Soil Mixture Instructions for Wooden Grow Boxes

Making All-Purpose Potting Mix

• Before making a soil-based potting mix, ensure that the soil you use is sterile. If you are using soil from your yard, you can sterilize it: Moisten the soil slightly with water, place it in a baking pan and cover with foil. Bake for at least 20 minutes to kill any seeds or organisms. Stir the soil every 5 minutes. Alternatively, use sterilized loam soil or garden soil purchased from a garden center. Mix equal parts soil, coarse sand and compost to make a nutrient-rich and slightly heavier but well-draining basic potting mix for most types of plants.

Making Potting Mix for Acid-Loving Plants

• The addition of peat sphagnum to potting soil makes it ideal for plants that prefer slightly acidic soil. It also provides exceptional water drainage, and it's texture is adjustable. Mix equal parts sterilized soil, coarse peat sphagnum moss and coarse sand, vermiculite or perlite. Adjust the amounts as needed to create the most ideal texture. The potting soil should feel fine and loose, not sandy or sticky. Sand, vermiculite and perlite all create space in the soil for proper air circulation and water drainage. Since the pH may be below 6.0, mix about 4 tablespoons of dolomitic lime per 3 gallons of potting mix to bring it up between 6.0 and 7.0. Use less lime for acid-loving plants.

Making Blocking Mix for Seedlings and Transplants

• Seedlings require special soil mix to create the perfect environment for germination. A combination of 30 quarts brown peat, 20 quarts coarse sand or perlite, 20 quarts compost and 10 quarts of soil create the base. Mix in 3 cups of equal parts blood meal, colloidal phosphate and greensand for fertilizer. Add 1/2 cup of dolomitic lime and mix well. This media can be used for soil blocks, and it's measured with a 10-quart bucket.

Making Potting Mix for Succulents

• Succulents require quick-draining soil, The best way to achieve it is through coarse materials such as gravel combined with coarse sand. Combine 2 parts basic potting soil, 1 part small gravel (pumice, turface or granite) and 1 part perlite. When moistened, the soil should crumble when squeezed in your hand. If it doesn't, add more gravel and perlite. Alternatively, equal parts basic potting soil and perlite work as a succulent potting mix.