Refreshing Container Soils Annually?

[Mary Ann]

I have lots of very large containers that are too big to move for winter, not only heavy but bulky. The majority do well, I thought it was the amount of soil surrounding them or other protection I provided. But some rotted after a couple years.

I was stumped until I read this article:
http://forums2.gardenweb.com/forums/loa ... 26870.html
It's a long read, but interesting.

It seems the peat in potting soils loses structure within 3 years causing the medium to lose drainage capability and aeration, leading to root rot.

The alternative is to re-pot these biggies every couple years with fresh medium. I didn't know that. Did you?

[kHT]

Yep

[Chris_W]

Hi Mary Ann,

I learned it the hard way too, but now I refresh my bigger containers with new soil each year. I may not replace all of it, but most of it.

One year I tried filling the bottom of the bigger containers with packing peanuts (not the kind that break down in water) and it helped to keep them lighter and helped the pots drain a lot better. The bad part came when I dumped out the container the next spring to change the soil Packing peanuts blew all over the yard. So if you try that trick, remember when you go to repot later...

[Mary Ann]

The solution to the loose packing peanuts is to enclose them in panty hose or nylon net bags. I've also used 2 liter soda bottles in the bottoms to take up some space.

I'll have to empty the bigger containers one shovelful at a time and I can't tip over the whiskey barrels.

[Tigger]

I had an interesting idea last year as an alternative to potshards or packing peanuts (or coarse stone) in the bottom of pots. For a drainage project I had bought some bags of rubber "playground mulch" to use instead of (heavy) gravel. Now I'm using the leftovers in the bottom of pots. It doesn't blow around like foam peanuts, it weighs less than half as much as gravel, and if you get it in green, it's easy to see to separate it out when/if you dump out the whole pot.

So far so good.

David

[thy]

Think it can be other things too

Firs one of my big pot have more or less the same potting soil after 10 years.. only some top soil is changed and 5 years ago I planted a hosta in it... and took out some of the soil.

Fact,, it is lifted from the surface
It have some grit in it
it have some of those ceramic like nuts used for insulation in the soil

Yes, the soil sink a bit every year...and till now I have just added some more potting soil...
Think the best you can do is giving it some air - in the soil and lifting it from the start.

Pia