The best substrate for your plants
Types of soil, pH, nutrients, and concrete recommendations for indoor & outdoor cultivation – everything you need to know about the ideal substrate.
Legal Disclaimer: in France, home cultivation of cannabis (THC) is prohibited by law. This guide is for informational purposes only and pertains to cultivation substrates in general, applicable to plants, herbs, and ornamental plants grown legally. No part of this content encourages illegal cultivation.
The main substrates
Not all substrates are created equal. Choosing the right medium greatly influences growth, terpene profiles, and yield.
Potting Soil
Classic pre-fertilized potting soil – ideal for beginners. It already contains nutrients for 3 to 4 weeks. Ensure a neutral pH and good drainage.
- + Easy to use
- + Pre-fertilized
- + Available everywhere
- − Often too little perlite
- − Very variable quality
Coco Coir
Sustainable substrate made from coconut fibers. Excellent water retention while ensuring good aeration. Must be fertilized separately.
- + Neutral pH
- + Reusable
- + Excellent drainage
- − Fertilizer needed from day 1
- − Cal-Mag supplement required
Living Soil
Living soil rich in microorganisms, compost, and worm humus. The most natural growing medium – the plant feeds through the soil life.
- + Better terpene profiles
- + Sustainable cycle
- + Little fertilizer needed
- − Higher price
- − More complex preparation
Perlite & Vermiculite
Additives for better drainage and aeration. Perlite lightens the soil, vermiculite retains water. Ideal in a 20–30% mix.
- + Improves any substrate
- + Prevents stagnant water
- − Not a nutrient on its own
- − Dusty to handle
pH Value & EC Value
pH determines nutrient availability, EC value the salt concentration. Regularly measuring these two values is key to healthy plants.
Pro Tip: Measure Regularly
Invest in a digital pH meter and an EC meter. Measure the watering water before and the drainage water after watering. This way, you can detect problems before they become visible.
Indoor vs Outdoor
Indoor Cultivation
- Coco-perlite mix (70/30) for maximum control
- Living Soil for organic terpenes
- Light Mix + liquid fertilizer for more flexibility
- Airpot or fabric pots for root aeration
Outdoor Cultivation
- Organic pre-fertilized soil with a portion of compost
- Larger pots (20–50 L) for longer cycles
- Mulch layer against drying out
- Prefer rainwater (neutral pH)
FAQ: soil & substrate
Want to learn more?
Discover our shop or continue reading with our guides on plant nutrition.
Key takeaways
- In France, domestic cannabis (THC) cultivation is prohibited; this guide is purely informative and focuses on cultivation substrates in general.
- The ideal pH for nutrient absorption is between 6.0 and 6.8.
- For beginners: an organic pre-fertilised potting soil with perlite is the most forgiving.
- Coconut fibre offers excellent drainage but requires fertiliser from day one.
- Regularly measure pH and EC values to detect problems before they become visible.