City Gardening By Bio Green Team Share Tweet Pin Share Orchids, especially the Phalaenopsis, today belong to the category of "normal" houseplants. But the title is somewhat misleading, because many were first optimised in greenhouse settings. Quick Navigation Where do orchids come from?Watering and feeding orchidsOrchids want to grow highLight and shadowsBottled fertiliser and nutrientsRepotting and substratesHow to combat pests on your orchids The long lifespan of flowers, their various and bizarre forms, their exotic colours, are in short, the beauty of over 30,000 different varieties of orchids worldwide and is a special fascination for many people worldwide. Whether miniatures or giants, orchids provide a world of diversity for everyone.The different origins of various orchids allows for their care in not only cold, but also tempered and warm greenhouses too. Even unheated greenhouses can be used for “frost hardy” specimens. The variety certainly makes for a exciting hobby.In a greenhouse, it is possible to cultivate orchids not only in a pot but also in a seemingly natural environment. It is also possible to establish a variety of orchids in a small space since miniature forms of orchids are commonplace and can be used to maximise small spaces. Where do orchids come from?Orchids grow on all continents, especially in tropical areas. In addition to natural forms, other breeds have emerged, including numerous genera (the plural of genus) and even multiple category hybrids. The location or origin of a particular genus gives an indication as to the correct temperature or environment for it, as well as any required rest periods.Orchids with bulbs (light onions – pseudobulbs), for example, need a rest period as they adapt to the changing seasons. This is quite similar to Slipper Orchids (Cypripedium), which lose their leaves in autumn and winter to the soil beneath. Their tropical relatives behave similarly, they either lose their leaves (Lycaste) or stop growing. Only bulb-less orchids, such as the Moth Orchid (Phalaenopsis) or Venus Slipper (Paphiopedilum), know no proper rest. They do not need it because their conditions are quite stable throughout the year. Generally, a rest period begins once a set of sprouts have finished growing and ends with the growth of new shoots.Watering and feeding orchidsThe correct amount of water and fertiliser depends on the growth stage of the plant, the current season and the individual condition of the plant. Bear in mind though, that the orchids do not easily show if they need water or not. Their mostly firm, almost succulent, leaves and bulbs rarely give the orchid a “limp” feeling. One can only determine whether the plant is still sufficiently moist, based on whether or not healthy roots are present and whether the plant is still growing at all.Only in the growing season do orchids need water (and nutrients). With a quick finger test, you can tell if they require water: To do this, push your finger lightly into the earth. If the substrate feels cold and wet, then it doesn’t require any water and it’s as simple as that! Many orchid care problems arise due to improper watering. Too much water, too little, too often, too rarely. Oftentimes this can cause root damage, which can even lead to the complete loss of a plant.Preferably, use soft, still water at room temperature. However, if you see twisted leaves, this can often indicates some damage to the roots. As mentioned, the reason is usually over-watering, but it can also be the result of not enough humidity. As a rule of thumb with orchids: Better too dry than too wet! Orchids want to grow highIn the case of tropical orchids, the epiphytes, literally translated as “overgrowing plants” are the predominant variety. The epiphytes derive their nutrition from small amounts of top soil. But it is not only orchids, ferns, bromeliads and many other plants grow in the same manner. Interestingly, epiphytes make up 30 to 50 percent of the total flora in some tropical forests. They are characterised by high adaptability to their environment.Orchids also have a special root, the aerial root. This allows them to “absorb” water and nutrients very quickly. This is particularly important when it comes to absorbing tropical rain and dew. Light and shadowsOrchids have different lighting requirements according to their origin. In indoor settings, plants with lower light requirements are able to survive. However, a lack of light can be recognised by yellow, soft leaves. A seasoned-gardener would refer to this as “etiolation”. Quite different are the possibilities seen in a typical greenhouse, where plants must be in shade from May to September. Without light, plants can not process water or nutrients. Bottled fertiliser and nutrientsPlants need a lot more fertiliser in the growing season – usually during the light-rich spring and summer seasons – compared to when they are not growing. Don’t forget that they also need some fertiliser in modern substrates! As a rule of thumb, you should remember to fertilise with every third watering. But do not fertilise dry plants – this poses the risk of burning the roots. Normal fertilisers are usually too nutrient-rich for orchids, the ratio of nitrogen to phosphorus and potassium is not right and some important trace elements are missing. Rather than aiding it, this can seriously injure the plant. The remedy for this problem is an individual fertiliser that is tailored to the needs of orchids. Repotting and substratesDepending on the growth cycle, orchids are usually implemented annually or only in 2-3 year cycles. You should always use special earth for repotting. This is because the epiphytic ‘lifestyle’ requires a particularly permeable, yet structurally stable substrate. Today, cocci are heavily used as fibre and chips, peat moss (sphagnum) and bark. How to combat pests on your orchidsAs with most plants, it is important to pay attention to pests, however orchids in particular, require special attention. Spider mites, the red spider, woolly and scale lice are all likely pests for your orchids and they can attack fairly often. Corrective measures in the greenhouse can involve beneficial organisms or various approved plant protection products. The original version of this article was published in the Greenhouse Post, issue 12/2015, text and image: Jörn Pinske.