There are two categories of orchid fertilizers available for purchase: inorganic fertilizers and organic fertilizers. Inorganic fertilizers are chemical-based and come in two types: single inorganic fertilizers and compound inorganic fertilizers.

Single inorganic fertilizers contain only one element, such as nitrogen (N), phosphorus (P), or potassium (K). Compound inorganic fertilizers, on the other hand, contain at least two elements, such as N and P or P and K, or even three elements like NPK fertilizer.

The proportions of these elements vary depending on the intended purpose of the complex mineral fertilizer. For instance, a balanced fertilizer like NPK 15:15:15, with equal amounts of nitrogen, phosphorus, and potassium, is suitable for post-bloom care of orchids. Different ratios, such as NPK 10:55:10, are suitable for promoting flowering while preventing premature falling off of the orchid flowers.

In addition to the main elements, inorganic compound fertilizers often include macro and trace elements in the form of compounds. These are commonly referred to as complete nutrient fertilizers. Manufacturers usually provide instructions indicating whether the fertilizer is classified as a compound fertilizer or a complete compound fertilizer.

Some popular compound fertilizers for orchids include Growmore, Hyponex, Vitabloom, Gandasil, Gaviota, and Dekastar. Organic fertilizers, on the other hand, are derived from various organic materials such as bones, blood, fishmeal, algae, organic vegetable waste, and even manure.

The majority of organic orchid fertilizers come in liquid form and are applied in the same manner as inorganic fertilizers. However, it is crucial to consider the content and application technique. Some suitable organic fertilizers for orchids are EM4, Long Fresh, Bio Greeny, Pokon, and Superbionic fertilizer.