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Mini greenhouses come in a wide variety of shapes, sizes and materials but fundamentally do the same thing. They provide a warm growing environment for germinating and growing your plants of choice.
Unlike large greenhouses they can be moved around and do not necessarily need a base of any kind. Any greenhouses are particularly good for germinating seeds and growing on young plants early in the season. Because mini greenhouses come in such a wide spectrum we have put together this step by step guide for you.
What is a mini greenhouse?
Mini greenhouse is really a blanket term for a whole range of smaller greenhouse devices and structures. They all do the same job as a large greenhouse but more flexible in terms of positioning.
By far the most common association for the term ‘mini greenhouse’ is the walk in or lean to greenhouse. These are very similar in construction to regular greenhouses but much smaller. These will usually be fixed to a wall or south side of a house.
Most mini greenhouses are not suitable for growing very large plants. They are however perfect for germinating young plants while growing a few tomatoes and chillies in summer.
I have identified thirteen types of structures which are commonly thought of as mini greenhouses. I have given a full breakdown of these below with some links to them on Amazon.
Propagators are typically small growing trays with domed, transparent plastic covers over the top. Their primary function is to germinate seeds and grow them on until large enough to handle.
Propagators are in their own way a type of mini greenhouse but far from such in many ways. These are used on south facing window ledges during the spring to get plants started early.
There are many variations of propagators on the market including some electric heated propagators. We have left a link to one of these below.
If you would like more information in general about how to grow in propagators check out our article here.
A terrarium is an enclosed or open transparent vessel which contains a unique growing environment. Usually domed a terrarium mimics the atmospheric hydraulic cycle within a small area.
This combined with sunlight warming the structure create a unique microclimate. Like a miniature tropical rain forest this is perfect for growing mosses, ferns and other unusual plants. In the past terrariums were used in scientific studies to study insects and rare plants.
Sometimes terrarium structures are created as a planted showpiece or an enclosure for warm loving creatures like snakes.
Cloches are used to cover plants which have just been planted outside early in the growing season. Young plants can go into shock when first planted outside.
Even in early summer nights can still be cold and cloches allow you to just give plants that transitional cover while they adapt. I would say cloches are used to protect from the cold rather than create a warm environment.
These come in a wide range of styles from domed individual plant covers to long foldable plastic tunnels. By far the most common are the long planting tunnels which are typically used by vegetable gardeners.
Mini pop up greenhouses
These rather fun mini greenhouses are very similar in set up to pop up tents. Simply allow the greenhouse to pop up and then you have a small space to grow what you want.
Although extremely convenient and portable these mini greenhouses are not very particle. Firstly you will need to make sure it is anchored so it does not blow away in any strong wind.
Such a small growing area can lead to extreme fluctuations in heat which can be testing for many plants. Pop up greenhouses to have their place but are probably best used as large propagators or cloches.
Cold frames are typically rigid structures made of timber and glass. They utilise horizontal space with lids to open and close. This allows you to place seedlings and young plants places outside to grow on and gain strength.
Cold fames are mini greenhouses that are usually used to ‘harden off’ plants before they are planted out. This involves taking plants out on sunny days but putting them back inside during the night.
Cold frames are very useful to bridge the part of the season that has warm days but cold nights. These miniature greenhouses do come in a wide range of types. We have put a selection of these below.
Cupboard cold frames
Cupboard cold frames do exactly the same jobs as conventional cold frames but they utilise vertical space. The added benefit with these is they can be mounted up against a warm wall.
This enables you to take advantage of a mild microclimate when growing. The main disadvantage with these mini greenhouses are they are usually shelved. This means there is not much potential to grow taller plants.
Furthermore the shelving can block the sunlight to lower levels. This can cause seedlings to lean and become leggy making them difficult to plant on.
Lean to mini greenhouses
Lean to greenhouses rely on another external vertical surface like a wall to create an enclosed growing area. They are extremely efficient at using unused vertical space for growing.
Placed up against a warm wall, lean to greenhouses can actually become warm on sunny, winter days. The only issue with these mini greenhouses is they can be a little pokey and become extremely hot on summer days.
They are however a great way to make used of an unused part of the garden. I have left a good example on one of these below.
Walk in garden greenhouses
Walk in greenhouses allow you to walk in via a central avenue and have planting areas and shelves on either side. These range from very shallow mini greenhouses that lean up against walls or deeper set glasshouses.
What the exact measurement of pathway is where a walk in greenhouse becomes a conventional greenhouse is unclear. I would say when a walk in greenhouse reaches as deep as it is wide it would become just a greenhouse.
This is a lose assumption but in general these have the feel of a walk in wardrobe but with plants.
Mini greenhouse dome
Mini greenhouse domes have slowly come into fashion in recent years for growing but also as a focal point. These range in sizes from window seal examples to larger greenhouse types.
Some larger examples are built with sophisticated metal work and glass. When it comes to growing plants however they are a little intractable. The sloping edges and circular walls make it difficult to add shelves and staging.
This makes for an awkward mini greenhouse to grow in but can still be fun for the garden. Admittedly dome greenhouses to look modern ad exciting.
Victorian mini greenhouse
The Victorian era saw its fair share of greenhouses. The Victorians used to build the most elaborate and decorative greenhouses which they filled full of exotic treasures they found from faraway lands.
Due to the beauty of these structures there are now many Victorian mini greenhouses on the market. Admittedly I find these all very well built and charming.
Probably best for smaller planting operations and to house novelty exotics like citrus perhaps. They come in a wide variety of colours and sizes. I have left a link to a favourite here.
Mini greenhouse tunnel
Some mini greenhouses that have become rather popular in current times are the small tunnel greenhouse. Technically a polytunnel these mini greenhouses can be quite large.
Generally real commercial polytunnels are absolutely huge but these garden varieties are a good greenhouse alternative. These typically consist of a stainless steel frame and durable polyethylene plastic.
Greenhouse tunnels are a great way to get a larger growing area with a less permanent infrastructure. Depending on what size you get you can grow everything from gherkins to chillies on mass. Greenhouse tunnels are also rather cost efficient for the amount of growing space you get.
Mini greenhouse shed
Another type of mini greenhouse is the greenhouse shed. It’s not that this space is miniature in any way it is just these are a greenhouse shed hybrid.
Typically they have all the characteristics of sheds but with one side completely glass. This allows for a modest area to grow multiple warm loving plants. At the same time much of the same space can be used to store tools and other typical accessories.
Greenhouse sheds vary greatly with some having large amounts of glass and some simply have large windows. Whether you want to sow a few seeds or grow a row of tomatoes there is a wide range to choose from.
When covering a subject as broad as mini greenhouses it is important to realise common greenhouses are small in comparison to commercial glasshouses. There are some standard garden greenhouses that are small in size and ideal for smaller gardens. I have included a link to a small traditional greenhouse below.
DIY mini greenhouse
In its simplest form a greenhouse is just a rigid structure covered in a transparent material. Therefore it is not too much of a difficult thing to build yourself with some basic DIY knowledge. You may wish to recycle some old materials you have or just want to custom build your own. For this reason I have linked to this video which gives inspiration for building your own greenhouse.
Plastic mini greenhouses
When it comes to buying a mini greenhouse you can try a tent like one with a plastic sheet to get you started. With these you have to realise the plastic will only last 3 years if you are lucky. Seeing these are generally cheep to begin with and very portable this is not a huge problem.
If you want to buy a plastic greenhouse try to buy one with a metal frame, preferably one that screws together. I say this because through experience ones with plastic connectors and frames become brittle very quickly.
This will leave them very vulnerable to wind damage pretty much from the first season. Much better to have at least one robust frame and you can purchase replacement covers as you need them.
Glass mini greenhouses
In general I would say if you are serious about gardening in a mini greenhouse the stronger the better. From experience when you get used to having a glass house it is very difficult to go back.
There is nothing worse than buying one and it fails within a couple of years. Hence any structure that is designed to hold glass will be sturdy and robust. Whether its metal or timber frames mini greenhouses with glass are always a better option.
With glass however there is always the threat of breakages. If you or your neighbours have young children you may have to consider how often they play ball.
What is the best mini greenhouse?
Seeing the term ‘mini greenhouse’ potentially spans so many options I would consider a few points. How big is your gardening operation? If you love gardening or new but expanding remember the larger the better.
It is difficult to expand when you already have a small greenhouse. If you are simply trying to geminate plants before the spring a walk in greenhouse is perfect. If you actually want to grow full sized crops such as tomatoes and chillies you are better off with at least a small tunnel.
In summer it is amazing just how large and quickly plants can grow in this warm environment. Measure out your space, have a think about what your maximum growing area should be and review this article again to help you make a decision.
Where do I position my mini greenhouse?
The best place to position your greenhouse is somewhere that gets plenty of light. A south facing position is always optimal but as long as it gets at least 6 hours sunlight a day it should be fine.
Remember that mini greenhouses can fluctuate in temperature during the summer months. If you do locate it in a very sunny area try to make sure there is enough air circulating the space.
This way in summer if it gets too hot you can easily ventilate the structure. Try to locate your greenhouse near a water source of some kind, there will be no plants if there is no way of watering them.
If you have a large garden try to keep it in view of the home, It is so easy to forget about plantings if you are busy. If you have young children who like to play ball try to locate it out of harm’s way. For more information on positioning your greenhouse we have provided an informative article here.
What can I grow in a mini greenhouse?
You can grow pretty much anything in your greenhouse that its size and growing medium will allow. During the winter months you can grow some leafy greens while in summer you can grow more exotic plants. Tomatoes, peppers, gherkins egg plant can all be grown in greenhouses in temperate climates. The best way to learn about the uses and limitation of greenhouses is to buy an informative manual. I have placed one for reference down below.
Mini greenhouse care
No matter what mini greenhouse you end up getting you will need to practice some annual care. After every growing season wash the inside of your greenhouse with soapy water and a sponge.
This will stop any fungal spores building up and get with of any pests and bacteria. Also try to clean pots, turn over soil to oxygenate and top up with fresh compost. With these annual hygiene tips your greenhouse will be productive for many years to come.
Enjoy your greenhouse
Once you are a proud owner of a new greenhouse you should be excited about this new adventure! You will now have much longer growing seasons and be able to dabble in some exotic wonders. Whatever you end up growing one thing is for sure! Your gardening will be just a little bit more exciting from now on.
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Paul Nicolaides is a Landscape architect and garden builder with over 30 years experience in designing, building and maintaining gardens. Contemplating just how important garden space is for nature and recreation he created 'Cool Garden Gadgets' to explore the best gadgets for enhancing outside spaces. From outdoor dining ideas to the latest garden technology we break it down for you here.