Alan Koch of Gold Country Orchids spoke to the Desert Valley Orchid Society on Thursday, February 16, 2017. He spoke of how it's important to know about the parents of hybrids to know how to grow the hybrids.
He also spoke about a wide scattering of plants and their peculiarities.
At the end was an interesting discussion of water, fertilizer and pH.
I took notes. I may have made some mistakes; I will correct the ones I notice or are pointed out to me.
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Zygopetalums get spots on their leaves because they have areas of tissue that concentrate salts from water, to keep it away from most of the tissue. To prevent spots, flush when watering with pure water, and don't let the medium dry out. Use a plastic pot, which helps in keeping medium moist. Salts don't accumulate on the plastic pot, but rather wash out with watering. When medium dries out the leaves concentrate salts even further, leading to spots. For Zygos, use long fiber New Zealand sphagnum moss in a plastic pot and keep moist. Do not pack the moss tightly; leave it loose so there is a lot of air, but it can stay moist. An Australian breeder wanted a Zygo that is warmth tolerant and doesn't spot. Advance Australia is the result of 30+ years of hybridizing; it tolerates 70 F / 21C nights, doesn't spot if grown in NZ sphagnum moss in a plastic pot.
Epidendrum polybulbon flowers better hanging over the pot or on a horizontal mount.
Sarcochilus australis - everybody says it grows in bright light. He found them in dense shade, 400fc. Now he can grow them. He said he killed more of this than any other orchid before learning they are low-light plants.
Brassavola nodosa and grandiflora are very similar, even grow in similar areas. May be two forms of the same species. Nodosa has thicker leaves; grandiflora wider leaves. But B. grandiflora grows on coffee trees under the canopy - gets more shade and water. B. nodosa grows near the tops of trees on twigs. It gets a lot more sun and dries out much faster. Which is a better hybrid parent for windowsill or light stand growing? The one needing less light.
Cattleya nobilior is always found on horizontal tree limbs. It grows better horizontally. He showed photos of nobiliors mounted on vertical pieces of wood. Many died. He put the remainder, still on mounts, in baskets that let the mounts lie horizontally. The plants took off and flowered best on the growths hanging out of the baskets.
Dendrobium / Dockrillia wasselii also needs a horizontal mount. It doesn't grow well on a vertical mount.
Cattleya luteola is a very low light plant. The lower the light, the more flowers it produces. In bright light, only 1 flower; in low light, 4 flowers. It is also very salt sensitive.
Dendrobium cuthbertsonii in habitat in New Guinea sees temperatures never over 75 F / 24C and gets 250" / 635cm of rain per year. His plants in Sacramento, California tolerate occasional days of 110 F / 43C. He has bred tetraploids for temperature tolerance. He deflasks in July in 100 F / 38C days to weed out the weaker plants. He gets 90% survival. His method is growing them in New Zealand sphagnum moss, using extremely pure water, and keeping them very moist. His plants flower 18 months out of flask. He showed several different color forms.
Sophronitis coccinea also needs lots of very pure water. In habitat it is cool and moist all the time. We shouldn't try it in metro Phoenix because even homes are too hot. It won't grow in south Florida, either. It does OK in coastal southern California, but not much inland. He keeps them alive in Sacramento for breeding purposes, but his plants do not look good, though they do flower.
Sophronitis cernua is a warm grower, and we should have no trouble with it in metro Phoenix on a windowsill. It has thick, succulent leaves. In habitat it annually goes 3 months without water. It is warmth tolerant and does fine on a windowsill.
Sophronitis brevipedunculata grows at 1100 feet / 335 meters. It also needs flushing with pure water. There was an extensive discussion of watering and fertilizing at the end of the talk - keep reading.
Cattleya intermedia regularly tolerates temperatures of 22 - 110 F / -6 to 43C and has just survived several days of 17 F / -8.3C. He told the story of a hobbyist who had a heater failure during a cold winter and lost an entire collection of Cymbidiums. The one C. intermedia in the greenhouse was the only plant that survived, albeit in poor shape. There is a dwarf coastal sand form; he measured the sand around one blooming at 110 F / 43C. There is also a higher-elevation inland form which is much bigger plant. The two forms are the same plant; when one kind is grown in the other place, it changes its form. The dwarfing is due to heat and dryness.
Cattleya loddigesii tolerates 117 F / 47C.
He could never get Macroclinium lexerzana to bloom well. He grew his in morning light, afternoon shade. It is pollinated by mosquitoes. He visited a friend in Florida and saw a plant blooming profusely, surrounded by mosquitoes, in afternoon shade. He moved his plant to afternoon shade and it began blooming profusely.
Oeceoclades spathulata is a terrestrial orchid from Madagascar. It grows from an annually renewing corm. People import them and, being orchids, they plant them just beneath the surface of the soil. They die. The plant needs to hide from predators so the corm is buried deeply in the wild. If you plant corms deeply they do well.
Brachypetalum Paphiopedilums like extra lime in their soil - egg shells, dolomite, oyster shells. There was an extensive discussion of lime and pH at the end of the talk; keep reading for that.
Some plants are unlike their relatives. Pleurothallis leptotifolia requires extremely bright bright bright light.
Leptotes bicolor flowers better in Phalaenopsis light, with a lot more flowers. In brighter light it gets many fewer flowers. Temperature doesn't matter to its flowering.
Paphiopedilum hirsutissimum grows in shady jungles. But even in the jungles it grows in sinkholes in even less light, much less than Phalaenopsis light. After he saw this he moved his to very low light and got it awarded.
Phalaenopsis will bloom in bright light but high-light flowers when dried weigh only 40% of flowers in low light. You get more and bigger flowers in lower light.
Paphiopedilum rothschildianum grows under deciduous trees. It gets a very bright winter. The multiflorals don't like root disturbance; most Paphs are fine to repot annually, but roth prefers a 2 year repotting cycle.
The Chinese Paphiopedilums like malipoense also need lime in their soil.
Aerangis hariotiana is salt sensitive and does better mounted. If you use rain water you don't have to worry. They grow in Phalaenopsis light.
Aerangis luteoalba must dry between waterings. They don't last long if kept moist.
Brassavola / Rhyncholaelia digbyana grows on the south side (Northern Hemisphere) of deciduous trees in full winter sun. Years ago he was visiting a nursery in Florida. The owner had him help carry an enormous Rh. digbyana with two 2" x 4" x 8' / 5cm x 10cm x 2.75m boards as carrying handles. The man left it exposed to full Florida sun all winter. The plant became red-tinged but bloomed spectacularly. He said a seedling Rh. digbyana should be able to tolerate this kind of sun once it has 4-5 pseudobulbs.
Cattleya schilleriana is the only Cattleya with stomata (breathing pores) on its roots. It must be mounted, or grown with roots exposed. This accounts for its reputation as difficult to grow.
Cattleya araguaiensis has photosynthetic roots. If you grow it in a clear pot or mounted it has 28% larger flowers.
Cattleya aclandiae also has photosynthetic roots and likewise does better mounted.
Laelia briegeri grows in detritus patches on bare rock where it might be 115 F / 46C. It does not grow on the bare rock! The detritus and moss keeps the roots cooler. Laelia crispata (formerly L. flava) grows nearby but in deep grass so it doesn't see those kinds of temperatures.
Cattleya dowiana needs a long, dry winter or it rots. It gets no winter rain.
Cattleya walkeriana blooms twice yearly if it has uniformly longish days and not too much day length variation. In metro Los Angeles it blooms twice a year; in Sacramento, only once. It needs to become completely dry between watering. It grows on twigs or rocks, so it does best in a clear pot, mounted or in a shallow basket. It also has photosynthetic roots. It walks out of any container, and often blooms best on the growths hanging off the edge. It imparts twice-yearly blooming to lots of its hybrids.
Cattleya nobilior must dry from December to February. It needs a horizontal mount, not a vertical mount.
When potting with New Zealand sphagnum in clay, never fill the pot with moss. As the plant grows the roots will compact the moss too much. Instead, wrap a collar of long-fiber moss around the base of the plant so the plant fits snugly into the pot, leaving the bottom portion of the pot empty. As the plant grows roots they will push the moss into the pot.
Laelia sincorana does better on a mount.
Laeliocattleya Sierra Doll needs to dry out well between waterings due to its Cattleya walkeriana heritage. It is C. walkeriana x C. Pink Doll.
Laeliocattleya (Cattleya) Love Knot has the best fragrance. It is Laelia (Cattleya) sincorana x Cattleya walkeriana. He showed a photo of a 2n and a tetraploid Love Knot side by side; the tetraploid flower was much bigger.
Laeliocattleya (Cattleya) Tahoe Rose is Laelia (Cattleya) purpurata x Cattleya walkeriana. It has excellent fragrance, too, especially caerulea forms.
Blue Cattleyas have the best fragrances.
Laeliocattleya Fuschia Doll is Laeliocattleya Sierra Doll x Laelia sincorana. He has remade this with very dark parents.
Cattlianthe Orchidglade is Guarianthe / Cattleya aurantiaca x Cattleya walkeriana. It blooms 3 times per year.
Benzyladenine is used in cloning to encourage proliferation of tissue. It causes mutations. Coconut water also causes proliferation without mutants. There are some orchids that will not proliferate with coconut water, but will with benzyladenine.
Fertilizer, pH and water discussion:
He said orchid roots absorb everything they can in 25 minutes. Because you want the plants to take up as much fertilizer as possible when you fertilize, you should apply fertilizer solutions only to dry roots. Watering first, then fertilizing, prevents plants from taking up as much fertilizer as they could if receiving only fertilizer solution. It is a bad idea as well as wasting fertilizer. An audience member challenged him on this. He pointed out he has a masters' degree in agriculture, and fertilizing dry has been standard teaching in agriculture for over 30 years. He reiterated never to water first before fertilizing.
He has well water with 700 ppm total dissolved solids. He waters most things with this water, then flushes with a small amount of RO water to rinse it out of the pot and keep salts off the roots. He does this especially with salt-sensitive plants. He says other well-known California orchid growers do this.
[Editorial note: Of course, reverse osmosis or rain water is better for almost all orchids. I don't think he was saying 700 ppm TDS is good for orchids. Rather, I think he was saying how he deals with his water situation. Nursery owners use huge amounts of water, and purifying huge amounts of water is hugely expensive. I discussed with him at the break that I collect rain for my orchids. He mentioned this was ideal, but I have to be careful about ensuring adequate calcium, magnesium and trace minerals. I said I use an MSU fertilizer for pure water, and he said this was good.]
He uses a lot of Cal-Mag fertilizer. Calcium requirements are proportional to growing temperatures. Some growers in Asia, where temperatures are high, must use calcium nitrate in addition to Cal-Mag or their Cattleya shoots turn black.
An audience member asked why the Cal-Mag is necessary when his water has 700 ppm TDS, since this is almost all calcium and magnesium salts. He said it is a matter of availability. Most water is alkaline so the calcium and magnesium are not taken up by roots. Orchids do well with pH 6.0-6.5; the calcium and magnesium are more soluble as pH drops. He said if we acidified our water to pH 6.0 and we have water with a lot of dissolved minerals, we will not need supplemental calcium. Calcium lack is the primary cause of blackening Cattleya shoots. He does not acidify his water due to the cost of doing it. He says he uses 10,000 gallons of water a day.
He uses the "Fertilizer then Flush" method for salt-sensitive plants. This means fertilize, wait 25 minutes so the roots have taken up as much as they can, then flush with fresh water to get salts off the roots.
There was a discussion of how to acidify water. Organic acids like vinegar are not good; they are weak, so you have to use a lot, and they contribute to rapid breakdown of bark. Sulfuric and hydrochloric acids are dangerous if splattered on a person or plant.
An audience member said golf course greenskeepers here use N-pHuric Acid
N-pHURIC Information to acidify their water, and the audience member uses this for his acid-loving plants in the ground. It is buffered so it will not burn people. Once you have done a titration and figured out how much to add to your water, you can do that for a long time, since most municipal water supplies and wells don't change much.
For checking pH of water it is best and simplest to buy a pH meter. They are not expensive, they last a long time, and they are simple to use. pH paper does not work well and has a large margin of error. Liquid pH test kits can work well, but solutions don't last very long in storage.
People using rain or reverse osmosis water need to use fertilizers with calcium, magnesium and trace elements. MSU blends work well, and ensure correct pH.
He also recommended using
Peters S.T.E.M. (liquid) to ensure adequate trace elements.
He said Phalaenopsis take up minerals even better when exposed to low pH, 4.0-4.5, briefly. He said to look up articles by Bill Argo on nutrition that were published in the International Phalaenopsis Alliance journal. These articles are now available at the St Augustine Orchid Society and First Ray's Web sites.
Alan Koch, Gold Country Orchids, DVOS 2017 02 16
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