April To Do List

General

• Review and continue to follow recommendations for March since continued cool temperatures throughout March, particularly on the coast, has delayed Spring flowering and onset of growth for some species and hybrids.
• Fine tune the shading of orchids as heat and light continue to increase.
• Remove with sterile utensils any dead flowers or leaves that were damaged by bacterial rot or fungal rot, being careful not to contaminate clean plants.
• If not done yet, spray benches and growing areas with Physan to decrease possibility of bacterial and fungal diseases.
• April brings on new growth for many orchids and the opportunity to repot and divide those orchids that initiate new root growth at this time. Try to repot when roots are small and just beginning to emerge in order to minimize damage to soft tissues and avoid transplant shock, giving plants a head start for the upcoming growing season.
• Repot when orchids have begun to over grow their pots and/or when media has started to break down.  Also consider repotting plants that have been in pots for 2 or more years and are existing, but not thriving. Repotting can revitalize and provide new vigor to such plants.
• It is helpful to thoroughly rinse and soak all media prior to potting. Dry media tends to wick moisture away from plants.  Then keep plants relatively dry to encourage root growth.  If you prefer to repot using dry bark mixes, water newly potted plants thoroughly (2-3x), then keep on dry side to stimulate root growth.
• To divide orchids, allow for 3-5 bulbs per division.
• Check plants for algae, as a crust of algae acts as a barrier to both water and fertilizer, thus preventing roots from breathing properly.
• Cautiously use any pesticide, fungicide or chemical keeping in mind that most manufacturers typically do not specify the use of their products on orchids.  Always use the lowest prescribed dose and avoid spraying flowers and buds. Recommended dosing for orchids can sometimes be found on the manufacturer’s website or on various orchid forums (such as The Orchid Source).
• Orchids that are in bloom require less water, which allows the flowers to last longer.
• More details on specific genera can be found on the AOS website

Indoors and Greenhouse

• Monitor for pests and diseases as temperatures begin to rise. Make sure fans and coolers are in good working order.
• Provide good air circulation for indoor plants to discourage diseases and pests such as mealy bugs. Treat early to avoid spreading to other plants.
• April is a good time to repot Paphiopedilums, which tend to benefit from a yearly repotting. Most do well in small bark and perlite containing a little charcoal.  It is a good time to check the roots. 

Outdoors

• Continue to monitor and control snails and slugs as weather warms. They can do considerable damage to new growths, buds and flowers in short order.
• Cattleyas, Oncidiums, Cymbidiums, and Aussie Dendrobiums should begin initiating new root and bulb growth.  Increase watering frequency and fertilizer as new growth is observed and repot as needed. 
• Australian Dendrobiums are in full bloom now. Dividing and repotting can be done after flowering is complete and new roots begin to form.  Dendrobiums like to be root bound so only repot when plants outgrow their pots or are not doing well.  Leave room for 2 or 3 years growth. 
• In addition to Cymbidiums, Zyopetalums should be flowering and be ready to divide and/or repot once flowers wilt.  Treat Zygos in the same manner as Cymbidiums and repot accordingly: repotting instructions at Casa de las Orquideas and under Speaker Handouts on our website.