Port St. Lucie
We had a wonderful speaker on Tuesday, April 9th who shared some wonderful tips for success with your Dendrobiums. I am pleased to present the following:
Tips from Roy’s presentation 4/9/2019
Best growers have several things in common.
The media pH is between 5 to 7.
Media is low in salt deposits.
Pest and disease absent.
Humidity near 70-80%
Avoid extremes of temperature and moisture. Thick leaved Orchids need a 10 – 30 degree differential in night and day temperatures. The stomatas will never open without the differential. Crassulacean Acid Metabolism CAM .
Nutrition is in balance with light, temperature, plant type
Dendrobium simple test for pH
One year in pot
Media: bark, perlite, peat
pH buffered with fine dolomite
without dolomite, pH is below 4.0 in three months
65 AG 65 mesh/inch screen
½ teaspoon per 4” pot
City water with low alkalinity and 40” of rainfall per year
How is your water? It may be the most important nutrient that we do not monitor for its content. Total dissolved minerals, pH, and alkalinity are strange factors to consider. They are critical for the end result
as we try to grow the perfect Orchid.
Best article: What’s in Your Water? By Jack and Cari Peters, Orchids Magazine, May, 2012.
Choices: Peters 20-10-20, Cal-Mag 15-5-15, Peters 10-30-20
Michigan State 13-3-15, Peters 20-20-20
Weakly weekly. What does it mean.
Nitrogen: Urea, ammonia, nitrates
Phosphorus 2% to 40%
Potassium 1% to 20%
Flower Boosting Summary
Roots and environment perfect. pH must be 5 – 6.
humidity 70-80% low salts in media
Give as much light as plants will tolerate with lots of aeration.
Use high calcium fertilizer one month before spike formation.
Use at rate of half teaspoon per gallon per week. With 1/8 teaspoon micro nutrient package.
Extra phosphorus does not help.
See “Without High Phosphorus” by Jan Szyren, Orchids, June, 2003.
Low nitrogen helps. Ammonia and urea will favor vegetative
growth at the expense of flowers. Nitrates ok.
Roy’s Secret Potion
On mature plants. Just before the spikes appear. Apply calcium type fertilizer llike Peter’s Cal Mag Special, at ½ teaspoon per gallon with a micronutrient package like Miller’s Microplex, at 1/8 teaspoon per gallon. Weekly until spikes and flowers appear. Maximum 3 months.
If it does not work. We need to run diagnostics. Something needs to be fixed.
Buying an Orchid.
The Flowers: Compare identical orchids. Select one with a few flowers and a bunch of buds. See if spike is branching. If so, the plant will produce more flowers.
The Plant: Does plant wobble? Leaves should be undamaged with pigment evenly distributed. Plant should not have any yellowing, spotting, or black tips.
The Bulbs: Bulbs should be firm and plump; the more the better.
Bugs and Pests: Peek underneath the leaves and in the crevices.
What to Ask
How long do flowers last? Is flower fragrant? How big will it grow?
The Deadly Ride Home
On sunny days shop early or late and go directly home. Secure plant in the car and shade it from the sun.
Repot when the medium starts decomposing or plant starts growing outside the pot. The best time is generally just after the plant has finished blooming and new growth starts appearing.
Sphagnum moss: The most porous medium. Buy the premium brand and never let the moss completely dry out or compact it firmly.
Orchid bark: Choice of fir bark or Orchiada which lasts 8-9 years
Orchid bark mix: 4 parts small to medium size bark, 1 part fine to coarse perilite, and 1 part charcoal chips. For Phalaenopsis add 1 part cut sphagnum moss.
Pots: Clay vs. Plastic
Clay: More stable, have a lip for hanging, porous so they dry out faster, cooler, roots attach to pot, and they break when dropped.
Clear Plastic: Unstable, no lip, retain more moisture, roots don’t stick to pot, cheaper, become brittle with age, and roots are visible..
How to Repot
For orchids stuck in clay pots, wet the pot, take a thin knife, and insert it between the root mass and the pot. Slowly work the knife around, lifting the plant as you go. Examine plant to determine health of the roots and type of new medium to be used. Trim away any dead roots using a sterile trimmer. Spray roots with 3% hydrogen peroxide solution. Use clean pot that will allow 2 years new growth. Keep in mind whether this is a monopodial or sympodial orchid. Place base of plant ½” below rim of pot.. Push and tap new saturated medium in so plant is secure. If plant is wobbly insert a stake and/or pot clip. Label plant and water. No roots at all? Make your own roots!
Know the water requirements of your orchid. Larger roots, larger or less porous mediums, and hotter temperatures require more frequent watering. Water drainage is very important. Never use cold or hot water. Don’t let water collect in crown of plant.
Forms: liquid, powder, or granular. The label represents the proportion of nitrogen, phosphorous, and potassium (N-P-K) in the mix. Types: one for growing (high in nitrogen e.g. 20-14-13) and one for blooming (low in nitrogen e.g. 11-35-15); apply after stem appears and use until the flowers fall. It’s best to fertilize more frequently (weakly, weekly) using a diluted mixture. Make sure the potting medium is damp. Don’t fertilized weak plants/roots. Plants not actively growing should be fertilized and watered less.
Good air circulation fights bud blast by insuring a gradual change of temperature.
Orientation to the Light
By being kept in the same orientation to the light, the orchid will not waste energy repeatedly bending toward the light. Mark the plant!
Bugs, Pests and Bacteria: Safe-Measures vs. BIOADVANCED 3-in-1 Insect, Disease & Mite Control or BAYER ADVANCED Rose & Flower Care (2 in 1 systemic granules)
Aphids: These look like skinny green flies with small eyes. Spray the plant with lukewarm water. Continue the treatment until bugs are gone.
Mealy Bugs: Little maggots with white hairy tufts—look like cotton balls. They are very common and easy to eliminate. Mix 4 parts warm water with one part rubbing alcohol and a few drops of liquid dishwashing soap. Thoroughly spray the tops and bottoms of all the leaves. Also spay other plants that were near the infested plant.
Spider Mites: Very small spiders and/or webs. They occur when there is low humidity and little air circulation. Bites cause yellowing of the leaves and red splotches. Use same treatment as for mealy bugs.
Scales: These look like little, brown, hard, half-dome bumps on the plant which are difficult to eradicate. Use a sprayer filled with 2/3 rubbing alcohol, 1/3 water and 10 drops dishwashing liquid. Sponge the entire plant with mixture. Use toothbrush and Q-tips to scrub entire plant. Spray entire plant again. Repeat process for 3 days.
Thripes: Very miniscule and can be very destructive. Flower buds are usually
deformed. Use Neem, horticultural oil, or insecticidal soap.
Rot: Usually caused by water sitting in base of a leaf and there is insufficient air circulation for evaporation. Peel off damaged or rotting leaf and spray with rubbing alcohol. Another type of rot affects the roots and spreads into the plant. Bulbs and/or leaves turn brown and mushy. Repot and cut off all damaged parts down to where only green and healthy growth remains. Spray remaining plant with rubbing alcohol.
Bacteria: Very invasive and causes black spots or patches on the leaves. If patches are dry the bacteria is dead. To clean off live bacteria, cut off all the damaged parts. Spray with rubbing alcohol, Check every day to ensure there is no new spotting.
Pest Repellents: Rubbing alcohol, garlic, onions and Cayenne pepper work well.
Dividing: Works only with sympodial-type orchids (ones that grow sideways across the top of the pot like cattleya). Each division needs at least 3 or 4 pseudobulbs.
Keiki’s: Baby plants that sprout on the stem of a mature orchid. Leave on the stem until they’ve developed at least three roots a few inches long. Then twist or cut the young plant from the stem and pot.
Cuttings: Come from orchids that have long canes. With a sterile pruner, cut sections that contain at least two nodes (circular scars around the stems). Treat cuts with a rooting mixture. Lay the cuttings horizontally, half buried in a bed of damp sphagnum moss in a shallow container. Cover container with glass or plastic lid/wrap. Place the container in diffused but not direct sunlight. In a few months small plants will sprout.