I use a mix of regular potting soil then I add vermiculite, peat moss, compost and a little perlite. I learned the recipe from a worker at a nursery. It helps the soil drain and retain moisture.

With roses I add a banana peel.

Edna

I have four half cask planters. My mix is similar to Edna's. I used a mix of soils, peat and compost. I put some stones in the bottom layer to assist with drainage. I also put three paver bricks under each cask. I was worried that the wood would rot on the bottom, so I thought elevating the wooden casks a bit would help prevent that (air circulation). I don't know whether that was a good idea, but I figured it couldn't hurt.

I recently decided to move one of them. I had to empty half of the soil out, to lighten the weight of it. Then I turned the half barrel on its side and rolled it to where I wanted it.

Lorna

Lorna made a good point, I also have bricks under my wine barrels. Drill a few drainage holes in the bootom if it's a wood barrel.

We want to picture too :-)

Edna

I use triple mix and add compost every spring.

Edna, I also give all my roses a good feeding of banana peel in the spring.

Sierra

Everyone has their own preferences but for a permanent or long term container planting, using a homemade or commercially prepared container potting mix is preferred over adding any type of garden soil. I would also be cautious about adding too much in the way of compost. Because of the unique requirements of container culture, a very fast draining soil is necessary. Too much reliance on organics or compost that will continue to decompose will reduce pore space and increase compaction, resulting in poor drainage and lack of oxygen. This is why the heavy garden soil is not recommended and it is substituted with peat, coir or bark fines which decompose very slowly. And the addition of non-organics like perlite, pumice or turface (high fired clay particles) will maintain porosity and good drainage. The Container Gardening forum discusses these issues at length and there are all sorts of excellent potting soil recipes to be found there.

Adding gravel, rocks, pot shards, etc. at the bottom does NOT improve drainage - this is a long held container gardening myth. Providing layers that are of different structure/texture will actually impede drainage and result in the bottom of the true soil level to become overly saturated, which can lead to root rots and fungal problems. It all involves a rather techincal bunch of stuff including soil intereface issues and perched water tables but it is worth investigating if you are intending long term container plantings. Providing adequate drainage holes IS necessary and raising the base of the container off the ground as mentioned will also improve drainage, not to mention extend the life of any wooden container.

Because container plantings need such frequent irrigation (leading to problems outlined above if drainage is not adequate), nutrients are rapidly leached out and need to be replaced on a routine basis. Regular fertilizing during the growing season with the product of your choice is recommended.

Here is a link that might be useful: water movement in container soils

Thanks for the replies.

Edna, it sounds like your mix of vermiculite, peat moss, compost and a little perlite to the potting soil is basically just like adding some Triple Mix. Triple Mix is Peat Moss, Compost and . . . I forget the third ingredient. Sounds about the same though.

What is the banana peel for? potassium?

I didn't think about drilling holes in the bottom of the barrel. That is a good idea. I was intending to raise it off the ground by a little bit. I also didn't know that stones in the bottom DID NOT help drainage. I always thought they did, but never really looked into it.

The only problem I had with just potting soil was the nutrients. Putting in potting soil and non-organics sounds better for drainage, but then it sounds as though you'll have to fertilize all the time . . . whereas mixing some triple mix (for example) would have some compost in it so that, presumably, you wouldn't have to fertilize nearly as often. Does it make that big of a difference in soil compaction?

I'm planning to grow a rose in one barrel, and a mix of flowers in the other . . . I'll post pictures later in the summer if I can get a digital camera by then :)
*fingers crossed*

I grew angel face rose in a barrell for about 6 years. If you will need to move the barrell from time to time, fill the bottom 1/3 with styro "peanuts.

Even using organics as a primary potting soil component you will need to fertilize regularly. The very frequent watering that container planting requires, especially during the summer months, leaches out nutrients regardless of source. These need to be replaced for proper plant care. In many cases, container gardeners fertilize weekly with a dilute liquid fertilizer (weekly - weakly). Otherwise a slow release type of fertilizer like Osmocote will continue to provide nutrients over an extended period.

You can get away with using a high organic mix for only seasonal or short term plantings but the longer the container is planted, the greater the risk of compaction leading to drainage and root rot problems. For any sort of permanent or semi-permanent plantings - like roses - I'd avoid going very heavy into the organic/compost ingredients.