Which Orchids Fertilizer should I used?

Which Orchids Fertilizer should I used?

In general, orchids don't require a lot of fertilizer. In nature, as orchids grow suspended from trees by grabbing their bark with their roots, orchids only get what food their is in the decaying organic matter in the nook of a tree branch or that washes down the tree as it rains. Yet, as we cultivate orchids in our homes they do require a modest amount of fertilizer.

Orchids do not thrive on standard ornamental or fruits plant fertilizers because the nitrogen source in those fertilizers is primarily urea which orchids cannot absorb very well. Similarly, the type of Potassium in many fertilizers is not optimal for orchids.

Orchids are more susceptible to over-feeding, which is why purchasing the correct formula is key.

There was a study done at Michigan State University (MSU) on fertilizer for orchids which was published in both Orchids magazine and the Journal of the International Phalaenopsis Alliance in 2003.

This study, and the resulting orchid fertilizer formulation is known as "MSU Orchid Fertilizer". This fertilizer formulation is known as the 'gold standard' fir orchid fertilizer.

Tropical orchids are epiphytic, which means they grow out of soil on the surfaces of other plants in their natural habitats. Because of this, orchids function differently than other varieties and have much more specific needs. This means that you can't use any old fashioned 20-20-20 fertilizer when you want to give your pretty orchids a boost.

Ahead, discover everything you need to know about feeding this house plant, including some of our favorite formulas to try.

While orchids can take in all forms of nitrogen found in fertilizers (like nitrate, ammonia, and urea), they prefer the nitrate form of nitrogen for long-term health, a study published in HortTechnology found that supplying a higher ratio of nitrate to ammoniacal nitrogen allows for larger flowers and better calcium and magnesium uptake.

There are a few factors to consider when shopping for orchid fertilizers, like the aforementioned nitrate to ammoniacal nitrogen ratio. It's important to have both forms, but focus on finding a fertilizer with higher nitrates

A robust fertilizer, such as 13-3-15 like the MSU Orchid Fertilizer 13-3-15 can be applied twice monthly (biweekly) and will do the trick, this is better than applying an extremely low-rate fertilizer every time you water.

Feeding your orchids too often with too much will lead to salt build-up, which can cause fertilizer burn, this is why we recommend half the label dosage from the manufacturer.

In our opinion there is no need to apply a BLOOM Fertilizer...

No fertilizer can trigger flower production in orchids, no matter what the bottle says. Instead, fertilizer can fuel orchid health to encourage blooming in the future producing healthy bulbs and extensive roots system—but it is not responsible for initiating flower spikes.

Most tropical orchid species are triggered to flower by a change in temperature, usually, that is a 5- to 10-degree temperature drop at night. Also, to encourage your orchid to bloom, we suggests provide them with good illumination in addition to the drop of temperature during the flowering season.

And no matter how much "bloom" fertilizer you use, if your orchids is not in her flowering season it will not flowers.

Others factors to consider when choosing a fertilizer, is that you should choose your Fertilizer based on your Water Quality. Your water quality is one of the factors you should consider when selecting your fertilizer.

If you have a naturally soft water with low alkalinity and total dissolved solids, your fertilizer of choice is probably one that is primarily nitrate nitrogen because the high nitrate content will result in a slightly basic reaction around your roots.

So if you use rainwater or reverse osmosis water, your public water supply is from reservoirs areas or your well is drilled in granite, your water probably has a very low pH, low total dissolved solids content and low buffering capacity so you should seek out high nitrate fertilizers.

For these pure water sources, avoid fertilizers with an acidic reaction like those containing more than 25% of the nitrogen in the ammoniacal form because it can cause precipitous drops in the pH around your roots.

A good Cal Mag fertilizer is probably a good choice for water's with an low alkalinity . Some potentially suitable fertilizers for pure water are:

MSU Orchid Fertilizer for RO/Rain Water -13-3-15-8-2 w/ micronutrients
Peters Excel Cal Mag Special - 15-5-15-5-2 w/ micronutrients

On the other hand, if you have hard water with high alkalinity and high total dissolved solids, you should probably use a fertilizer that will cause an acidic reaction around the roots so the naturally occurring calcium and other supplied nutrients will be more available to your plant.

You'll look for a fertilizer with up to half the nitrogen in the ammoniacal form. Some potentially suitable fertilizers are

MSU Orchid Fertilizer for Well Water 19-4-23-2-0 w/ micronutrients
Jack's Professional Orchid Well Water -16-4-20-3-1 w/ micronutrients

We recommend MSU Orchid Fertilizer for use with reverse osmosis (RO), rain or tap water low in alkalinity.

We offer in our SHOP a granular versions of MSU orchid fertilizer, in a 8oz resealable packages.

As seen in the American Orchid Society Orchids Magazine! Nutrient Analysis of MSU Orchid Fertilizer granular is 13-3-15 8Ca-2Mg


Total Nitrogen 13% (Nitrate Nitrogen 12.5%, Ammoniacal Nitrogen 0.7%)
Phosphate 3.7%
Potash 15.9%
Calcium 8%
Magnesium 2.6%
Derived from calcium nitrate, magnesium nitrate, potassium nitrate and monopotassium phosphate


Iron 0.177%
Manganese 0.088%
Zinc 0.044%
Copper 0.044%
Boron 0.018%
Molybdenum 0.018%
Derived from Iron EDTA, manganese sulfate, zinc sulfate, copper sulfate, boric acid, ammonium molybdate

We recommend use 1/2 a teaspoon every other week or weekly, and you should store the granular MSU Orchid Fertilizer in a cool dry place, humidity liquefied the product but still is appropriate to use.

For Additives we do recommend:

Super thrive, Mycorrhizal fungi, Seaweed Kelp and Amoniacids - Vitamins, these should be applied once a month.

For Supplements we do recommend:

Once a year, every March or April, we should apply our Slow Release Osmocote which is 8-9 months duration, in addition with our Super thrive Granular Plant food, enough to support your orchids during the growing season.

Refer to our store to the FEEDING PROTOCOL Category for all the products recommended!


XOXO @LaForestaOrchids

1. UnderstandingPlantNutrition


2. WaterQuality


3. Fertilizers


4. Substrates


5. Conclusion





American Orchid Society's Orchids Magazine, www.marthastewart.com, staugorchidsociety.org, MSU Fertilizer label recommendations!

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