STIHL tip
Supermarket plastic fruit tubs with transparent lids make ideal seed trays.
Growing and planting tomatoes
Find out how to successfully grow your own tomatoes and what matters in tomato planting, care and harvesting.
21.11.2025
Overview: Growing tomatoes
- Choose a bright, wind-protected and sheltered location
- Soil should be loose, and rich in humus and nutrients
- Seedlings can be raised on a windowsill from mid-March
- Tomatoes can also be planted as purchased young plants in mid-May
- Regularly remove superfluous side shoots
Tomatoes grow well with basil, bush beans, nasturtiums, garlic, cabbage, kohlrabi, leeks, carrots, parsley, all kinds of radish, beetroot, lettuce, celery and spinach. If French marigolds are planted as a companion to tomatoes, they can even deter pests.
Tomatoes should be fertilised at the earliest 2-4 weeks after the young plants have been planted out. After that it is advisable to fertilise regularly until harvest, applying nettle tea and compost around every two weeks. For tomatoes in a vegetable bed, the soil can even be prepared for the young plants by “pre-fertilising” – enriching the ground by adding compost during the previous autumn.
Cucumbers and tomatoes should not be planted together, especially in greenhouses. Both like plenty of light; however, while cucumbers thrive best in a warm and humid environment without draughts, tomatoes need an airy location protected from moisture. If the two are planted as neighbours, often the tomatoes will be affected by blight or the cucumbers will be affected by diseases such as powdery mildew.
In theory tomatoes and peppers can be planted together, as they have similar requirements in terms of soil and growing site. However, both are heavy feeders, which means they have high nutrient requirements and as they belong to the same family of plant (nightshades) they will compete for the same nutrients. That is why gardeners who subscribe to the growing rules of polyculture – and also don’t want to do as much additional fertilising – don’t plant tomatoes and peppers together.
Growing your own tomatoes
Growing tomatoes offers more benefits than just the pleasure of harvesting your own ripe fruit; unlike shop-bought tomatoes, you are also in control of what fertiliser is used, so you know just what you are eating. Last but not least, planting your own gives you the opportunity to enjoy tomato varieties that you simply won’t find in the shop or at the weekly market.
Choosing a tomato variety requires some consideration.
Selecting suitable tomato varieties
There is a huge selection of tomato varieties available: you will find everything from a small red cocktail tomato to yellow, green or purple varieties in a huge range of shapes and even up to pumpkin-sized fruits.
When growing tomatoes in your own garden, you should consider the growth habit and growing site of the plants when choosing tomato varieties, as well as the appearance and taste of the fruit. Where you grow your tomatoes – covered or unprotected in the garden, on the balcony or in the greenhouse – is an important factor to consider for choosing more or less suitable varieties.
Strong-growing cordon tomatoes, which need to be tied in to a support, should preferably be grown outdoors or in a greenhouse. Compact bush tomatoes up to 100 cm in height, as well as small-fruited cocktail or cherry tomatoes are a great choice in a pot on a balcony or terrace, as they have smaller root systems. For example you could try “Utenok” or “Tumbling Tom Red”.
If you want to grow tomatoes outdoors and without a roof, you need robust varieties such as “Philovita” and “Fantasio”, which are particularly resistant to diseases and pests and can also tolerate cooler summers.
Many varieties will thrive in a covered, rain-protected spot in the garden. This kind of site is also suitable for heirloom and true-to-seed tomato varieties, which generally have thinner skins. Examples of these include “Moneymaker”, “Saint Pierre” and “Yellow Pear”.
If you grow your tomatoes in a greenhouse, you can choose more delicate and temperature-sensitive tomato varieties such as “Zuckertraube” or “Ananas”.
With tomatoes, the right growing site is crucial.
The right growing site for tomatoes
For your plants to develop healthy, vibrant and delicious tomatoes, they need heat and plenty of light, but above all a roof over their head. This is because water on the plant leaves – from rain as well as manual watering – creates conditions which invite the infamous scourge of tomato blight. Ideally you will choose a growing site where tomato plants are protected from strong winds but still well-ventilated, so that damp leaves can dry quickly.
With that in mind the best location for planting tomatoes is close to the house wall under a projecting roof, in the garden under a DIY plastic canopy or, best of all, in an open-sided tomato growhouse or a well-ventilated greenhouse.
What soil do tomatoes need?
Tomatoes are best planted in a nutrient-rich, humus-rich, loose and permeable soil to avoid root rot and the plants becoming waterlogged. Before planting out young tomato plants, improve the soil with compost or ready-made vegetable soil. For successful tomato growth, don’t forget to fertilise the soil regularly: tomatoes are heavy feeders and need a lot of nutrients right up until they are ready to be harvested.
For sowing tomato seeds in spring, on the other hand, nutrient-poor growing medium is better so that the seedlings’ roots are encouraged to grow quickly in search of nutrients.
Planting tomatoes – how to do it
There are two ways to get started growing your own tomatoes: you can either buy ready-grown young plants from the garden centre or you can raise your tomatoes from seed. Take care to choose true-to-seed varieties, so you can save the seeds from your summer crop of tomatoes and then regrow your favourite varieties next year.
The most satisfying way to grow tomatoes is by raising the plants from seed yourself. The first important matter is when you start your tomato seeds: this should ideally happen between mid-March and the beginning of April, so that the seedlings are ready for planting out from mid-May, but have not yet grown too much.
The seeds need light to germinate, and should be lightly pressed into shallow seed pots or trays with seed soil, watered and then placed on a sunny windowsill. In temperatures from 20 to 24°C and with moderately moist soil, the first shoots will be visible after 5 to 10 days.
The seeds will germinate particularly quickly if you can cover the growing containers with cling film or glass. By the way, faster germination usually produces stronger tomato plants.
Once the first true leaves have developed above the seed leaves, after about three weeks, the plants need more space to continue growing. To ensure that your tomato plants are as healthy and strong as possible when you plant them out, the tomato seedlings should be pricked out at this point, i.e. separated and individually replanted.
To do this, fill 8-10 cm plant pots with growing medium or potting soil. Use a dibber (a chopstick or an old ballpoint pen will also do) to make a deep hole in the centre.
Use the dibber or similar tool to carefully lift each seedling out of its soil and then place it into the prepared hole, so it is buried all the way up to its first leaves. Press the soil in firmly, water, and position the pots in a cooler (16-18°C) but very light spot so that the seedlings grow into strong plants.
Warmth-loving tomato plants can be planted outside from mid-May at the earliest, once the risk of overnight frosts has passed. The young plants should now be about 30 cm tall. Plant them in the soil all the way up to the lowest leaves – more roots will form on the underground part of the stem.
If you plant the tomatoes with spacing of at least 50 cm, all the fruit will get enough light to ripen and tomato diseases are less likely to spread between plants. Apart from compact-growing bush tomato varieties, all tomatoes need a growing support. Put the support canes in place while you are planting out the young plants; during the growing phase you should keep regularly tying-in the main stem to this support.
STIHL tip
Harden off tomato seedlings! For around a week before planting the young plants out into the garden, balcony pot or greenhouse, you can keep them outside during the day. This is called hardening off, and it gives the seedlings a chance to adjust to their future outdoor conditions, so that they grow faster and cope better with temperature fluctuations at their final location.
Tomato plant care: fertilising, watering, etc.
Appropriate watering and fertilising is key when growing tomatoes. It is also important to “pinch out” side shoots from the tomato plants.
The most important thing is to water tomato plants at the base, wetting the soil, because keeping the leaves from getting wet helps to prevent tomato blight. If you water your plants in the morning, any wetness on the leaves will dry out faster than in the evening.
Keep the soil consistently moist, especially during the flowering period and while the fruits are developing. Frequent alternation between wet and dry soil conditions makes fruit more likely to split. If you mulch the ground under your home-grown tomatoes, the soil will stay moist for longer and you will need to water less often.
Tomatoes are heavy feeders and need to regularly be given nutrients. Start fertilising your tomatoes two weeks after planting them out. As a guideline, fertilise every two weeks until flowering starts. After that, the increased nutrition requirements needed for fruit formation mean you should fertilise the plants more often.
How often you need to fertilise your tomatoes after planting depends on the tomato variety, soil condition, growing site and, last but not least, the type of fertiliser. Garden centres sell tomato fertilisers with a nutrient composition that is perfectly tailored to the requirements of tomato plants. A good organic fertiliser option is (home-made) nettle tea, which simultaneously offers the additional advantage of protecting tomatoes against fungal diseases and leaf aphids.
Growing tomatoes and hoping for a bumper crop? Then you should regularly pinch out your tomato plants; in other words, remove the side shoots which emerge at the junction between a leaf and the main stem. Doing this ensures the plant’s energy is directed towards the main stem, so the plant produces more and larger fruit. Pinching out is necessary for large cordon tomato plants growing in the garden or greenhouse. It does not need to be done for shrub, cocktail and wild tomatoes, as they naturally form delicious fruit on the side shoots too.
During the strongest growing period between June and September, you should inspect your plants every week or so to pinch out side shoots – simply snap or pinch off the shoots with your fingers.
In our latitude, tomatoes are usually newly grown every year, because our winters are simply too cold for these light- and heat-loving plants. But if you want to try to keeping your tomato plants growing over several years, it is best to do so with potted balcony tomatoes which are still healthy in autumn. To overwinter the plants you will need a bright, frost-free location, for example on a windowsill or in a conservatory.
Harvesting tomatoes: when and how?
It happens from mid-June in the greenhouse, and around four weeks later outside: tomato harvest time! To check if the fruit is ripe, give it a gentle squeeze: if it is slightly tender, it is ready to harvest. The pressure test is more useful than checking by colour, because not all tomatoes turn bright red.
Your tomatoes can be carefully picked at the thickened node on the fruit stem: you will be able to effortlessly release the fruit at this natural breaking point, if it is sufficiently ripe.
STIHL tip
The tomatoes closest to the main stem will ripen first.
Only really ripe fruit should be harvested.
Alternatively, you could use secateurs to cut the tomato off at the same point (or even a whole truss in the case of vine tomatoes). Fully ripened fruits should always be harvested with their top leaves and stem attached, so that they last longer.
At the end of the autumn harvest, some fruits may not be able to reach full maturity on your tomato plant. If this happens, you can harvest the unripe fruits and leave them to mature in the house, wrapped in newspaper or in a paper bag. You should not eat green tomatoes (apart from naturally green tomato varieties) because at this stage they contain a lot of solanine – a toxic chemical compound which breaks down as the fruit ripens.
