Whats a good base for a cold frame?

It depend what you want to use the frame for, Alif. Paving slabs are good if you want a hard base to stand pots on as the gaps between the slabs allow drainage.
If you want to grow cucumbers, for example, I would leave a soil base so that the roots of the plants can go down into it.
My frames are filled with either bulbs or primulas in pots. I have a weed protecting membrane at the bottom and then six inches of sand over this. The pots are plunged into the sand.

Thanks Bulbaholic. I want to get a head-start for seedlings in the spring, so lots of pots. I'll get busy.

the pioners of cold frames needed some were to transfer plants from hot houses to grow on and get them used to being outside, what they did was put the cold frames on piles of well strawed manure so that when they closed them at night they had the heat from the roting manure' it is still the best way,

Not if you are using them to grow alpine bulbs Cliffo which is what B & I do, all they need is protection from winter wet :-)

Well I never heard that on Gardners World. I've plenty of manure to rot but wont I spend the whole time pulling weeds out of the manure?

a pile of manure, as it rots gets hot in the center that deals with weeds,it also stops the cold coming as a shock because when it goes cold at night and there is frost about it keeps the plants worm rember what time of year the cold frame comes in to it's own, proberly gardners world find no need to go back with the modern ways like solur and electrick heating but if you go back in time to the grate gardners that did not have all this morden and expensive stuff you can save money and have grate results. Moon grower I don't know how to answer your point as I have not a clue about growing alpine plants, shorly the name it's self states that it dose not need protection but there what would I know.

I agree with Cliffo about the 'old' ways of using a compost frame. To do this the frame would have to be raised a couple of feet off the ground on a base of concrete blocks or bricks and the base filled with hot, fresh manure. A sheet of corrugated iron was then laid across the base as a floor for the frame. I have not used this metheod but have seen it described in the older gardening books.

Alpine bulbs often need protecting from winter wet Cliffo as they are under a natural blanket of snow in the mountains. Equally many of the bulbs need a period of dry dormancy in summer to mimic the mountain conditions. Thankfully B. keeps track of which ones need dry winters and dry summers and I just get on and enjoy looking at them.

thank you Moon grower, that was real good info and well put, I have learned today, and I love learning,

spot on Bulbaholic and it is nice on a cold and froste morning to sea the steem rise as you lift the lid of the frame , that's gardning

wow, didn't expect more than one, one-word answer. Thanks guys. I have such a long way to go, but as they say, even the longest journey begins with a single step.happy gardening

you know what robi said keep right on to the end of the road, I bet that song will be runing through head for the rest of the day now,

Thanks Cliffo I love learning too... for me it is the main reason to be on GoY to discover things I didn't know in the gardening world.

the base of mine is wood.. with plastic sheeting on it and covered with gravel... mines is only for keeping stuff in pots and trays which sit on plastic trays to hold any water that comes out of the pots etc.
mainly for overwintering young plants and seedlings.

I've never heard about the strawed fresh manure method for heating a cold frame before. What a brilliant idea. I'll keep it in mind.
Thanks Cliffo.
ps. I don't have a cold frame...yet!

I know this is an old thread, but no-one seems to have pointed out that what Cliffo is talking about is a hot bed: a popular way of growing Pineapples and other Tropical/subtropical plants on the grand estates.
A cold frame on contrast is called a cold frame because it was not heated in this way.