Cold frames are used to grow plants in a protected environment. They have been around since the beginning of time. There were even times when they were considered scientific experiments! When it comes to growing plants indoors, there are two main types:
1) Cold Frames (or Greenhouses) – These are structures where plants are grown under controlled conditions, usually with artificial lighting and temperatures.
2) Grow Bases – These are large structures where plants are grown without any special environmental conditions.
The advantages of using a cold frame over a greenhouse include:
– You don’t need to worry about pests or diseases that may attack your plants during the winter months. Your plants will not get frostbite because they won’t be exposed to it. The temperature inside the cold frame is always constant and never changes.
– You can plant your plants later in the year, so they’ll mature faster. If you start them too early, they might not come up high enough to survive the winter.
– Because of their small size, you can fit many more plants into one space than if you grew them in a greenhouse. Also, you don’t need as much room for equipment like fans and lights.
The disadvantages of using a cold frame over a greenhouse include:
– They are not as sturdy or durable as greenhouses. You can’t grow crops as big inside a cold frame, or the sides will bend inwards and crush your plants. Also, it would be very difficult (if not impossible) to try to move a cold frame.
If you did, you’d probably crush all your plants when it fell apart.
– Because cold frames are not as strong, they will let in more outside elements. It’s very easy for the temperature to suddenly change inside one. Your plants could freeze if it gets too cold, or cook if it gets too hot.
Rain or snow can get inside your cold frame and damage your plants.
Greenhouses vs Cold Frames:
Greenhouses are more durable and stable than cold frames. This makes them better for growing bigger plants that need more room to grow. Greenhouses are often used to start vegetable and flower seeds early so that they can be transplanted into the garden early in the growing season.
Greenhouses have an additional layer of protection against extreme heat, cold and wind and this helps to create an ideal environment for your plants to grow in.
Greenhouses are usually made of plastic, metal or fibreglass and are often built on a frame to ensure strength and durability. Most have extra insulation materials added to help protect your plants from extreme temperatures. The roof is usually slanted and made of a special material that lets the sunlight in but spreads it out so it doesn’t get too hot inside.
The walls are also slanted and made of whatever material the greenhouse is constructed from. This design allows the sun to pass through and relieve some of the shadows that are cast within the greenhouse.
Whether you decide to build a cold frame or a greenhouse, you will need a good base on which to construct it. You can build this base either directly on the ground or if you live in a very frost-free area such as Florida, you can set it on posts that lift it off the ground. If you live somewhere with very hot summers such as Arizona, you should build it on posts that allow air to flow underneath to keep it from getting too hot.
Your base can be made of whatever material you choose, but it should be sturdy, level and large enough to allow you to build your frame on it. It should also be strong enough to support the weight of the structure you are putting on it. If you have large plants that need to be transplanted into your greenhouse or cold frame at some point, the base will have to be strong enough to support their weight as well.
You will also need to construct your frame. This can be made of wood, metal or plastic. If you are making a cold frame, the sides should be able to be opened so that you can get to your plants.
Whatever material you choose, your frame will need to be sturdy enough to support the weight of the walls you will place on it. The size of the frame will depend on the size of greenhouse or cold frame you want to build.
Your next decision is whether you want a cold frame or a greenhouse. A cold frame is basically a box with glass or plastic sides that can be opened up when you want to tend your plants. It sits right on the ground.
A greenhouse is usually set up on a base and stands above ground on posts, it also has glazing on all sides.
If you decide to build a cold frame, the next decision you will need to make is whether you want one that is rectangular or square. A square cold frame will be stronger than a rectangular one of the same size because there is less angle to contend with but it won’t hold as much as a rectangular one. The largest cold frame you can make using standard 8×4 foot timber is 48×48 inches.
If you decide to build a greenhouse, the next decision you will need to make is whether you want an arched roof or a flat roof. An arched roof will look nicer but a flat roof will be stronger and let in more light. You can also add vents to a flat roof to help control the temperature.
What you build your greenhouse or cold frame out of is also something you need to consider. It used to be that greenhouses were made of glass because this allowed the most light in for the plant life. They were, however, very expensive to construct and the plants still got too cold in most climates.
Fiberglass has come a long way over the years and is now an ideal material for constructing the roof of your greenhouse because it is lightweight, strong and cheap. It can also be made in a variety of colors which helps to control the amount of light let in. It is very easy to work with and comes with its own supports, these can be installed directly into the roof of your greenhouse.
If you are a little short on money or just want to try something different, you might want to consider using plastic as a roof. Used plastic bottles can provide a surprisingly effective covering and all you need to do is weave them in a tight enough pattern so that they won’t fall down.
Sources & references used in this article:
Four-season harvest: organic vegetables from your home garden all year long by E Coleman – 2012 – books.google.com
Low root reserve accumulation during drought may lead to winter mortality in poplar seedlings by DA Galvez, SM Landhäusser, MT Tyree – New Phytologist, 2013 – Wiley Online Library
Hobby greenhouses by JW Worley – 2009 – esploro.libs.uga.edu
Cold truths: how winter drives responses of terrestrial organisms to climate change by CM Williams, HAL Henry, BJ Sinclair – Biological Reviews, 2015 – Wiley Online Library
Taylor’s Weekend Gardening Guides to Cold Climate Gardening: How to Select and Grow the Best Vegetables and Ornamental Plants for the North by CC Starring – 1924 – University of Montana, Agricultural …
Antifreeze proteins modify the freezing process in planta by RA Briccetti – 2000 – books.google.com
Propagation environments [Chapter 4] by M Griffith, C Lumb, SB Wiseman, M Wisniewski… – Plant …, 2005 – Am Soc Plant Biol
The influence of cold in stimulating the growth of plants by DF Jacobs, TD Landis, T Luna – … manual for native plants: A guide for …, 2009 – fs.usda.gov