Orchid Tip of the Month by Scot Mitamura

Here we are in the middle of our Hawaiian Summer.  I hope we are taking advantage of our great weather and long days.  In these summer days, our orchids can really grow and store energy for blooming.  The question is: Are we taking advantage of it? 
 
I'm hearing from some members that it is just too hot to go out into the yard and work on their orchids.  I find myself spending almost every late afternoon and evening, working on my plants.  It is actually recommended that, if you were to spray fertilizers or any insecticide, it should be done when the temperatures are cooling down. This way you minimize the chances of chemical burn. 
 
Watering at night is fine. As long as you have good air circulation, you should not have fungal problems.  In nature, most of the rainfall is in the afternoon and by evening the orchids are beginning to dry out.  Wilbur Chang talked about how he always wanted to water his orchids in the morning.  Once he retired he was able to make the change, but soon found that his orchids were not doing as well, so he went back to watering in the evening. 
 
Living close to sea level can be challenging because the diurnal change in temperature may be only five degrees or less.  Watering late may extend the change a few more degrees, which could make the difference in the blooming of a high elevation orchid. 
 
Another benefit of evening orchid work is that you get to see what is happening at night.  This is when the creepy crawlers emerge and do their damage.  The main one is often our biggest problem, slugs and snails.  This is their time.  There are more than just the large African Snails, there are many smaller snails that may be hiding within your potting media.  Tiny Bush Snails and others, often the size of a pin head, come out at night and feed on young root tips.  In the day you will never see them and you may not even notice their damage to the orchid roots, but they can really set back your plants.  To control them, very lightly sprinkle any commercial slug bait in and around your pots.  Make sure that you do a follow up application withing two weeks, so you can kill the emerging young. 
 
Another thing you might see are cockroaches!  They come and feed on the sugars excreted by the new growths and flowers of the orchids (it’s the same thing that the lizards do in the daytime, but at least they don't actually cause damage, as some folks feel).  Cockroaches can also chew, yes chew, on flowers creating damage that mimics grasshopper damage.  They love cattleyas and phalaenopsis!  I like to control them by spraying the Bayer 3 in 1 on the spikes and buds. This must make the taste less appealing because it seems to deter the roaches, as well as the Bulbul birds. 
 
Australian Roof Rats are also nocturnal and if you are not baiting, you will often see them at night in the trees, telephone wires and along roofs.  They love anything sweet, so they love cattleya flowers!  I have actually used a half eaten flower on a snap trap to kill a huge rat.
 
There are also enjoyable things at night in your greenhouse.  Many white or green orchids are highly fragrant at night.  They are the only visible colors to the night pollinators, in which the fragrance coincides with.  The one that comes to mind is the sweet fragrance of Rhyncholaelia digbyana, it will knock you off your feet, when smelt at night.  I think I will go out to my orchids now and enjoy my evening.
 
A reminder:  Please send questions and photos to Orchid ER on our website and I will be happy to try to answer your questions.  A benefit for me is that it gives me ideas on what to talk about in future newsletters.  So no shame, surely someone else will have the same questions!
 
Aloha,
Scot