At our Minneapolis-based mom & pop seed shop, we love helping home growers get the best start possible for their indoor cannabis grows. In Minnesota especially, growing cannabis indoors can be an ideal option due to a short outdoor growing season.
Whether you're a first-time grower or a seasoned pro, setting up your grow space will set you up for a healthy harvest. Here are our top tips to help you prepare your indoor grow from start to finish!
Choose the Right Space for Your Grow
Size of Space: Whether you're using a small closet, a spare room, or a grow tent, make sure your space is large enough for your plants to grow and that you can easily move around in it. Start small if you’re new to growing 2 to 4 plants are manageable for beginners. In Minnesota, it is legal to grow 4 plants in a vegetative state and 4 in a flower state.
Ventilation: Good airflow is essential to prevent mold and keep plants healthy. Choose a space where you can install fans and vent out heat if needed.
Light Proofing: Cannabis needs total darkness during the dark periods of its light cycle. Make sure your space is light proof, so plants don’t get interrupted during "nighttime." Before putting plants in your tent, it can be helpful to zip yourself inside it to check for any light entering corners, etc. Even a small light from an extension cord can be bothersome to plants.
Select the Right Growing Medium
Choosing your growing medium will depend on your experience and preferences. Here are some common options:
Soil: Soil is the most beginner-friendly and forgiving medium. Use high-quality, nutrient-rich soil. Look for organic options made specifically for cannabis.
Coco Coir: A soilless medium made from coconut husks, coco coir allows for faster plant growth and better oxygenation but requires more frequent watering and nutrient management.
Hydroponics: For more advanced growers, hydroponic systems (growing without soil) offer faster growth and higher yields, but they require more attention to water, pH, and nutrients.
Choose the Right Cannabis Seeds
Your seeds are the foundation of your grow, and different strains perform better in different environments.
Auto Flowering Seeds: These seeds automatically switch from vegetative growth to flowering, making them a great option for new growers or those with limited space. They also have a shorter growing cycle. Auto flower seeds are also feminized seeds.
Photo Period Feminized Seeds: These seeds produce female plants, which are the ones that produce the buds you want. Avoid male plants unless you’re planning to breed, as they will pollinate the females and reduce the quality of your yield.
Consider Strain Characteristics: Choose strains based on your grow space. For small spaces, compact indica strains are ideal, while larger sativa's need more vertical space to thrive.
Set Up Your Grow Lights
Lighting is one of the most important factors for successful indoor cannabis growing. Here’s what to consider:
Types of Lights:
LED Grow Lights: The most energy-efficient and low-heat option, LEDs are ideal for beginners and experienced growers alike. They provide a full spectrum of light, from the blue spectrum for veg growth to the red spectrum for flowering.
CFLs (Compact Fluorescent Lights): These are cheaper upfront but less efficient than LEDs. They work well for smaller grows or for supplemental lighting.
HID (High-Intensity Discharge) Lights: These lights are powerful and effective, but they generate more heat and use more electricity, making them better for larger, well-ventilated spaces.
Light Cycles:
Vegetative Stage: Keep your lights on for 18 hours and off for 6 hours daily to simulate long summer days.
Flowering Stage: Switch to 12 hours of light and 12 hours of darkness when you want your plants to start flowering.
Set Up Ventilation and Air Circulation
Cannabis plants thrive in a fresh, well-ventilated environment. Proper airflow helps to prevent mold, pests, and diseases. Here’s how to set up your ventilation system:
Inline Fans and Exhaust System: Use an inline fan and exhaust system to pull stale, hot air out of the grow space and bring fresh air in. Make sure your fan is powerful enough to replace the air in your space every 1-3 minutes.
Oscillating Fans: Install oscillating fans to circulate air evenly around your plants. This strengthens stems and reduces humidity pockets that can cause mold.
Carbon Filter: To control the smell of your plants, you may want to add a carbon filter to your exhaust system, especially if you’re growing in a shared building or don’t want the odor to spread.
Control Temperature and Humidity
Maintaining the right temperature and humidity levels is crucial for healthy cannabis plants.
Ideal Temperature: Cannabis grows best between 75-85°F during the vegetative stage and slightly cooler during flowering, around 75-80°F.
Humidity Levels:
Seedling Stage: 70-80% humidity.
Vegetative Stage: 60-70% humidity.
Flowering Stage: 50-60% humidity.
Late Flowering: Aim for 50% humidity or lower to reduce the risk of mold.
Use a thermometer and hygrometer (humidity meter) to keep an eye on these conditions and adjust with humidifiers, dehumidifiers, or fans if necessary.
Water and Nutrients
Watering and feeding your cannabis plants properly is key to ensuring they thrive:
Water Quality: Always use filtered or distilled water if possible. Tap water can contain chlorine and other chemicals that may harm your plants.
Watering Schedule: Water when the top 1-2 inches of soil feels dry. Overwatering is one of the most common mistakes in indoor grows, so be mindful not to drown your plants.
Nutrients: Cannabis plants need different nutrients during the vegetative and flowering stages.
Vegetative Stage: Focus on nitrogen (N) for leafy growth.
Flowering Stage: Increase phosphorus (P) and potassium (K) for bud production.
pH Levels: Keep your pH between 6.0 and 6.5 for soil grows, or between 5.5 and 6.0 for hydroponic setups.
Plant Training Techniques
Training your plants can increase your yields and help you manage space. Some methods include:
Low-Stress Training (LST): Bend and tie down branches to create an even canopy. This technique allows more light to reach all parts of the plant.
Topping: Cut off the top of the main stem during the vegetative stage to encourage more branches to grow, increasing the number of colas (flowering sites).
Defoliation: Remove some of the large fan leaves that block light from reaching lower parts of the plant.
Monitor for Pests and Diseases
Indoor grows are not immune to pests, so keep an eye out for:
Common Pests: Spider mites, aphids, and fungus gnats are common indoor pests. Use organic pest control sprays or beneficial insects like ladybugs to keep them at bay.
Mold Prevention: Keep humidity levels low during the flowering stage to prevent mold from forming on your buds.
Weekly Home Grow Get Together at the Shop
Every Thursday from 6-8pm at our Mom & Pop shop we have a Home Grow Get Together.
South Minneapolis has a great and growing community of plant enthusiasts. If that's you, stop by to meet other growers in your community, trade tips & tricks for the best home-grow, and get your questions answered. We welcome you to learn, grow and connect with us and fellow home growers in Minnesota.