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INCE THE BULK OF PHALAENOPSIS sold these days arrive potted in New Zealand sphagnum moss , with the moss packed in like a brick , it ’ s more important than ever to adjust many of our old cultural practices . Often the plant is in a clear lightweight grow pot , much like a liner . Unfortunately , many growers have experienced root and eventual plant loss due to either over- or underwatering as a result of this new cultural challenge of growing in such a densely-packed medium .
For answers to my questions about adjusting our cultural practices for these plants , I went to Norman Fang , of Norman ’ s Orchids and www . orchids . com , with orchid nurseries in both the United States and Taiwan . In addition to his 24-plus years of experience in growing phalaenopsis in moss , Fang has an extensive background in horticultural science , having received his Bachelor of Science in Ornamental Horticulture from California State Polytechnic University in Pomona , California .
WATERING AND FERTILIZING
People often make the mistake of watering both bark- and mosspotted plants at the same time . Fang ’ s first suggestion is to separate the moss-grown plants from those in bark or other media because plants in moss will retain moisture longer . As a result of placing the moss-grown plants in a separate location , you can avoid inadvertently overwatering them by splashing or dripping when watering the remainder of your collection . It ’ s also a good idea to grow moss-potted seedlings in an area separate from mature plants .
Plants in transparent pots filled with New Zealand moss will show a distinct line of green moss in the upper half of the container , with the moss in the lower half retaining its natural color . This is an indication that the moss dries from the bottom up , the exact reverse of bark ’ s drying properties .
Complete all watering early in the day , according to the current day – night temperatures . The plants will benefit from their pots being placed on a tilt so water can ’ t collect in the crown , which will help avoid bacterial rot .
For the most efficient watering , don ’ t allow the plants to become more than 50 percent dry ; this is most easily observed when they ’ re growing in transparent pots . Then , instead of watering by soaking the pots from the bottom , handwater from the top with a small water breaker such as the red Dramm water breaker . Double watering usually works best for plants grown in moss . Water until the water backs up to the rim of the pot , let it soak in and then water again until it drains out the bottom hole . Growing your plants in open shuttle trays will more readily allow the medium to dry from the bottom up , in addition to helping with better plant spacing . When the moss dries from the bottom up , there is less risk of rotting the roots at the bottom of the pot .
Do not fertilize a plant that has become too dry between waterings . Instead , water it thoroughly so the moss is remoistened and then fertilize on the following day . Because moss doesn ’ t leach , due to its need for less-frequent watering , a dry plant will soak up more fertilizer than is needed , thus causing fertilizer burn on the leaves and roots .
A good rule of thumb to apply to a fertilizer regimen is this : if there ’ s no light , don ’ t water and don ’ t fertilize . For plants growing in moss , there is no need to fertilize at every watering , with the frequency of watering depending on the climate . In the autumn and winter , apply a balanced fertilizer containing all the essential micronutrients at a dilute strength every other watering , and only on sunny days . From spring through the summer , it can be applied at one-half to full strength once a month . Alternatively , if the medium is still moist , foliar feeding is an option . During these warmer and brighter months , the plants will dry out more quickly and watering frequency will need to be increased . In addition , watering with a Physan 20™ solution once a month at the rate of 1 teaspoon per gallon of water ( 5 ml per 3.8 L ) will help prevent bacterial and fungal problems . Never use slow-release fertilizers on plants grown in moss because the release of the elements is affected by temperature or moisture , causing either over- or underfertilizing problems .
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20 Phalaenopsis | First Quarter | Volume 23 | 2013