Orchid Culture - 2011 Questions & Answers
by Sue Bottom, from the St. Augustine Orchid Society Newsletter.
Email us with any orchid question, if we can't answer it we'll find someone who can! Send photographs too!
Dividing a Vanda
Q. This vanda has a keiki growing at the base of the plant and then there is a bare spot above which there are leaves and new roots.
I know I should wait until spring, but I'm thinking of dividing the plant where the arrows are, rebasketing the top section and continuing to grow the new keiki.
I've added arrows where I think it should be cut, does this look like a good idea?
A. Trust your instincts, your plan sounds like a winner.
Q. I bought this orchid from Jaxma in 2009 and the tag say it is Blc. Chiaun ‘New City’ but I can't seem to find it. This year the flowers are very floppy and not as pretty. Any idea what its name is or why the flowers are so floppy?
A. Jaxma confirmed this plant to be Blc. Taiwan Queen ‘Golden Monkey’ HCC/AOS. Floppy flowers can occur because of genetics in which the pedicel (stalk of an individual flower on an inflorescence) is too long to support the flower or the plant isn't getting enough light.
Q. My orchid plant is so tall, it has two huge shoots from about half way up the stalk, on one of these shoots are 3 long blossom shoots blooming that are so heavy I have to prop them up.
Also from the bottom is another shoot with 3 blossom shoot, one with opening flowers. I am in Leesburg Fl where we have really hot weather.
I kept the plant inside during the winter but need to know what temperatures it can take. It is in a wide coconut fiber planter but think it needs something else. What is the best pot and potting medium?
A. The phalaenopsis type dendrobiums (whose flowers vaguely resemble a
phalaenopsis flower) like to be warm, about 55 or 60 is as low as they like,
otherwise the leaves start to yellow and drop.
Like most dendrobiums, they
don't like to be repotted so you're best sticking with a largely inert mix
that won't degrade.
They also like to be in smallish pots, the canes grow
so close together that they can last for many years in the same pot.
I'd probably wait until spring, and then transfer it into a much smaller clay pot and hang it with a long
double wire hanger.
If you're good, you'll tie the canes up as they grow
and you can use the wire hanger to do this, they always seem to get away
from me and grow sideways.
I use a mix of hydroton, charcoal, spongerok
and maybe a little tree fern. They can be watered every other day in summer
and maybe every fourth or fifth day in the dead of winter. You know, you have a keiki (baby plant) growing on the mother plant. When
it stops blooming, you can twist the keiki with all those roots off and pot
it up separately and then pot down the mother plant into a smaller sized
It's a beautiful plant!
Broad Mites on Phalaenopsis Orchid
Q. I bought this plant recently. Two of it leaves are discoloring to a lighter green. I have read it could be a fungus or sunburn or microscopic mites, what do you think it is?
A. It's not sunburn, that would start on the highest point of the leaves. I think it is broad mites that are microscopic in size.
You can put 2 tablespoons of dish soap in a quart spray bottle and fill with water, perhaps adding 1/4 cup of isopropyl alcohol for additional toxicity.
Spray the top and bottom of the leaves every week for 3 weeks. You can also spray a miticide on them, the Bayer 3 in 1 product is a good one that's available in the big box stores. Spray plants in close proximity to this plant and separate it from your others until you notice no spread of the discoloration.
Deformed Orchid Flowers
Q. This fall it seems that I have a higher proportion of mutant flowers than I have seen before, weird lips or deformed sepals. What do you suppose causes it? I've sprayed a lot for thrips, do you think the flower deformity is chemically induced?
A. Courtney Hackney answered this one: Even approved pesticides impact plants so that would be my guess. Hot weather during bud formation can also cause flower deformities, but at this time of year I would bet on pesticides as the causative agent. Some of the pesticides actually damage chromosomes and can lead to permanent deformity. I noticed what looked like virus symptoms on buds where I had deposited powdered Sevin on some of my orchids.
Upside Down Orchid Flower
Q. Why did this flower open up side down, the other flower opened today and it is fine.
A. When the flower is in the bud stage, the lip is the uppermost petal. In most orchids, as the flower opens, the flower twists 180 degrees around its flower stalk to position the lip on the bottom (called resupinate).
Shifting the plant's location as the flower buds are growing can "confuse" the plant's orientation.
As the buds mature, the flower spike may also be unable to support the weight of the flowers especially for hybrids with robust blooms, if the orchid has a long pedicel (the stem that attaches single flowers to the main stem of the inflorescence) or you removed the sheath that gives the growing flower some structural support.
Staking the flower bud as it emerges will help orient the flowers for their best presentation.
Hard Armored Scale on Orchids
Q. Many of our orchids have these small black things attached to the leaves that look like small non moving ladybugs. Some leaves have 30+ of them. Additionally some of the leaves now have a sticky feel to them. We did just recently add an orchid to our collection. We were hoping you had some advice about what they are and what to do about them.
A. That is armored scale. You can take isopropyl alcohol and a Q tip and wipe
it off the plant to get rid of the obvious infestation. The real question
is where are they lurking. Perhaps you could pour some isopropyl alcohol
into a spray bottle and spray it into the nooks and crannies and areas of
emerging growth. Then just keep an eye out for the little buggers.
Soft Brown Scale on Phalaenopsis Orchid Flowers
Q. I am writing to you from Pittsburgh hoping you can help us identify
whatever it is that is 'bugging' our orchid.
What is unusual about these spots on the orchid is that they become more
defined as these spots age, and develop patterning of lines that might be
some kind of circulatory system. They remind me of jellyfish I've seen on
A. I think that is brown soft scale that crawled up the flower spike and onto the back of some of the flowers.
You can see the scale on the flower stem in the first close up picture and in the second mother scale that have set up homemaking laying eggs. You usually find the white boisduval scale on cattleya leaves and pseudobulbs, but the soft brown scale seems to enjoy the tender flowers.
I would take a Q tip dipped in isopropyl alcohol and gently wipe the scale off the back of the flowers. Then start working down the flower stem and remove all scale. Inspect under leaves and in leaf axils and remove all visible scale with a Q tip. You can also spray all the nooks and crannies with isopropyl alcohol poured into a spray bottle. They are climbing up the flower spike from somewhere and you need to eliminate the source. Here's a great article on identifying and controlling scale. (Nov-11)
Dry Wood Termites on Orchid Mount
Q. We mounted orchids at one of the spring Keiki Club meetings. I mounted mine on a thick cypress branch and throughout the summer noticed deposits like corn meal on the orchid leaves. I'd wash them off and they'd be back the next day, what gives?
A. That is drywood termites eating the cypress wood, the deposits you see are the frass that is pushed away from the termite population through pinhole openings in the wood. They are an insidious pest because they do not require moisture in addition to that which is present in the wood (even kiln dried), the damage is often caused in places that are hidden from view and you'll be surprised to know that your household termite policy is for subterranean termites only, it excludes drywood termite damage. Termites can infest orchid mount material, even rot resistant woods like cypress, so be vigilant. If you see signs of termites on mounted orchids, remove the orchid from the mount and discard the wood. (Nov-11)
Growing Dendrochilum magnum
Q. I recently purchased Dendrochilum magnum from Carter and Holmes because it looked pretty in bloom. Looking at OrchidWiz I see its natural range is in the Philippines at 5,000 feet elevation and daytime temps in the upper 70s. Any suggestions on how to grow this one in our heat?
A. Mike Heinz responds: If you can't keep it as cool as it wants to be, keep real good ventilation on it.
I know of people that have grown that plant warm, maybe just not as warm as St. Augustine gets. My two divisions are
doing great for me.
One trick is to double pot it. Put it in a clay pot with loose sphagnum moss in it, and then put that pot in a bigger clay pot with sphagnum between the two pots. The evaporative cooling will drop the temp a couple of degrees and that may make the difference.
You could also grow it in more shade then you think it will like because shade equals cool.
Aphids on Paphiopedilum Orchid
Q. I was recently given 15 beautiful paph orchids, most in bloom. Now I see two have small whitish insects even on the blooms.
I washed off most with water but I suspect I should spray with something. I do have pets though and the plants are inside. What should I use that won’t ruin the blooms?
A.Those nasty little buggers are aphids, destructive but easy to kill. You can start with soapy water under the sink faucet until you can drench with one of the Bayer products containing imidacloprid. It can be applied as a drench rather than a spray so it's easy to use, even inside. Just dilute it with water (5 tsp/gal for the 1.47% strength one or 15 tsp/gal for the 0.47% strength) and pour through the pot, they'll be dead by the next day.
Vanilla Leaves Wilting
Q. A few months ago I bought a young vanilla orchid. I am looking for some advice about why the leaves are drooping and how
can I get the vanilla orchid feeling good again.
A. I think the vanilla looks dehydrated because it is not getting enough
water. That can be because it's not being watered enough (doesn't sound
like it in your case) or because the roots aren't taking up enough water (I
suspect this is the case for your vanilla).
I'm betting the vanilla you bought was a new cutting that was dropped in the
potting mix and sold to you before the plant became established. Its roots
probably had not grown and now it has exhausted its store of water and is
showing the signs of dehydration. Knock it out of the pot and see if there
are viable roots.
If the roots are rotten, then this is a different problem. If there aren't
roots, I would do this. I would take the plant and cut it into about 4
pieces, with each piece having two or three nodes where the leaf comes out
and where roots will form. Then get your pot that will accommodate all the
pieces, fill it with a peat based soilless mixture with some added
spongerok, dust the pieces with some rootone and situate them in the pot so
there is a node or two into the mix and 1 or 2 leaves out of the pot. Then
keep it in a shadyish place until you notice the plant vigor returning and
then move it slowly into brighter light.
Bacterial Brown Spot on Zygopetalum
Q. I came across your orchid pests and diseases photos while trying to identify a problem on one of my
zygopetalums. Am I correct in thinking that the problem with my
zygo leaves might be Guignardia or perhaps a bacterial brown spot?
A. That could be a bacterial brown spot with the sunken
black spots. Guignardia is more diamond shaped and has a raised surface
that feels like sandpaper. The best treatment is spraying with copper,
Kocide is copper hydroxide, easily available and cheap.
It'll leave a blue
residue on your leaves, don't spray it on anything in bloom or on
dendrobiums. I spray it a couple times of year on phals and out of bloom
plants as a preventative (avoiding dendrobiums that don't like copper).
Calcium Deficiency Causes Necrosis on New Cattleya Growth
Q. I was planning to repot my cattleya that has 2 new leads forming with fresh roots peeking out. This morning the new leads are black, is this the heat?
A. You might think this is a bacterial or fungal rot, but more likely it is a calcium deficiency similar to blossom end rot in tomatoes. It affects cattleyas primarily generally during periods of rapid growth in the spring and summer. Insufficient calcium can stunt new root and vegetative growth, create black spots on leaf tips that progress toward the leaf base sometimes preceded by a yellow halo. The lack of sufficient calcium can deform and eventually kill new leads. Use a good cal mag fertilizer, add calcium nitrate at the rate of 1/2 teaspoon per gallon to your water (alternating with Epsom salts) between fertilizations or top dress with powdered dolomite as a source of calcium and magnesium during the hot months when calcium requirements are high.
Sooty Mold on Catasetums
Q. The common advice about new catasetum growth is to withhold water until the new roots are several inches long. This is to prevent water from rotting the new growth. At what point is it OK (if ever) to get the foliage wet and perhaps have water enter the center growth point? Will that create a rot situation? My catasetums are quite mature and have exuded a lot of nectar which is now nurturing black sooty mold.
Is it OK to wash the stuff off or should I wipe it, which is a pain in this heat?
A. Once the whorl of the leaves has unfurled and the growth is mature, you do not have to worry about water standing in the crown and rotting the growth. Fred Clarke adds: Just wipe off the mold with warm water. Check for mites and thrips too because sometimes they have an exude that will mold and looks similar. Once the first roots that start with the first growth are 3-5" long begin watering. If a second growth starts later in the season do your best to keep water out of the center of that newest growth but don't stop watering as the newer roots are in good working order and the first bulb still needs to mature and bloom.
Recently Planted Phalaenopsis Keiki
Q. My phalaenopsis grew a keiki and once the roots looked healthy I cut it off with sterile scissors and planted it in an orchid bark mix and watered it. I was told that transplanting is stressful so the plant should be placed in a shadier spot for a week. It has been about a week and I am concerned about the keiki. The leaves are now limp and one of them even looks slightly wrinkled even though the potting mix is bone dry. What’s wrong?
A. Fresh bark is often very hydrophobic, which means it repels water, so it is often recommended that you soak the bark before using it to hydrate it as well as remove the fines. The keiki is used to getting nourishment from the mother plant and now it is on its own in a bone dry mix, so it is a little dehydrated. Why don't you try watering it every other day or so until the bark feels like it is not so dessicated and the leaves plump up. Once the bark and plant get rehydrated, you can resume your normal watering schedule.
Mites on Dendrobium Leaves
Q. I couldn't find my disease on your website. The greyish color is not on the surface of the leaves, it seems to be within the leaf. There is no indication of insects.
A. The culprit appears to be mites. The dendrobium has the characteristic silver stippling on the undersides of the leaves. You can get a magnifying glass and look for these small, eight legged arachnids. For a household remedy, get a quart spray bottle, put in 2 tablespoons of dishwashing soap, fill with water and spray the leaves top and bottom weekly for 2 or 3 weeks. Some other homemade remedies.
For a bigger infestation, you can also apply a good miticide like Kelthane, Talstar and Avid.
Repotting Summer Blooming Phalaenopsis
Q. My Phal. Sweet Memory 'Bubbles' is a near primary hybrid (violacea, amabilis, amboinensis) with a summer blooming habit. Conventional practice is to repot phals in the June time-frame, but this plant started blooming in May and has a new 7 inch spike forming. When should I repot?
A. Summer blooming phalaenopsis should be repotted in February so the plants will be established in time for the blooming season. If you missed the February time frame, let the plant bloom over the summer. When the weather cools in mid September, you can repot the plant if the mix has degraded or make a mental note to repot in February if the mix is fresh enough.
Creased Leaves from Mechanical Damage
Q. We have a medium size orchid plant that has leaves with brown lines across them, like someone cut them with an exacto knife. What is the cause and what is the solution, we already lost one plant with this.
A. The creased leaf on the left looks like mechanical damage from being shipped or moved or someone brushing against it when they walked by the plant. The crease down the center of the leaf on the right looks like it split when the leaf was very young and tender and it either grew too quickly or the leaf broke from being touched or moved. A disease will not develop in a straight line.
Snails or Slugs Eating Orchid Flowers
Q. My wife and I have several orchids in our California home. One of the orchids has flowers that look like they are disappearing. The body of the flower petal (the color) is disappearing, leaving an x-ray like image of the flower itself. Then it starts to disintegrate.
A. Something is chewing on your orchid flowers, and it looks like slug or snail damage (although it's also possible it is scale / mealybugs. If it's snails or slugs, they must be hiding in the media during the day and coming out at night to feed. A good way to detect this pest is to place a piece or apple, potato or lettuce on top of the pot as bait. Leave it for a day or two then go to the plant at night in the dark with a flashlight, lift the piece of bait you put on the pot and look for the tiny little black snails underneath.
If you find them, use a bait or poison to get rid of them or just bait the snails with apple, potato or lettuce and squash them until there are no more. If it's not snails, you'll have to hunt for the scale, or more likely mealybugs, in the phalaenopsis. They'll hide in the crown of the plant and deep in the leaves, you'll see a white cottony mass. You may also see them on the flower spike. If you find them, you can just put some isopropyl alcohol in a spray bottle and spray all the crooks and crevices, repeating once a week for 2 or 3 weeks.
Cattleya Orchid Care
Q. I bought a cattleya orchid at Home Depot marked on tag as \"LV .25 SLC: Tutakemen \'Pop\' red. I bought my 2nd, 3rd and 4th orchid at JAX orchid show this 2011. How do I take care of this orchid?
A. You bought the cattleya orchid Slc. Tutankamen 'Pop' AM/AOS. It is a cattleya orchid, an orchid that likes to be in bright but not direct sun, and watered a day or so after the mix dries out. If it is in a largely inorganic mix without bark or coconut husk, you'll water it every 3rd day or so in the summer and once a week in the winter and only repot after it grows out of the pot. If the plant was in a bark or coconut mix when you bought it, the organic matter will break down about 2 years after it was potted, and because you don't know when it was put in that mix, you'll have to keep feeling the mix. When the mix breaks down, it'll feel like dirt and then it'll be time to repot it. Read up on cattleya culture, they're beautiful!
Repotted Phalaenopsis from Sphagnum into Bark Mix
Q. I bought a phalaenopsis orchid in February. After the blooms died, I repotted it from sphagnum moss into a bark mixture and continued to water once every 10 days. I noticed that the leaves are droopy. What should I do?
A. The phalaenopsis was acclimated to sphagnum moss around its roots and changing to a new mix required the orchid to grow completely new roots. Your orchid got dehydrated because the old roots weren't allowing it to absorb enough water from the new potting mix. Try repotting it into a sphagnum moss mix. A lot of people don’t like sphagnum moss because they feel it stays too wet, so we ended up making a mix that's about 2/3 sphagnum and 1/3 inert stuff like charcoal, sponge rok and aliflor / hydroton. The inert stuff seems to lighten up the sphagnum moss so more air can get around the roots but there is enough sphagnum that the roots don't skip a beat when they're put into fresh mix. Repot and see if your pretty phalaenopsis doesn't return to its former glory!
Orchid Leaf Wrinkling Suggests the Plant Needs More Water
Q. I live in Arizona where it is very dry, even with a humidifier running. I potted this brassia orchid in bark last year and to me it looks like the new leaves are getting stuck and can't grow out, so they crinkle and bunch up. Should I mix in some peat to help it retain water?
A. Trust your instincts! The leak crinkling suggests the plant isn't getting sufficient moisture, but you already knew that. You can either water more frequently or add peat or other water retentive material to your mix to increase its water holding capacity.
Mites Pock Marking Phalaenopsis Leaves
Q. My boyfriend gave me this orchid. I have watered and fed it regularly for the past few months and it has produced new growth but the markings on the leaves have worsened and have now begun to appear on the new leaf too. I keep it next to two other orchids and they are fine, flowering with no symptoms.
A. I think you may have mites causing the pitting on the leaves. To be sure, take a white Kleenex and rub both sides of the leaves and if you have a reddish smudge, it's mites. You can treat indoors by getting a quart spray bottle and put in 1 tablespoon of dishwashing solution and spray the entire plant, top and bottom leaves and all nooks and crannies, repeating weekly for two weeks. Check your other plants, you might want to treat them too. You can also take the plants outdoors and spray with a miticide. Mites are not insects, so a miticide rather than insecticide is required.
Seed Pod on Epidendrum radicans
Q. I think these are seed pods on my Epi. radicans. Do I just leave them there or what?
A. You can take them off if you want the plant to reserve its strength for flowers, or let them develop seeds and spread, in the one in a million chance that some volunteers will sprout somewhere. If they do, go out and buy some lottery tickets!
Water Softener Using Potassium Chloride
Q. My public water supply has about 700 ppm total dissolved solids so I had a water softener installed and will use potassium chloride instead of sodium chloride for the brining solution. The water softener people estimate that the potassium level in the water after treatment will be about 330 ppm. There is an article in the February, 2007 Orchids magazine dealing with the effect of potassium on phalaenopsis growth that found the peak growth to be in the 300 to 400 ppm potassium. Last year I switched from a water soluble fertilizer to the Dynamite product (13-13-13) trying to avoid some of the salt build-up problem I have. I notice that there is a Dynamite product with an 18-6-8 analysis. Would it be better to switch to the Dynamite product with the lower potassium content (18-6-8)?
A. Our Go-To Guy Courtney Hackney writes: My suggestion is that you use the 18-6-8 product. What you will likely see is thicker leaves that are harder, but perhaps a bit more brittle. Many growers try to increase the potassium level just for that effect. The only suggestion and concern I might have is the high concentration of salts. You want to be sure you really flush occasionally, perhaps twice a month. If you have a way of occasionally using rainwater or RO water that would be much better. Try this out and just watch the plant roots. If the tips start turning black you will need to flush more or reduce the TDS levels.
Paphiopedilum Leaf Dessication
Q. I have had my paphiopedilum for two years and it seems to be growing well although it hasn't yet bloomed. It's in an east-facing greenhouse window in my kitchen, where my phals are thriving, but this winter it developed irregularities in the leaves that look like embossing, except that the marks are depressed and only appear on the top surfaces of the leaves. The marks aren't discolored or wet. Did I let the plant get too dry? Or is it a virus?
A. I thought perhaps mites but there were no red smudges when the leaves were rubbed and it had been treated with Safer 3-in-1 soap, so we went to our Go-to Guy Courtney Hackney who wrote: It appears that there is desiccation on the leaves, possibly from cold, too bright of light, too little water or rotten roots. The fact that there is neither rot nor small striations on leaves suggests that cold may not be involved. Desiccation can also be caused by higher light and lower water supply. East facing windows can produce sun scald, especially if there had been long periods of gloom followed by a few bright, clear days.
The same orchid could burn under the same conditions as the previous year if it had lost its roots and water supply this year. You should be sure there is no other underlying cause of the leaf desiccation, i.e. dead roots. New growths look good, so check the roots and wait for the plant to grow out of it. New growths will be fine if I am correct. It is unlikely that you have a virus.
photos by Robert Cating
Leaf Blisters from Edema
Q. My cousin had someone take care of her orchids for her while she was hospitalized during the winter. When she got her plants returned, she saw that one of them had something on the leaves of one plant that we have never seen. It appears as if it has a "water blister" - as if a person burned themselves and a water blister formed. Could this be caused by too cold temperature or too cold watering?
A. Your instincts are excellent, that is edema. Excess water is absorbed by the roots more quickly than it is lost by the leaves, causing swelling of plant cells and producing a blister-like lesion. It occurs when plants are watered during warm days and the nights turn cool or during periods of cool weather when water quantity and/or frequency is not reduced.
Miltoniopsis Orchid Culture
Q. I picked up a miltoniopsis on the way home from Ace. It's planted in sphagnum moss, which looks pretty fresh. Should I leave it in there for a while or change it out?
A. I think I’d leave it in the fresh sphagnum moss for now. They like to be kept evenly moist, though not wet. The miltoniopsis are sensitive to our summer heat. While they like brightish light, they will have to be put in a shady cool spot for the bulk of our summer.
Orchid Keiki on Phalaenopsis Spike
Q. I received a phalaenopsis orchid last fall and it went though the normal phase of losing the flowers and I cut the spike about 1.5 inches above a healthy node. Meanwhile, it grew two beautiful new leaves but no activity from the node for several months until a couple of weeks ago. It looks like leaves growing from the node instead of a spike and the node was dormant for so long. Can you tell me what is going on with this?
A. You are the mother of a new orchid! That is a keiki, a baby orchid, that is sprouting from the node rather than another flower spike. You can pull or cut it off the spike once it has a couple of roots that are say 2 or so inches long or you can air layer it by getting some sphagnum moss and putting it around where the roots will grow and holding it in place with a piece of stocking so the roots will grow into the sphagnum and it will pot up very easily. Congrats on the new addition to your family!
Fungus or Virus on Cattleya Orchid
Q. From Chicago: My Lc. Angel Love x C. skinneri has necrotic spotting forming streaks in very young new growth on the inner part of the new leaf. If caught in time and treated with an anti fungal/bacterial agent I can arrest the spread of it, but often it occurs within the first inch or so of growth I can't see what's happening to it until it's too late and I have to cut off the whole new lead. I really don't know if I have a virus, bacteria or fungal infection. It grows in full sun east window of my home with good air circulation and humidity around 40% (winter early spring).
A. We went to our Go-To Guy Courtney Hackney for a response, who wrote: "It looks like a virus to me. If the plant was grown bright and hard the sunken streaks would not show up as early and be soft, but they would still appear. My bet is that flowers will be badly virused. Each time I have had a plant show these symptoms it has tested positive for Cymbidium and tobacco mosaic virus, it probably has odontoglossum ringspot virus, too". You should segregate the plant from your other plants in case it is virused (you could try a virus test kit from Agdia), or dispose of the plant and replace it with another. You have to wonder why when you treat it the symptoms disappear, but they maybe are just suppressed rather than truly disappear because they come back the next year.
Cut Phalaenopsis Spike to Encourage Reblooming?
Q. How do I prune a phalaenopsis orchid spike to encourage
A. There are two schools of thought on how to handle a phalaenopsis spike. ;Some folks will tell you that after the flowers are gone, cut the spike two or three nodes up from the bottom of the spike, and often times the plant will send out a side spike from one of the remaining nodes and a few more flowers may form. I don't do this because I think you're robbing the plant of strength it would otherwise develop over the summer and use for next year's blooms. In other words, you're sacrificing next year's beautiful blooms for a second rate bloom now.
Check out this video.
Ant Infestation Inside Orchid Pots
Q. I was in the garden yesterday and noticed I have an ant infestation on more than a few of my plants. As they are inside a screened porch I found this disconcerting. How do I get rid of them? Can I use ant spray on the pseudobulbs and inflorescences? Or is there some other less poisonous method?
A. Pour a solution of Orthene or liquid Sevin (1 tsp/gal) in the pot. You'll chase them out of the pot, so maybe you'd rather take them outside to do it. I don't know if I'd spray the pseudobulbs and flower spikes, you need to treat inside the pot where they're nesting.
Accordion Pleating on Oncidium Leaf
Q. I bought a blooming oncidium three years ago and it soon started developing crinkles in its leaves. It puts out new leaves with good color, but every leaf has crinkles about an inch from the end. It has never bloomed, although I keep it in the same window with a dendrobrium that is healthy and blooms. What is wrong?
A. When the leaf crinkles like that, it is telling you that it needs more water. Perhaps you should wiggle the plant and see if it is loose in the pot. If it is, it would suggest that it is ready for some fresh mix. Perhaps potting it in a sphagnum based mix that would hold some more water would help.the infection set in. Now that it's spring, it should start to grow and grow new pseudobulbs, so it will recover by the end of the summer.
Vanilla Orchids Can Produce Vanilla Beans
Q. I am interested in growing vanilla beans with my grand-daughter. I’m from Volusia County, where can I find vanilla orchids?
A. The best place to get the vanilla orchid is at an orchid show or call EFG in Deland. You need two different clones to get a vanilla bean and the plants have to be pretty large to produce the flowers, that you have to hand pollinate to produce a pod. Be careful what you wish for, they'll take over your growing area! (Apr-11)
photo by Greg Allikas
Orchids Won't Bloom
Q. For the last few years I have had several orchids that are healthy with plenty of foliage but no flowers. Do I need to start again or what?
A. For healthy plants that don't bloom, gradually move them into brighter light. If you're talking about cattleyas or dendrobiums that have beautiful green foliage, you are not getting enough light. The leaves should be hard as cardboard (when mature) and have a slight yellowish cast to them. If you're talking about phalaenopsis, deep green leaves are fine because they are understory plants. If they're not blooming, perhaps they didn't get cool enough around Halloween to set their spikes. Check out the AOS Beginner Newsletter series. (Apr-11)
Try Cocktail Cattleyas on Windowsills
Q. Should I buy some cattleya orchids for indoor growing along with my phals? I hear they are difficult plants to grow.
A. I don't think cattleyas are difficult to grow, they are just different. They need very bright light to bloom although some of the smaller 'cocktail cattleyas' can be grown and bloomed on a windowsill. You'll use a freely draining mix letting them dry between watering and repot only every 2 to 4 years (so you must use a nonorganic mix that won't degrade quickly, thus the coarse, freely draining mix). Look for some of the smaller windowsill rather than standard cattleyas and give it a try! (Apr-11)
Phalaenopsis Mites on Phalaenopsis
Q. From the UK: Please could tell me what is attacking the leaves of this orchid? I have had the plant for a year now and this problem has started to occur over the last few weeks and is now working its way up the flowering stems. I am wondering whether it is false spider mite.
A. I think you are right, it looks like false spider mites or flat mites. Dr. Robert Cating suspects it is Tenuipalpus pacificus
that often feeds on the upper surfaces of leaves and creates a pock-marked appearance from empty and collapsed leaf cells. If you are growing inside, just take them to the sink and spray all the leaves, top and bottom, giving the plant a good bath. Then get a spray bottle and add some isopropyl alcohol and dish detergent to it and spray the leaves top and bottom. You may want to repeat this every week or so for a couple of weeks during the winter when the dry heat inside the house favors spider mites. Read this article
by Dr. Paul Johnson for more information.
Fungus Gnats in Old Potting Mix
Q. From South Africa: I have 3 phalaenopsis orchids. There is a grayish flying insect flying around and crawling underneath the bark. Do these insects cause the roots in the plant to rot? Are the insects attracted to the wetness of the bark or the roots?
A. That sounds like fungus gnats. They are more of an annoyance than a real threat to the plant, but who wants to be annoyed? The presence of gnats, which feed on fungus in the potting mix, indicates your bark has gotten old and degraded and the plants need to be repotted in fresh mix. Phals seem to enjoy being repotted every year after they are done blooming.
Read this excellent article
by Dr. Paul Johnson for more information. For gnat control, the first line of defense would be controlling the wetness of your potting mix. Next Johnson recommends traps (yellow sticky cards that can be hung or inserted into the pot). Then there is Bt or Bacillus thuringiensis, a naturally occurring soil bacterium that kills the larvae of fungus gnats, mosquitoes and black flies. It is a very safe product that can be sprayed directly on vegetables to kill caterpillars and you can eat the vegetables the same day).
Remove Hard Water Spotting and Shine Orchid Leaves
Q. At one of our meetings, our speaker had a home remedy to clean orchid leaves. Do you remember what it was?
A. There are lots of household items you can use to clean orchid leaves. You can clean the leaves with a mildly acidic solution like white vinegar, lemon juice, pineapple juice, Sprite, 7 Up, etc to remove calcium build up or other spotting. Dip a soft cloth in whatever cleaning solution you choose and gently wipe the leaves. Some people use milk to shine the leaves, but be sure to wipe the excess milk off so you don't get fungus or mildew growing on the leaves.
Dendrobium Orchid Leaf Loss from Environmental Changes
Q. From Tanzania: I brought a beautiful orchid back from Singapore two weeks ago. A few days later the lower leaves of the plant changed to yellow, one at a time and fell off. I have repotted the plant in a slightly bigger pot using charcoal medium, but the problem continues and now even the leaves under the flower. Please help!
A. Your orchid is a phalaenopsis type dendrobium orchid. It's not unusual for them to drop their leaves if they get too dry or too cold. Given the radical change in environment from the number of miles this plant has traveled in the last few weeks together with repotting while in bloom, it would be a surprise if it didn't lose a few leaves.
The good news is that dendrobium orchids are incredibly resilient and yours will recover from this short term blip Keep it in nice bright light, when the nighttime temps are above 60 F find a place outdoors where it gets very bright but not direct light (acclimating it slowly to avoid sunburn) and water and fertilize it copiously when it is growing and then less water and fertilizer in winter while it rests. It will reward you with blooms in the next blooming cycle.
Bud Drop on Phalaenopsis Orchid
Q. About a month ago I got 3 phalaenopsis and have tried to be diligent with their care. I watered them once so far and put one of them on the bathroom sink counter 4 feet from a southern exposed window. It was doing great until this past weekend when the flowers began to drop. There are 3 or 4 stems and some still have buds on them but they are dropping too. Help!
A. That plant looks very healthy so I don't think there is any problem with the way you are taking care of it. It's either one or both of two things, the normal life of the flower and/or the plant being moved around. On the one flower spike where there are no buds just open flowers (and some with dropped flowers), you don't know how long this flower spike was blooming before you got it. They'll normally bloom for 2 or 3 months, but if it began to bloom in December, it may be the end of its normal cycle. Once all the flowers and buds are gone from this flower spike cut the flower stalk back to the base of the plant and let it gather strength for blooming next year.
Then there's the flower spike with just flower buds. Flower buds can drop for a variety of reasons (and sometimes no reason that you'll be able to confirm). You'll hear that buds will drop if they're too dry or too cold, and that's undoubtedly true, but even more true I think is they resent being moved and sometimes drop buds in response. If you were the phal growing in this cozy greenhouse then got thrown into a box, then trucked to a store, and then set out and not treated too well until someone brings you home to give you some TLC, well you might drop a bud or two too. Maybe you'll be able to stabilize it and get the remaining buds to open. Try to keep the plant oriented at the same angle to the sun and hope for the best.
Phalaenopsis Repotted from Sphagnum into Bark
Q. Here are some pictures of my wounded phals. When I bought my phals most of them were in sphagnum moss, so I repotted them into a bark mix. I bought this phal 3 months ago and it had 6 leaves when I got it. One month later, its leaves fell off.
A. I’m guessing the leaf loss occurred because when the plant was repotted in the bark mix, the roots died and could no longer sustain the leaves (fresh bark is much drier than moss). Most of the commercial growers grow in sphagnum moss, and the roots become accustomed to growing in this more water retentive medium. If you switch over to a bark mix, they have to grow new roots to acclimate to the new mix. Either repot in sphagnum or try a mix of half sphagnum and half bark if you prefer bark to reduce the transplant shock. Phals grow upward, gaining a new leaf or two each year and possibly losing a bottom leaf or two. When you repot, you should cut the old woody stem at the bottom of the plant until you reach vibrant tissue. Give the bottom roots a haircut and reset the plants to the new elevation in the pot so you don't have to tie them up to hold them erect
Scale or Mealybugs on Phalaenopsis
Q. I have had this phal for about 2 years and it has looked poorly for awhile.
A. Look at the white stuff at the base of the plant, it's either scale or mealybugs. This is where the little suckers are reproducing. On some of the other leaves, it looks like there are white spots. If it is scale, these are the crawlers looking for a new home; if it's furry, it's mealybugs.
It doesn't much matter whether it's scale or mealybugs, the treatment is the same. The easy thing to do is get a Q tip and isopropyl alcohol and wipe away all the white stuff. You can also pour the isopropyl alcohol into a plastic spray bottle and spray all the surfaces between the leaves, because that's where they hide. You'll have to repeat the treatment because they are stubborn little suckers.
If you have a bunch of plants and can take them outside, you can spray with an insecticide like malathion, summer oil or orthene. They move between plants so treat all of them. You can treat them inside with the isopropyl alcohol and watch for recurrence.
Spread Pests and Disease by Dunking Orchids in Bucket
Q. I water my phals by soaking them in a bucket one per week for one hour. Every day or every other day I spray their leaves. This phal had 6 leaves before. I cut the top leaf in half because it had disease. I have used peroxide and cinnamon on their leaves when they looked sick last month.
A. The problem with dunking all your plants in the same bucket of water is that you'll spread whatever baddies are there to the other plants. It’s better to water each plant with fresh water. If you're growing inside, just bring them to the sink and water them thoroughly (as long as it's not softened water), let them drain and move them back. The scale can be transferred between plants as can any bacteria or fungus.
That top leaf looks like it had a bacterial infection. The yellow halo on the phal leaf would also suggest a bacterial infection, similar to when people have a skin infection and there is a red halo around the infected part. With the orchid, there is a yellow halo. The easiest way to treat this is to pour some hydrogen peroxide on the yellow spot like you have been doing. Copper fungicides are also very effective bactericides for phals. If the spot doesn't increase in size, just keep an eye on it. If it does, cut off the leaf with a sterile single edged razor blade like you did.
Bacterial Brown Spot on Cattleya
Q. My Brassavola nodosa has four new leads with four new spikes emerging. There is dark, sunken discoloration on all the new growth. What's the problem?
A. That looks like Bacterial Brown Spot caused by Acidovorax cattleyae (syn. Pseudomonas cattleyae) on your cattleya. It is particularly serious on phalaenopsis though it obviously affects cattleyas. On cattleyas, the disease appears as sunken black spots that are clearly delineated. On older seedlings and mature plants, the disease does not travel rapidly, but as you have discovered, a young lead can be quickly killed. It probably entered the plant through the stomata rather than damaged tissue.
The most effective treatment is a copper bactericide/fungicide such as Kocide, although hydrogen peroxide will do in a pinch. If the spots enlarge, you may have to sanitize the plant by removing infected tissue with a single edged razor. That one lead where the spots have all coalesced should be removed entirely.
Q. I have had a Den. polyanthum for a while though it is a poor bloomer. Is this one of those that does not want water during the winter? I also have a Den. Himezakura 'Sanokku' which is a great grower, I think it is a nobile dendrobium. It has no leaves but is starting to bud. Due to the fact that it has buds, should I keep watering?
A. Den. polyanthum (previously known as Den. primulinum) is indeed a nobile dendrobium. Baker's culture notes state that "Growers sometimes recommend eliminating water in winter, but plants are healthiest if for most of the winter they are allowed to become somewhat dry between waterings but do not remain dry for extended periods. For 1-2 months in late winter, conditions are clear, warm and dry with humidity so low that even moisture from morning dew is uncommon. Plants should be allowed to dry out completely between waterings and remain dry longer during this time". Baker also notes that "Den. primulinum is difficult to grow in warm uniform climates or warm greenhouses. The cool, dry rest is essential to induce flowering". You should find a cool, bright place for this one in your house and let it dry a bit between watering.
The Den. Himezakura is a hybrid of several nobile dendrobiums, mostly Den. nobile and monoliforme. Hybrid vigor may be responsible for its good growth habit. If it is budding already, it never slowed down for its winter rest. Let it dry a bit between watering and resume heavy watering and fertilizing after the new growth begins.
Nectar Glues Lip/Sepals Together
Q. My B. Little Stars has 4 spikes, one of which is fully opened. As each bloom opened, the tip would not separate to complete the opening process. Now the tips of the petals and sepals are brown. I grow it in bright light with other brassavola primary hybrids. What's wrong?
A. We were stumped, we thought possibly sepal wilt or genetic defect, but we were guessing so we asked He Who Knows Such Things. Courtney Hackney says "I was going to diagnose a genetic defect until I saw the photos. It looks like the dorsal tip of the sepal is glued to the lip. That happens a lot in vandas too and is caused by an excess of secreted nectar. The solution for vandas is to provide lots of water on the buds when they are forming until they open. Usually that dissolves the sugar and keeps it from crystallizing and holding other flower parts. The brown damage is coming from the sepal trying to pull free from the lip damaging the sepal."
Cercospora on Cattleya Leaves
Q. This summer some of my cattleyas developed large irregular yellow spots with reddish purple to dark markings on the leaves but I could not find any pictures of similarly afflicted orchids to make a diagnosis. Enter Dr. Ruben Sauleda!
A. Ruben took one look at the leaf and said it was the fungus Cercospora. Baker's description of the pathogen is very apt "The first symptom is light yellow spots on the underside of leaves. Soon after infection occurs, the yellow-green area may be noted on the top surface of the leaf. The spots continue to enlarge in a circular or irregular pattern and may eventually cover the entire leaf. With age, the spots become slightly sunken and necrotic and change to purple-brown or purple-black. The advancing margin remains yellow". Mystery solved! The cure is to cut away any infected leaves to prevent spread of the disease and spray with a good quality fungicide like Banrot or Cleary's 3336.
Winter Dendrobium Care
Q. I see from my notes that most dendrobiums need a dry 6 weeks but not all of them. I have the "stick-like" ones, the fat, cigar shaped ones and the ones that are small and grow sideways in separate clumps with lots of roots. Which ones of these need - or don't need - water in the winter? Can you let me know how to take care of each of these?
A. The ones you describe as stick-like sound like the evergreen type dendrobiums that don't lose their leaves over winter and bloom most robustly in the fall. These are the phalaenopsis type dendrobiums because the flowers look like a phal. They like to be warm in the winter (55 to 60 min temp) and treated like a cattleya, so you can water and fertilize regularly though about half what you would normally do in the summer.
The ones you describe as cigar shaped or growing sideways in clumps with lots of roots I am guessing are the nobile or callista type dendrobiums that like to be cool, bright and drier in the winter. Most growers now recommend just restricting watering to every 2 to 4 weeks in winter and absolutely no fertilizer until the new growth begins in the spring.