I struggled for years to find good “insider information” on how to grow rock-star phals; and I never did find a single source for that information. So, I started focusing my efforts scouring the internet and books in an effort to learn the grueling details of the Phalaenopsis Genus. I’ve tried to be critical about understanding why phals grow better under specific conditions rather than just regurgitate what’s already out there. In this article you’ll find a couple visual resources and a few videos at the bottom which are intended to help you better-understand the phalaenopsis genus and how to grow them with more success.
First, some of my phals “as proof” (that I know what I’m talking about)
What are Summer vs Winter Blooming Phalaenopsis?
To kick this off, like the title of this article indicates, there are Summer (warm) and Winter (seasonally-cool) blooming phals. There are also phals that need long photo periods (12-14h) to bloom, AND a select number of cold-growing phals that need temps down to 10-14C in order to thrive.
Most “common” grocery-store phals are going to be winter-blooming and will require a cool dip in temperature to set spikes. When I say a “cool dip”, I mean down to about 14C at the lowest during the evenings. If you go much lower than that you’re risking bud blast or fungal (rot) issues. For these winter-blooming phals, high daytime temps (28C+) may also stop spike and flower production—leading to bud blast in the warmer months of summer.
Summer-blooming phals are a little less common (you likely won’t find them at a grocery store) and a little harder to care for (they don’t like drying out as much between waterings). But the pay-off for these more-challenging growers are: vibrant colors (pinks, yellows, purples), fragrant flowers (some, not all), and ever-blooming spikes that can produce flowers on and off for years (so don’t cut old spikes until they turn brown).
Understanding why some phals are “summer blooming” vs. “cool spiking”
Maybe you’re wondering, what makes some phals “summer blooming”, while others need that dip in temp to flower? It all comes down to the habitat of each individual species. Specifically, the global position from the Equator and its elevation from sea level. The bottom line is, the further away from the Equator your plants are native to, the more variability they will have experienced in annual seasons (cooler & dryer winters). AND the higher up from sea level they grew, the cooler their day-to-day temps were and the greater the gap was between day-to-night temperatures. Plants which have adapted to specific climates, will rely on (and in some cases require) those conditions and queues to signal their growth and blooming cycles because it would have ensured their success in that habitat.
If a plant came from an area that was both up from sea level and away from the Equator, it will have adapted to cooler temps, greater variability between day-to-night temps, and more-pronounced seasonal changes (think, “Phalaenopsis japonica”). This also means it will likely be easier to grow for a someone who lives in a cooler climate. At the opposite extreme, if a plant came from an area that was at sea level, right on the equator, it would be used to higher humidity and a denser atmosphere (which has the effect of locking in the heat from the sun and increasing the ambient temperatures, stabilizing the environment), and this plant would be easier to grow for a person who lives in a more tropical & humid climate.
Visualizing the relationship between temperature & habitat
Elevation – Day & Night Temperature Variation
Longitude – Seasonal Temperature Variation
Why are some Phalaneopsis Warm-Blooming vs Cool?
It’s pretty simple really – it all comes down to this:
- Hot growing (summer-blooming) phals come from habitats close to the equator and near sea level (under 500m)
- Cool-spiking phals grow further from the equator and tend to grow at moderate elevation (500-1,000m)
- Cold-growing phals grow the farthest from the equator and the highest in elevation (1,000-2,500m)
- The select few phals that need long daylight hours (Phal pulcherrima & buyssoniana) require longer hours to bloom because they grow on the ground near sea level but they come from a more northern longitude (and therefor are used to experiencing longer daylight hours during the dry season).
The reason temps play such a major role in flowering is that those temperatures signal the change of seasons and the onset of the rainy season. More rains mean more bugs for pollination, more nutrients and higher humidity for continuous growth and seed pod development. After 6-8 months the seed pod breaks open as the dry season hits its peak, giving the seedlings a chance to be blown around, land, and start growing with a friendly fungi without being immediately washed away by heavy rains.
When it comes to orchid care, cycle are very important. If you want better results, understanding the species and it’s requirements can give you the ability to customize the requirements (even if that only means setting your light timer to turn off 3 hours later in the summer than in the winter).
Phalaneopsis in the Wild: Elevation & Temperature
This is all pretty interesting, right? Let’s look more into the details of individual phalaenopsis species (or you can skip past to the “easy version”)
Below is a table of the phalaenopsis species. It shows each species, it’s natural distribution, elevation, and the temperature associated with that elevation. (open this table in Google Sheets). Down past that is a simplified infographic that “generally” summarizes and groups the subgenus and sections of the Phalaenopsis Genus. It’s good info because it can help us better-understand phalaenopsis care & bloom times from a high-level without having to remember EVERY SINGLE SPECIES. Please be aware, the infographic is not gospel and edge cases exist (for example, Phal mannii is grouped with the “warm growers”, but it’s technically a cool grower because as the table indicates, mannii comes from the Himalayas and India at elevations up to 1,500m).
Table of Phalaenopsis by Elevation & Temperature Preference
View Source Table
For something less complicated
So, maybe you’re not a phal expert…yet. That’s okay. We can take a step back and generalize care by grouping phalaenopsis species together by their subgenus. Like I said above, it’s not 100% accurate…but it’s easier than memorizing every single species and it’s helpful for broadly understanding phalaenopsis care at a glance. Just make sure you check out the care requirements for each species you grow to ensure best results.
Phalaenopsis Infographic on Warm-Blooming vs. Cool-Spiking species
Get the high-res version: you can download and print this Phalaenopsis “Advanced Care” reference graphic.
Phalaenopsis temperature requirements are a guideline…
Even though over 60% of phal species are heavily in the “Warm” and “Hot” low-elevation habitats, it doesn’t necessarily mean they can’t withstand cooler temps. I am able to grow phal bellina, gigantea, appendiculata, violacea, and many other “exclusively hot growing phals” at cool-to-intermediate temps here in Canada (Winter: 14C-22C, Summer: 17C-28C) without any major effects. I do find that there is a slow-down in growth rate over the winter; however, the key to reducing this “growth stall” has been to provide adequate light, good nutrients, adequate airflow, and consistent hydration. And no, this doesn’t mean high humidity; the humidity in my home is frequently as low as 18%. Ideal temperatures simply help us control growth rates, growth cycles, and bloom times.
The exception: cold growing plants often rely on cool temps to throttle their metabolism. If you try to grow cool-growing plants at high temps, they often do not deal well with the higher temperatures and can exhaust themselves after many months of high temps, or simply collapse if temps go too high for a short period.
Now that we understand that there are warm and cool growing phals, AND we know why, AND we know which are which, let’s get the question you really care about:
Advanced Care Tips: How do you get more Phalaenopsis flowers?
Easy…in 4 simple concepts but difficult achievements:
1. Grow perfect plants – Duh, right? That’s likely everyone’s goal.
Let me explain: once an orchid is established and “happy”, it will put it’s surplus energy into flower production. Think of this like how we eat carbs; if we’re fat and happy, and 3 years into our very-comfortable relationship, we get a little chubby. Unlike us, plant’s don’t store fat, but instead they direct surplus energy to reproduction. More energy == more flowers. To get your plant to a point where it can collect extra energy it needs:
– LOTS of leaves. Leaves are a plant’s solar panels and they absorb the sun’s energy. You need a lot of leaves in order to collect a lot of energy from the sun. Leaves also take up nutrients (foliar feeding); so get them wet, just make sure they dry within 4 hours. Leaves will drop and redirect nutrients to new leaves if the plant has a nutrient deficiency…so that leads to my next point;
– LOTS of roots to take in nutrients. Anyone who tells you “orchid roots are just for anchoring them to a tree”, is flat-out wrong. Sure, that’s part of the story, but orchid roots (like every other plant on earth) take up nutrients. More roots == more nutrient uptake.
Here’s a key concept you should embrace: The more total biomass your plant has (the bigger your plant is), the more it has the potential to harness energy for flower production. It takes a lot of energy to build plant tissue, but a lot less energy to sustain it. So getting a lush and rooty plant should be your #1 objective. This process takes a bit of time (and I often find new phals can take a year or two to really establish and beef up under my conditions), but once your plant has put on size, keeping it large is just a matter of ensuring even conditions, good light, healthy roots (repot every year) and well-balanced nutrients. If you grow perfect plants you’ll be rewarded with more flowers. How exactly does one grow a perfect orchid? With good potting culture! That includes: wet/dry cycles between watering, lots of air flow around the roots, frequent flushing of the pot to remove the build up of toxic chemicals and salts, adequate light, and well-rounded nutrients—it’s so simple, right? (Don’t worry…it literally took me over 8 years of orchid growing to finally grasp how this all works together, and because I think we all should experience the same joy of orchid care, that’s why I’m sharing this info with you)
2. Provide perfect nutrients – I mentioned above about leaf drop; it’s a condition that happens when nutrients are not ideal and the plant needs to pull nutrients from old leaves in order to grow new ones. You don’t want that; you want every leaf to stay put, stay green, and help your plant produce more blooms.
If you want to get “perfect nutrients”, you should consider pH adjusting your water to 5.8ph when you fertilize. pH adjusting allows the nutrients in your fertilizer to dissolve properly and not be bound up as unusable compounds. It’s smart to cycle your fertilizer routines with vital secondary nutrients like Calcium and Magnesium, and maybe even a little iron now and then.
Tip: Don’t feed micro nutrients at the same time as your regular fertilizing, I’ve heard that they can bind up with your standard fertilizer and result in non-usable compounds (more or less cancelling each other out). This might not be accurate…but there’s no harm in playing it safe.
3. Grow in BRIGHT LIGHT, but keep leaves cool! Yup…another repeat. “Low light” isn’t going to cut it if you want lots of flowers. You need to stuff your plants with energy until they’re ready to barf chlorophyll! Ideally, you want your plants at the upper limit of light that they can tolerate. The leaves of warm-blooming phals should be vibrant green but not yellow; in a perfect world, you want the leaves to just start having chlorotic patching that you can then remedy by providing “perfect nutrients”. Cool-spiking phals will have leaves that are a deeper green but they should be a vibrant deep green, rather than a dark forest green. Light freckling is common if the light is at the upper limit for these phals as well. Yellowing leaves is always a sign there is too much heat. Cold-growing phals will be similar to the cool-spikers: dark green, often with spots when grown under ideal conditions. If you want more information about light, I’ve created a comprehensive overview of how to evaluate LED grow lights – that post is a bit technical, but it’s a really good place to start if you’re looking at adding more light to your growing area.
Be aware – HEAT CAN KILL: Growing plants in bright light does not mean you want HOT plants! Leaf burn will kill your plant and it’s caused by heat on the leaves. Direct-sun is often hot and it can burn leaves, BRIGHT-light alone rarely burns leaves so you need to understand that there is a relationship with light sources and heat…but they’re not one-to-one. In rare cases too much light can destroy cells, but that’s hard to do (you’d really need to go out of your way to spend a LOT of money on high-output lights) and in those cases it’s not from heat, but instead from too much light. Your goal is to grow your plants under bright light but have the leaves be cool to touch. LED lights are great for pumping out efficient light that doesn’t push heat as well. If you’re growing by a window, that’s okay, you still want to put your plants in direct sun, but then reduce/filter it with a sheer curtain so that the plant is still getting some direct rays of sun, but not ALL the rays of sun (and not all of the heat). If you move your plant in and away from the window, you’ve essentially put it in 100% shade. Think about a bridge…around a bridge, plants grow; under a bridge…very few plants grow (or none at all). The walls and roof of our home do not “filter light”, they completely block it. So most places in your home which are away from the windows are not actually as bright as you think they are.
4. If appropriate for the species, flip the temperature switch! Temperature cycling is just the button that triggers blooming in the seasonally-cool bloomers. The longer you keep that switch open for (the longer you keep your plants at the cool end), the better your results will be. But here’s the raw truth, if you’re not meeting points 1, 2, and 3… if you’re not growing really happy plants, even if you do flawless temp cycling, you’re not going to get as many flowers as you could. Temp cycling will initiate spikes though (even if your conditions are less-ideal).
Something to be aware of regarding hybrids: some complex hybrid phals may need warm temps and a bunch will need cool temps. You can use the resources to generally help you guess what conditions your plant will need to signal blooming…but it may also largely come down to trial and error if your plant has many species contributing genetics.
Rrrrrrright…but does temperature cycling actually work? (OBVIOUSLY YES)
Watch these three videos and I’ll explain AND SHOW YOU just how effective temps changes for Phalaenopsis increases bloom count
Video 1: Advanced Phalaenopsis Care & Culture
Summer vs. Winter Bloomers
Video 2: Follow-Up Video Showing Spike Progress
Video 3: 7 Months Later – Seeing the Effects of Temp Cycling on Select “cool spiking phals”
FYI – Some Phals Need Long Photoperiods to Spike
In general light duration doesn’t have an effect on bloom initiation; however, reportedly Phal pulcherrima and the section “Esmeraldae” require longer photoperiods to initiate blooming. You can read more about the details of the study here. The gist of the study is this:
In a 2005 study conducted in growth chambers, Phalaenopsis pulcherrima, Phalaenopsis buyssoniana, and Doritaenopsis ‘Purple Gem’ all spiked under a 14-hour period at 77°F day/68°F night (25°C day/20°C night). The light intensity in growth chambers was adjusted, allowing plants under both 14- and 9-hour photoperiods to receive 8.4 µmol•m-2•day-1 PAR.
None of the plants under the 9-hour photoperiod spiked. All of the plants in the greenhouse started to spike in late April and continued to produce more spikes through September under the natural long photoperiods. It is not clear if flower bud initiation would take place under short photoperiods after spiking.
A Small Number of Phals Need COLD Temps (down to 10-13C nights)
Those are from the Subgenus, Aphyllae. The nice thing is, you likely won’t find these very often because they’re more difficult to care for because they do indeed need those cool temps. What you need to know for culture is that they need cooler temps, that they’re heavily seasonal (often dropping leaves in the dry winter), and that they bloom in the early spring.
Advanced Phalaenopsis Care – pH and Watering
This section is much longer than a paragraph and deserves its own page. I mentioned that pH-adjustment can help you get more nutrients into your plant, and that ultimately results in more flowers and faster growth. If you’d like to know more about pH-adjusting for Phals, follow this link, watering orchids with tap water & pH adjusting.