It can be some what costly to replace your soil every year. But if you make your own like I do, its much cheaper. So to answer your question, yes I like to replace my potting mix every year. I would say 40 sounds too cold, I would wait for the weather to warm up. But if you have sowed them already they will probably and eventually come up when the weather warms up a bit. Good luck.

Damon

When gardening on a retirement income, it is necessary to save where ever possible. These are almost entirely containers with soil not more than a year old. My potting soil is a commercial nursery mix, bark based with no peat. All recovered potting soil is combined and refreshed with the addition of 30% fir bark,(available free)a teaspoon of 18-6-12 time release fertilizer per gallon, and a tablespoon of dolomite lime, per gallon. I only use it for containers of one gallon or larger. New nursery mix is used for 4 inch and smaller containers. For those containers destined for several years with the same soil, I only use one of Al's(taplas)mixes. Al

I have certainly learned my lessons about plants in containers.

Now, if I was to have a very heavy soil or peaty mix, I would definately change out the mix every year to avoid compaction and suffocation of roots.

But now since I use very lttle peat, I will only change out my plants if the roots get cramped for space and when it starts to affect the vitality of my plants...

Only on an as needed basis since my soils do not collaspe like the bagged ones I use to use.

How about that! I agree with everybody. ;o)

I replace each time I repot or at the end of the growing season.

Al

Cue-Clapping sound............

Hi here is what I do I have 25 15inch pots I empty them all in the fall in the garden and make on big mountain then in spring I empty a 2 bags of topsoil and some peat moss and some vermiulite and mix it all then i refull all my pots and then wait about 2 weeks and plant my anuals in there and they do very well
Anna

I've tried several mixes for my SWCs. One mix I'm still using 4 years later is 3:2:1 Turface:bark:peat. (this mix only worked for me in a shallow container like the store bought ones, didn't work in 5 gallon container).

Other mixes with more peat were too waterlogged even after one year.

Also about saving money, I've been able to reclaim turface by placing old mix in a wheelbarrow running water through it while mixing it up. The peat & bark will float out and turface (or pumice) will remain.