If you want to sow tomatoes yourself, you can start very early. Pre-breeding in the greenhouse or on the windowsill is possible as early as February. The right timing is crucial. If you want to be on the safe side, consult the moon.
time
Why is timing important?
Tomato plants are heavy feeders and therefore need a good combination of soil, light, moisture, nutrients and warmth. Even the young plants depend on plenty of light and sufficient warmth in order not to wither during the first few weeks. If you sow them too early, this is exactly what happens and the health of the plants suffers greatly. If you sow too late, the nightshade plants cannot mature sufficiently and a possible crop failure is imminent. So when is it time to sow the seeds?
small tomato plants grow up
This depends on several factors, first and foremost:
- where to sow the tomatoes
- light
- lunar calendar
Together, these three points allow for an extremely precise date when it is worth sowing the fruiting vegetable in order to obtain a bountiful harvest of tasty Solanum lycopersicum fruits. The location of the sowing is particularly important, as this determines exactly the period in which it can take place.
The typical locations for sowing are:
- outdoor
- windowsill
- Glasshouse
Since all these locations offer different amounts of light, the gardener sows at different times accordingly. For example, it is not suitable for sowing on the windowsill, if sown as early as in a heated greenhouse. The required amount of light is not given and the vergeilung occurs. It is therefore important to compare the individual locations with one another in order to be able to determine the exact point in time.
Notice: Withering is an unnatural growth spurt where tomato plants overgrow due to lack of light or excess nitrogen. The stems grow towards the insufficient light, become longer, brittle and threaten to snap over, which of course finishes off the weakened plants.
lunar calendar
The lunar calendar will help you to determine the date of your sowing more precisely. If you don't know the meaning of the lunar calendar, you should definitely make use of it, because the moon has a positive effect on tomato plants. According to the experience of farmers, the power of the moon has enabled vigorous and healthy growth of tomato plants and an extremely high-yield harvest for centuries.
Vegetable farmers make use of the following rules:
- downward-growing plants are sown in the waning moon
- upward-growing plants are sown in the waxing moon
Sow tomato seeds
Just as the moon determines the tides, the celestial body is also said to affect the saps within the tomato plants. The tomatoes are said to ripen faster, are healthier and better able to cope with pests and harsh weather. Although scientists do not agree on how the moon affects plants, tomatoes are best suited to the rising phases of the moon, when the plant saps can flow upwards. The signs of the zodiac are also important here. So if the moon is in front of a fire sign such as Leo, Aries or Sagittarius, this can also favor the sowing of tomatoes. Here you can use the lunar calendar to directly determine a day that is worth sowing. Depending on where you sow the seeds, the favorable days and therefore the timing for sowing will vary.
Notice: Growing up and down of course means the individual fruiting bodies, roots and other parts of the plant that are being harvested. Tomatoes should be sown on a different day than carrots because they grow in different directions.
outdoor
Sowing outdoors is the classic variant of tomato cultivation and, due to the natural course of the seasons, quite late compared to other locations. It strongly depends on the weather and light conditions, as it is difficult to place artificial light sources or heating elements in the vegetable patch. It is therefore particularly important not to sow the seeds too early, otherwise they will not germinate and perish in the soil. Tomatoes are pure light germinator, so they need the following conditions in the vegetable patch.
- Temperatures of at least 15 °C at night
- at least ten hours of sunlight
These values can only be reached in late spring, since spring can still be very cold in Central Europe. In addition, late frosts could prevent the seeds from germinating, since the moisture in the soil cannot be used by them when the temperatures are too cool. This makes earlier sowing impossible. You can only sow the seeds from mid-May, but you must keep an eye on your weather forecast for frosts. The ice saints in particular can clog the seeds if they have been freshly planted in the ground.
Plant tomatoes in the garden
So refrain from sowing during the following days:
- May 11: Memorial Day of Mamertus
- May 12: Feast of Pancratius
- May 13th: Feast of Servatius
- May 14th: Feast of Saint Boniface
- May 15: Memorial Day of Cold Sophie
Of course you can also sow the tomato plants during the ice saints, but only if you are absolutely sure that there will be no more frost. But you're always safe when sowing tomatoes outdoors once those days are over. Thus, the period for sowing is measured from mid-May after the ice saints to the beginning of June and is then further adjusted with the favorable days of the lunar calendar. When are these?
Anyone who sows outdoors should do so on the following days:
- May 18th and 19th
- May 26th and 27th
- June 4th and 5th
The auspicious days of May are excellent for sowing the tomato plants and allowing the moon's effect on the seed. The days in May are particularly recommended, because the days in June can be a bit late. The cooler it is where you are, the later you should sow the seeds of the tomatoes outdoors. Pick one of the days and benefit from a satisfying fall harvest.
Tip: Be sure to use a spot in the bed that was occupied by new potatoes for sowing. The tomato plants feel particularly comfortable here and you can effectively use the empty space and save space when growing vegetables.
Properly prick tomatoes
windowsill
If you decide to grow on the windowsill or in a heated conservatory, the timing of sowing is fundamentally different from that in the vegetable patch. Since the seeds have it warmer here, they can sow much earlier, even if the sun has not been visible for as long as in May. It can always be a bit difficult on the windowsill in terms of hours of sunshine and amount of light, so an important point in determining the right time is the orientation of the window and the associated light incidence.
Use the following rules as a guide:
- North windows should always be avoided
- these offer far too little light
- bright window sills allow earlier sowing
- in locations with less light you should sow later
North windows are never a good idea for seed germination and even north west and east windows should be avoided due to the same problem. The brighter the location, the sooner you can sow the seeds in a pot or seed tray on the windowsill. When is this possible? late February to mid-March. However, mid-February is only possible as soon as you really have enough light available and the young tomato seedlings do not have to suffer from a lack of light. It is recommended here to bet on later days, as these are safer.
young tomato plants
The lunar calendar offers the following auspicious days:
- February 7th to 9th
- March 3rd, 4th, 8th, 15th and 17th
This period is ideal for sowing within your own living space. It is essential that you refrain from sowing them earlier, otherwise the lack of light is too dangerous and the chance of wilting becomes greater. For this reason, even the first days of the lunar calendar can be too early, especially in northern Germany. Also make sure that the temperature in the apartment never falls below 20 °C, otherwise the seeds will get too cold and cannot germinate properly. However, it must not become too dry for them, so keep the soil always nice and moist.
Glasshouse
The situation in the greenhouse looks very different compared to the open ground and windowsill. Since a greenhouse has enough light due to the mostly transparent walls and ceilings, the tomatoes can be sown quite early without wilting. The most important thing here is the temperature offered to the seeds. The tomatoes must not get too cold in the greenhouse either, so you have to make sure that each type of greenhouse uses a different time period for sowing.
- heated greenhouse: mid-February to mid-March
- unheated greenhouse: mid-March to mid-April
A heated greenhouse with sufficient light represents the earliest period of possible sowing, even before the appointments on the window sill. It is important to keep the temperature between 18°C and 21°C, which remains constant and does not change, otherwise the seeds cannot germinate after sowing. A light quantity of at least ten hours of sunshine is also recommended, which should not be a problem in a greenhouse, especially if you live in southern Germany. The favorable days for sowing in a heated lunar greenhouse are as follows.
Growing tomatoes in the greenhouse
- February 7th to 9th
- March 3rd, 4th, 8th, 15th and 17th
Here it is advisable to sow a little later. When you sow the seeds in an unheated greenhouse is also easy to determine by the lunar calendar. Here the time is shifted by a whole month, which is still earlier than sowing outdoors.
Tomato plant with ripening fruits
According to the lunar calendar, these are the following auspicious days:
- April 1-2, 10-12, 20-22 and 29-30
This period is optimal for sowing the tomatoes and watching the seedlings grow into small tomato plants. The tomatoes germinate for about three to five weeks, depending on the location, and then have to be pricked out. If you sow on time, you will be able to separate them earlier, which allows you to plant the young plants in the vegetable patch earlier. The earlier you sow, the earlier you can reap your harvest.