So you’re looking for some tips on Paphiopedilum Care and Grow? Ok, let’s find out. These plants from Southeast Asia feature heavy, one to three-month-long blooming flowers. There are numerous different sizes, shapes, and colors available in multi-flowered, sequentially flowered, and single-flowered variations. Paphiopedilums cannot currently be accurately cloned, making bulk production challenging. Because many kinds of Paphiopedilum are simple to grow indoors, they are among the most distinctive and widely collected orchids in the world.
Paphiopedilums are always associated with low light. They prefer intermediate light, in my experience, which is bright enough to promote healthy development and brilliant leaves but not so hot as to scorch the foliage. What does that imply then? East-facing windows that receive some early direct sunlight or South/West windows covered with sheer fabric that blocks at least 50% of the sun seem to be preferable. Because you can supply low-to-moderate light for lengthy periods of time (10–14 hours), but only need roughly 8–20 watts per square foot of coverage, LED growth lights are very useful.
Several species of paphiopedilums have distinct lighting needs.
These are broad aims for each group, not specific values, so please use them as a starting point and modify them based on how your plants behave.
Paphiopedilum with mottled leaves, as those found in the genus Maudiae or the genus Delenatii, require little light—certainly less light than multi-floral Paphiopedilum —roughly 3-8% of the sun, 66-175 PAR/ppfd, or 300-800 footcandles.
Sequential-blooming plants, like Primulinum, Pinocchio, or Glaucophyllum, and strap-leaved plants, like Spicerianum or Villosa, thrive in low-to-moderate light environments (approximately 5–15% sun, 110–330 PAR/ppfd, or 500–1,500 footcandles).
Light levels should be increased to Cattleya levels in the fall during inflorescence formation for multi-floral paphs (such as philippinense, sanderianum, and rothschildianum) (roughly: 10–35% sun; 220-770 PAR/ppfd; or 1,000–3,500fc).
Temperature and Humidity
It’s important to have “moist roots, but not always damp or dry”…
When first started cultivating paphiopedilums, this was really confusing. It was particularly difficult to comprehend, “Not dry, always moist, but not wet,” because in the dry Alberta climate, it only takes 24-48 hours to get from one extreme to the other.
Never let the roots completely dry out! If the roots are dry, you should have watered yesterday, goes the proverb, and I thought that was terrific advice. With that information on when to water, you may carefully watch how quickly your potting mix dries out (in your specific climate, in your specific conditions, in your pot size, and in the type of media used) and then follow a fairly predictable watering schedule going forward.
The fourth day should be used for watering the following time if you watered five days ago and the bark and roots are completely dry. Use transparent or clear orchid pots to help with this because you can see what’s going on inside; if there isn’t any condensation between the bark medium or if the roots in the middle or bottom of the pot appear dry, watering is necessary.
On the day of watering, soak the entire pot in water for at least five minutes, up to the plant’s base. My 4.5′′ pots fit perfectly in a coffee mug, so I just plop the pot inside and soak the media from the top till the mug is full before setting it aside for at least 5–10 minutes. If your climate is particularly dry (less than 50% rH), you can leave them in the water for a solid 20 to 45 minutes without any problems. In the beginning, err on the side of caution and keep your soak times to around 30 minutes.
Root rot is caused by anaerobic conditions rather than water (more on potting media below).
Root rot is caused by calcium, nutrient shortages, and low pH, not water (more on this below).
To assist oxygenate the roots AND waterlog the bark, you should actively irrigate and flush lots of water through the pot when watering. A microclimate of high humidity will be created in your pot when the bark is saturated since it will release moisture over the course of a week. As a result, “dribble watering” is probably ineffective because it can result in a top area that is completely dry and a moist bottom section.
To uniformly moisten the entire pot, you should soak the bark completely (allowing the shorter new roots to succeed as well as older longer ones). To maintain the health of your roots and prevent desiccation, soak and flush your pots every 5 to 10 days. If your plant is just a little dehydrated, this method of root soaking also enables it to rehydrate.
Your individual temperature, the size of the pot, the type of pot (terracotta actually SUCKS water out of the potting media while plastic pots store moisture), and the size of the potting medium may all require you to change the watering cadence. Please don’t take that to mean that every 10 days is all you need to water your plants. If your humidity is 30% and you have a small pot with chunks of bark, you might need to water that plant every other day just to keep the roots moist.
Extend root moisture: After the potting media has been soaked and drained, you can add another 1/8-1/4″ inch of water to the tray. Since most care sheets make it very explicit to “never soak Paphiopedilum roots,” I realize that this may sound like the cardinal sin of paphiopedilums, but we’ve already broken that rule, and I’m here to help you change your results. The way my Paphiopedilum grew was fundamentally altered by using this piece of advice.
If you know what you’re trying to achieve—which is to maintain the roots constantly moist between waterings and to keep them oxygenated—it’s a pretty potent suggestion. You should first pay extremely close attention to this procedure to avoid using too much water. You only want to use enough water for it to dry out within 24-48 hours.
If you water on Sunday and there is still water there on Wednesday morning, you should drain out what is left and use a bit less water the next time. The idea isn’t to have the pot sit in water for the entire week. Be aware that seasonal variations may affect your evaporation rates and that what works in the winter may need to be changed in the summer.
Paphiopedilum used to have spring and summer growth spikes in their roots before I started doing this. Now that they receive consistent moisture throughout the week, I get nearly a full year of root growth.
Frequency of Watering: “How frequently should I water Paphiopedilum?
As said above, the frequency for you will depend on your potting mix, your environment, and your way of life in general. Some gardeners use a chunkier medium that dries faster because they love often watering their plants. I can say that if it takes your potting media more than 10 days to dry, you may have to deal with anaerobic conditions as it could indicate insufficient ventilation or compacted media. If in doubt, repot.
Humidity: Although most care instructions state that “paphiopedilums demand high humidity,” I’ve found that to be untrue, so I’ve delayed this till the end of the hydration section (as long as you keep your plant hydrated and avoid drought). As you can see, this care sheet places a lot of emphasis on hydration strategies, watering frequency, and preventing extremes of moisture or dryness at the roots. This is how I’ve been able to successfully produce Paphiopedilum in my extremely dry climate (which seldom goes above 50%rH and frequently hovers around 20-35%).
Increasing humidity will likely make it easier to care for the plant week after week and reduce the likelihood of extreme drought, just like with caring for all tropical plants. Low humidity, however, isn’t a death sentence as long as you can prevent hard drying of the roots, in my experience cultivating a broad variety of uncommon plants and Paphiopedilum for many years (including Paphiopedilum , lowii, philippinense, henryanum, tigrinum, primulinum, helenae, and a number of hybrids).
What kind of potting mix do paphiopedilums require as a potting medium?
Paphiopedilums require sufficient ventilation at their roots, as was already mentioned. Although many of them are terrestrial and grow in a mixture of leaf litter, decaying forest debris, rock, and once again, moss, they often grow as epiphytes (on trees with their roots covered in live moss) or lithophytes (on a rock with their roots similarly covered in live moss).
In general, all of these will be water-retentive yet well-draining (not dense, muddy, or compact), and they all are often rained on. Many species originate from regions with seasonal monsoons when it rains every day for weeks or months at a time. To prevent the roots from choking and rotting, your potting medium must be able to hold water while still allowing for drainage and circulation.
I’ve been working with it for a few years and recommend using a baseline blend. A top-dressing of sphagnum moss is placed around the base of the plant and the composition is nearly equal parts bark and rock (pumice or big perlite). The sphagnum helps keep the plant’s base moist (where new roots begin) and it moderately slows evaporation, although it is only a thin covering, measuring only 1/8 to 1/4 inch thick. I prefer Orchiata (pine bark) over fir bark since it lasts longer and reliably holds onto water (which can fragment and get soggy as it ages faster than pine bark). If available, I’ll also substitute horticultural-grade charcoal for some of the rock (up to 5% of the total media ratio).
Additional advice for potting media
If the bark/rock media is drying up too quickly, you can optionally add a tiny amount of peat moss or broken-up sphagnum moss; however, you shouldn’t utilize this option and should instead repot the plant if the medium is keeping moist for longer than 10 days.
When should paphiopedilums be repotted? This is a wonderful question. Most individuals will advise you to repot Paphiopedilum frequently—even once a year. Only every two to four years do repot, an awkward face. But use alkaline water, which prevents the potting media from becoming acidic because the calcium in my tap water constantly buffers the pH, and at least 50% of my potting mix includes rock, which provides structure and prevents compaction as the organic ingredients decompose.
Therefore, to be safe, you might want to repot every year (just be careful as Paphiopedilum roots break easily as they are less flexible than other orchids). If you plan to repot plants less frequently, I strongly advise using a well-draining potting mix with more inert chemicals, like the ones we just discussed. You should also seriously consider adding an oyster shell to prevent the media from becoming too acidic.
Additionally, repot plants regularly enough to prevent them from becoming pot-bound; if the roots circle the inside of the pot excessively, they may build a barrier that hinders future root growth. While not over-potting it to the point that the medium takes too long to dry up, make sure your plant has enough room for its roots to spread out.
How do fertilize Paphiopedilums?
Fertilize “weakly, weekly” (about 1/4 to 1/2 strength of the recommended dose; for Paphiopedilum, it’s even better to tread closer to 1/8 the recommended dose) as you would with the majority of orchids. Salts are known to cause reactions in some Paphiopedilum, and unfortunately, by the time you notice a problem, the plant is already under a lot of stress.
Synthetic feed: I use 1/8 to 1/4 teaspoons of MSU orchid fertilizer per gallon (4L) of water because the tap water I use for my plants is alkaline (7.5-8.3 pH with 200-250 ppm total dissolved salts). Immediately after a meal, give the plants two waterings alone (which flushes and removes the old fertilizer). strongly suggest utilizing organic fertilizer in addition to synthetic fertilizer because I don’t believe synthetic fertilizers are always as complete as we’d like them to be.
Organic fertilizer for paphiopedilums: I add a small amount of organic fertilizer to the potting soil 2-3 times a year (in the spring, early summer, and whenever I repot a plant).
In general, organic fertilizer is not water-soluble and gradually decomposes in the potting medium, releasing nutrients. If you watch Ed’s Orchids on YouTube, he also practices this, and the plants he grows are really robust. If you haven’t, you should because it’s a fantastic resource for Paphiopedilum care in general.
Gia Green’s All Purpose 4-4-4 is an organic fertilizer that contains bat guano, bloodmeal, rock dust, oyster shell, and many other beneficial ingredients. Find bloodmeal, oyster shells, and rock dust if you can’t get this product. Bloodmeal delivers nitrogen, the oyster shell provides calcium as a pH buffer, and rock dust offers minerals from crushed rock. Only use a tiny bit of organic fertilizer if you’re going to use it. like a tiny pinch for each pot.
Nutrients are released as it decomposes, but using too much will alter the pH of your pot media and kill all of your roots. Since I’ve seen it done, I can attest to its veracity. So for 4.5″ pots, only a pinch, and for a 6″ pot, literally less than 1/8 tsp.
Calcium and pH: This subject is crucial when it comes to paphiopedilums, and in my opinion, a calcium deficit in the plant or overly acidic potting soil are the main causes of brown and black rot in most cases. You see, many Paphiopedilum and slipper orchids originate from environments that are particularly alkaline or high in calcium carbonate, and they thrive among serpentine ultramafic rock.
They are indigenous to mountain ranges with mineral-rich soil and limestone regions, where elements like calcium, iron, and magnesium are more readily available than in other ecosystems. In order to grow well, develop strong cell walls, resist infections, absorb nutrients, and eventually outperform other plants in the same habitat, plants that have evolved to calcium-rich environments like this rely on those particular conditions, including non-acidic soils.
Because they can grow in such unusual places as the edge of a limestone cliff, between two stones, or on the side of a tree, with thick moss covering the bark, orchids are hardy. If you’re using “clean water” like rainwater or RO water, or if your tap water is deficient in minerals or even somewhat acidic (7pH), you might want to think about adding a little bit of oyster shell to your potting medium. If there is any degradation taking place in your pot, this will aid in preventing a pH plunge (like as wood or sphagnum moss breaks down).
Add oyster shells to your potting medium if your plant is prone to brown or black rot. However, be aware that you might not see a difference until the following season when the new growth has had time to develop in the calcium-rich environment you’ve created. This calls for close monitoring of active infections and increased caution in limiting the spread of bacterial or fungal diseases. Cell walls created in a deficient state will remain deficient because calcium is immobile.
What stores carry oyster shells? It can be found in the bird department of pet stores and is probably available online in the pet section of Amazon.
Interested in learning more about this subject? Read Tony Budrovich’s “Calcicolous Slipper Orchids”
Fighting black and brown rot in Paphiopedilum: It has been demonstrated that applying Dragon’s Blood (sap from Croton urucurana) directly to the infection site would help stop and manage subsequent infections if you have a plant with an active fungal or bacterial infection. To dry up tissue and stop the infection from spreading, it may also be helpful to make holes around the infection’s the outside perimeter. Once the holes have dried, you can fill them with Dragon’s blood to prevent further infection.