Mixing your own potting soil is cheaper than purchasing potting soil from a garden center. You also can be assured your potting soil is organic, while commercial soils may be treated with chemical pest or fungus killers or have chemical fertilizers in them. When creating an organic potting mix, you must use compounds that drain well while still retaining enough moisture for the plants to grow healthy. Nutrients must be added to the soil by using amendments and fertilizers. A good potting soil is a mix of the right elements in the right amount.
Place compost on top a screen or sieve. Shake over a bucket to separate the smaller particles from any bark or uncomposted materials in it.
Mix 2 parts of the small compost particles with 2-parts peat moss. Add 1-part coarse builder's sand and combine well.
Moisten the soil in the bucket and cover. Leave it to absorb the moisture for 12 hours before using so it doesn't dry too quickly in the seedling pots.
Add an organic fertilizer to the pots once seedlings are 2 weeks old. Seedling-starting mixtures have no added fertilizers, as these may damage young plants.
Standard Potting Mix
Mix 5-parts mature compost with 4-parts sterilized topsoil. Sterilize topsoil by baking at 180 degrees Fahrenheit for 30 minutes, then allow it to cool to room temperature.
Add 1-part coarse sand to the mix and combine well. Sand will slip to the bottom of the soil if not mixed in well.
Moisten peat moss by soaking in water overnight. Drain and add 1-part peat moss to the soil mixture and combine well.
Mix in 2 tbsp. of lime for every shovelful of peat moss. This keeps the potting soil balanced and lowers acidity.
Mix equal parts of blood meal and bone meal together. Add 1/2 cup of the mixture for every 10 lb. of potting soil mixed.
About this Author
Jenny Harrington is a freelance writer of more than five years' experience. Her work has appeared in "Dollar Stretcher" and various blogs. Previously, she owned her own business for four years, selling handmade items online, wholesale and via the crafts fair circuit. Her specialties are small business, crafting, decorating and gardening.