A hotbed is similar to a miniature greenhouse. It can be used to get an early start on tomatoes, peppers and melons. Cold frames can provide shelter for tender perennials; to "harden off" seedling plants; or to start pansies, cabbage, or lettuce. But there are several factors to consider.

Produced by the Department of Communications at Kansas State University. For more information, visit our website at: http://www.kansasgreenyards.org

Coldframes and Hotbeds

This is a combination of a hotbed and a cold frame. Think of these as miniature greenhouses. The hotbed does have heat within it. And in this case, it’s electric heat. The cold frame does not, and therefore, I always start my plants over in a hotbed. But when they’re ready to be hardened off, just before they’re transplanted, they get moved to the cold frame. That gets them toughened up enough so that when they go outside, they’re not going to undergo any shock due to the change in environment.

So, I don’t want it to get too cold in the hotbed, nor too hot in either one. I need to have a way of controlling that temperature. What a lot of people do now is use an automatic vent opener. As the temperature rises, the gas inside this cylinder heats up. And as it heats up, it pushes this rod further out. That’s actually what lifts that cover.

Early in the season, I’ll use just a watering can. You can water once, and It’s going to last maybe three or four days. Later in the season, I’ll use an automatic method, as you’ll notice here where we have those tubes. They have very small holes in them that allow them to drip water onto the material that you see here. This is called a capillary mat. It holds a lot of water, and it can then release it to the bottom of these containers. I like that later in the season because it eliminates any problems you may have with disease – that foliage never gets wet. It also allows me to totally automate this, so that if I need to water twice a day, I can do that automatically without having to be here.

This feature story prepared with Ward Upham, Kansas State University Research and Extension Research Assistant. For more information, visit your local county extension office or visit our website at KansasGreenYards.org.

Horticulture Newsletter

KSU Horticulture Newsletter

Get more information from our weekly newsletter.

Find Your Local Office

Have questions or need help?

Local Extension Office Map

Click the map to find your Local Extension Office.

YouTube Videos

YouTube Videos

Watch K-State Research and Extension Videos.

Kansas Healthy Yards Tagline