Citrus plants – care, pruning and wintering

In the Mediterranean climate, citrus plants usually thrive and grow into stately, meter-high trees. However, if you keep them in local areas, they sometimes turn out to be true mimosas among the plants. An optimal location for these plants:

• a protected bright place, if possible without extreme temperature fluctuations and cold weather.
• Better than in the middle of the meadow is a wind-protected place on a house wall or a garden shed, which provides a little shade in the midday heat.

fertilization

Special fertilizers for citrus plants are often available on the market. From time to time, however, these fertilizers do not contain the correct ratio of the individual nutrients. When fertilizing, it is important which ingredients are present and not what the intended use is on the packaging. Sometimes a cheap universal product is more suitable than an expensive special fertilizer. In principle, you should only fertilize in the growth phase, i.e. in spring from March, about every four weeks. Stop fertilizing at the beginning of autumn.

• Citrus plants need a lot of nitrogen.
• The fertilizer should contain equal amounts of nitrogen and potassium.
• The amount of phosphorus is somewhat reduced in a good fertilizer.
• The ratio of NPK is always indicated on the packaging: nitrogen – phosphorus – potassium.
• First and last value should be equal plus/minus one point.
• A good ratio would be 8 – 6 – 8, for example, 7 – 7 – 7 is also tolerable.
• A bad ratio would be 5-7-9.
• The citrus plant needs calcium in the same amounts as nitrogen.
• The pH value is suitable for checking calcium. It is sufficient to check this in the soil once a year.
• Buffer or repot with a little lime if the pH value is too low.
• If the pH value is too high, use acidic fertilizers.
• If iron deficiency occurs in the plants, this is usually not due to the fertilizer but to the high pH value of the soil, because at high pH values ​​the iron is present in the soil but not available to the plants.

Mineral fertilizers are pure salts and are directly available to the plant. Biological fertilizers from animal and plant materials require microorganisms in the soil, which must make the elements accessible to the plant. A healthy soil life requires relatively high temperatures (over 20 degrees) to ensure an optimal supply. Since citrus plants usually live in tubs or pots, such fertilization can make sense, but quickly reaches its limits due to a lack of space.

propagation

Under ideal conditions, limes flower after two years, while oranges do not flower for the first time after about seven years at the earliest, sometimes even decades if they are grown from seed.

• For this reason, the plants available in commercial cultivation are usually grafted: a branch of the desired citrus plant is placed on a plant of a similar type that is already capable of flowering.
• The offspring can also be done by cuttings.
• A successful method, but difficult for the layman, is moss removal (root formation on the mother plant).
• If you have a lot of patience, you can of course also plant a citrus stone and grow your own plant from a seed. However, it takes several years until the first flowering.
• To do this, remove the seeds from ripe organic fruits and separate them from the pulp.
•  Rinse with water and let dry for a day.
• Plant about 1-2 cm deep in potting soil and water lightly.
• Cover the pot with foil and set in a warm place.
• After about 4 weeks, the first leaves can be seen. Remove foil.

hibernate

Most native plants shed their foliage in the fall and adjust to a winter dormancy period. That’s why many gardeners believe that they have to store their plants as cool and dry as possible when they hibernate. With citrus fruits, however, this usually leads to problems such as unwanted leaf fall. Citrus plants are evergreen. If the leaves are falling, then this is not normal and indicates that the citrus plant is under greater stress.

• The fine root system is damaged by the ice crystals in frost: it can no longer absorb enough water.
• at temperatures below 12 degrees, root growth and the water absorption function come to a standstill.
• Below 18 degrees leaf activity is reduced.
• Root temperatures between 15 and 18 degrees are optimal: the functions of the plant are minimized, but the water intake is high enough to maintain all important processes.
• Citrus plants also need a lot of light in winter: bright location, if possible without hours of extreme sunlight through the window pane.
• High humidity is beneficial. No dry heating air!
• If no bright location is available or the weather has been bad for weeks: additional lighting.
• Water regularly even in winter. However, significantly less water is used, so do not overwater.
• Always water with warm water: 25-30 degrees. This supports the root functions.
• A heated greenhouse is ideal. It is also possible to spend the winter in a stairwell that is protected from drafts or in a less heated bedroom.
• When the plant starts shedding fruit and leaves, it’s more likely to be too cool than lacking light.
• Place the plant a little warmer, ensure higher humidity.
• If all the leaves have fallen off, water more moderately and keep the bale relatively dry. Then there is a good chance that it will fully recover next spring.
• Always avoid rapid environmental changes.
• If you cannot offer your citrus plant an optimal winter location, you should place it in a nursery during the cold months.

repot

Since citrus plants are not hardy, they are grown almost exclusively in tubs or pots. Repotting is a basic requirement for good growth and thriving, a high number of flowers and fruits. Above all, the selection of a suitable potting soil and the right pot is decisive. Buckets and soil do not have to be changed every year, but at regular intervals.

• After the ice saints in May, the Mediterranean plants can be cleared from their winter quarters.
• Now is the time to repot if necessary.
• The rule of thumb is: repot every two to three years.
• Indication that a larger pot is urgently needed: roots sticking out of the pot hole.
• If necessary, carefully remove the salt-encrusted surface.
• Clay pots with a hole are best suited as planters. They offer stability and buffer high levels of water and salt.
• Lay a drainage layer of gravel or clay pebbles (expanded clay) in the lower part of the pot. A few centimeters of filling height are sufficient.
• Fill a little soil into the new planter and put it down on the ground with a jerk to compact it.
• The new bucket should be at least two centimeters larger than the old one.
• Place the plant in the middle of the new pot and fill in the soil around the edge with both hands.
• Compact the potting soil with your fingers.
• After repotting, the plant must of course be watered.

The right potting soil is crucial

• The soil should be water-permeable and structurally stable.
• There is special citrus soil on the market, but a good cactus soil will also work as an alternative.
• For your own mix: mix high-quality garden soil, sand and crushed gravel or expanded clay.

The cut

• Ideal time: late winter or early spring, this costs the plant the least energy
• Use very sharp secateurs.
• Remove dead branches, the cut goes into the green wood, i.e. a little beyond the dead spot. This cut is called a maintenance cut.
• Young plants should be pruned regularly, but cautiously, so that they become bushy and the desired shape of the treetop is established early on.
• Remove any shoots that grow inward or cross other branches.
• All in all, less is more: only cut moderately.
• Shorten the main shoot so much that it overhangs the side shoots by about 10-15 cm.
• This allows light and air to reach the crown better.

Pests: small animals and fungi

• Scale insects, spider mites and other sucking pests are more common in winter than in summer.
• Spray with commercially available agents or a mixture of soft soap and water or oil (such as petroleum).
• Multiple applications are usually necessary, since the pests also live underground and are difficult to reach with the means.
• Dried parts of the plant or a black coating on the leaves indicate a fungal disease.
• Cut away infested parts of the plant, wash the leaves if necessary and fight with chemical agents.

Diseases

Actually, citrus plants are robust plants that are not very susceptible to diseases or pests. Nevertheless, it is relatively common for potted plants to wither or die. The cause can be diseases, pests or care errors. The environmental conditions are not optimal, because a healthy plant can defend itself against parasites and diseases to a certain extent. So if the plant is ailing, there is usually a care error in the broadest sense.

• Curled leaves – drought stress: lack of water or roots that are too wet.
• Very soft shoots or monster growth: too little light and too much water.
• Yellow leaves: iron deficiency, check the pH value in the soil, lower it if necessary.
• Light to white leaves: lack of nutrients, rarely due to lack of fertilization, but due to root damage due to roots that are too wet.
• The root ball has been kept too wet for a long time, rot and fungal infestation in the lower part of the plant are spreading (rotten roots are difficult to recognize).
• Hypothermia of the root ball has the worst effect: leaves and fruit are shed.
• It is also essential to prevent short-term strong cooling of the roots.
• Especially in spring and autumn, pay attention to what temperatures are forecast at night and prefer to put the plant in a warmer place for the night.
• Fruits also fall off prematurely when there is insufficient light.

Conclusion
In summer, citrus plants are easy to handle and absolutely easy to care for. In winter, on the other hand, they need special conditions that not everyone can provide at home. Anyone who cannot provide their citrus tree with accommodation between 13 and 18 degrees with high humidity and sufficient light, such as in a conservatory, a greenhouse or in a draft-protected stairwell window, should look for their darling in a nursery.