KC asks, “My friend said I should be fertilizing my orchids with Miracle-Gro fertilizer. Is that right?”
My business motto is “to assist others with their gardening dilemmas,” and long ago when I worked in garden centers, our goal was “to ensure the customer’s gardening success.” When it comes to recommending gardening products, it therefore only makes sense for me to recommend a product that will be used only in accordance with the instructions on the label. It would remiss for me to suggest using a product not in accordance with the instruction label.
Therefore, to answer KC’s question, do not use “regular” Miracle-Gro fertilizer for your orchids, because the package likely does not have an instruction specifically for orchids. However, you could use “Miracle-Gro Orchid Food” which is designed for orchids and other “acid-loving” plants, that is, plants that prefer a slightly acidic potting media.
What’s the difference? I have not read the labels on either of these fertilizers, but I would assume that the instruction for “regular” Miracle-Gro would have you mix a fertilizer that would end up being too strong for orchids. Any orchid fertilizer is typically much more diluted (weaker) than “regular” fertilizers.
Why is that? Most orchids are native to nutrient-poor environments (e.g. epiphytes living in trees), and therefore suffer when given strong fertilizer. Suffering from excess fertilizer is a common phenomenon for other plants native to nutrient-poor environments, like cacti or certain plants native to Australia, for example.
I like to recommend the Grow More Orchid Fertilizers, simply because they are easy to find at an independent garden center like Walter Andersen Nursery. That’s the fertilizer brand with all the different colors, pink, blue, yellow that you mix into water.
Which color should I use? First off, let’s review the three numbers (e.g. 15-30-15) found on every fertilizer package (it’s actually required by law). The three numbers refer to the percentage of nitrogen, phosphorus, and potassium, respectively. Nitrogen helps with growing foliage; phosphorus helps with growing roots and flowers, while potassium helps with overall functioning of the plant.
Therefore, if your orchid is growing leaves you want to use the pink Grow More with the numbers 30-10-10. As new growth matures and the plant is getting ready to bloom, you can switch to the blue Grow More, 10-30-30, and use that while the plant is blooming. For basic orchid growing, you don’t need the other colors.
What if I just want to use one fertilizer? Use the pink Grow More, 30-10-10, if you just want to use one fertilizer.
Why is that? To mimic the conditions found in their native habitat, orchids are grown in a potting media that has not yet decomposed (e.g. bark, moss). Naturally, the potting media will decompose over time and the microorganisms decomposing the potting media use nitrogen to perform their task. Therefore, if you only wanted to use one fertilizer, use the pink 30-10-10 Grow More which will help supplement the nitrogen loss in the pot due the natural decomposition of the potting media.
The instructions indicate to fertilize every 10-14 days. I like to interpret that instruction as “fertilizing with every other watering.” I think this works great because I like to encourage occasional watering with no fertilizer to help flush out excess salts that can accumulate in the pot, especially given all the “stuff” in our San Diego water.
The Walter Andersen Nursery in Pt. Loma is closed for the moment, but the Walter Andersen Nursery location in Poway remains open.
Thanks for the question, KC. For more on watering orchids and orchid fertilizers, see Chapter Two of my book How Orchids Rebloom. May your orchids rebloom!