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Orchids are among the most popular houseplants in Germany and enchant with their intense blooms and lush green leaves. If the substrate is right, orchid plants require little care and bear fresh leaves every year. But every now and then it can happen that a mistake occurs during the care that turns the leaves yellow and causes brown spots on the orchid. There can be a variety of causes that should be treated immediately.
causes
The causes of the symptoms
The right substrate, fertilizing, watering and light are important when caring for orchids. Due to its hardy nature, it takes quite a long time for the orchid to develop yellow leaves or brown spots, which indicates a serious imbalance in the plant's nutrient balance. There are many causes, all of which need to be treated differently.
- waterlogging
- excess lime
- dryness
- excess sun
- over-fertilization
- pests
Please note if your orchid has yellow leaves you should never cut off the leaf or the tips. The risk of infection via the cut surface is too high and will damage the orchid even more.
waterlogging
Eliminate waterlogging
When orchids are watered or drown for any other reason, the leaves turn yellow. This is because the roots need to dry out a bit every now and then to keep the roots from rotting. If the roots rot, the absorption of moisture and nutrients is inhibited and the plant can only grow to a limited extent. As a result, the leaves turn yellowish. You can recognize waterlogging when the substrate is too wet and the orchid can often only be saved by fresh substrate. Depending on the type of orchid, a typical orchid substrate or ordinary soil is used. Renew the substrate as described below.
- Detach the plant from the substrate
- Rinse roots
- Cut off rotten roots with a sharp, sanitized knife or scissors
- fill dry pot with substrate
- Allow the roots to dry a little before planting
- then set in the substrate
- Fill in the rest of the substrate and carefully fix it
If you have repotted the orchid, you should not water the orchid, but spray it regularly for the first two to three weeks. Also, no fertilizer may be used for the next two weeks. If you have a terrestrial orchid, drainage can also be integrated into the pot.
Tip: Dip the root ball of the soil in soft, low-lime water about every two weeks. In this way, the roots can soak up water and do not have to be watered for a long time, which is extremely good at preventing waterlogging.
yellow leaves on an orchid plant
dryness
Don't let it dry out
While too much water isn't good for the orchid, it shouldn't dry out either. The moth orchid Phalaenopsis, for example, which is so popular in Germany, is one of the classic tropical orchids and requires very little water, but watering should never be forgotten. If an orchid is too dry, three symptoms appear in the following order.
- Plant material becomes soft, slightly rubbery
- Leaves turn yellow
- Some leaves turn brown
Soft plant material is not always noticeable, as not everyone examines their orchid with their hands on a daily basis. Therefore, for many people, the drought only becomes noticeable when the leaves change color. If the leaves turn brown, the plant is dying of thirst and needs moisture immediately. The best solution to this is to carefully lift the plant out of the substrate and then immerse it in soft water. Let the orchid sit in the immersion bath until all the air bubbles have disappeared and the roots, which were white at this point, have turned green again. Repeat this procedure every two weeks.
Notice: If the humidity in the room is too low, the plant can also dry out. For this purpose, lime-free, lukewarm water is administered daily via a spray bottle.
lime
Harmful excess of lime
Due to their natural habitat, orchids do not do well with lime and this means that the roots can no longer absorb nutrients from the fertilizer. This is followed by yellowing of the leaves with subsequent brown spots. An excess is only possible if you use the wrong fertilizer or tap water with a high lime content, which is typical for Germany. From this point on, you should only use soft water. This can be obtained as follows.
- collect rainwater
- use a water filter
- filter water with peat
- Boil water and let cool
Now you can fertilize again without any problems and the lime is slowly washed out of the substrate and dissolved. This allows the orchid to absorb the nutrients from the fertilizer again and recover over the next few weeks.
Fertilize
Fertilized too much - discoloration follows
As is well known, orchids need a special fertilizer that is tailored to the needs of the plant. Conventional fertilizer for flowers and other plants contains too high a concentration of salt, organic fertilizer is only recommended for terrestrial orchids due to the substrate. Many new orchid growers make the mistake of using the wrong fertilizer or using too much concentrate. Here we recommend: less is more! Orchids require little preparation and can even withstand long periods without fertilizer. If yellow leaves with brown spots appear, the suspicion of over-fertilization is obvious. Then you should proceed as follows.
- remove the orchid from the substrate
- look at the roots and remove any rubbery strands that are black or brownish in color
- be sure to leave the other roots on
- rinse the roots thoroughly
- prepare new substrate
- place the plant in the fresh substrate
- Don't fertilize until next season!
With this measure, the orchids can take up enough fertilizer again in the coming season, but is satisfied for the entire season due to over-fertilization. When fertilizing, also pay attention to the following typical mistakes.
- Never put fertilizer directly on the substrate, but in the irrigation water
- always use less fertilizer than prescribed, unless it is high-quality, special natural fertilizers such as the Guano preparations from Neudorff
- some algae extract in the irrigation water helps the stressed roots to recover
sunburn
The sunburn in detail
Orchids are tropical plants, but that doesn't mean that they can stand direct sunlight for hours. Owners often place their specimens in full sun and wonder why the leaves are turning yellow and sickly brown. Immediately change the location of the plant if sunburn is suspected. You can also recognize this by the extremely dry leaves in this discoloration. A bright location with little direct sunlight at midday is ideal for the orchid. Then spray daily with lukewarm water or install a humidifier near the flower.
Sunburn on orchids in the form of dark leaf spots
pests
Pests sap vitality
Although orchids are robust, they cannot do anything even against pests without the right care. The most important pests of the plant, which are often responsible for yellow and brown leaves, are mealybugs and mealybugs. These are found on the shoots and leaves of the Orchidaceae and feed on the plant saps that the plant needs to survive. During the infestation, the pests continue to multiply rapidly, compounding the problem. They can be recognized by the white down they weave around themselves for protection. Use the following means to remove the pests.
Mealy bugs and wool lice on orchid blossoms
- wet a cloth with denatured alcohol and wipe the plant
- dip a cotton swab in alcohol and dab the mites
- pack the orchid in a plastic bag for two to three days to prevent the mites from getting oxygen
If you are lucky and the mites are no longer visible, you can also rinse the orchids with water daily to protect them from an additional infestation.