Greenhouses – reliable protection for your plants
Whether it’s fresh fruit, aromatic herbs or home-grown vegetables: with a greenhouse, you can enjoy freshly harvested ingredients for cooking or snacking for many months on end. In summer, you can grow heat-loving varieties inside; in the colder months, depending on the model, it serves as a sheltered spot for potted plants. Greenhouses made from aluminium, plastic sheeting, steel, multi-wall panels and other materials protect your plants from strong winds, hail, heavy rain and temperature fluctuations.
Before buying, it’s worth comparing carefully: how much space do you have in the garden, on the terrace or on the balcony? Which plants do you want to grow? And do you need a small greenhouse for herbs and seedlings, or a large greenhouse for tomatoes, cucumbers and several vegetable beds?
Planning location, use and size
Buying guide: materials, ventilation and anchoring
Planting your greenhouse correctly
What different types of greenhouses are there?
Glass is used less frequently in small greenhouses these days, as the interior can heat up significantly and the material is comparatively heavy and expensive. For many hobby gardeners, models made of aluminium, plastic sheeting, steel or hollow-core panels are therefore the more practical choice. Which option suits you best depends on whether you want to remain flexible or are looking for a permanently stable greenhouse.
Aluminium greenhouse
An aluminium greenhouse is a good choice if you want to grow vegetables, herbs or seedlings on a regular basis. Models with hollow-core panels are common, as they offer good light transmission, retain heat and are lighter than glass. Aluminium is also rust-free, low-maintenance and stable enough for long-term use in the garden.
For delicate plants, roof vents or automatic window openers are particularly practical. Spare parts and accessories also play a role: with greenhouse accessories such as greenhouse clips or hollow-core panels, you can maintain or expand your greenhouse as needed.
Plastic greenhouse
A plastic greenhouse is particularly recommended if you’re looking for an affordable and flexible greenhouse. It’s well-suited for seasonal cultivation, growing seedlings or as simple protection against rain and wind. Compared to fixed greenhouses, however, plastic sheeting is less stable and does not insulate as well. For windy locations or to ensure the longest possible lifespan, a fixed model is usually the better choice.
Tomato greenhouse
A tomato greenhouse protects tomato plants from direct moisture and creates a warm climate through the greenhouse effect. This supports the growth and ripening of the fruit. Good ventilation is particularly important, as tomatoes like warmth but not permanently damp, stagnant air.
If you want to grow several tomato plants, you should ensure there is sufficient height and space for trellises. This allows the plants to grow better and makes it easier for you to reach them for pruning, watering and harvesting.
Balcony greenhouses and mini greenhouses
If you only have a small garden, a terrace or a balcony, a balcony greenhouse or mini greenhouse is ideal. These small greenhouses are ideal for growing herbs, lettuces, strawberries or young plants. Many models make good use of the height with multiple shelves and require very little floor space.
Cold frames and raised beds with covers
Cold frames or raised beds with covers are ideal for cultivating young plants and getting an early start on the gardening season. They take up less space than a large greenhouse and are particularly practical for lettuces, radishes, herbs and small vegetable plants.
Greenhouse Location, Use and Size
If you’re thinking of buying a greenhouse, you should first ask yourself the following questions: Where is a spot that’s sunny yet as sheltered from the wind as possible? Which plants do you want to grow? And how much space do you really need? The location is important to ensure your plants receive optimal light and warmth. A sunny spot with some protection from strong winds is ideal.
Ideally, the ridge of a freestanding greenhouse should face east-west. Leaning greenhouses or add-on greenhouses are ideally oriented towards the south to maximise light exposure.
What size do I need?
The right size depends on how you intend to use your greenhouse. For herbs, lettuces or individual seedlings, a small greenhouse is often sufficient. If you want to grow tomatoes, cucumbers, peppers or several types of vegetables, you should allow for more space and sufficient height. A large greenhouse also offers you more freedom of movement when watering, tending to and harvesting your plants.
- Balcony or small terrace: balcony greenhouse, mini greenhouse or narrow polytunnel
- Small garden: compact greenhouse for herbs, lettuces and seedlings
- Vegetable growing for several people: a larger model with sufficient floor space and headroom
- Tomatoes, cucumbers and peppers: allow for enough height, depth and space for trellises
From an ergonomic perspective, a greenhouse can easily be around 50 cm taller than you are. For tomatoes, cucumbers and similar crops, the original text recommends a minimum size of approximately 3 x 4 m and a ridge height of approximately 2 m. If your space is limited, a smaller model may also be a sensible option, provided that ventilation, plant spacing and maintenance remain feasible.
Buying guide: What should you look out for when choosing a greenhouse?
Before purchasing, you should compare materials, stability, ventilation, anchoring and intended use. For occasional cultivation in spring and summer, a simple polytunnel is often sufficient. If you intend to use your greenhouse intensively every year, a fixed model made of aluminium and hollow-core panels is usually more durable and convenient.
Polytunnel or fixed greenhouse?
A polytunnel is the right choice if you want to remain flexible and start off affordably. It can usually be set up quickly and is well-suited to seasonal crops. A fixed greenhouse is more stable, better insulated and better suited to regular use in the garden.
- Polytunnel: affordable, flexible and ideal for seasonal growing
- Fixed greenhouse: more stable, longer-lasting and more comfortable for frequent use
- Aluminium greenhouse: low-maintenance, rust-proof and ideal for long-term use
- Balcony greenhouse: space-saving for herbs, lettuces and young plants
Which greenhouse is suitable for tomatoes?
A tomato greenhouse is suitable for tomatoes, as it protects the plants from rain whilst allowing for good ventilation. Tomatoes thrive in warmth but are sensitive to leaves that remain damp for prolonged periods. Therefore, ensure there are windows, doors or ventilation openings to allow air to circulate.
If you’re growing several tomato plants, the greenhouse shouldn’t be too cramped. Sufficient space between the plants helps drain moisture more effectively and makes care easier.
What should you bear in mind regarding ventilation?
With a greenhouse, you create a protected environment for your plants both in summer and during the transitional seasons. At the same time, the interior can heat up quickly due to the greenhouse effect. The original text mentions an optimal temperature of around 30 degrees Celsius. If it gets significantly hotter, you should ventilate.
Roof vents, doors or side openings are essential to allow warm air to escape. Automatic window openers are particularly handy if you cannot monitor the greenhouse yourself at all times. Regular watering is also important, as plants in a greenhouse may require water more quickly.
How is a greenhouse secured?
A greenhouse should be stable and secure so that it does not shift in the wind or during a storm. Small polytunnel greenhouses are often secured with pegs, guy ropes or ground anchors. A fixed aluminium greenhouse stands particularly securely when mounted on a greenhouse base.
The ground should be level, load-bearing and as sheltered from the wind as possible. For larger models, a foundation is advisable as it increases stability and protects the frame. On a balcony or terrace, you should also check whether the greenhouse can be securely fixed in place.
Planting the greenhouse: When should I plant which vegetables?
For planting, you can use ready-made greenhouse compost or vegetable compost. Ordinary potting soil mixed with fertiliser is also suitable. It is important that the soil is well aerated. This allows water to distribute more evenly, ensures plants are supplied with nutrients consistently, and prevents waterlogging.
If you wish to fertilise your greenhouse, you can use natural materials such as bark mulch or coconut coir. These release nutrients and support healthy plant growth. For flexible planting ideas in the garden, on the terrace or in the greenhouse, planters are also ideal.
In spring, plant fast-growing and cold-tolerant vegetables such as lamb’s lettuce, leaf lettuce, rocket, radishes or daikon. From March onwards, depending on conditions, herbs, spinach, Swiss chard, tomatoes or courgettes can be started off early.
From May onwards, plant the greenhouse with heat-loving vegetables intended for harvest in late summer. These include tomatoes, aubergines, peppers, cucumbers, melons or courgettes. From June onwards, you can often harvest the first lettuces and herbs and replant the freed-up space, for example with runner beans or winter endives.
From September, autumn crops and late-sown vegetables such as radishes, carrots and lettuces are suitable. During the winter months from October onwards, the greenhouse is usually no longer replanted. You can then use the free space to shelter potted plants from the garden or balcony.
After buying a greenhouse: How hot can it get inside?
With a greenhouse, you create the right environment for your plants to thrive. Ideally, the temperature should not remain too high for extended periods. A temperature of around 30 degrees Celsius serves as a guideline. Especially in summer, you should ensure that the maximum temperature is not significantly exceeded.
If it gets too hot, you should ventilate your greenhouse. Practical roof vents, doors or automatic window openers help to regulate the temperature. Due to the greenhouse effect, you should also water regularly and ensure a consistent water supply.
Choosing the right greenhouse
The right greenhouse depends on your available space, your plants and your intended use. Mini or balcony greenhouses are practical for balconies and small areas. A polytunnel is a cost-effective option for beginners, whilst an aluminium greenhouse with hollow-chamber panels offers greater stability and comfort. If you primarily wish to grow tomatoes, ensure there is sufficient height, rain protection and good ventilation.
By comparing size, location, material, ventilation and anchoring before purchasing, you’ll find a greenhouse that suits your gardening routine and reliably protects your plants. For maintenance, assembly and general work around your greenhouse, gardening tools are helpful, whilst a tool shed provides additional storage space for tools, soil, pots and accessories.