Fertilizing your orchids

Orchids require the  optimal balance of factors that influence their healthy growth. Fertilizing your orchids  can be a real game changer if you get it right. Your orchid will be in robust form and will bloom generously during the season. The trick is in tweaking it to suit your grow conditions. In this post, I am touching upon the fundamentals of fertilizing orchids and giving tips on getting good results.

Aerangis biloba – first time  blooms under my care

My first four years into the orchid hobby  were spent on learning how to tend to my orchids. While I had a sizeable  and healthy collection, the blooms were few and far between. My family even began convincing me that I had been duped by the sellers and these plants could bloom well only in green houses.

But YouTube offered many success stories of growing orchids at home, and I knew that I had to keep trying out new ways to increase blooming. I kept fertilizing my orchids once a week by spraying them with concentrations of 200 TDS of NPK fertilizer, but it just did not seem to be enough. The few orchids that bloomed produced one or two flowers. That’s  when I realised that perhaps they required more frequent application at higher concentrations.

I got new insights on nutrition for orchids by watching Rick L’s Orchids  channel on YouTube. His explanations seemed logical and his orchids looked healthy and bloomed abundantly. I laid down a similar strategy for fertilizing my orchids. I fine-tuned it to suit my climatic conditions and my orchids are responding well by producing more blooms with each passing season.

However, I have achieved results after experimenting repeatedly. I am sharing my insights and tips on applying fertilisers that helped improve blooming.

Basic orchid care comes before fine-tuning your fertilising routine

Cattleya labiata Coerulea blooming for the first time

Getting a beautiful bloom show is every orchid lover’s dream. And while some orchids put on their best show without any special care, the majority of orchids, especially cultivated hybrids, require the right balance of light, moisture, temperature and nutrition to coax them to bloom. From my experience as an orchid hobbyist, I have realised that missing out on even one of the above mentioned factors will affect the outcome of an entire year’s care. So when we talk about fertilising your orchids, it is utmost important that you do not overlook  basic factors such as suitable light, moisture and temperature to achieve good results.

Orchids are mostly epiphytic, and in their native environment depend on the trees on which they grow to provide them with nutrition – not as parasites sucking the sap of the tree, but by absorbing the the nutrients from dust that has  settled over time, bird and insect droppings that run down the trees along with rain water. Rain water, which collects Vitamin B12 producing bacteria and fungi from the air, also helps the orchids absorb these nutrients, thereby optimally meeting their requirement of Nitrogen, Phosphorus and Potassium. Along with these, Calcium, Magnesium and other trace micronutrients are also made available to the orchid.

When there are no rains, the aerial roots absorb moisture from the air and thereby help the orchid survive. The orchids also have thick fleshy pseudobulbs and leaves, which serve as reservoirs of stored energy. This is used up by the orchid to grow and bloom during periods of drought.

With this understanding, we need to now provide nutrition in similar ways and mimic nature. Of course, with the growing number of special hybrids, the need for fertilising year round has become a norm as these orchids produce large blooms and also have more number of spikes and blooms. However, the basic principles remain the same, wherein the orchid requires maximum nutrition during its growth period, and the stored nutrients get utilised during the bloom period. However, opinions differ, and some hobbyists continue to feed minimally or nominally even while they are in bloom.

About orchid fertilisers

Initially, the Brassocattleya Jimminey Cricket did not bloom due to low concentrations of fertilizer. After tweaking the concentration, it bloomed repeatedly.

Orchids need to be fertilised when they are in vegetative growth. This is crucial for their proper development and blooming. So when you observe new leaf or root growth or the development of a bud spike or new shoot, then you need to feed it with fertiliser to meet its increasing requirement for growing new tissue.

To this end, we should apply a fertiliser that is rich in basic building blocks (macronutrients) such as Nitrogen, Phosphorus, Potassium as well as Calcium, magnesium, and other trace micronutrients such as zinc, manganese, cobalt, boron, , copper, iron and molybdenum. Most fertilisers have these components in a form that can be easily absorbed by orchids. Nitrogen promotes good leaf and shoot growth. Phosphorus promotes healthy root growth as well as development of bud spikes and blooms. Potassium makes plants robust and strong, builds resistance to pest attack.

Orchid fertilisers can be grouped into Chemical and Organic fertilisers. Chemical fertilisers are those that are manufactured in an industrial process and are in a chemically pure form, either in a powder form or as a solution. Examples of these are NPK 20:20:20 and solutions of Calcium Nitrate and Magnesium Sulphate (Cal-Mag).

Organic fertilisers, on the other hand, are made from plant or animal matter and even their excreta. These substances are in the form of bio-compounds that need to be further broken down by microbes in the medium to get absorbed by the plants. Examples are sea weed kelp, fish fertiliser and other home-made fertilisers such as soaked rice water, green tea extract, garlic extract, banana peel extract, diluted coconut water etc.

While the above fertilizers enhance vegetative growth, commercial growers use bloom booster fertilizers to improve bloom production. This is an NPK type of fertilizer with a higher proportion of Phosphorus.  A balanced NPK 20:20:20 fertilizer application alternating with a high phosphorus and potassium fertilizer helped my orchids grow and bloom just as well.

How often should you fertilise?

Include weak fertilizing every week with a number of different fertilizers to provide all types of nutrients and micronutrients

Well, there is no one-size fits-all answer to this question. It all depends on your climatic conditions, your grow area – whether indoor or outdoor, your frequency of watering, the medium in which the orchid is growing, ambient temperature,  etc.

West facing window sill set up

Generally speaking, you can fertilise once a week, or you could divide the same dose into half and do a twice weekly routine, if you are watering your orchids twice a week. Remember to flush your orchids with plain water in between to avoid build up of fertiliser. Initially, I fertilised my orchids once a week, but that just didn’t get them to bloom. After going through Rick L’s videos on YouTube, I began fertilising my orchids twice a week at recommended concentration, but I varied the type of fertilizer I applied so that they absorbed different types of nutrients and trace minerals.

North facing window sill

Before I talk about my fertilizing routine, it would be good to give you an idea of my setup. I grow my orchids on my windowsills, and they get plenty of natural light and air. I grow orchids in well-draining bark chips along with some moisture-retentive sphagnum moss or coco chips. My setup allows me to water my orchids lightly by spraying them everyday.

For instance, I apply NPK 20:20:20 along with Calcium nitrate and  Epsom salt once in 4 days. I repeat with the same after  four days. After 3 more days, I apply a high phosphorus and potassium fertilizer such as NPK 00:52:34. In between, I apply organic homemade liquid  fertilizer twice a month and Silicon dioxide fertilizer once a month. This method of appropriate dose fertilizer application, either stand-alone  or in combination, has helped me improve growth in my orchids. Lots of healthy roots, pseudobulbs, and leaves will ensure healthy blooming in your orchids. I will cover this aspect at length in a separate post.

Applying the right quantity of fertiliser to your orchids

Orchid hobby guide
Apply optimal concentrations of fertilizer to coax your  orchid to bloom

Having said this, there are some ground rules to begin with. Doing it right and understanding the basics of applying the right quantity of fertiliser is important. Following the recommended doses and frequency as advocated by the fertiliser manufacturer helps if your fertiliser is designed for orchids. But if it is a general plant fertiliser, it is always better to start with half the recommended dose and increase or decrease it based on the response of your plants.

If the leaf and root tips start drying out, it is an indicator of leaf tip burn, then it means the concentration of salts is too high. The quantity of fertiliser needs to be reduced in such cases. However, if the orchids show healthy development, then the dosage caters optimally to the plant’s nutrient requirement. On the other hand, if the plant shows no improvement in growth, and new growths die back or have stunted growth, then you need to increase the dosage gradually until your plants become healthy and lush green. These healthy growths will then produce blooms during the season.

Healthy roots are good news. It’s one step nearer to blooming your orchids.

Concentrations matter based on size of orchid, the thickness of the leaves and roots. Orchids with thick, spongy velamen and thick leaves such as Vanda and Phalaenopsis orchids require regular doses of fertiliser like a teaspoon of fertiliser in 5 litres of water. But for thin leaved and thin velamen-root orchids such as Oncidiums, Tolumnia, Catasetums and Bulbophyllums and others, the dilution can be reduced by adding half teaspoon of fertiliser in 5 litres of water. If the orchid fertiliser is not improving growth, then you can marginally increase dosage until these orchids start developing healthy roots, leaves and shoots.

When not to fertilize

You should fertilise your orchids during periods of active growth. This is usually during the warmer summer months and rainy season. Your orchids will produce new roots, leaves and new pseudobulbs. The right amount of fertiliser application will help in their healthy development. However, as ambient temperature drops down with the advent of winter, you need to minimally water and fertilise your orchids based on their growth.

There would be a few exceptions, such as Oncidiums, which would start producing new growths in winter. In such cases, you can continue fertilizing these orchids. However, a major portion of your collection would be done with the growth period, remain dormant, and conserve energy for the bloom period in spring. In such cases, water them sparingly and allow them to rest in a near-dry condition. Don’t worry if you see the pseudobulbs 66. That is a part of their cycle, even in the wild. Once the temperatures rise back to normal, the orchids will push out new growths such as sheaths, spikes, new shoots, and roots. At this stage, you need to resume watering and fertilizing.

Do not fertilize if your orchid is not doing well

Another instance of when you should avoid fertilizing your orchid is when your orchid is sick or has undergone a shock such as a transplantation shock or sudden change in ambient environment. This could be when you buy a new orchid and bring it home, repot it or if it has some underlying infection and is therefore not growing normally. In such a scenario, it is best to not increase stress by fertilizing it during this period. Gradually, when the orchid shows sign of recovery and growth, you can begin fertilizing it with very low concentrations to begin with and gradually resume to normal levels.

As you tweak your fertilizing method, your orchids will bloom in significant numbers

With these fundamentals in mind, you can go ahead and experiment with different kinds of fertilizers.  You can check out which ones are most suited for your grow conditions. Remember to keep it optimal. Your orchids will thrive and reward you with healthy blooms during the season. 

Happy growing!

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