Cold frames and raised beds are interchangable!
Make a cold frame and convert it in june to a raised bed or simply thin the cold frame and your raised bed is already to go! Add some manure or compost material a foot down below the surface of your cold frame with some good seedless potting soil on top and have a warmer cold frame. You must cover it good to hold the heat and maybe even prop it open on warm sunny days! Raised beds and cold frames are always interchangable!
What were the results when you did this (this suggestion is based on personal experience, isn't it)? How big was the raised bed/cold frame--width, height, length?Bobberman wrote:Make a cold frame and convert it in june to a raised bed or simply thin the cold frame and your raised bed is already to go! Add some manure or compost material a foot down below the surface of your cold frame with some good seedless potting soil on top and have a warmer cold frame. You must cover it good to hold the heat and maybe even prop it open on warm sunny days! Raised beds and cold frames are always interchangable!
It seems to me, based on my own experience and reading that of others, that raised beds do best when they're deeper than cold frames are recommended to be. Cold frames want to let in as much sun as possible, while raised beds want to allow for as much root development as possible.
These two needs (maximum sun, maximum root development) can easily come into conflict.
None of the instructions I've read for making cold frames recommend 12" sides all the way around the frame. Some recommend a 12" tall back with sides which slope towards the front, which may be as short as 4", but which is more often 8" tall (e.g., Eliot Coleman's design in Four Season Harvest). This would render the suggestion of
impossible.Add some manure or compost material a foot down below the surface of your cold frame with some good seedless potting soil on top
I have five raised beds this year. One of them is 10" deep all the way around; the other four are 12" deep. They're filled with soil/planting mix to within 1" of the top. There is no way I could add cold frame "lights" (protective glass/plexiglass) to them without some major rebuilding.
I thus fail to understand how "Cold frames and raised beds are interchangeable." Please provide your experience and/or more specifics.
Cynthia H.
Sunset Zone 17, USDA Zone 9
Cynhia, here's an idea I just had. What if you made a wooden frame that was the same dimensions as your raised bed? You could then set it on top of the bed (like a vertical extension) and then put the glass on top of that.
You could even have the sloping sides, etc, since this is only the top-part of the extension. The bottom part would still be level and would sit right on top of your existing raised bed "walls." A few modifications may have to be made if the walls are not wide enough, but it should work.
You could even have the sloping sides, etc, since this is only the top-part of the extension. The bottom part would still be level and would sit right on top of your existing raised bed "walls." A few modifications may have to be made if the walls are not wide enough, but it should work.
I have done this for years with raised beds! I myself see no difference since my cold frames are made with 8 inch 2 by 8 lumber. I dig down below the boards when I add manure or leaves for compost heat! If the raised bed is filled to the top the sides will not shade it! The only difference in the cold frame s it has a cover on it!
+++Making a raised bed with compost material a foot below the surface I have done many times even using a finished lettuce bed for compost material in july! Cold spring raised beds grow better with the deep warmth of a manure or compost base burried deep within the bed! The nitrogen of the manure is absorbed by the brown material added to the mix and will not make the plants surge as does too much nitrogen in the soil! Its more work to dig the top layer then replace it but it is better in the long run.
+++ My dads lettuce beds that had chicken manure burried deep below the bed was never bitter like grass that grows near a barn exposed to to much nitrogen from the excess manure! Cows will not eat that grass because of the bitterness.
+++Making a raised bed with compost material a foot below the surface I have done many times even using a finished lettuce bed for compost material in july! Cold spring raised beds grow better with the deep warmth of a manure or compost base burried deep within the bed! The nitrogen of the manure is absorbed by the brown material added to the mix and will not make the plants surge as does too much nitrogen in the soil! Its more work to dig the top layer then replace it but it is better in the long run.
+++ My dads lettuce beds that had chicken manure burried deep below the bed was never bitter like grass that grows near a barn exposed to to much nitrogen from the excess manure! Cows will not eat that grass because of the bitterness.
You have me confused Bob. If you have your raised beds filled to the top, and then you add a cover to make it a cold frame, where's the room for the plants you are starting? I'd think you'd want at least a good 6" between whatever surface the seedlings will be sitting on and the under side of the lid.
Unless you're just talking about creating a greenhouse over your raised beds to start seeds that you won't move.
When I think cold frame, I think of a short wooden box outside with a glass lid to get plants started, but plants that will be in pots or cell packs and moved out to their permanent spots later.
If you're not going to move the plants from the raised bed/cold frame, you may as well just put pvc semi-circles from side to side on the sides of the raised beds permanently and then throw plastic over it when you need to. I think it'd be easier than removing all of that glass. Just a thought.
Unless you're just talking about creating a greenhouse over your raised beds to start seeds that you won't move.
When I think cold frame, I think of a short wooden box outside with a glass lid to get plants started, but plants that will be in pots or cell packs and moved out to their permanent spots later.
If you're not going to move the plants from the raised bed/cold frame, you may as well just put pvc semi-circles from side to side on the sides of the raised beds permanently and then throw plastic over it when you need to. I think it'd be easier than removing all of that glass. Just a thought.
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DoubleDogFarm
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The plastic cover on top of the raised or cold frame can be raised as the plants emerge easily by a border of brick or 2 by 4s under the cover. As the season gets close to spring the cover is raised so it has a 6 inch space under it so it does no get too hot in the bed! I even take the cover off on warm days in april! I really think this .8 mill plastic cover is going to work excellent instead of the 4 mill and will let more light into the cold frame!
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I am not trying to confuse anyone its just the way I have been doing cold frames for years! I also use a angled cold frame with the lowest point facing the noon sun and it works great also but is a little harder to make so I stick with the level ones! The thing I liked about the angled ones was putting water bottles on the back wall of the cold frame since it was higher than the front for heat storage!
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I am not trying to confuse anyone its just the way I have been doing cold frames for years! I also use a angled cold frame with the lowest point facing the noon sun and it works great also but is a little harder to make so I stick with the level ones! The thing I liked about the angled ones was putting water bottles on the back wall of the cold frame since it was higher than the front for heat storage!
Last edited by Bobberman on Wed Mar 02, 2011 4:30 pm, edited 1 time in total.
Eric, it looks like you are using rubber tubing over re-bar instead of PVC pipes. That's a good idea.
Does that mesh netting come off easily to get to the plants?
Bobber, I see what you are saying. You are just building a cold frame.....and setting on top of your raised beds instead of on the ground.
Good idea.
Does that mesh netting come off easily to get to the plants?
Bobber, I see what you are saying. You are just building a cold frame.....and setting on top of your raised beds instead of on the ground.
Good idea.
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DoubleDogFarm
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Jeff,
Thank you. Here is an old post with more pictures.
https://www.helpfulgardener.com/forum/viewtopic.php?p=126170&highlight=low+tunnel#126170
Garden5,
We don't remove the mess, instead we just roll the whole frame over. They are held up by the adjacent berm.
Also, Not rubber covered rebar, but black waterline. If I had a better rebar bender, I may try that. 
Bobber, I also like how you raise it as the plants grow taller.
Eric
Thank you. Here is an old post with more pictures.
https://www.helpfulgardener.com/forum/viewtopic.php?p=126170&highlight=low+tunnel#126170
Garden5,
We don't remove the mess, instead we just roll the whole frame over. They are held up by the adjacent berm.
Also, Not rubber covered rebar, but black waterline. If I had a better rebar bender, I may try that. Bobber, I also like how you raise it as the plants grow taller.
Eric
The hoop house is a combination of a raised bed ,a cold frame and a greenhuse all combined. Think about it. The name of the game is extending the season in any way possible. Enjoyed your Nice pictures. Wish I could do pictures but I use a msntv web tv and canot do pictures yet but will try in the future.
I like the hoop house. I may make one using the A frame as the A frame house with 2 by 8s and a board at the bottom. It looks like it would be a easy build and last. Just roll it on its side like Double Dog does when you want to remove it. It would be like a 8 foot long dog house with the center 6 foot high and 8 feet wide done with covered with plastic and very light. Its like a greenhouse that is planted on the ground or on a slightly raised bed. Very cheap to build with $2 - 2 by 4 by 8s. I would have to say 10 boards and a $7 -10 by 20 - 4 mill plastic one piece. Plus a small piece for the ends. $30 to $35 to build one. You can plant the whole bed then roll it over on the bed and fasten to the ground. Two years with one plastic sheet. I may put two on the farm I am planting this year and try them in about 2 weeks since I plan o selling some produce this year at the flea markets. That would be excellent for starting cabbage and broccoli plants.