With the lemon tree in the summery garden, the magic of the Mediterranean is within reach. When the temperatures drop in autumn, the question of care in winter arises. Are lemons hardy at all? Can she stay outside with winter protection? Should the Mediterranean gem be better placed in the apartment? We will not leave you alone with these and other important questions. This guide explains in detail how to successfully overwinter a lemon tree.
Overwinter outdoors
Wintering outside is like squaring the circle
Native to the sun-drenched regions around the Mediterranean Sea, the harsh winter climate north of the Alps is unknown to the lemon tree and is therefore by no means hardy. In order for the picturesque flowering shrub to show itself from its most beautiful side and give us the fruits we long for, it should only stay under the open sky throughout the summer. When the mercury column approaches the freezing point in autumn, it is high time for protective measures. If the temperatures fall below -1 degree Celsius for just a few hours, the existence of the Mediterranean beauty is threatened.
At this point in the care program, ambitious citrus gardeners have to submit to the laws of nature. Thanks to the tolerant and robust constitution of a lemon, there are nevertheless several options available to successfully overwinter the valuable ornamental and fruit tree. All relevant criteria are explained in detail below.
time
wintering at the right time
The lemon is one of the sun worshipers, because it needs a lot of light for the synchronous formation of shiny green leaves, white flowers and golden-yellow fruits. The Central European summer still covers the light requirement sufficiently. When winter is just around the corner with falling temperatures, things get tricky. Darkness increasingly dominates until the winter solstice on December 21st.
The lemon tree can perfectly compensate for this development if the decrease in light and temperature is proportional to each other. Artificially created framework conditions hardly come close to the natural climatic conditions.
Therefore, arrange your lemon tree according to these criteria:
- leave the lemon outside for as long as possible
- only concede at night-time temperatures close to the freezing point
- an appointment in mid/end of November is ideal
- until then provided with protection against wind and pounding rain
With a minimum-maximum thermometer, the course can be easily checked without getting up in the night to take a look at the mercury column. Correctly adjusted, you can reproduce the lowest temperature of the previous night in the morning. If this approaches the freezing point, give the lemon. Thanks to this strategy, a Citrus limon can adapt to the cold season in harmony with nature, which will benefit the successful overwintering.
winter quarters
Ideal winter quarters are bright and cool
Even in mild wine-growing regions, the time window for spending time in the open air closes at the latest at the end of November/beginning of December. The best possible option for a successful wintering of your lemon is a combination of light and cool. The advantages are obvious. Low temperatures allow the citrus to compensate for the lack of light. This knowledge is based on centuries of experience in orangeries beyond the Alps.
This is how you hibernate your noble lemon tree healthy and lively:
- a bright to shady location
- slightly tempered between 3 and 8 degrees Celsius
- keep fairly dry with a moderate watering every 4 to 6 weeks
- do not fertilize from November to February
A large number of locations have the potential to become winter quarters for a lemon. A cold conservatory or greenhouse equipped with a frost monitor is perfect. Unheated garages, stairwells and outbuildings that have windows or sources of daylight are shortlisted. In contrast, all dark, warm rooms are completely unsuitable, such as the boiler room.
Overwinter indoors
Wintering in the living room - this is how it works
If the apartment acts as winter quarters, your lemon tree will continue to grow at a reduced level. The choice of location and care are designed accordingly. The following measures make a significant contribution to keeping the interplay between photosynthesis and water evaporation in balance.
- A sunny, south-facing location is ideal
- Water with room-warm, lime-free water when the substrate has dried
- Pour out the coaster after 10 minutes or fill it with expanded clay balls
- at intervals of 2 to 3 days spray the leaves with boiled water
- either do not fertilize or add liquid citrus fertilizer to the irrigation water every 6 to 8 weeks
- air every few days without the lemon getting a cold draught
Please subject all shoots and leaves to a thorough inspection for pests before putting them away. Under the influence of a warm hibernation there is already an increased risk of pest infestation, so an involuntary transport of aphids and their ilk should not unnecessarily increase the threat.
Mobile orangery
Mobile orangery solves space problems
If there is no suitable winter quarters, this is no reason to do without a lemon tree. In order to successfully winter the valuable ornamental tree, it is worth investing in a mobile orangery or a winter tent. The specialist trade offers suitable models for every budget and plant size.
The general conditions of a cold conservatory are simulated here in a mobile version, so that your lemon tree does not have to be allowed to hibernate. In the following we present the practical and inexpensive version for the balcony as well as the luxury version with every imaginable comfort.
winter tent
Overwintering tent with frost guard for balcony and terrace
If the budget for winter protection is tight, the practical winter tent is a reliable retreat for the cold season. With a height of 220 cm, it offers enough headroom for the noble tree. Thanks to a footprint of 100 cm x 80 cm, it can be placed on almost any balcony.
The translucent PVC grid film is stabilized by a strong tubular structure. A total of 4 window openings guarantee a supply of fresh air and easy access for maintenance work. By upgrading the tent with a frost guard, you ensure a constant temperature around your lemon tree. Overall, the investment is around 160 euros plus shipping costs.
Mobile orangery with a lot of comfort
If the focus is on aspects such as comfort, durability and decorative appearance in addition to winter protection, the mobile orangery becomes the focus of interest. The double-layer special film is not only UV-stable, but also does not give up at -25 degrees Celsius. The insulated floor is constructed in such a way that it does not have to be additionally fastened on balconies and terraces.
The hexagonal floor plan sets decorative accents that go beyond the pure pragmatism of classic tents. The medium-sized model has a floor area of 4 square meters and a height of 2 meters. An electric frost monitor is already integrated and does not have to be purchased separately. So much luxury has its price from 890 euros.
leaf shedding
Leaf shedding in winter - what to do?
If, despite professional care, there is leaf loss in the winter quarters, an imbalance between light and temperature is responsible. The countermeasures depend on whether the lemon tree is in the cool winter quarters or warm living room.
In a cool winter, the air temperature is allowed to approach freezing. The root ball, on the other hand, must not cool down that much. Scientists found that the roots of a citrus plant completely cease their activity below 12.5 degrees Celsius. In the light-flooded location, the warmed-up leaves activate photosynthesis without being supplied with water and nutrients. The reaction is loss of leaves.
To prevent this from happening, do the following:
- warm up the irrigation water to 23 to 25 degrees Celsius
- place the bucket on an insulating base
- suitable materials are styrofoam and wood
- alternatively warm up the root ball with a heating mat to 18 to 21 degrees Celsius
- From February, equip the windows with a shading net
In this precarious situation, the supply of water poses a particular challenge. If you lack experience in this regard, it is worth purchasing a moisture meter. Even a simple, mechanical device provides information about the condition of the root ball. Pushed into the substrate like a roasting thermometer, you can see the actual watering requirement on a scale within a few minutes: 1 to 2 for dryness, 3 to 5 for slight moisture, 7 to 8 for waterlogging.
When wintering in a heated apartment, a cooled root ball is not the problem. In the cosy, warm living room, the high demand for light is not always met, even with the south-facing window.
To compensate for the deficit, proceed as follows:
- Install a grow light at the first sign of leaf fall
- ideally use a lamp with a blue-red light spectrum and at least 15 watts of power
- place the light source about 80 to 100 cm above the crown
- illuminate in the dark room about 8 hours daily
In the vicinity of the window, you can reduce the lighting duration according to the amount of light available. Preferably choose a lamp with a reflector screen for optimal light output. Daylight lamps are also suitable for this purpose, whereas light sources with conventional incandescent bulbs do not help against leaf loss.
Tips winterization
Tips for winterizing
The best strategy for an undamaged winter time will come to nothing if you clear out your lemon tree too early after the winter. In the winter quarters you can also set the course for a vital and blooming summer time. We have compiled the best tips for competent winter storage for you here.
- Thin out the lemon in February/March and cut moderately into shape if necessary
- Repot into fresh substrate and a larger pot if there is root pressure due to lack of space
- Clear out in regions with mild winters from the beginning/mid-April
- in most of Germany only winter out after the ice saints in mid-May
- first harden off for 8 to 10 days in a partially shaded location
During the transition phase, the constantly improving light conditions require a corresponding modification in the care program. As a result of the rising temperatures, the leaves and roots gradually resume their activities. The need for water and nutrients increases proportionally. Therefore, check the moisture content of the soil every few days with a thumb test in order to water on time. From March, the nutrient supply starts again by initially fertilizing every 2 weeks. Once the lemon tree has regained its place in the open air, fertilize every week.
If spring comes with capricious weather, ground frost can still occur after mid-May. Experience has shown that these are around the tolerable minimum temperature of -1 Celsius, so no complex protective measures are required. If in doubt, wrap your lemon tree in a breathable fleece or blanket overnight.