renewing container soil?

[venturabananas]

OK, this is clearly the question of a rookie:

When you grow tomatoes in containers, do you start with new potting soil each year or just "renew" last year's soil by adding fert, etc.?

For perennials in containers, obviously you are forced to continue using the same soil year after year, except when you pot up. But what about annuals and things that are treated like annuals, e.g., tomatoes?

[rnewste]

I use the "One-Third Rule" of pulling out the old root-ball without shaking it off, then replace that amount with new Mix, stirring it all in. You should be able to get 4 or 5 Seasons by using this approach.

Of course, new Lime and Fertilizer additives need to be replenished each Season.

Raybo

[venturabananas]

Thanks Raybo. I'd never heard of the "one-third rule" but it makes good sense. With the price of bagged potting mix, the prospect of replacing it all every year was slightly daunting!

[venturabananas]

PS -- My mom is moving to San Jose (from Los Altos). You must live pretty close to her new place.

[rnewste]

The "One-Third Rule" is my guideline to strike a balance of re-using as much as possible - but introducing some new blood into the equation. Works well for me, as this Combo Mix is essentially a soil-less mix to start with, it is pretty benign to reuse for 4 or 5 Seasons.

San Jose is now the 10'th largest City in the U.S. (over 1 million population). I am on the border of Los Gatos and Campbell about 10 miles from downtown San Jose.

Raybo

[Zana]

Like Raybo, I probably add 1/3 new material which includes compost, lime, fertiliser, peat to my mix. At the end of each season I dump most of the "soil mix" in my containers/pots into large rubbish/garbage bins on wheels, add in about 1/3 compost and then secure the lid and set it out of the way for the winter - sometimes stored outside, sometimes in a garage or shed. This winter I left mine outside. I generally prefer to leave them outside as the cold kills off allot of the bugs etc in the soil....the ones you don't want....at least usually...but not sure about this year as we didn't get that many days below -20 to ensure that happening.

When I was living at my Dad's, after soil had been used in the containers/pots for more than 5 years, I added it to the flower beds...or at least half and augmented that with new soil-less mix, compost, etc.

Its almost like having sourdough starter....I'm sure I still have some of the original soil-less mix combo I've concocted still in the current mix - somewhere.

Zana

[johno]

I run mine through the compost tumbler with a batch of compost.