, and maintaining optimal environmental conditions, you can achieve top-shelf results in any season.
At Seed and Soil, we’re committed to empowering South African cannabis growers with the knowledge and resources needed to succeed. Explore our wide selection of premium indoor seeds, growing equipment, and educational content to take your indoor cultivation skills to the next level.
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