Seed starting mixes are designed to nurture young seedlings. Unlike potting soil or garden soil, seed starting mixes are light, sterile, and optimized for moisture retention and root development.
Why Not Just Use Potting Soil?
- Too heavy and nutrient-rich for delicate seedlings.
- Can compact around roots, reducing oxygen flow.
- May contain pathogens that harm young plants.
Essential Qualities of a Good Seed Starting Mix
- Lightweight and fluffy
- Moisture-retentive but well-draining
- Free of pathogens and weed seeds
- Low in nutrients (young seedlings rely on seed energy first)
Key Ingredients
- Coconut Coir or Peat Moss (40–50%)
- Acts as the base.
- Holds moisture and provides structure.
- Choose coir for a more sustainable option.
- Perlite or Vermiculite (30–40%)
- Keeps the mix loose and airy.
- Perlite: boosts drainage.
- Vermiculite: holds more moisture.
- Compost or Worm Castings (10–20%)
- Adds mild nutrition for early growth.
- Must be well-aged and screened to prevent pathogens or clumps.
- Optional Extras
- Micronized rock dust for trace minerals.
- Cinnamon or chamomile powder: Natural antifungals to prevent damping off.
Basic DIY Seed Starting Mix Recipe
- 2 parts coconut coir or peat moss
- 1 part perlite
- 1 part vermiculite
- Optional: ½ part screened compost or worm castings
Directions:
- Combine all ingredients in a large bucket or bin.
- Moisten the mix with water until it’s damp but not dripping.
- Fill trays or containers and press lightly without compacting.
Store any leftover mix in an airtight container or bucket with a lid to prevent contamination or mold.