Historical Note:  This formula was perfected by Dutch horticulturalists in the 16th century. (The first written record in German is dated 1511). Just about any commercial greenhouse crop will grow in this mix called “One-One-One” or written 1-1-1.

How To Do It:  Following is the original recipe for the standard greenhouse potting mix used for the past 500 years. This mix contains only natural ingredients and so is suitable for “organic” production.

1 part “well-rotted turf” = topsoil.

1 part coarse sand.

1 part peat moss.

Total = 3 parts by volume.

Topsoil provides nutrients and biology. Coarse sand provides aeration and drainage. Peat moss holds water. Work components through a 1/2 inch screen before mixing. Use level not heaping measures. Pack peat firmly to get true volume.

How to Prepare Topsoil:  Use a spade to cut grass sod into blocks. Stack turf upside down to kill grass. Sod pile can be any convenient dimensions. Cover turf with straw or other mulch to keep soil moist and prevent weeds. Let sod compost for at least 6 months before use. For long term storage sow pile with a multiple species cover crop to keep soil “lively”.

Special Purpose Potting Mixes:

Fern Mix:  Add 1 extra part of peat moss.

(1 earth + 1 sand + 2 peat = 4 total parts by volume).

Cacti Mix:  Add 1 extra part of sand.

(1 earth + 2 sand + 1 peat = 4 total parts by volume).

Geranium Mix:  Add 1 extra part of topsoil.

(2 earth + 1 sand + 1 peat = 4 total parts by volume).

Earthworm Friendly Mix:  Substitute composted hardwood bark or composted wood chips for sand. Sand is abrasive; earthworms do not like soils with more than 10% sand.

(1 earth + 1 composted bark + 1 peat = 3 parts by volume).

Hand Mixing:  Layer ingredients on top of a potting bench: Peat moss on bottom, Topsoil in middle, then Sand on top. Sprinkle lime and fertilizer (if needed) over sand. Mix with a garden fork or flat spade. Slide fork or spade under pile then lift up and shake. Work from one end of the pile to the other end. Repeat 3 times until mixture is uniform. This is the easiest way to mix large quantities of potting soil by hand. (Layering by density uses gravity to make work easier. Heavy ingredients sift down through tines of fork or fall off edge of spade. The process of shaking a fork or spade to mix ingredients is called “feathering”).

Fertilizer:  The traditional greenhouse fertilizer is 1% or 2% bone meal by volume. For 1 bushel = 8 gallons of potting soil add 1.25 to 2.5 cups of organic fertilizer to the mix. For vegan potting soil substitute earthworm castings, cottonseed meal, or weed seed meal.

Substitutions:  If you do not have topsoil use clay subsoil sifted through a 1/2 inch screen. If sand is not available use any other aggregate or substitute composted hardwood bark or composted wood chips. If there is no peat use compost, leaf mold, composted manure, or composted sawdust.

Raised Beds:  To fill raised beds cheaply mix 1 part screened subsoil + 1 part wood chips + 1 part manure = 3 total parts by volume. Seed immediately with a multi-species cover crop. Let cover crop grow a full year before planting cash crops. Roots, earthworms, symbiotic fungi, and beneficial bacteria transform dead dirt into live topsoil.

Related Publications:  Burbank’s Grafting Wax; Burbank’s Seed Germination Mix; Cow Manure Potting Soil; Hot versus Cold Composting.

Would You Like to Know More?  For more information on greenhouse management and potting soils, please visit: www.worldagriculturesolutions.com – or — send an e-mail to: worldagriculturesolutions@gmail.com – or — send your questions to: Eric Koperek, Editor, World Agriculture Solutions, 413 Cedar Drive, Moon Township, Pennsylvania 15108 United States of America.

About the Author:  Mr. Koperek is a plant breeder who farms in Pennsylvania during summer and Florida over winter. (Growing 2 generations yearly speeds development of new crop varieties).

Index Terms:  1-1-1 (potting mix); Cacti Potting Mix; Dutch Potting Mix; Fern Potting Mix; Geranium Potting Soils; Greenhouse Management; Potting Mixes; Raised Beds; Vegan Potting Mix.

Original Publication Date:  March 1976 Meyersdale, Pennsylvania.

Update:  October 2023, Evans City, Pennsylvania.