Correctly fertilizing Orchids

Eva Monning Eva Monning

Caring for Orchids is not difficult if one knows what the plants want. We will explain to you the process of correctly fertilizing your Orchids at home.

Phalaenopsis Orchids

Colorful Phalaenopsis bloom in almost every household. Correctly fertilized even a little more vibrant.

Table of Contents

Orchids, especially the Moth Orchid (Phalaenopsis), are among the most popular houseplants in Germany. Most of the commercially available varieties of the elegant exotic plants are easy to care for and have long flowering periods. To promote flowering and healthy growth, as with all potted plants, it is necessary to fertilize them regularly. When fertilizing Orchids use your intuition and the right dosage

Fertilizing Orchids: Key points

In the growing phase, fertilize your Orchids every 14 days by enriching the water in which the Orchid is immersed with a special Orchid fertilizer. If you are new at growing Orchids and do not yet know the needs of your plant, we recommend using a commercially available mineral fertilizer. You can also use a liquid fertilizer so that the nutrients are optimally distributed. If your Orchid is in a dormancy phase, do not fertilize it.

What nutritional requirements do Orchids have?

Orchids grow in their natural habitat as epiphytes ). With their aerial roots, they draw nutrients from the rainwater and fog that constantly surrounds the host trees. The nutrient concentration dissolved in rainwater is relatively low, but is available all the time. Therefore, Orchids are accustomed to being regularly supplied with small doses of salts and trace elements such as phosphorus, potassium, calcium, magnesium, nitrogen, zinc, manganese and a few others. It is extremely difficult to reproduce this continuous supply of nutrients at home because the Orchid substrate hardly provides the plant with any nutrition. Fortunately, however, only very exclusive varieties of Orchids require a complex and special treatment. The commercially available Phalaenopsis and Cattleya-Orchids or Lady’s Slippers Hybrid (Paphiopedilum) are very robust and therefore well suited for cultivation on the windowsill, even at low humidity.

Dendrobium Orchid

The Dendrobium Orchid regularly needs fertilizer for abundant flowering

Which Orchid fertilizer is the right one?

Always use a special Orchid fertilizer to fertilize Orchids. The nutrient composition and concentration of these fertilizers matches the requirements of wild plants. Conventional flowering plant fertilizer has high doses of nutrients and houseplant fertilizer does not have the right nutrient composition. Organic fertilizers are also not suitable for Orchids because their nutrients have to be released by the microorganisms first — and the biotic activity in the airy orchid substrate is too low for this. So it's best to buy a commercially available mineral Orchid fertilizer - you can use it all year round. If you want to fertilize your Orchids even more precisely and know the needs of your plants well, you can also switch between nitrogen-based fertilizer (leaf growth) and phosphorus-based fertilizer (flower formulation) depending on the growth phase.

What do Orchids need - liquid fertilizers or fertilizer sticks?

Orchids planted in pots do not grow in soil, but in a special, roughly structured Orchid substrate. This substrate usually consists of small pieces of wood or bark, which are often mixed with bast, coconut fibers or spaghnum (peat moss). The coarse texture enables the Orchids to hold on well to their roots and to cover their high oxygen demand. At the same time, it stores moisture from the water, which it passes on to the plant without the roots having to be wet. Orchid roots that are exposed to permanent moisture rot and become useless for the plant. The large gaps in the substrate ensure good ventilation. These considerable differences to normal potting soil,explain why it is most effective to use liquid fertilizers when fertilizing orchids. Fertilizer sticks and granular slow-release fertilizers cannot dissolve properly in Orchid substrates. The nutrient concentration around the nutrient sticks or globules is very high, which can damage the sensitive aerial roots. Some of the fertilizer balls also fall through the coarse substrate and accumulate at the bottom of the pot. Liquid fertilizer, on the other hand, enables balanced dosing and uniform distribution of nutrients.

Orchid substrate

Orchid substrate is very coarse and permeable

When and how often do you fertilize Orchids?

The more the merrier is a misconception when it comes to fertilizing Orchids. The light feeders are sensitive to excessive salt concentrations and many varieties cannot absorb the nutrients all year round. Strictly speaking, Orchids are only fertilized regularly in the growth phase. If the plant is currently dormant, which is the case with many species in winter, it does not need any additional nourishment. The plant is fertilized only when a new leaf, stem or umbel is formed. That’s when the nutrient requirement is highest. In the growth phase, a liquid fertilizer administered every two weeks can support growth. If you wish to, repot your Orchids, do not fertilize it for the first four to six weeks.

Moisten the roots with a spray bottle daily

If you don't want to keep your Orchids immersed in water, you can wet the roots with a spray bottle every day. Then regularly add small amounts of fertilizer to the spray water

What is the best way to fertilize Orchids?

If you want to take perfect care of your Orchids water them with lime-free rainwater. Orchids are not watered with a watering can, but the entire root ball is immersed in water for several minutes. Then let them drain well and put them back in the planter. Orchids are optimally fertilized by simply enriching the immersion water with a dose of liquid Orchid fertilizer every 14 days during the growth phase. This low-concentration fertilizer optimally covers the nutrient requirements of this exotic houseplants. Nevertheless, always use a little less fertilizer than stated on the package. Fertilize regularly to get as close to the natural nutrient intake as possible. This way, your Orchids grow evenly, stay healthy and produce abundant flowers. Tip: After watering, do not pour the water into the drain, but use it to water your other houseplants or the potted plants on the terrace.

Immersion bath

The best way to water your Orchids is to give them an immersion bath

How do you recognize fertilization mistakes in Orchids?

Many Orchid species naturally take a break after an intense flowering period. That period can vary. During this period, the plants don’t need any fertilizer. As soon as a new leaf or shoot appears, the Orchid should be provided with extra nutrients again. If growth stagnates or the plant does not form new leaves for many months, this may be due to a lack of nutrients. Then carefully and regularly add fertilizer to the water in which the Orchid is immersed. If the underside of the Orchid turns red, it is lacking in phosphate, if the leaves turn yellow (not to be confused with the natural yellowing of a dying leaf), they are not getting enough nitrogen. Unnaturally light green leaves indicate a magnesium deficiency. If the fertilizer is overdosed, the salts are formed as white crystals on the roots and the soil. If the fertilizer concentration is too high, the aerial roots burn, which in the long term leads to the death of the plant. To avoid overloading the roots, the plants are immersed in fertilized water and rainwater on a weekly basis. In this way, excess fertilizer salts are washed off the roots, regularly.

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