Last updated on October 23rd, 2023 at 08:24 pm
Depending on how fast a plant’s roots grow, after two or three years the time has come for a larger container. A look at the root ball will tell you if you should repot your potted plants. After the winter dormancy period, most plants are at the start of a new growing season in spring, so at this time of year the roots are particularly grateful for fresh soil and more room. You will soon notice the spring cure in their vigorous growth and lush greenery.
Repotting potted plants: why it is so important
Younger plants are placed in a somewhat larger container annually from March onwards before new shoots appear (except for Agapanthus: it likes it a bit cramped). Older potted plants can be repotted every one to two years. If the soil is thick with fine root tangles or if the roots have already outgrown their pots, it is high time. Otherwise, it will soon come to stunted growth and meager flowering.
The more densely the roots grow, the less substrate is left in the pot. For the plant, this means that it no longer has a water and nutrient reservoir and can no longer develop further. If the cramped roots can no longer find room, they often grow round and round along the pot wall until the plant virtually constricts itself. In this way, a lack of oxygen can also become a problem.
Repotting: This is how you proceed
The new pot should be about three to five centimeters wider in diameter than the old one, and also a little deeper. Be careful with pots that are too big: Unfortunately, it makes little sense to give a plant an oversized pot as a precaution. The plant will put all its energy into root growth, so to speak, in order to secure enough space in the ground. In addition, waterlogging can easily occur.
Carefully remove the root ball from the old pot. With heavily rooted specimens, it usually falls off almost by itself. Roots that have already grown out of the drainage holes are untangled so that the pot can be detached from the root ball.
If a larger pot is not possible, reduce the size of the root ball with a knife to make room for fresh soil. Experts advise not to prune the root ball all around, but to cut out only wedge-shaped pieces. In this way, a large part of the important fibrous roots is preserved.
slightly loosen heavily matted root balls, fill the space between them and the new container with high-quality potted plant soil and lightly press it. When choosing the soil, consider the needs of the plant. For many there are special mixtures that guarantee an optimal composition. Place the root ball in the center of the new pot so that the plant can grow evenly on all sides. A small watering rim should be left to the edge of the pot.
Finally, water penetratingly. As the day progresses and the temperature increases, the roots will quickly grow into the fresh substrate.
When repotting, mix slow-release fertilizer into the substrate. It will ensure a steady supply of nutrients over the following four to six months. For older plants that do not need to be repotted, simply carefully drill two to three holes in the surface of the soil, pour in fertilizer and refill with soil.
More tips for repotting potted plants
Bring into shape
When you repot your potted plants in the spring, it’s also a good idea to do some pruning around the top. Before new shoots appear, potted plants can be brought back into shape or rejuvenated. Cut out all diseased and withered shoots. Also remove branches that grow inward or cross each other, as well as severely cut back pale, soft, yellow shoots. They are susceptible to disease and pests, and they are no match for the intense sunlight and wind outside anyway.
For a bushy, compact growth, cut back all shoots that protrude from the crown. This promotes branching. In the case of senescent, lazy flowering or overgrown specimens, you should also remove some of the oldest shoots completely. Oleander is a special case: Here it is advisable to cut back overlong, shortened shoots by at least half, but leave the rest unpruned so as not to endanger flowering. Climbing plants such as passionflower or mandevilla should be thinned out and shortened annually. Otherwise, a confusing tangle of old shoots will soon form.
Watering with tact
As budding begins, the plants need more water. But be careful: In the cool winter quarters, standing water can cause great damage! Especially species that have shed some or all of their foliage should be watered with a lot of tact – literally. Feel the moisture content of the substrate with your fingers. They are reliable sensors.
The rule is: the darker and cooler the location, the less watering. Also, always allow the substrate to dry thoroughly before reaching for the can again. Plants in bright and warmer winter quarters, for example in the conservatory or glazed stairwell, want correspondingly more water now.
Although the ideal time to repot is spring, you can still repot your potted plants in summer if you water thoroughly afterwards. Especially if there is an imbalance between the plant’s small pot volume and sprawling shoot, you should not wait until next year.
During the repotting of potted plants, they are also put under the microscope in terms of health. Winter quarters sometimes cause problems. In warmth and dry air, for example, spider mites feel right at home. Scale and mealybugs, whiteflies and thrips also often appear. They are not kept in check here by natural enemies, frost, rain or the like. Regular inspections help to detect infestations early. Take a special look at the shoot tips and undersides of leaves.
Whiteflies and thrips can also be detected by means of yellow and blue panels, respectively. Control should be carried out immediately – by stripping, the use of beneficial insects or finally suitable plant protection products. Excessive humidity and stagnant air promote harmful fungi, so ventilate from time to time on mild days.