8 Tips for Growing G13 Marijuana [Grower’s Guide]

There are few more mysterious marijuana strains than G13. This indica dominant (70%) strain is the subject of numerous rumors. For example, it is alleged that the FBI, CIA, and several other government agencies joined forces to create the ‘ultimate’ super-strain. According to legend, it was bred at a secret lab in the University of Mississippi, which is where the feds grow their weed.

In reality, this story is almost certainly complete nonsense, but in the absence of any hard evidence relating to its real origins, the tale of government-produced cannabis makes for interesting discussions if nothing else. Whether it is an FBI or CIA creation or not, G13 is very potent with a THC content of up to 24%.

Even so, you can enjoy G13 at any time of the day, and it is a popular strain in social settings. It begins with a euphoric head-high but will eventually make you feel sleepy, especially in higher doses. It is used for chronic stress, depression, and insomnia, and can also be used to manage pain. If G13 is your favorite stain and you want to learn how to grow it, read on for some quick tips and tricks.

1 – Should You Grow G13 Indoors or Outdoors?

Although you can try an indoor or outdoor grow, it is important to note that G13 likes space to branch out. It may even need additional support during the flowering stage. As it can thrive in temperatures of up to 85 degrees Fahrenheit, it is an easy enough strain to cultivate outdoors. G13 also handles cold temperatures better than most marijuana plants, but keep the temperature above 65 degrees during the day.

If you grow indoors, G13’s flowering time will be at least 9 weeks. It will reward you with a high yield of up to 21 ounces per square meter. If you grow it outside, G13 can yield an incredible 40 ounces per plant! It harvests late, anywhere between late October and mid-November.

2 – Try the Sea of Green (SOG) Method

G13 responds well to the SOG method and should boost the overall yield. It is best to use SOG when you have limited space in your grow room because you can maximize space without losing out on yield. To begin, germinate your seeds or create clones using cuttings from a healthy ‘mother’ plant.


Expose the plants to at least 18 hours of light per day until they are around 12 inches tall. Next, space them out so that there are no more than two plants per square foot. Force the plants into flowering by changing to a 12 hours of light, 12 hours of dark schedule. When the dense bud canopy forms, remove the branches beneath and use them for clones. Within weeks, your G13 should be ready for harvest. You’ll find that your plants will grow to the recommended height within a couple of weeks.

3 – Consider a Hydroponics Setup

A hydroponic setup involves using a growing medium other than soil. Common options include Rockwool and coco coir. There is a variety of hydroponics options, but the following tips ring true no matter which one you select:

  • Make sure all equipment, plus your water tanks, is sterile. If a pathogen gets into your system, it will spread throughout your crop in record time.
  • The water used in your hydroponics system should be around 65 degrees. However, the air temperature should be 75+ degrees.
  • Always begin with pH neutral water (7.0). If this is an issue, invest in a reverse osmosis system.
  • Keep the humidity level at 70% during the early vegetative stage and lower gradually. It should be no more than 40% after a few weeks of flowering.
  • Maintain a pH level of between 5.5 and 6.5 in your growing medium.
  • Keep records of everything. Otherwise, you won’t know what worked, and what didn’t.

4 – G13 Plants Need a Lot of Nutrients

Although certain marijuana strains are easy to overfeed, G13 does not fit into that category. These plants have a BIG appetite so don’t skimp on the nutrients. Nitrogen, phosphorus, and potassium are the building blocks. Use nitrogen liberally during the vegetative stage, and reduce it significantly during flowering.

Other important nutrients include calcium, magnesium, sulfur, zinc, iron, chlorine, silicon, copper, boron, and cobalt. Pre-mixed soils should have at least trace amounts of them all. If you are concerned about overfeeding and nutrient burn, learn the symptoms. For example, early indications include extremely deep green leaves, if the leaf tips are bent at a 90-degree angle, and if the stalks and branches turn red, purple, or magenta.

A common symptom is yellowing leaves with a burnt tip. If you have overfed your G13 plants, remove the damaged material, and flush the soil with pH balanced water. When you return to regular feeding, use half the original dose.

5 – What is Electrical Conductivity (EC)?

It is especially important to learn about EC when using a hydroponics setup. It is a measure of the total dissolved solids in your water. It tells you how nutrient-rich the circulating water is. If the level is too low, your G13 plants aren’t getting enough nutrients. If the EC is too high, you risk nutrient burn.

When you place your clones or seedlings into the hydroponics system, the EC level must be between 0.5 and 1.3. For clones especially, the level should be closer to 0.5. As your plants grow, the EC level should rise with them. It can reach 2.0 by the beginning of the flowering stage, and as much as 2.5 near harvest depending on the strain. As G13 needs plenty of food, you can err on the higher side.

6 – Don’t Forget Airflow!

To get the best out of G13, you need to make sure that there is plenty of airflow between the plants. As such, your grow room’s ventilation system is as important as the nutrient regimen or lighting. This system keeps humidity, CO2 levels, and temperature in check; and these atmospheric conditions have a direct impact on photosynthesis.

If nothing else, make sure you invest in a motorized fan. If your grow room is small enough, a single fan might be enough. An exhaust fan is also a useful purchase because it removes excess heat and draws fresh air into the room. This process reduces overall temperature and boosts CO2 levels.

When it comes to finding the right air conditioning system, you need to take into account the size of the grow room, the ballasts you use, the lighting system, CO2 equipment (if applicable), and other electrical equipment.

7 – Boosting CO2

As you know, CO2 (carbon dioxide) is a gas in our atmosphere and is necessary for plants to complete the photosynthesis process. Plants convert CO2 into energy. When you elevate the level of carbon dioxide in your grow room, you could increase the yield significantly. We don’t recommend using CO2 equipment if you’re a novice grower. Instead, it is best to focus on the basics and learn how to grow high-quality bud.

When you have a few grows under your belt, you can consider adding carbon dioxide to the room. A common method is the use of a CO2 generator which powers on or off automatically once the room’s CO2 levels reach a pre-set part per million (ppm) level. There are also compressed CO2 tanks available which enable you to release controlled quantities of the gas into the atmosphere.

CO2 levels in our atmosphere have increased rapidly in the last century and hurtle towards 400ppm. Most growers find that boosting the CO2 level in their grow room to 1,200ppm boosts growth. The benefits begin to dwindle once you surpass the 2,000ppm mark. The higher the CO2 level in a room, the higher a temperature your plants can handle. Also, excessive levels of CO2 are harmful to humans, so don’t spend too much time in a high CO2 environment.

8 – Controlling the Smell of Your G13

Even if it is legal to grow weed in your area, it is still a good idea to keep your grow a secret. Remember, in the United States it is federally illegal to grow weed, so you’re not 100% safe. Air circulation is crucial when trying to minimize the scent of marijuana in an indoor grow.

Once your G13 begins to bloom, the smell could become overpowering. There is now odor-neutralizing gel on the market. All you need to do is open a couple of jars in the grow room and allow the gel to attract and trap the odor. Activated carbon filters are also effective because they trap odors from the air. Make sure the filters are attached to an extraction fan.

Finally, don’t waste your money on air freshener sprays! At best, they help to mask the scent for a very short time before it begins to waft through the air! Also, there is a possibility that the chemicals they contain will contaminate the buds.

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