Cold Frame vs. Greenhouse: Which One Is Right for You?
This post is all about DIY cold frame vs. greenhouse.
If you’re looking to extend your growing season and protect plants from unpredictable weather, a cold frame or mini greenhouse could be the perfect solution. But which one is right for you? Both options help shield plants from frost and provide a more controlled environment, yet they serve different purposes. In this guide, we’ll compare cold frames and mini greenhouses, outlining their pros, cons, and best uses to help you make the best decision for your garden.
This post is all about DIY cold frame vs. greenhouse.
Table of Contents
What Is a Cold Frame?
A cold frame is a low, enclosed garden structure designed to trap heat and shield plants from harsh weather. It typically consists of a transparent top (glass or plastic) and a wooden or brick base. Cold frames act like a mini greenhouse by retaining warmth from the sun, but they don’t have internal heating. It creates its own little atmosphere underneath the transparent top, and therefore creates moisture. This allows for the plants to be pretty low maintenance and I’ve found that there’s really no need to water the plants. The only time you might have to water them is if you have seedlings.
Best Uses for a Cold Frame
There are several uses for a cold frame. They can be used to:
- Extend the growing season in early spring and late fall. This is particularly a good idea if you’re growing cool weather crops. It might not be a viable option for warmer to hotter weather crops, depending on the temperatures in the evening and overnight.
- Hardening off seedlings before transplanting. Hardening off plants is a super important stage to transition them out into the world from indoors.
- Growing hardy crops like lettuce, spinach, and carrots in winter. It’s a great option for cooler weather crops and ones who can handle low temps.
Pros & Cons of Cold Frames
To know where this option is good for you, lets take a look at the pros and cons of cold frames.
✔ Affordable & DIY-friendly—Easy to build with repurposed materials. You can do this yourself right in your own backyard!
✔ Energy-efficient—Uses sunlight, no electricity required. This is definitely a pro because, depending on the size of the cold frame, it can get costly. There’s no insulation to trap the warm air with, so the heat would just keep pumping to maintain the temperature.
✔ Low maintenance—Requires little effort to operate. You may not have to do anything with the plants in your cold frame. You may even find them easier to maintain than your warm weather garden. Plus there really aren’t many pests during the colder months.
✖ Limited space—Best for small plants and seedlings. Cold frames typically don’t have a lot of space.
✖ Temperature control can be tricky—Can overheat in direct sun. As the weather warms up, you’ll have to prop the cold frame open for ventilation. It may get too hot in there for the plants.
What Is a Mini Greenhouse?
A mini greenhouse is a smaller version of a full-sized greenhouse, often made of plastic or polycarbonate panels over a lightweight frame. Unlike cold frames, many mini greenhouses have shelves and zippered covers for ventilation.
Best Uses for a Mini Greenhouse
- Starting seeds early before spring.
- Overwintering tender plants that need protection.
- Providing a controlled environment for herbs, flowers, and vegetables.
In the spring time, I usually use a little greenhouse and a hoop tunnel in my raised bed. Some of my seeds are started in the greenhouse, while the others are started indoors. Once my seeds have become seedlings and the weather has warmed up, I transfer them outside into the greenhouse.
Pros & Cons of Mini Greenhouses
✔ More growing space—Can accommodate potted plants and multiple layers. Depending on the size, it may come with shelves to put your plants on.
✔ Better temperature regulation—Some models include vents and covers. This is still a structure that isn’t heated. However, there are very genius ways to make them heated, such as having a large drum of water that’s heated up by the sun. The drum then lets off heat at night. However, the drum would take up a lot of space.
✔ Portable & versatile—Easy to move and set up in different locations. Ours is “built” every year and then taken down. Since it’s so lightweight, I don’t trust it out in bad weather. It has to be weighed down. Once I’m done with it, it either goes in our attic or our shed.
✖ Can be more expensive than a DIY cold frame. You can either build one yourself or purchase one. Since this is a bigger structure, it can be more expensive.
✖ Less durable in extreme weather—May need extra reinforcement. As I said, I don’t trust my greenhouse in bad weather. It’s weighed down with stones, but I’d also be worried it would rip in high winds.
Key Differences: Cold Frame vs. Mini Greenhouse
Lets now look at the cold frame and greenhouse side-by-side to compare. I’ve included comparisons between sizes, cost, portability, and what they’re best used for.
| Feature | Cold Frame | Mini Greenhouse |
|---|---|---|
| Size | Small, low to the ground | Taller, can hold shelves |
| Cost | Cheaper, DIY-friendly | More expensive, but versatile |
| Portability | Stationary | Often portable and lightweight |
| Best for | Hardy crops, seedlings | A wider variety of plants |
Which One Is Right for You?
Now that we’ve done a side-by-side comparison, which one is right for you Choose a cold frame if you want a low-cost way to protect plants from frost; you mainly grow leafy greens, herbs, or root vegetables, or you prefer a simple, low-maintenance solution. It’s a fixed structure, so you won’t have to worry about putting it up and taking it down.
Choose a mini greenhouse if you want more control over temperature and humidity, you grow multiple types of plants, including flowers and potted herbs; or you need more space. This structure may or may not be permanent. If it’s not, you may have to take it down and put it up.
How to Build a DIY Cold Frame (Step-by-Step Guide)
How do you make your own cold frame? It’s pretty simple and you might have some of these at home already. Here’s what you need and what you need to do.
Materials Needed
- Wooden boards or bricks for the base
- A transparent top (glass, acrylic, or polycarbonate)
- Hinges (if you want an openable lid)
- A thermometer to monitor temperature
Step-by-Step Instructions
- Choose a sunny location in your garden.
- Build a rectangular base using bricks or wooden planks.
- Attach the transparent lid at an angle (to capture more sunlight).
- Add ventilation holes or prop the lid open on warm days.
- Monitor the temperature and adjust airflow accordingly.
How to Set Up a Mini Greenhouse (Beginner Tips)
Choosing the Right Type
- Plastic pop-up models—Budget-friendly and easy to store.
- Shelving units with covers—Great for small spaces.
- Polycarbonate panel greenhouses—More durable, better insulation.
Placement & Setup Tips
- Position it in a sunny spot with at least 6 hours of light per day.
- Ensure good ventilation to prevent mold and overheating.
- Use shelves wisely—Keep fragile plants on top, hardier ones on the bottom.
Conclusion: Making the Right Choice for Your Garden
Both cold frames and mini greenhouses offer unique benefits. If you’re looking for a simple, cost-effective way to extend your growing season, a cold frame is an excellent choice. However, if you need more flexibility and space, a mini greenhouse is a better investment. No matter which one you choose, both will help you grow healthier plants and enjoy gardening year-round!
FAQs
1. Can a cold frame work as a greenhouse?
Yes, but with limitations. A cold frame relies solely on sunlight and is best for hardy crops, whereas a mini greenhouse offers better temperature control.
2. What are the best crops for a cold frame?
Lettuce, spinach, kale, carrots, radishes, and hardy herbs like parsley and chives.
3. How do I keep my cold frame warm in winter?
Use straw or mulch for insulation, add black water jugs to absorb heat, and ensure proper positioning for maximum sunlight.
4. Can you start seeds in a mini greenhouse?
Yes! Mini greenhouses provide a warmer, controlled environment, making them ideal for seed starting in late winter or early spring.
This post was all about cold frame vs greenhouse.
