Friday, January 06, 2006

Keeping Warm

This post is not about chickens, at least not directly. It’s about ideas on keeping the cold frame, that I plan on building, warm. I’ve already written about the site of the cold frame and about ventilation and today I’ll write about some of the ways I hope to keep it warm.

The Sun – This is the most obvious. The sun will provide heat and light for the plants. On sunny warm days it may actually provide too much heat. The challenge will be retaining and storing the heat that the sun provides.

Heat Stores – One heat store will be the masonry wall of the house that the cold frame is build against. I don’t think this will be a very good heat store, but the other side of the wall is the cellar and due to my inefficient furnace the temperature of the cellar in winter is probably in the upper 60Fs so there should be some heat leakage from the cellar into the cold frame. The second heat store will be water. This will be in the form of the one-gallon plastic milk containers that I’ve been saving. They will be filled with water and kept in the cold frame. The idea is that the heat stored in the water while it’s sunny will leak back into the cold frame when it’s not sunny.

Insulation – The plastic, covering the top of the cold frame, will have two layers with an air space between. This double ‘glazing’ will allow less heat to escape than one single layer. I also plan on insulating around the bottom wood frame of the cold frame, but am not sure what material I will use for this yet. I may also create a blanket type cover to put over the cold frame at night.

Composting – Here’s where the chickens come in, or at least the chicken litter, which is a mixture of pine shavings and chicken manure. I plan on having a compost pile of chicken litter in the cold frame. Because a compost pile heats up, it should be able to add some heat into the cold frame.

Add Heat – The possibility of many days in a row with no sun has me convinced I will probably need to add some extra heat into the cold frame at some time. One possibility is cracking opening the cellar window that the cold frame is built against. This window is in a separate room of the cellar and I don’t think this would affect the house temperature upstairs in the living area, but that’s an unknown. Another possibility is electrical heat tape. I would really like to minimize this, but will consider it for backup.

The challenge for me will be to see just how early in the season I can set up and use my cold frame while adding little or no external heat except the sun. I’ll be busy for the next two week and won’t be able to build the cold frame for a while, but I hope to get it built quite a while before I actually put plants in it, so I can see how all these ideas are working out.

I would love to hear from other gardeners who have tried similar ideas.


  1. Anonymous10:21 PM

    I'm curious to see how your manure works for your cold frame. I am almost done with my insulated cold frame just west of you in Westborough, MA and an trying to save the heat during the day. I took my design idea from . I have not been satisfied with over night heat retention yet and I will try some of your ideas.

  2. As of 3/31/06 my cold frame is complete. I find compost inside the frame does heat up. My cold frame overnight lows are about 10 degrees warmer than the outdoor low at this point. I'm not sure how that compares to other cold frames, but it's working for cool crops now. I'm debating when to move the tomatoes in though. For updates on the cold frame go to the search box at the top of this blog and search for - cold frame and click 'search in ths blog'
    It's a work in process and I plan on posting new info

  3. Anonymous11:53 AM

    my poo is in also and during the day it was 20 to 30 degress hotter when i stuck a thermometer in... during the night i think it's keeping things a bi t warming... tonight it's gonna get get cold, so i'm going to take my currently germinating tomatoes inside. a few my heirloom tomatoes have sprouted.

  4. Have you looked at rainbarrels to capture water from your gutters? There is a company in massachusetts that has pick up days all across massachusetts. I've order 5 and will be getting them in Newton the end of April.