As of: March 6, 2024, 2:08 p.m
By: Alina Wagner
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Cold frames accelerate plant growth, protect against frost and extend the growing season.
© PantherMedia / Melpomene
The gardening season can be year-round thanks to cold frames.
But how exactly do they work?
Tips about mini greenhouses can be found here.
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The most important thing in
this message
When
do you start with the cold frame?
- Different times for different plants
What kind of cold frames
are there?
- There are cold frames for every requirement.
Where
should a cold frame be?
- How an ideal growth climate is created.
Do-it-yourself:
How do you set up a cold frame correctly?
- Build your individual cold frame with the right tips.
What
can you
grow
in the cold frame ?
- These plants can be grown early.
Which is better:
cold frame or greenhouse
?
- These are the advantages and disadvantages.
How high
should a cold frame be?
- Pay attention to the minimum height.
Which film
is suitable for a cold frame?
- This type of film protects plants and vegetables from the cold.
Which is better,
weed control or film
?
- A question regarding sustainability and costs.
Does a cold frame have a
bottom
?
- Direct connection to the ground.
All chapters
Cold frames are an excellent way to start plant growing earlier in the season and extend it into late fall.
They act like small greenhouses by providing a warmer and protected environment for the plants, which is particularly important in changeable weather.
Cold frames allow gardeners to not only extend the growing season, but also protect sensitive seedlings from frost and accelerate the growth of vegetables and flowers.
When
do you start with the cold frame?
In Germany, the best time to use a cold frame is usually from February or March.
However, this time varies depending on the climatic conditions and weather in each region.
It is advisable to sow frost-resistant vegetables such as spinach and radishes early.
Heat-loving plants, such as tomatoes and peppers, should be planted later.
Close observation of the weather forecast is very important.
This way you can determine the ideal time to use the cold frame and provide additional protection if necessary.
What kind of cold frames
are there?
Cold frames can come in different types and designs, which differ in material, size, shape and functionality.
Here are some common types of cold frames:
Classic cold frames
These usually consist of a wooden or metal frame with a glass or plastic cover.
They are close to the ground, offer protection and a warmer microclimate for growing young plants.
Wooden cold frame
with 2-part plastic lid
, 116 × 54 × 42 cm in brown
Double cold frame made of
heat-insulating hollow-chamber panels, 100 × 60 cm
Juwel cold frame Biostar 1500
, with automatic window, opens and closes automatically, 149.86 × 81.28 × 10.16 cm
Polytunnels or greenhouse films
Polytunnels or greenhouse films are movable or partially stationary structures made from a frame made of metal or plastic.
A transparent plastic film is stretched over this frame.
Thanks to their mobility, they can be easily moved around and offer a good solution for growing on large areas.
PVC greenhouse for flowers and crops - length approx. 2.9 m
Foil greenhouse with window in green, 350 × 200 × 200 cm
Foil greenhouse with 3 roll-up windows in green, 270 × 90 × 90 cm
Mini cold frames or growing boxes
Smaller versions of the classic cold frames often used on balconies or in smaller gardens.
They are portable and can be placed on windowsills or patios to start seeds early.
Translucent cold frame box, 78 × 58 × 30 cm
Mini wooden greenhouse 60 × 30 cm
Wooden planter box 100 × 60 × 30.5 cm
Editor's tip: 2-in-1 cold frame
The Gaia Jumbo cold frame from Vitavia not only serves as a cold frame, but can also be used as a raised bed by placing it on a pallet frame.
The glazing made of clear safety glass ensures high stability and, in the event of breakage, less risk of injury as it does not break into sharp pieces.
With a height of 72 cm, the cold frame offers enough space to allow plants to continue growing even after the cultivation phase.
The roof with opening windows guarantees ideal ventilation.
It is available in aluminum or black, although you can also choose a version with insulating panels for better thermal insulation.
The external dimensions are 83.1 cm wide, 119 cm deep and 71.9 cm high.
Buy from Obi
Where
should a cold frame be?
Place your cold frame in a sunny location protected from wind.
Facing south is optimal to capture lots of sunlight.
This creates an ideal growing climate: the heat is retained and the plants get enough light.
The windbreak reduces heat loss and protects plants from damage.
Do-it-yourself:
How do you set up a cold frame correctly?
Many gardeners build their own cold frames to tailor them to their exact needs.
They use materials such as old window frames, polycarbonate panels or recycled wood.
This creates affordable and individual solutions.
What
can you
grow
in the cold frame ?
Many plants can be grown in a cold frame that need an early start and protection from the cold.
The following plants are particularly suitable for the cold frame:
Leafy greens
: Lettuces, spinach and arugula, which prefer cool weather and grow quickly.
Root vegetables
: radishes, carrots and new potatoes, which can be sown directly in the cold frame.
Brassicas
: Broccoli, cauliflower and kohlrabi, which are preferred for an early harvest.
Onion family
: Spring onions and shallots that require a cool start.
Herbs
: Many herbs can be sown in cold frames or started as young plants, including parsley, dill, coriander and chives, which prefer cooler weather.
Flowers
: Some flowers can be started in the cold frame to enjoy early blooms or to prepare them for transplanting outdoors.
These include marigolds, sunflowers, petunias and primroses.
Heat-loving vegetables and fruits
: Tomatoes, peppers, eggplants and cucumbers can be grown in the cold frame before being moved outdoors or into the greenhouse after the last frosts.
Which is better:
cold frame or greenhouse
?
Whether a cold frame or greenhouse is the better choice for your garden depends on several factors, including your personal needs, available space, and budget.
Both options have their own advantages and disadvantages.
criteria |
Cold frame |
Glasshouse |
|---|---|---|
Cost |
lower |
higher |
Space requirement |
smaller, space-saving |
larger, requires more space |
Growing season |
mainly spring and summer |
Growing season all year round |
Plant diversity and quantity |
limited by size and height |
more variety and larger quantities possible |
Climate control |
limited options |
better climate control possible |
What can go into the cold frame at what temperature?
The temperature in the cold frame plays a crucial role in determining which plants can be successfully grown there.
In general, the plants can be divided into four categories: frost-tolerant, cold germinators, temperate-temperature loving plants and heat-requiring plants.
Here is a quick overview.
Temperature range |
Plant examples |
Below 5°C |
Spinach, peas, broadleaf and lamb's lettuce, types of cabbage (e.g. kale) |
5°C to 10°C |
Radishes, spring onions, carrots, leafy greens |
10°C to 15°C |
Tomatoes, peppers, eggplants, cucumbers (for pre-growing) |
Above 15°C |
Warm-loving plants (later moved outdoors) |
How high
should a cold frame be?
The ideal height of a cold frame can vary depending on the specific needs of your plants and the space in your garden.
In general:
Minimum height:
A cold frame should be at least 30 cm high.
This height allows for adequate soil warmth and protection for young plants from cool temperatures.
Optimal height:
It is between 40 and 50 cm.
This height not only makes it easier to care for the plants, but also creates a favorable microclimate for their growth.
It also supports good ventilation and helps regulate the temperature in the cold frame.
A higher cold frame is recommended for growing larger plants or those that require a lot of roots.
The height can also be adjusted to suit your ergonomic needs to reduce bending over.
Good insulation, sufficient ventilation and effective sunlight are also important for optimal plant growth.
Which film
is suitable for a cold frame?
For cold frames, a clear, UV-resistant polyethylene film is ideal as it allows light to pass through well and protects the plants from the cold while using the heat effectively.
The Aquagart greenhouse film optimally protects plants.
It is UV-stable, very resilient and made of strong plastic fabric.
Their green-transparent color promotes plant growth.
The film is available in different sizes and is suitable for many garden projects.
Order foil
Which is better,
weed control or film
?
The decision between weed control and film depends on your goals regarding sustainability, costs and the health of the soil.
Weed control fabric allows air and water to pass through, improves the condition of the soil, but costs more.
It is durable and protects the environment, ideal for long-term projects.
Film is cheaper and blocks weeds immediately, but can remove water and nutrients from the soil and pollutes the environment because it does not rot.
For an environmentally friendly solution, weed control is better.
Foil is more suitable for short-term or budget-conscious projects.
Buy weed control
Does a cold frame have a
bottom
?
A cold frame typically does not have a solid base in the sense of a wooden or concrete slab.
Instead, it sits directly on the garden floor.
This means the plants can grow directly in the ground.
This gives the roots access to natural nutrients and water.
It also helps with water drainage and keeps the temperature in the bed stable.
The direct connection to the soil is particularly beneficial for the growth of young plants that are later transplanted outdoors.
They are already growing in the conditions that they will later expect outdoors.
Also read about what gardening work needs to be done now in March or get ideas for the balcony garden in the city.
The editor wrote this article and then used an AI language model for optimization at his own discretion. All information has been carefully checked. Find out more about our AI principles here