An equal-parts mix of pasteurized soil, coir or peat, and perlite or vermiculite for starting seeds indoors.
What You’ll Need
1/3pasteurized soil or compost
1/3sandvermiculite or perlite
1/3coconut coir or peat moss
Directions
To pasteurize the soil or compost, moisten it lightly, spread it in a heat-safe pan, and cover it with a lid or foil.
Bake it at 250°F, checking with a candy or meat thermometer. When the soil reaches 180°F, keep it there for 30 minutes. Don't let it get hotter.
Let it cool, then mix it with the coir or peat moss a little at a time.
Mix in the sand, vermiculite, or perlite.
Notes
Start vegetable and flower seeds indoors 4 to 12 weeks before your last spring frost. Wash pots and trays before sowing and rinse them in 1 part bleach to 9 parts water. Wear gloves and a dust mask when handling dry, dusty mix.