Hey Guys,

I’ve had quite a few emails just lately about orchid fertilizers and how to fertilize orchids (such as the one below), so I thought I’d try to answer them all in one go by posting an article all about orchid fertilizers.

Here’s an typical example of the sort of emails I receive:

Dear Danny,

I have just got together the ingredients for my orchid fertilizer. What I need to know is how to apply it. Does it need diluting? And should I use it every time I water or more sparingly? A quick answer would be appreciated.

Thank you.

Yours sincerely,

Dinah

Why the need for orchid fertilizer?

As well as light and water, orchids also require additional chemicals that provide them with nutrition.

In the wild, an orchid will scavenge these nutrients from decaying matter that they obtain from the forest floor or that has been collected by rainwater as it flows by.

Domestic orchids require these nutrients to be supplied to them in the form of fertilizers or orchid food.

What’s nutrients do orchids get from fertilizers?

There are three main nutrients that an orchid needs to grow healthily; Nitrogen (N), Phosphorous (P) and Potassium (K). The letters in brackets refer to their chemical symbols. In lesser amounts, Calcium (Ca), Magnesium (Mg) and Sulfur (S) are also required.

These six chemicals are referred to as Macronutrients. There are also a number of Micronutrients; Boron (B), Chlorine (Cl), Copper (Cu), Iron (Fe), Manganese (Mn), Molybdenum (Mo) and Zinc (Zn) that provide nutrition, however an orchid will need much smaller amounts of these chemicals.

Manufactured orchid fertilizers

Most manufactured orchid fertilizers will have an NPK ratio printed on their containers, which refers to the percentage of Nitrogen, Phosphorous and Potassium they contain. For example, a fertilizer with an NPK of 30-10-10 will be made up of 30% Nitrogen, 10% Phosphorous and 10% Potassium. The remaining 50% will be made up of other macronutrients and micronutrients, as well as other chemicals.

Some good manufactured orchid fertilizers are this general purpose (20-20-20) fertilizer (which can be used for most orchids) and this high-nitrogen (30-1-10) fertilizer (which is good for orchids grown in tree bark).

Home-made orchid fertilizers

If you have a penchant for chemistry, you may consider creating your own organic orchid fertilizers at home. For those that do not have the scientific foundation, you can obtain homemade orchid fertilizer recipes here (if you try them, please let me know how well they work for you).

A breakdown of the pros and cons of manufactured and home-made orchid fertilizers can be found here.

How to fertilize orchids

So, we’ve learned that orchids need fertilizer to provide them with essential nutrition to keep them healthy and that the main decision to make when using an orchid fertilizer is whether to use a manufactured or home-made solution.

Next, we will look at exactly how to feed the fertilizer to the orchids.

Many orchid enthusiasts use what is known as the ‘Weakly, Weekly‘ approach to fertilizing their orchids. This simply means that an orchid is fed a weak or highly diluted fertilizer every week.

In my own opinion, orchids should be fed at the same time you water them, which may not always be weekly. Again a weak solution of water and fertilizer should be used.

The best way I know of to water an orchid (and, of course, feed it at the same time) is to add a little fertilizer to a watering can (or similar container) of water, then pour the solution into the pot ensuring all the potting mix is well drenched. Then, wait for almost all the liquid to drain out of the bottom of the pot before watering and draining again.

This video about watering a phalaenopsis orchid shows how to water an orchid properly.

Orchid fertilizer for orchids planted in fir bark

A little earlier, I recommended an orchid fertilizer with high nitrogen content for orchids growing in tree bark.

This is because bacteria in the bark mix contains micro-organisms that consume large quantities of Nitrogen and can potentially starve an orchid of their Nitrogen nutrition.

For this reason, if you grow an orchid in a bark potting mix it is recommended that you use a fertilizer with a higher Nitrogen content.

Orchid fertilizer for orchids planted in sphagnum moss

If you have an orchid that is growing in sphagnum moss, I recommend using an even weaker fertilizer/water solution.

This is because sphagnum moss holds on to or absorbs salts much better than other potting mediums so the nutrients have a lot more chance of staying within the pot rather than draining out of the bottom with the water.

Summary

In this post, I’ve explained why orchids need fertilizer and that your main choice when deciding on a fertilizer is whether to buy a manufactured version or create your own.

I’ve also explained that orchids should be fed whenever they are watered and that a low concentration of fertilizer should be used.

Finally, I explained how different potting mediums may affect your orchid feeding technique.

I hope you’ve found this useful and if you have any further questions or require any more clarity, please drop me an email at [email protected] or leave a comment below (I can’t promise to answer all questions individually but I do try and answer as many as I can).

Danny