Cannabis Soil Mix: Base, Drainage, and Nutrition

Cannabis Soil Mix: Answer

A cannabis soil mix supplies roots with water, air, and nutrients. A basic mix has three parts: a base, a drainage agent, and a nutrient source. The base holds water and roots. The drainage agent adds air pockets. The nutrient source feeds plants.

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Base Materials

Peat moss and coco coir are common bases. Peat moss holds water and has a pH near 4.0. Coco coir holds water and has a pH near 6.0. Both are inert. They supply no nutrients.

cannabis soil mixture recipe

Drainage

Perlite is the standard drainage agent. It is volcanic glass that expands when heated. Add 20% to 30% perlite by volume. Vermiculite holds water and nutrients. Use vermiculite in small amounts, 5% to 10%.

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Nutrition

Compost and worm castings supply nutrients. Use 10% to 20% compost by volume. Worm castings add microbes. Bat guano and kelp meal add phosphorus and potassium. Blood meal adds nitrogen. Mix dry amendments into the base. Let the mix sit for 2 to 4 weeks before planting. This time lets microbes break down the amendments.

pH

Cannabis grows best in soil pH 6.0 to 7.0. Test the mix with a pH meter. Adjust with lime to raise pH. Adjust with sulfur to lower pH. Water with pH 6.0 to 6.5 water.

Common Recipes

1. Recipe 1: 3 parts peat moss, 1 part perlite, 1 part compost.
2. Recipe 2: 3 parts coco coir, 1 part perlite, 1 part worm castings.
3. Recipe 3: 2 parts peat moss, 1 part perlite, 1 part compost, 1/2 part worm castings.

Watering

Water when the top 1 inch of soil is dry. Lift the pot to check weight. A dry pot feels light. A wet pot feels heavy. Water until 10% to 20% of the water runs out the bottom. Do not let the pot sit in runoff.

Troubleshooting

Yellow leaves mean too much water or too little nitrogen. Brown leaf tips mean too much fertilizer. Slow growth means cold soil or low pH. Flush the soil with pH 6.0 water if nutrients build up.