The Orchid Doctor Articles under the Heading Temperature

Temperature Comments
TEMPERATURE: Control In a confined area where fluorescents are used such as in a space four feet by five feet heat is generated by the ballasts which can be rewired to operate outside the closet; a fan circulating the air inside is not effective, it should be exhausting out. A72-1003 0
TEMPERATURE: Controlled Cold nights artificially supplied substitute for the real thing for some genera; cymbidiums, odontoglossums and some dendrobiums can be set inside a refrigerator at night for a time to set buds. A69-246To induce flowering, growers used to heat greenhouses at the end of summer when night temparatures lowered; the contrary method at that time of lowering greenhouse temperatures surprisingly was found to produce abundant flowers. A75-704 0
TEMPERATURE: Controls An Electronic Aspirated Screen designed for the grower that wants reliability and close tolerance of temperature and the option of day and night temperatures; for technical details and specifications; data on remote alarm sysyem, refer to OR85-94 0
TEMPERATURE: Cool-growing Conditions They are wide-spread in Mexico; orchids there thrive on their cold, dry winters in higher elevations; the night temperatures hover in the low 40's; little if any rain falls from November to May. A77-1082 0
TEMPERATURE: Day-night Differential For cymbidiums in summer a differential of 25 deg.F. between night and day is usual. A71-202The number of hours of cold necessary to set buds in phalaenopsis is less than ten nights below 60 deg.F. to start new blooming shoots; cymbidiums need periodic accumulation of cold to near 60 deg.F.; but more information is needed on this, A78-698 0
TEMPERATURE: Day-night Variation Recommended Warm greenhouse, Summer: Nights -- 65 to 70 deg.F, or 18 to 21C., Days -- 70 to 80 deg.F, or 21 to 27 C.; Winter: Nights -- 60 to 65 deg.F. or 16 to 18 C., Days -- 65 to 70 deg. F. or 18 to 21 G.; Intermediate, Summer: Nights -- 60 to 65 deg.F. or 16 to 18 C., Days -- 65 to 70 deg.F. or 18 to 21 C.; Winter: Nights: 55 to 60 deg.F. or 13 to 16 C., Days -- 60 to 65 deg.F. or 16 to 18 C; Cool, Summer: Nights and Days, if possible, 60 deg.F, or 16 C; Winter: Nights -- 50 deg.F. or 10 C. or less; Days -- 55 to 60 deg.F. or 13 to 16 C. Sander's Orchid guide, 1927, 2 0
TEMPERATURE: Effect on Plants Lower temperatures at night aid the growth process; it slows the rate at which reserves are burning themselves up to form carbon dioxide and water; also, when the weather is dull it helps plants to lower the daytime temperatures; most growth takes place at night; refer to A64-218+ 0
TEMPERATURE: Intermediate Definition and discussion, the variables met with in nature and ways of achieving them in the Kew greenhouse; refer to OR86-252; A81-640 0
TEMPERATURE: Maximum During daytime in summer 85 deg.F. should be the maximum; above that the harm may not be apparent but it does no good; better to control the temperature as much as possible. A73-487In the greenhouse anything over 95 deg.F. is too hot. A78-309 0
TEMPERATURE: Minimum For cattleyas; for relatively dormant plants which have been exposed to a night or two of lower temperatures in the 40's can stand a few days just above freezing; with new growths developing a night or two in low temperatures in the 40's will stunt their growth; a sudden drop from 55 to 61 deg.F. down to 35 deg.F. or so will possibly cause tissue injury. A65-439The lowest temperature that cattleyas can stand is, at times, down to 32 deg.F.; at others, injury occurs at 37 to 38 deg.F.; flowers may discolor below 45 deg.F.; some growers claim virus-free flowers will stand 40 deg.F, or 41 deg.F. A73-338 0
TEMPERATURE: Recommended for Winter in the Greenhouse Cool: December -- Night 50 and Day 55; Intermediate: Dec. -- 58 and day, 58 to 65; Warm: Dec. 68 and Day 68 to 73; with a slight difference in January Cool: Night 50 and Day 55; Intermediate 59 to 61 and Day 61 to 65; Warm: 66 to 70 at Night and only 70 during Daytime. OD86-219 0
TEMPERATURE: To Set Buds Paphiopedilums and phalaenopsis initiate buds after two or three weeks of night temperature below 14 dC; hardcane dendrobiums require near 18 dC, and softcane dendrobes need about 13 dC; in cymbidiums the low does not matter because the crucial factor is the difference of aear lO dC between day and night and this must occur when the bulb is beginning to mature; in cattleyas it is complicated with daylength. AU84-278 0
TEMPERATURE: To Set Buds on Paphiopedilums and Cymbidiums 50 deg.F. is not necessary, 55 deg.F. is low enough; for early cymbidiums (blooming November to January) a cool temperature to 55 deg.F. during the mid-March to May period will set buds; for mid-season flowerings cool to 55 deg.F. from June to August. A77-798 0
TEMPERATURE: Warm, Intermediate and Cool In greenhouses, plants are divided into Warm (65 dF minimum at night) such as for Phalaenopsis; Intermediate (60 dF) as for cattleyas, and Cool (50 to 55 dF) as for cymbidiums. F81-84 0

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