Tunnel house, greenhouse and cold frame garden structures are all great choices growing plants in the winter, but what, exactly is the difference between the three of them?
Technically they do the exact same job which is protect plants from the cold weather outside during the winter months.
However each one has a slightly different purpose, although they are very interchangeable depending on what you intend to do with them.
Personally I prefer tunnel houses and greenhouses instead of cold frames simply because I like to be inside in the winter.
However you may feel completely different.
Here is a breakdown.
What Is A Greenhouse?
Think of a greenhouse as a small room made out of glass or plastic.
The walls and roof are generally clear, although this is not always the case.
The idea behind a greenhouse is that you control the temperature inside it making it possible to grow plants, such as orchids or other tropical plants, all winter long even in cold, northern climates.
What Is A Tunnel House?
A tunnel house is very similar in size to a greenhouse, but it is unheated.
These tunnel-shaped structures are usually covered with clear plastic.
Depending on the design of the tunnel house, the sides may raise and lower to allow adequate ventilation into the structure.
Tunnel houses are the ideal structure for growing cool season crops all winter long because you can walk into them.
This makes harvesting crops nicer.
What Is A Cold Frame?
A cold frame is the simpliest of these structures.
It is nothing more than a box-like structure with a clear glass or plastic top.
It can be square, rectangle or any other shape you wish it to be.
Cold frame garden structures are easy to make at home using four bales of straw and an old window.
Most cold frame garden structures are unheated and used to protect cool weather crops over the winter.
They are also useful for hardening off indoor grown seedlings.
Hardening off is the process that occurs when seedlings or plants are gradually exposed to weather elements they are not accusomed to.
If this process is done too fast, the seedlings or plants could die of shock.
Is it Necessary To Heat A Garden Structure During Winter?
The answer to this question depends on what you intend to grow.
Cool season crops and perennial plants do not need heat to survive the winter inside a garden structure.
This is why tunnel houses and cold frames are such popular items.
Are Garden Structures Expensive?
Some garden structures run thousands of dollars, while others cost less than $25.
The cost depends on what you want.
It is possible to build a large greenhouse for under $1,000.
That same greenhouse, bought through a greenhouse company, could run $5,000 or more.
Learn More About Year-Round Gardening
If you want to know more about year-round gardening or gardening structures, The Complete Idiot’s Guide to Year-Round Gardening, is a great book that covers all aspects of gardening indoors and out, all year long.
Best of all it was written by two authors who live in cold climates – one in Indiana and one in Pennsylvania.