I struggled for years to find good “insider information” on how to better grow phals; and I never did find a single source for that information. So, I started focusing my efforts over the past few years on 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 some good visual resources, and a few videos at the bottom that are intended to help you better-understand the phalaenopsis species and how to grow them.
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 there are a select number of cold growing phals that need temps down to 10-14C. Most “common” grocery-store phals you find 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 issues. Summer-blooming phals are a little less common, a little harder to care for (they don’t like drying out between waterings), but they also tend to be more vibrant (pinks, yellows, purples), fragrant (some, not all), and ever blooming (don’t cut old spikes until they turn brown).
Understanding why some phals are “summer blooming” vs. “cool spiking”
What makes some phals “summer blooming”, while others need a dip in temp? It all comes down to the plant’s habitat: its 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 grow, the cooler their day-to-day temps are, and the greater the gap between day-to-night temps are. Plants that have adapted to specific conditions, will rely on those conditions and queues to signal their growth and blooming cycles.
If you go both up from sea level and away from the Equator, you get cooler temps, greater variability between your day-to-night temps, and greater seasonal changes. At the opposite extreme, when you’re at sea level you have higher humidity and a denser atmosphere that locks in the heat from the sun and increases your climatic temperatures and stabilizes your environment; so if you’re right on the equator at sea level, your day-to-day (and day-to-night) temps are much more consistent and your seasonal variation is minimal.
An extreme example to help anchor the concept: if you were heading up to visit me here in Canada (way North of the equator)…the winters get hella cold and they day-to-night temps are drastically different. If you were to climb to the top of Mount Everest…it’s freezing! Make sense? If you go up or away from the imaginary belt strapped around the Earth…life gets cooler and more harsh and plants from areas will have adaptations to better manage those conditions.
Why are some Phalaneopsis Warm-Blooming vs Cool?
Relating this all back to phals:
- 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 be higher in 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) need this because they grow on the ground fully exposed (not in direct sun, but filtered with lots of clouds), near sea level (hot growing). The day lengths change summer to winter because they are further from the equator.
The reason temps play such a major role in flowering is really simple…temps signal the onset of spring (the rainy season). Spring means more bugs for pollination and more rain and high humidity for faster growth and seed pod development. After 6-8 months the seed pod breaks open as the rainy/summer season ends, giving the seedlings a chance to be blown around, land, and start growing with a friendly fungi without being immediately washed away by the rains.
So you see, cycles matter. If you want better results, you just have to understand those cycles.
Phalaneopsis in the Wild: Elevation & Temperature
This is all pretty neat, right? Let’s look more into the details of individual phalaenopsis species. Below I’ve created a table that shows each phal, it’s natural distribution, elevation, and temperature associated with that elevation (click it to open the Google Sheet). Down past that, you’ll find an infographic I created that “generally” groups the subgenus and sections of the Phalaenopsis Genus and how that info can help us better-understand their care & bloom times. It’s not gospel and some edge cases exist so just beware that the infographic is a guideline based on this table.
Table of Phalaenopsis by Elevation & Temperature Preference
View Source Table
Temperatures are not a rule!
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 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 (other than a slow-down in winter). The key is providing adequate light (quite bright actually), good nutrients, adequate airflow, and consistent hydration (and no – this doesn’t mean high humidity…my humidity is frequently very low…down to 18% low). Ideal temperatures simply help us control growth rates, growth cycles, and bloom times.
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.
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:
How do you get more Phalaneopsis flowers?
Easy…in 4 simple concepts but difficult achievements:
1. Grow perfect plants – Duh, right; that’s everyone’s goal.
Let me explain why. A plant will put surplus energy into flower production. To get your plant to a point where it can build up 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 them in order to collect a lot of energy. Leaves also take up nutrients (foliar feeding); so get them wet just make sure they dry within 4 hours.
– 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. Orchid roots take up nutrients, period. More roots == more nutrient uptake.
Here’s a key concept you should embrace: The more biomass your plant has (the bigger it is), the more energy it can use to harness energy for flower production. It takes a lot of energy to build plant tissue, but less energy to sustain it…so getting a big plant takes a bit of time, but once your there, keeping it big is just a matter of ensuring even conditions. If you grow perfect plants you’ll get more flowers.
How does one grow a perfect orchid? Good potting culture (wet/dry cycles between watering and lots of air flow around the roots), adequate light, and well-rounded nutrients—simple, right?
2. Grow in BRIGHT LIGHT, but keep leaves cool! Yup…a 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. Cold-growing phals will be similar to the cool-spikers: dark green, often with spots when grown under ideal conditions.
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 can be 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 block 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. The walls and roof of our home do not “filter light”, they completely block it. So most places in your home that are not near a window are not actually as bright as you think they are.
3. Provide perfect nutrients – start by pH adjusting your water…it allows the nutrients in your fertilizer to dissolve properly and not be bound up as unusable compounds. Also, cycle with vital secondary nutrients like Calcium and Magnesium, and maybe even a little iron now and then. I wouldn’t feed micro nutrients at the same time as your regular fertilizing, I’ve heard that they can combine and result in non-usable compounds.
4. Flip the temperature switch! Temperature cycling is just the button that triggers blooming. The longer you keep that switch open for, the better your results will be, but the reality is, if you’re not meeting points 1, 2, and 3…even if you do flawless temp cycling, you’re not going to get as many flowers as you could. Temp cycling will help though…even if your conditions are less-idea. And remember some complex hybrid phals may need warm temps and a bunch need cool temps…so use the resources above to help you approximate what conditions your plant needs to signal blooming.
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” may 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.
Advanced Phalaenopsis Care – pH and Watering
This section is much longer than a paragraph and deserves its own page. pH adjustment can help you get more nutrients into your plant, and result in more flowers and faster growth. If you’d like to know more about pH for Phals, follow this link, watering orchids with tap water & pH adjusting.