For years fir bark has been a staple in orchid mixes. Small fir bark is especially suited to seedling mixes or in mixes for orchids with very fine roots. Fir bark breaks down more quickly in wet humid environments and as it breaks down it uses nitrogen. Fertilizer with a higher nitrogen component is required for fir bark mixes. Fir bark comes from the bark of Douglas Fir. Almost 2 quarts in a resealable bag.