Generally, you can use a cold frame or greenhouse for all year round gardening. Also, both of the structures extend the gardening season. Whether you need a cold frame or greenhouse depends on your growing goals, how much space in the garden you have and what is your budget.
The main difference between a cold frame and a greenhouse is that a cold frame is a smaller and shorter rigid structure that you can use to harden off plants. A greenhouse can be any size and you can use it not only to harden off plants but to grow off-season crops.
So, do you need a cold frame or greenhouse?
If you are on a low budget and lack space in the garden, use a cold frame to harden off seedlings, shield crops from rain and to overwinter plants. However, if you want to grow exotic plants and a variety of flowers, fruits and vegetables, you need a greenhouse.
In this blog post we will talk about the differences between cold frames and greenhouses. It will help you to decide which option is best for your needs. I put together a short comparison between two and then we will talk about main features in more details. Let’s dive in!
Cold Frame Or Greenhouse?
| Feature | Cold Frame | Greenhouse |
|---|---|---|
| Size | 8’ wide x 4’ deep x 1’ tall | 6′ x 8′ x 7′ with with 48 sq. feet of growing space |
| Shapes | Wide range of shapes and styles | Wide range of shapes and styles |
| Temperature | 5-10 degrees warmer than the outside temperature | 20-30 degrees warmer than the outside temperature |
| Maintenance | Low maintenance | Low to medium maintenance |
| Control | Can’t control air and temperature | Can control air, temperature and humidity |
| Cost | $100-$600 depending on size and materials | From 665$ to $16,500 depending on size, materials and site preparation |
Cold Frame Vs Greenhouse
1. Size
Cold frames come in a variety of shapes, styles and sizes but on average they are around 20 -27 inches high. It can be a perfect option for gardeners with the lack of space in the garden. It is ideal for small spaces and you can easily put it away when not in use.
In contrast, a standard size for a hobby greenhouse is 6′ x 8′ x 7′ with with 48 sq. feet of growing space. You can choose a structure which is 12 to 20 foot wide for a large collection of plants. The options are not limited and you can find structures of different sizes according to your needs.
2. Shape
The shape of the cold frame or greenhouse determines how many plants you can grow. Let’s start with the cold frame. The traditional cold frame shape is a box with a clear hinged roof. It is hinged for an easy access, so you can reach into all corners of the structure to work with your plants.
You will notice that its style is sloped, so that water can runoff when its raining. Hinged cold frame lets the air inside the structure whilst sheltering them from winds. Most cold frames are low to the ground so you can place it over the existing raised bed. Also, that makes it easier for you to work at.
Greenhouse structures come in a variety of shapes and designs. Go for a tall greenhouse where you can move freely. Also, vertical gardening can maximize the growing space. Moreover, you can save on ventilation and heating costs.
I put together an ultimate guide on types of greenhouse structures. I am a fan of a freestanding greenhouse but many growers swear by lean-to structures. Nevertheless, you should have enough space in your backyard to make the most of the greenhouse.
3. Temperature
Cold frame uses solar energy and insulation to increase air and soil temperature. Mainly because the clear roof lets in the sunlight and the structure itself blocks off the wind. That way the temperature inside the cold frame is 5-10 degrees warmer than the outside temperature.
It is enough to create a micro-climate in your backyard to harden off seedlings, to preserve cold loving vegetables or to give extra heat for tender summer plants. You can’t heat a cold frame, maybe just insulate it with bubble wrap for extra protection.
So, if you are planning to grow tender and exotic plants or want to pick up fresh produce all year round, cold frame is not enough. You will need to heat the structure. If set up and positioned efficiently, a greenhouse temperature will be 20-30 degrees warmer than the outside temperature.
There are 11 ways to heat a greenhouse without splashing cash. I personally like to use a heater. A simple electric fan heater will be enough for a hobby greenhouse. You can find out what is the cheapest greenhouse heater to run and what size heater do you need in this post.
Heating a greenhouse structure lets you grow exotic plants like coffee. Also, you can heat a greenhouse without electricity by following these 10 easy steps. However, a lot of plants can grow in a cold greenhouse. For example, you can easily grow cacti in unheated structure.
4. Maintenance
Cold frame is way easier to take care of in comparison to greenhouse. Mainly due to the size of the structure. Both are exposed to nature elements, so it is very important what are they made of. Most of the cold frames are made of wood and glass or aluminum and polycarbonate.
Aluminum frame is lightweight and stable withstanding rain, hail, and snow. It is super easy to maintain and clean a cold frame. All you need to do is to pick up yellow leaves and add compost to the soil. Wash the roof and the sides when dirty. I would recommend checking the structure daily.
In comparison to a cold frame, a greenhouse can be low, medium and high in maintenance. A minimum requirement is to deep clean the whole structure twice a year. Weekly spot cleaning is a must. Also, you need to make sure that plastic or glass cover is always clear so it doesn’t affect light transmission.
If you choose the appropriate materials, you can cut down on the maintenance. For example, aluminum frame is easy to take care of in comparison to wooden frame. Another important consideration is drainage. If you have it sorted, you will never worry about dirty pathways and standing water.
The last but not least, building greenhouse foundation significantly reduces maintenance costs. The best option for a hobby gardener is building a perimeter base, laying in with plastic ground cover and installing gravel flooring. It helps to keep the structure clean and tidy at all times.
5. Control
Although you can use cold frame to harden off seedlings and protect plants from rain and snow, you can’t control the environment inside. If you want to control temperature, air circulation, humidity and light, you need to buy a greenhouse.
The lack of control results in the restriction of use. However, you can still use it to overwinter plants just make sure to get a cold frame with a thicker polycarbonate. You can overwinter plants that survive during cold winter months and revive in spring. Cold frame is not suitable for overwintering tender plants.
On the other hand, you can create the desired environment in the greenhouse. It includes temperature, lighting, ventilation, humidity and watering. These factors can also be controlled automatically. If that is something you are after, I would recommend installing greenhouse sensors.
6. Cost
The last but not least, when deciding whether you need a cold frame or greenhouse, you need to think about initial costs and how much you will spend in the long run. The cost of a cold frame starts from 100$ up to $600 depending on size and materials.
Invest in good materials and well-made cold frame which will last for years. If your main goal is to germinate seeds, propagate cuttings and harden off seedlings, buy a cold frame. You already know that maintenance costs are zero, so make an initial invest and save money on fresh produce.
On the other hand, building or buying a greenhouse can cost as little as 665$ and up to $7,375 and $28,367 according to Home Advisor. On this website you can find an estimate cost of your project, just enter your ZIP Code. Also, check you this post where we are breaking down the costs of building a greenhouse.
Also, you need to keep in mind ventilation and heating costs. Most of the time you can rely on natural ventilation or just install automatic vent openers which open automatically when temperature rises. Wooden frame greenhouses will require high maintenance as well as glass glazing. Keep these aspects in mind when planning your gardening budget.
Conclusion
To sum up, a cold frame is suitable for anyone with a limited space in the garden. With a cold frame you can harden off seedlings that you started indoors. Start plants earlier in the season and preserve cold weather crops for the harvest throughout the colder months.
However, if you have space in your backyard and are willing to grow a variety of plants all year round, then it makes sense to invest in a greenhouse. I have put together a checklist for anyone who is questioning whether you actually need a greenhouse, click here to check it out.
What have you decided to use in your backyard – a cold frame or greenhouse? Let me know in the comments section down below!
Happy Growing 🙂