How To Make Your Own Tomato Plants Work On The Windowsill

How To Make Your Own Tomato Plants Work On The Windowsill

The new garden year is in sight. Finally! At the end of the month we may already sow the heat-loving southerners such as tomatoes, peppers and cucumbers. Of course, well protected in the house on our windowsill.

The fruiting vegetables that are popular with us, such as tomatoes and peppers (and also cucumbers), originally come from warmer regions. The season with plenty of warmth and light is much shorter in our latitudes, so these “southerners” need our start-up help on the home windowsill: Thus, from mid-May or early June – depending on the weather and region, but in any case after the Ice Saints – they can move outdoors as vigorous young plants and still provide us with a decent yield until the end of the season.

When can I grow tomatoes in advance?

“March time is sowing time,” says an old farmer’s and gardener’s rule. “Until mid-March, the relationship between temperature and light intensity is still extremely unfavorable for the seedlings. The seed box is very warm in order to accelerate germination and not endanger the sensitive seedlings. The sun, however, still has too little power to provide sufficient light for the seedlings, which grow rapidly due to warmth.”

As a result, the seedlings form long thin stems with small yellow leaflets – they “get fast growth,” as the gardener says, easily bend over and are very susceptible to disease. Better to wait until the end of March to sow. And do not worry, this is not too late: if the young plants are already too large and well developed, when it goes into the field in May, they often do not develop as well as their “younger” siblings.

Tomatoes – egg carton

How To Make Your Own Tomato Plants Work On The Windowsill

Tomatoes usually germinate very willingly, so you can sow them right away in individual containers. If you don’t already have special pots for this in stock, empty toilet paper rolls, egg cartons or pots rolled from newspaper are an inexpensive and plastic-free alternative: fill each container with growing soil, press down lightly and distribute three seeds on each.

How deep do you need to plant tomato seeds?


Cover the tomato seeds with about half an inch of soil and gently water or spray the whole thing – and keep it continuously moist.

Important: Unlike plastic planters, paper ones draw more moisture. Therefore, you must be all the more careful to ensure adequate watering: Once seeds dry out, they will not germinate.

Optimal for germination is a temperature between 20 and 25 degrees. As soon as the seedlings become visible, you should move the containers to a cooler place, otherwise the plantlets will grow too fast and unstable. Now is the time to pluck out the two weaker sprouts; the strongest remains.

Prick out tomatoes

As soon as it shows the first real leaves, the seedling should move to a larger pot with a width of about eight to ten centimeters and normal planting soil. Additional fertilization is not necessary. The important thing is to “plant it deeper.” Always plant it a little deeper in the new pot now and with each subsequent “move” – this will cause more roots to form and these will give the plant better support, while also providing a better supply of nutrients and therefore a higher yield.

Depending on the weather, after a hardening-off period, the tomato seedlings can be moved outdoors to a place protected from above in mid-May to early June.

What is a sowing soil?


To get your plantlets off to a healthy start: sterilize the potting soil. Put it in an old roaster in the oven at 100 degrees for 30 minutes; this will kill any fungal spores that may be present.

Seeding soil or growing soil has a lower nutrient content than regular potting soil. This prevents the seedlings from growing vigorously but becoming thin and unstable – so-called “wilting”. In addition, the plantlets form more roots in search of the nutrients in the soil, which makes the seedlings more vital and resistant.

What to do if mold threatens my young plantlets? We clarify: Here’s how to protect your freshly seeded vegetables from mold

Pre-growing peppers

Bell bell pepper and eggplant seeds are relatively small and rather finicky to germinate – so it’s worth sowing two to three of them in a small pot or a loo roll. Cover with about half a centimeter of soil and keep moist, then after about one to three weeks the seedlings appear. Like tomato plants, bell pepper seedlings should be “lowered” with each repotting to encourage root development. They can later move outdoors along with the tomatoes.

How much light must be?

Seedlings need enough light for growth, otherwise they will form long but unstable stems and lose vitality. However, full sun on the south side can be dangerous: The seedlings quickly dry out, especially if they are additionally covered with a film. On the safer side you are with east and west windows; whereby the plants should be turned daily by 180 degrees, in order not to let the stems grow permanently in one direction. If this is too much work for you, you can look for special plant lamps in the trade, which provide an optimal light supply for your young plant nursery on an LED basis.

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