Secrets to Phalaenopsis (revised June 7th, 2011)
EZ! by Lee Bredeson
Some say Phalaenopsis are hard to grow. Well, they should not be treated like other house plants. However once the difference is understood, they require less care than house plants. Most orchids are bought with blooms. Kept in the house with you at room temperature (68 to 72 degrees Fahrenheit/20 to 22.2 degrees Celcius) they may not bloom again. However coincidental blooming can be prompted by the seasonal light levels, length of the day or nearness to a cold window pane in the winter. Also a few species don't follow this growth habit.
Phalaenopsis orchids originate from the area of the Philippines. They are prompted to bloom by the natural cycles of the seasonal monsoons. We can simulate the effects of these monsoons. It is easiest to do this in the spring and fall when daytime temp lingers for weeka at about 70 (21.1 degrees C). Often the night time low temperatures will follow along at about 55 degrees(12.7 degrees C). We need 21 days in a row! One daytime temp above 80 (26.7 degrees C) can inhibit the flower spike from forming. What we actually need is a 15 to 20 degree (8-11 degree C) drop from day to night. The lack of nutrients and the cool nights prompt the orchid to set flowers that in turn may get pollinated. That leads to seed and thereby produce offspring to survive this famine and chill... whew! The specie lives on.
So if the Phal blooms twice a year lasting 2 to 4 months... well, that's beautiful! You get to enjoy blooms during eight of the twelve months each year!
To simulate the effect of the monsoon rains use a drench (1 teaspoon of Epsom salt per gallon water). Pour enough to fill the pot so that it runs out the bottom for a few seconds. Do this once and then again one week later without watering or fertilizing between soaks. The solution will leach almost all nutrients from the roots and growing media (bark/sphagnum mix). The month long heavy rains in the Philippines have the same affect. After the rains subside, cool winds also blow for about a month. Therefore one week later, we place the phals where the temperatures can daily fluctuate by 15 to 20 degrees. Be careful not to let the Phals be exposed to even cooler temperatures, especially below 45 degrees(7 degrees C). Water sparingly without fertilizer. After 21 consecutive days of these cool nights, almost every Phal should have sent up one or more flower 'spikes' (inflorescences). This method is referred to as 'cool induction'. Once you see a spike, the orchid can be brought inside and resume watering and fertilizer while the spike matures into blooms. Some people do not fertilize Phals with blooms but experiment for yourself. I have found that "weak fertilizer weekly" gives better results, more and larger blooms. All orchids primarily metabolize phosphorus (the middle number of the NPK formula on fertilizer containers) by making blooms. A healthier approach is to feed a weak solution throughout the growing season. Healthy leaves and roots store the 'energy of life' which is naturally expressed in the blooms.
To ensure healthy size and many flowers, fertilize your orchids regularly during the summer AND winter. The water needs may decrease in winter as the bark/moss in the pot cycles more slowly from moist to almost dry. If it is a balanced general fertilizer with 10-10-10 or 20-20-20 composition, use 1/4 of the recommended rate (so if one teaspoon is called for per gallon water, cut it to 1/4 tsp). The old adage fertilize 'weakly... weekly' works very well. If the fertilizer was made specifically for orchids, follow the label directions. Fertilizer made according to the 'MSU Formula' (developed by Michigan State University to meet the specific needs of orchids) is available online.
Did you know that Phals 'expire' most often due to over watering? If left constantly wet, both the bark mix and the roots will surely rot. By the time the leaves show signs, it may be too late to save the roots or the orchid. Phals thrive on a full cycle of soaking wet to almost dry. I suggest that you use what I refer to as a "water-o-meter". This is simply a wooden BBQ skewer or old pencil that is pushed deep in the potting material. Leave it there. When you think the orchid needs water... pull it out. I place it on my cheek. Remember this rhyme: "Cool and wet, don’t water yet". Wait until the end of the stick is slightly damp/beginning to dry out. However a Phal has no water storage pseudobulbs like other orchids. If the stick becomes 'bone dry', the orchid has already started to pull upon the water stored in its leaves. After 3 days of being completely dry, the affect may be severe. In a 'typical' home it takes an orchid about 2 weeks or more to reach that point of dangerous dehydration.
Small or young orchids are often sold planted in sphagnum moss. They can be grown in it indefinitely if the Phal is repotted regularly in fresh sphagnum. However when the Phal has 3 pairs of leaves or is ready for a 6 inch pot, consider switching to a regular bark mix, semi hydro ceramic pellets or other media. Transfer to semi hydro should be done when there are new roots are forming. The organic sphagnum and the bark mix decompose after about 6 months to a year. With it goes the roots! Therefore the condition inside the pot should be monitored or simply repotted once, possibly twice a year. The bark becomes spongy to the touch or easily breaks up. If so, repot.
A summer growing season is essential to healthy and plentiful blooms. A
good way to start that is to cut the spikes off after the blooms are finished.
However if the Phal is a known “sequential bloomer”, don't cut the spike since it
will be blooming again and maybe again. The flower spike (inflorescence) is cut away using a sterile blade above the first growth node where the spike
emerged between the plant's leaves. Nodes are narrow leaflets that grow around the spike at 2 to 3 inch intervals up to where the blooms begin. The node acts as a natural barrier to stop infection where it is cut. A smear of powdered cinnamon spice is also an effective way to protect the cut. Temperatures
above 80 degrees inhibit the emergence of flower spikes. So commercial growers maintain Phals at
a target of 83 degrees. The 'season' is spent growing big thick medium green
leaves and a healthy root system. With all of this stored up energy, they are
just waiting for that monsoon.