The leaf edges become dry and curl
The leaves of a plant will dry out at the tips or edges first if the temperature is too high or the plant does not get enough moisture. If you put your hand in the pot and feel a large temperature difference, your garden may have received too much heat, which means that the visibility should regulate again. Leave the terrarium open for a few hours before closing it again. You will probably need to move your Growing Concepts, at least during the season, so that the sun's rays don't fall on them. If the soil looks too dry, follow the directions for watering.

There are insects in my Growing Concepts
Not all insects are harmful to your Growing Concepts. If you see earthworms, centipedes, snails or flies in the moss, you can leave them quietly; they do not harm the plants (unless you are bothered by them, you can remove them). If there are large nudibranchs and snails in them, remove them to prevent them from eating your plants. They probably came along as larva or eggs when you filled your growing concepts with moss. Sometimes you will also see small fluffy spots appear on or under the leaves and branches. These are mealybugs. In that case you will have to treat your growing concepts with appropriate means. Other parasites that can show up are spider mites and aphids. Treat it in the same way as mealybug.

Green leaves fall off
This is a natural process when the leaves age or need to be replaced with new buds. If the leaves fall off repeatedly in the first weeks, it is because the plants need time to become strong, develop their roots and get used to the humidity in their new environment.

The leaves turn yellow
This can be the result of too much or too little moisture. If the substrate under your plants is muddy or sticky, if the moss is dark green and you can squeeze it like a sponge, you have been watering too much or too often. In that case, leave the jar open until the excess moisture has evaporated. Close it again when the substrate is moist from above but not soaking wet.

If the substrate feels dry to the touch, it has been exposed too often and / or it is time to water. The foliage can also turn yellow if you water lime-rich. It is important to give only filtered, mineral or rainwater and no tap water.

Black spots appear on the leaves
These spots are caused by a fungus. Immediately remove the affected leaves by hand to prevent further spread. And don't forget to leave the pot open for 2 hours so that the plant can heal. Black spots can also form when the pot is in direct sunlight. Because the glass strengthens like a magnifying glass, burns can occur.

You can see that there is mold
In the first weeks, fungus sometimes forms on the mosses, branches, leaves or pebbles. That usually looks like a white or gray fluffy deposit. Mold can develop if the various elements of a terrarium have not yet acclimatized. Remove the fungus as soon as possible with a clean cloth to prevent it from proliferating and then wait until a biological balance is established. If there is mold on a whole leaf or a large part of it, cut the leaf with stems and all. Light naturally inhibits the formation of fungi. Therefore, follow the advice for exposure to light to prevent the formation of fungi.