4 to 6 charcoal briquettes
1/4 c. salt
1/4 c. ammonia
Aluminum pan
1/4 c. bluing
Food coloring

Place briquettes in aluminum pan. Mix salt, bluing and ammonia together in a jar. Sprinkle a few drops of food coloring over the briquettes, then evenly pour mixture from the jar over the briquettes. Crystals will begin to grow that day. Make more salt mixture and add to garden every few days to keep it growing.