Are Mini Plastic Greenhouses Any Good? What You Must Know


Mini plastic greenhouses are increasing in popularity. When I began to research whether mini plastic greenhouses are any good, I found many useful and interesting information on this topic. In the following article, I’ll share my findings with you.

Mini plastic greenhouses are indeed good additions to a garden or allotment. They are especially effective at seed starting and plant cloning. Another advantage of using mini plastic greenhouses is that they are mobile, and also they take up little space.

With many gardeners working with limited space, they are turning to alternative methods.

For some people, it’s not possible to fit a full-sized glass greenhouse in their outdoor area.

These traditional greenhouses require plenty of space and are difficult to transport into some gardens.

Thankfully, mini plastic greenhouses provide a useful and practical alternative. These smaller units are good at many aspects of gardening, whether you need a place to start your seeds or to nurture clones and keep the lineage of your favorite plants alive.

Obviously, it’s impossible to grow as many plants in a mini plastic greenhouse as it is a full-sized glass one, but they are a great way to grow small numbers if you have limited space to work with.

The advantages of mini plastic greenhouses

Mini plastic greenhouses are a good alternative to full-sized glass greenhouses. They vary in dimensions but usually have a base that is less than 10 square feet.

They are very popular amongst gardeners who have limited space available, want a greenhouse to start their seedlings early, or need high humidity to propagate certain types of plants when used indoors.

One of the good aspects of mini plastic greenhouses is that they are pretty easy to make. Indeed, there are plenty of commercially made options out there to choose from, but gardeners can also construct their own.

It’s as simple as building a makeshift frame out of wire and fitting it with a plastic cover. If you would rather purchase one, they’re not too expensive, especially when compared to larger-sized glass greenhouses.

As I briefly mentioned earlier in this article, perhaps the thing that mini plastic greenhouses are most useful for is seed starting.

This is the case, especially if the mini plastic greenhouse has a singular shelf rather than multiple.

They are so good at seed starting that they provide plenty of sunlight whilst protecting the seeds from the elements. Amorphous plastics are transparent materials that let most of the sunlight through to the seeds.

The mini greenhouse stops strong winds or rain from disturbing the seeds and prevents unwanted pests from potentially harming them.

Another purpose that mini plastic greenhouses are good for is cloning plants that are already in your garden. Plastic is a great material for trapping humidity.

Cuttings require humid conditions to thrive, so mini plastic greenhouses are great environments for improving the chances of successfully taking.

When it comes to hardening young plants, mini plastic greenhouses are also a good choice.

By hardening, I am referring to the process of allowing young plants to benefit from as much sunlight as possible while protecting them from heavy rain and strong winds.

The small seedlings can be adversely affected when grown indoors because the amount of light they are exposed to is always limited.

Mini plastic greenhouses are an ideal solution because they are mobile enough to be moved around the garden to maximize the young plant’s exposure to natural light.  

The disadvantages of mini plastic greenhouses

To establish whether mini plastic greenhouses are any good, we must look at both sides of the argument.

As I’ve discussed, there are several reasons that they are a worthy addition to your garden.

However, as with all pieces of equipment, there are some negative aspects to be aware of.

Gardeners’ main issue when using mini plastic greenhouses is that they are susceptible to being damaged by heavy wind. This can cause the plastic covers to tear in some cases, especially around the greenhouse door.

A good way to combat this is by positioning the mini plastic greenhouse somewhere that doesn’t get too much wind, or if this is not possible, at least position the door side away from the most common wind direction.

Another solution to the prospect of wind damage is reinforcing your mini plastic greenhouse.

This can be done using ground anchors or weighing down with small rocks and bricks. The materials that the frame is constructed of will also impact the mini greenhouse’s resistance.

Galvanized frames are by far the strongest option, but their price reflects this.

Other than potential damage from wind, there aren’t really any other disadvantages of using mini plastic greenhouses. Their versatility, convenience, and low-cost fair outweigh any minor pitfalls.

As long as you consider that they are under threat of being broken by extreme weather conditions, you can plan accordingly to prevent this from happening.

Another thing to consider when using a mini plastic greenhouse is the presence of rainwater. If the rain collects on the mini greenhouse, this will cause it to become misshapen and potentially destroy the structure.

It’s therefore important to shape the roof of your mini plastic greenhouse so that water can run off it easily.

The durability of a small plastic greenhouse will depend greatly on the way it is built. The poles used to make the structure of the greenhouse need to be sturdy and made from strong materials.

This is especially important if you get a lot of wind in your garden.

What are mini plastic greenhouses good for growing?

Mini plastic greenhouses are particularly useful for hardening-off young plants in the spring and early summer months.

Vegetables and half-hard annual growers are well suited to the benefits of a smaller greenhouse. They enjoy the middle-ground between a full-sized greenhouse and the more extreme weather conditions of a garden.

Smaller plastic greenhouses are also good for providing some much-needed warmth for tender summertime growers.

The heat built up within the plastic greenhouse speeds up the ripening process and can help the crop grow larger. Tomatoes, chilies, and aubergines are three examples of summer crops that would be well suited to a mini plastic greenhouse.

Plastic greenhouses generally help heat-loving plants to grow. This is because they retain warmth from being exposed to sunlight for long periods of the day.

However, their effectiveness is not limited to full sun annuals or easy growing vegetables.

If a gardener is precise and intentionally creates the right microclimate within a mini plastic greenhouse, there’s no limit to what you can grow.

There’s a range of fruits, veggies, and annuals that can be nurtured, but also more experimental growers like cacti or orchids are a possibility if the right measures are taken.

You can also use mini plastic greenhouses for seed starting indoors. The extra protection from the elements used in an indoor environment will ensure the seeds aren’t damaged.

It’s important to place them somewhere that gets frequent sunlight exposure throughout the day, then when they start to grow you can transfer them outside.

Starting seeds is much easier in a humid environment. You can use fluorescent lights and heat pads to create the perfect setting for an indoor mini greenhouse.

If your greenhouse has a zipper to open the door, it’s essential to remember to open it when it is a hot sunny day; otherwise, the plants may overheat and be irreparably damaged.

Mini Plastic Greenhouses vs. Glass Greenhouses

The majority of greenhouses are made with glass panes. The reason that glass is so popular is that it lets almost all of the sunlight through and is considered durable enough to withstand extreme weather’s inevitable rigors.

Compared to mini plastic greenhouses, the downside to glass greenhouses is that they are much bulkier, harder to set up, more costly to purchase, and more hassle to replace if a plane of glass gets smashed.

Mini plastic greenhouses, notably polycarbonate varieties, have many benefits over their glass alternatives regarding convenience and performance.

Some garden experts predict that polycarbonate plastic will overtake glass as the main material used for greenhouses in the not too distant future. Let’s take a look at the main reasons that this is likely to be the case.

1) Longevity

Mini plastic greenhouses made from polycarbonate material will last longer than glass. Surprisingly, it’s actually a stronger material and can withstand more wear and tear before breaking.

Because plastic is lighter than glass, there’s less chance of getting damaged when it is being handled or moved.

Replacing parts of a mini plastic greenhouse is a straightforward process, whereas glass panes can be difficult.

It’s also well within an average gardener’s capabilities to either construct or set up a mini plastic greenhouse. Still, a glass one usually needs help from a professional due to the complexity of fitting the windows to the frame.

2) Insulation

Mini plastic greenhouses are great at insulation and retaining warm temperatures.

Polycarbonate plastic is particularly good at this. Less heat is lost through plastic material than glass.

This keeps the average temperature of a plastic greenhouse consistently higher, especially when you consider the small size. Keeping a mini greenhouse warm is essential to help plants thrive and grow to their maximum size potential.  

Heat retention is perhaps the best quality of a mini plastic greenhouse.

3) Shatter-proof

Small plastic greenhouses are in no danger of being shattered. Unlike glass alternatives, they can withstand impact from other objects without being damaged.

For people whose garden is also a part-time playground for youngsters, this is a valuable benefit of mini plastic greenhouses.  The risk of injury is greatly reduced when compared to larger glass greenhouses.

4) Light

Plastic is a thicker material than glass, so another benefit is that it spreads out light more evenly.

This process is known as light diffusion. The plastic diffuses the sunlight equally throughout the mini greenhouse, so if you have multiple plants growing in there, none will be deprived.

Some plastics also naturally block harmful radiation such as ultraviolet, so the contents of a mini greenhouse would be well protected.

5) Longer Growing Season

The aforementioned benefits of mini plastic greenhouses all accumulate to impact the length of the growing season positively.

Using them, you get better results from your plants, vegetables, and fruits all year round. This ultimately saves a gardener time, money, and effort.

Due to the mobility of mini plastic greenhouses, you can constantly move them to be in the best positions to thrive.

The best plastics for mini-greenhouses

We’ve established that mini plastic greenhouses are great additions to a garden, but it’s important to note that the type of plastic you use will greatly impact the structure’s effectiveness.

Here’s a breakdown of the different varieties and their benefits.

Polyethene is considered the industry standard for making mini plastic greenhouses.

It’s a fairly cheap material that is readily available and easily repairable if it breaks.

Polyethene comes in many different grades, with some well suited to general utilities and others specifically listed for agricultural use.

The only negative aspect of polyethylene is that it lacks the durability of other plastic types.

It will likely need repairing now and then, which is a hassle that most gardeners would like to avoid.

The low-cost makes this less of a problem, but it does use up more time and effort.

Polycarbonate is a little more expensive than polyethylene, but it is much more durable and robust. It’s made from a composite of sheets, and the multiple layers make it great for insulation purposes.

It’s also a pretty flexible type of plastic and lets in a good amount of sunlight.

The final option is polyvinyl carbonate, or PVC, as it is commonly known. Many gardeners use PVC for their mini-greenhouses due largely to its exceptional durability.

It can last for many years without needing to be repaired, but this is reflected in the cost. It usually comes in short sizes, which makes it perfect for constructing a mini greenhouse.  

Conclusion

To conclude, yes, mini plastic greenhouses are good for many purposes. If you have limited space in your garden, they provide a convenient alternative to bulkier glass greenhouses.

They are also much lighter, easy to move around, and more affordable.

However, the type of plastic you use to make the mini greenhouse will have a noticeable effect on its ability to grow plants.

For seed starting and protecting young growers, small plastic greenhouses are very effective.

You can use them both indoors and outdoors, and provided the structure is sturdy; there’s no reason why they couldn’t last for a few years.

Humidity and heat retention are also two great qualities of mini plastic greenhouses.

The small, compact size and the multiple layers of material mean that the sun’s heat is absorbed well and stays within the greenhouse for decent amounts of time.

It’s important to air out the greenhouse on a particularly hot day, though.

Related Questions

Do mini plastic greenhouses protect from frost?

Frost’s damage is a gardener’s nightmare. For late spring and summer growers, a cold night can do serious damage. Thankfully, a mini plastic greenhouse can provide adequate protection to plants in bitterly cold conditions.

If the small greenhouse has had a good amount of light during the day, it should retain some heat and circulate it during the night.

Obviously, extreme weather poses a challenge for any structure, but it should withstand a bit of frost and protect the plants inside.

What is the ideal temperature for a greenhouse at night?

This depends on the type of crop grown inside the greenhouse. Still, generally speaking, it is ideal for keeping the temperature at around 32 degrees Celsius (90 degrees Fahrenheit) in the daytime and 24 degrees Celsius (75 degrees Fahrenheit) at night.

Most plants and vegetables will flourish at these temperatures, but it’s worth researching the particular crop you are growing.

There’s a lot of variation depending on the origin of a plant, its biological makeup, and how it responds to the environment. 

What’s the difference between greenhouse plastic and regular plastic?

The main difference between plastic that has been specifically formulated for greenhouses and everyday plastic is that the former is more durable.

Due to the harsh weather conditions it is likely to face, agricultural plastic is more robust and.

There are many types of plastic, all with differing qualities. Greenhouse plastic is made to resist tearing, breaking, and being damaged by the sun or the weather. Sometimes, it is knitted and layered for added reinforcement.

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Tony O'Neill

I am Tony O'Neill, A full-time firefighter and long term gardener. I have spent most of my life gardening. From the age of 7 until the present day at 45. My goal is to use my love and knowledge of gardening to support you and to simplify the gardening process so you are more productive

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