How to Fertilize Orchids

orchids and fertilizers

The Spruce / Letícia Almeida  

Project Overview
  • Working Time: 10 - 15 mins
  • Total Time: 10 - 15 mins
  • Skill Level: Beginner
  • Estimated Cost: $20 to $50

No subject is more hotly debated among orchid growers than how, when, and if to fertilize these spectacular, unique plants. Despite what some naysayers maintain, orchids need fertilizer in order to thrive, just like almost every other flowering plant. It's true that orchids need less than most other plants—and too much fertilizer can quickly burn an orchid’s sensitive roots—but there is no doubt that well-fed orchids are healthier, hold their leaves longer, and bear more flowers. Thus, it's crucial to know the best way to feed your orchid collection.

When to Fertilize Orchids

This is an old rule of thumb among orchid growers: "Water weekly, weakly." This means that most orchids need a weekly feeding, but with a fertilizer mixture that is more diluted than is normally used for most flowering plants.

You can judge the strength of commercial fertilizer by the concentration of the major nutrients. In general, you'll probably be safe using a standard 20-20-20 fertilizer at 1/4 strength, and a 10-10-10 fertilizer at 1/2 strength. If you are using specialty orchid fertilizers, make sure to follow the label directions precisely.

Unlike most flowering plants, which are most in need of fertilizer during the active flowering period, fertilizing orchids is most critical during the period of vegetative growth that takes place before flower buds appear. Once the plant begins to flower, fertilizer can be withheld until the plant completes its next dormant cycle and is beginning to emerge into its active growth cycle once more.

While vegetative growth is underway, experienced growers sometimes use a "three weeks on, one week off" routine, fertilizing weakly for three weeks, then taking a week off to flush any built-up salts out of the potting mix by simple watering.

Before Getting Started

There are many, many species of orchids comprising several different genera, so it's a mistake to think that all orchids will respond to the same feeding routine. Generally speaking, most orchids alternate active growth periods culminating in flower production, followed by a dormant period. These cycles usually correspond to the wet season-dry season cycle found in their native habitats. These are the orchids that will need to be fed during their active growth seasons, then slightly starved during their dormant periods. But there are a few orchids, such as Maxillaria tenuifolia, which seem to actively grow constantly, and with these, you should feed lightly year-round.

Do a bit of research on the types of orchids you are growing and feed them in a manner that's appropriate to the species—your collection may well have different types with much different feeding needs.

It's increasingly easy to find specialized bloom-boosters that offer slightly different nutrient balances or micronutrients designed to enhance orchid flowering. These are tempting, but unless you're a professional grower, there's little benefit to these products. First, many home orchid collections carry species in multiple genera that flower at different times of the year. Second, different genera have different flowering requirements and different needs for feeding—not all will respond well to so-called "bloom-booster" fertilizer products.

When you get down to basics, a high-quality, well-balanced fertilizer is just as effective at producing blooms as a booster, and it will benefit all your plants, not just the bloomers.

What You'll Need

Equipment / Tools

  • Watering can


  • Appropriate orchid fertilizer


fertilizer options for orchids
The Spruce / Letícia Almeida  
  1. Use High-Quality Fertilizer and Water

    There are lots of opinions on which fertilizer is best, and a whole industry has sprung up to sell specialized orchid foods. You can quickly get lost in the advanced chemistry of various fertilizer claims, but here's the skinny: One nitrogen molecule is very much like another nitrogen molecule. In fact, the quality of your water matters more than your brand of fertilizer.

    Tap water that is overly hard, high in dissolved minerals, is not a great choice for mixing fertilizer for orchids, but softened water may also contain an elevated level of ionized sodium that is also less than ideal for orchids. The best choice is distilled water that is free of chlorine, fluoride, and minerals, but a strong second choice is ordinary rainwater, which can be collected in a rain barrel. But many growers find it sufficient to simply let tap water sit out for 24 hours, which allows the chlorine and some of the ions to evaporate out of the water before irrigating the plants.

    When it comes to fertilizer, buy a high-quality, balanced fertilizer that contains the three major elements (nitrogen, phosphorus, and potassium), plus all the minor nutrients (sulfur, calcium, magnesium, iron, manganese, boron, copper, zinc, molybdenum, and chlorine).


    Use a low-urea or urea-free fertilizer because urea is not a truly available source of nitrogen for epiphytic orchids.

    White and pink orchid near fertilizer

    The Spruce / Letícia Almeida  

  2. Take Care Not to Overfeed

    Overfeeding will not benefit your plants. Synthetic fertilizers contain mineral salts, such as potassium, calcium, and others. Over time, these salts build up in your pot and potting medium and can seriously harm the plant. Additionally, overfed orchids often grow too quickly, making them weak and susceptible to disease. Finally, many kinds of orchids actually bloom less if they're overfed. Find the fine line and stick with it.

    Dead roots on orchid plant

    The Spruce / Viktoriya Stoeva

  3. Feed Only During the Growing Season

    Many orchids—dendrobiums, for example—go into dormancy over the winter months. Others, such as Cattleya, slow way down in their growth. There is little purpose in feeding a dormant plant. Start fertilizing again once the plant shows signs of fresh growth in the spring.

    Some experts recommend that active feeding should occur during the vegetative, non-flowering cycle of the plant's growth and that regular feeding should be withheld once the plant begins to actively flower.

    Cattleya orchid in pot being watered

    The Spruce / Letícia Almeida