Macdonald medium (Macdonald, personal communication)

Originally cited by Hicks, 1999. Asymbiotic Technique of Orchid Seed Germination. Socorro, New Mexico: Orchid Seedbank Project.

This medium was developed by Macdonald as a simple formula for the germination and culture of seedlings at home. It consists of readily available components.

Place 3/4 ounce of agar from a Chinese food store (approximately 1/2 of a 1.5 ounce packet) in a large stainless steel stew pot. Add 6 cups of water, set heat to high.

Take four bananas that have been frozen and thawed (to reduce them to  mush), two cups of water, 1/2 teaspoon of Peter's 20-20-20 fertilizer with minor elements, 1/2 teaspoon "SUPERthrive" vitamin additive, and place in a blender and liquefy. Add this mix to the stewpot, which should now be hot. Stir constantly to keep from burning.

Add two tablespoons of powdered activated charcoal, made by reducing fish tank activated charcoal to a powder in the blender. Stir to create a homogeneous mix.

Add 1/3 cup of this mix to each of 24 pint Mason jars. Cap each jar  with lids prepared in the following manner. Drill or punch each lid to create a 1/8" hole. Plug hole with cotton, fabric, or other type of vent (such as 3M "Sterile Spots" band-aids). Put the lids on the jar, but do NOT tighten the band- leave it on loosely (turn back 1/4 turn). Autoclave at 15 psi for 15 minutes. Allow jars to cool.

If desired, medium may be improved through the addition of a vitamin B tablet. Dissolve 1 vitamin B1 or B-50 tablet in 120 ml (4 ounces) of  water. Add 1/2 to 10 ml of this liquid to the media before pouring;  there are few gains to be made above 1/2 ml of this solution.

Source: Hicks, A. Asymbiotic Technique of Orchid Seed Germination. Orchid Seedbank Project, Socorro, New Mexico. 1999.