Seeds are the kernels of fruit, before every cake or schnitzel enjoyment there is the battle of sorting out lemon kernels – there should be enough lemon seeds in the average German household. As a rule, a lemon tree will also emerge from these lemon seeds if you follow the growing instructions below. However, it does not necessarily mean that this core / seed then also produces a lemon tree that is able to produce fruit. You will learn why that is and why it does not matter.
This is how you get fertile seeds
Citrus plants have an interesting habit, which is reproduction without sex. They can form seeds (dormant plant embryos) not only through fertilization, but also in the tissue of the mother plant that normally nourishes the seeds. From these seeds a lemon tree arises, but one with seedless fruits. Some species of the genus Citrus can only reproduce in this way because they are partially male-sterile or because their stigma is sterile, others use a double strategy of reproduction with and without pollination.
Lemon trees, from which lemons are harvested for trade, are created through breeding and / or grafting processes that do not necessarily take into account the fertility of the lemon plant. It can go under, sacrificed to a more lemony taste, to a peel that is easier to remove or a more yellowish peel. With these cultivars, new lemons are only produced through refinement by grafting the cultivar onto a base.
So you would have to buy a seed that is sure to produce fertile plants from a dealer who guarantees exactly that.
If you have found lemons with fertile seeds or the lemon seeds you ordered on the Internet have arrived, you can start growing your lemon tree (which, however, will not necessarily bear the lemon from which the seeds came and will not necessarily resemble the mother plant. cultivating lemons is quite complicated). But that is a topic of its own, once your lemon tree bears its own fruit, you are sure to taste every variety. If, because:
The lemon tree needs patience
Aside from the question of what kind of citrus fruit might come out of this experiment, a little warning in advance:
If you want to grow a lemon tree because you want to harvest it yourself, you need patience, a lot of patience, even with exemplary successful cultivation: It will take at least a decade before your seedling sets the first flowers and with them the first fruits, maybe even one more half a decade longer. This unfortunate fact is not prefixed here to discourage you from growing lemons, on the contrary. But you should know so that you can decide freely.
In this case it is often recommended to buy a finished plant, which is even available with fruits. This is actually a better idea for the impatient, but: If you always want to harvest organic produce from your own plants, you would have to buy a lemon plant that has been grown organically. Otherwise it is worth doing your own cultivation, where you have to wait a long time, but at least you can be sure that the soil and plants only contain what you have admitted yourself.
With the treated lemon plants (“not suitable for consumption”) you only need to wait a few weeks until the pesticides have grown out? Sometimes yes, the word “not suitable for consumption” must always appear when selling plants, otherwise the seller would have to observe all the hygiene laws that apply to food; sometimes no, if the plants were imported from countries in which pesticides are used with an unknown breakdown period – if you want to be absolutely sure that you don’t have any pesticides in your lemon, you have to know the seller well or go to the cultivation yourself.
For the patient, but not 10 to 15-year-old patient, there are other citrus fruits that fruit more quickly, withstand the attitude with us better and are actually more interesting from a culinary point of view: calamondin, kumquat, kucle (cross between kumquat and clementine), limequat (cross between Kumquat and lime) are available e.g. B. as easy-care citrus plants for beginners, which bloom relatively quickly and bear fruit even with some cultivation. If you now want to switch to these citrus plants, which are a little quicker to get started: It is still worth reading the article, the seed care and rearing of the seedlings is similar for all citrus plants:
Preparing the seeds
You can often read that lemon kernels can be sown indoors at any time. That is theoretically correct, in practice you should treat a young lemon plant in our broad spring sun (which is really poor in light for it). So: It is best to start sowing in spring, so the young plant gets all the German sun and warmth that we can offer.
If you have lemon seeds in front of you, they can be carelessly put in the next flower pot and forgotten. Many amateur lemon growers have done this already, with good results, they are even of the opinion that it works better than fearful sowing with constant observation …
… but these are of course not regular sowing instructions, and of course you should get them, namely the instructions that seem to be most successful:
- Remove the seeds from fresh lemons and clean them so that all the pulp is gone
- Then soak the dried and fresh seeds in lukewarm water
- Until the seed sinks to the ground and / or the seed coat looks like it is transparent
- This takes 8 to 24 hours, depending on how dry the seed was
- The outer skin of the seed should now be fairly soft and can be carefully removed
- Now the kernels are placed on damp kitchen paper (folded several times, made wet and squeezed out)
- Kitchen paper with cores is put in a plastic bag with a snap closure, which is then sealed
- The whole thing comes on a moderately warm heater and is allowed to germinate with high humidity
- The temperature should be somewhere between 22 and 25 ° C; this is the warmth that lemon trees like to germinate
- The dark germs themselves do not need light to germinate; only the primary leaves developed after the cotyledons are photosynthetically active
- This should be a good persuasion (stimulus) to germinate, which shows success after a week to 10 days
- When the seedlings have developed (already quite strong) roots, they can be placed in small pots with potting soil
Have you read about stratification of seeds? In case of doubt, the dealer will take care of the purchased seeds; for lemons from the supermarket, a sign with the country of origin hangs on the network. As a rule, it is so warm there that the seeds are not used to or need no cold stimulus to germinate. The question of a stratification of lemon seeds only arises in the case of special cultivars such as the frost-hardy “Poncirus trifoliata”, which is one of the most important grafting documents and is also cultivated in parts of the world where it gets really cold.
By the way: When twins or triplets germinate from a seed, it is not a “small miracle” (or at least, a seedling is always), but a sign that sexual and asexual reproduction take place in parallel – with the citrus genus it occurs frequently to several embryos per seed.
The potting soil
Lemons are grown in many parts of the world, in Italy and Spain, America, Asia and Africa, so they know the soils of many parts of the world. But not in Germany, the microorganisms in our earth therefore do not know the seedlings, and the “strenuous” germination is not the right time to get them used to these microorganisms.
That is why lemon seeds are grown in a sterile growing medium for the first time, which you can make from the following ingredients:
- Coconut soil, it is unfertilized, mold-inhibiting due to its high lignin content and thermally sterilized
- Ready-mixed potting soil from the trade (caution, often disproportionately expensive, often not yet peat-free, often pre-fertilized)
- Normal garden soil (must be sterilized)
- Sand, so-called medium sand with a grain size of 0.2 and 0.63 mm
- Looks like semolina, it is cheapest in the building materials trade, but then announce that the sand is intended for plants
- Cultivation granules and minerals such as perlite and bentonite
- Mixtures of all of these substrates
Whenever garden soil, sand stored outside or purchased substrates that have been stored for a long time are used, you should sterilize them to be on the safe side. This kills germs, pests, too many microorganisms (unknown to lemons) and foreign seeds. There are various options for sterilization:
- Coconut soil is often sold pressed and must swell before use
- If you pour boiling water over coconut soil that has already been stored for a long time, that should be enough
- You can heat the soil mixture in the microwave
- Or you can put it in the oven, a full, large roasting pan for 45 minutes at 180 ° C (don’t worry, the outside will be most effectively sterilized)
When the substrate is ready, it is well moistened, then the seedlings can be planted, very carefully. Because it is the fine roots on which the lemon will now live; In the citrus root system there is a taproot, thicker retaining roots that go to the side and thin, tufted fiber roots for the supply.
Raising the seedling
Sunlit or heated, just warm window sills or small greenhouses (on the heater, with underfloor heating) are the best locations for the cultivation pots with the seedlings.
The young lemons should now stand lightly, otherwise you only need to moisten the soil evenly and wait until it is warm enough outside. Because even the young lemon is allowed outside as soon as the outside temperature is pleasant. How friendly cannot be precisely determined, it depends on your microclimate, how your lemon is usually pulled, etc.
It is best to avoid any shock when moving young lemons, so they come outside when it is just as warm there as inside. It is best to move to a permanent location there, relocating is also stressful again.
When the young lemon shows the first half dozen pairs of leaves, you could isolate them. But you don’t have to do that, the little lemon plants should even feel more comfortable in company, they can spend their first year together in one pot.
If you cut the tips of strong young plants, you encourage branching, the small plants usually do not branch out on their own until the second year. The decision is entirely up to you, according to the individual desired growth shape of the lemon.
In order to give the tree a beautiful shape, you can occasionally and carefully lend a hand with scissors, but a lemon does not need annual pruning.
Young lemons are carefully accustomed to fertilizer, when to start it depends on how many nutrients are in the initial substrate (which are not lost during sterilization). In the first season, a little weak fertilizer once a month is a benchmark.
You don’t need any special citrus fertilizers, lemon trees, like all plants, live on nitrogen, phosphorus and potassium. They only have their own requirements for the ratio of these substances, one part nitrogen (N), half to a third part phosphorus (P) and (almost) one part potassium (K), a few micro-nutrients may also be included.
During the season, lemon trees need fertilizer every two weeks, with water with a total hardness below 10 ° dH (i.e. quite soft) a little lime from time to time, preferably with magnesium. Most finishing documents grow best at pH values around 7, from 6 they can be limed up.
If the lemons have to be repotted, you can mix the nutrients straight into the soil: half of ripe compost, a quarter of medium-sized white sand and a quarter of perlite, coconut and co. Feed the lemon for a while, they can be added after one or two Months with organic fertilizers such as horn shavings or guano, which the plant can retrieve as desired.
Don’t be confused by the many rumors about citrus fertilizers circulating – citrus plants don’t automatically need iron, only when they lack it (almost never the case), and most rootstocks grow better on calcareous than on acidic soils.
Conclusion: Lemon seeds can be easily pulped from the nearest supermarket lemon, their germination and cultivation is usually successful. Inexpensive fun that is well suited to gain first experience with the beautiful lemon plants. But be careful: The beautiful lemon plants are supposed to be addicting, and there are much more exciting lemon varieties for the German gardener, from the fast-fruiting small trees mentioned above to the well-known Poncirus trifoliata grafting base, which can also be grown as a separate plant and planted in the garden.