Temperature and orchids

Completely different from most of pot plants, orchids are adapted to environments which have experience with not only seasonal temperature change but also noteworthy day/night change. These seasonal and daytime changes are frequently crucial to suitable growth and blossoming. When not given, the plant may be weak and the development of temperature-stress related disorders is allowed.

Cool, Warm or intermediate?

Orchids are generally categorized as either cool-, warm or intermediate- growing relying on their temperature requirements and the general explanations of these ranges are: Warm 80-90F in daytime and 65-70F nighttime, Intermediate 70-80F daytime and 55-65F nighttime and Cool 60-70F daytime and 50-55F nighttime.

Firstly, these temperature ranges are for winter limitations. Clearly, cattleyas and several oncidiums can bear summer days into the 90s or no one in three-quarters of the country could grow them. Nevertheless, temperatures above the low 90’s do make physiological stress happen on the plants and their ability to bear. It is involved in an important fall in night temperature in addition to the generally short time length of summer heat. The same plants continually exposed to high daytime temperature with little diurnal change very quickly form symptoms of heat stress such as black rot and calcium-deficiency can cause leaf-tip dieback.

Secondly, these ranges are SAFE calculations. We all know individuals who regularly expose their plants to temperatures above and, more significantly below, these ranges without obvious damage but the ability to continue to live temperature extremes is closely connected to many other environmental and cultural practices in addition to the duration. A few hours of temperatures in the 40’s will have a surprisingly different effect on phalaenopsis than an entire growing season of too-cool states. Remember these ranges like traffic danger warning signs. Does a sign for a curve in front at 35mph mean that you can’t take it at 50mph? Of course not, But if you are an experienced driver, you might be able to. The same is true about plants. If your plants have been grown under equally warm conditions they will get much more stressed by immediate cold snaps than they would get if they were allowed to gradually become acclimatized to lower temperatures and wet plants can get more easily damaged by cold than dry plants. Some clones can exist in extreme conditions much more than others. That fact from which warmth tolerant or especially cold tolerant landscaping plants can be developed.

For those which need a little cooler nights, moving them closer to the windows will help while those which need to be a little warmer can be organized further away given sufficient light can be provided.

The Requirement for a Day/Night Difference

The majority of the orchids that we grow do their best below intermediate temperature conditions. Given sufficient humidity and air flow, many of the orchids will stand higher daytime temperatures than the ranges which would indicate that as long as they cool off at night. Nighttime temperatures which are too warm or too cold are more frequent than not, much more making damages to plants than daytime temperatures.

Suitable nighttime temperatures are crucial to good growth and blossoming. Most of the orchids do their best with a 10-15F variation between daytime and nighttime temperatures with those from lower elevations and more tropical weather needing somewhat less but without this day/night temperature difference the plant’s respiration and metabolism have noticeable effect. Cool nighttime temperatures let orchids to store instead of expending the carbohydrates which they manufacture during the day. Night temperatures that are too high or day/night variations which are not enough may be the second important cause of failure to bloom. If your plants are growing well, with strong and healthy growth but not succeed to blossom and you are sure that your light is adequate, try falling your nighttime temperatures by a few degrees. You may be amazed by the results. In some cases, plants will not blossom unless both the day and night temperatures are below a sure threshold regardless of the day/night variations. For example, phalaenopsis grown below 90F/80F (day/night) temperatures will not flower even though there is a 10F difference. It is because day temperatures above 85F and night temperatures above around 75F prevent blossoming independently of each other. Conversely, try increasing or decreasing your nighttime temperature a few degrees, if your plants are not producing a strong and healthy growth.

Seasonal Fluctuation

Know the orchids. Many of the orchids, particularly species, are adapted to important seasonal changes and without them will either not flower or may not develop at all. It is particularly true of plants from higher elevations or more northerly weather. While Dendrobium lindleyi (aggregatum) grows perfectly well all through the summer months with temperatures in the 90’s during the day and 70’s at night, it will not flower without a suddenly colder (and virtually dry) winter season. The same kind of seasonal fluctuation is at play in the blossoming of nobile dendrobiums and plants like Dendrobium kingianum. In their indigenous natural home, summers can be very hot with temperatures even more than a 100F but winters are low in temperature and dry. Without a little cold winter, flowering is prevented and the plants make many keikis where there should have been inflorescences. For every orchid which requires a wide seasonal fluctuation. There is an orchid adapted to regularly warm or a little cold conditions. In some cases, these species live in small natural homes that do not feel important seasonal fluctuations because of altitude or near the equator place or they may come from high or low altitudes. This is where a little research into the indigenous natural home of your plants will go very far to successful culture.