Reuse Miracle Grow Potting Mix

[TheClaw]

Last year I spent several hundred dollars on Miracle Grow potting mix and am wondering if anyone has ever used the same potting mix in the same container more than one year?

If so what can I do to recondition it? I am considering adding green sand for starters. Any other suggestions?

Or should I just toss it all and start fresh?

I should add that they are regular containers ranging from 5 to 20 gallons, and are not SWC's.

Thanks!

[rnewste]

I think it would be very wasteful to toss the Potting Mix after only one Season of use. In my own containers (SWCs) I pull the root ball in the Fall along with all of the Potting Mix hanging on. This removes about one-third of the old mix. I then add new mix the following Spring and stir it all together to disperse the new, into the old.

I am using a Combo Mix of 3 parts Potting Mix, two parts bark groundcover (Fines), and one part Perlite. This keeps the Potting Mix from compacting, and permits some degree of aeration.



This may (or may not) be suitable for your Containers - - but in any event, don't toss out all of your mix every year.

Raybo

[geeboss]

I'm mixing in 1/5 Perilite, 1/5 new Miracale Potting mix along with 2 cups Dolimite Lime, 1/3 cup bone Meal mixed in the rest is the old potting mix. If you note Rabo's mix of Perilite.
Then put in your firtilizer strip and cover with black on top till mid June and switch to a white plastic ccover.

George

[Zana]

I'm pretty much in agreement with Ray and George. No need to toss it after one year. I add last year's to a the new year's mix. Add in more sieved compost, perlite, lime, meal, new potting mix and old potting mix.

[dustdevil]

If you reuse it, you run the risk of harmful pathogens such as a wilt killing your new plants. The soil in your containers should be treated like ground soil, no peppers or tomatoes for three years.

[Zana]

I don't reuse soil the following year that has any contaminated plants. That gets "stored" in a lidded rubbish bin/garbage can on wheels for at least a year before using again. But since I've rarely had any issues here in my backyard, I haven't had to do that often. However I had more problems last year with late blight in my surrogate garden, which happens to be about 5 miles from where I live. There isn't anybody else in my neighbourhood growing any veggies that I am aware of at this time. So I figure its not a major issue for me in the long run, and only keep that mix isolated for about a year.

[TheClaw]

Are there any methods to test for harmful pathogens? My plants gave out early last year and initially I attributed it to overcrowding and lack of good air circulation. Now I am starting to wonder if the soil is harboring anything that might harm the new plants. I appreciate your comments.

Maybe I should save it for sometime in the future, but not reuse it this year.

Originally Posted by dustdevil

If you reuse it, you run the risk of harmful pathogens such as a wilt killing your new plants. The soil in your containers should be treated like ground soil, no peppers or tomatoes for three years.

[geeboss]

I forgot to mention that I cover the container with clear plastic to heat up the mix over the winter and early spring.

George

[nctomatoman]

I toss all of my pots (and yes, there is alot of $$ in it) in a pile and use it for working in to our flower beds for potting up herbs, annuals or perennials. I bleach each pot and grow bag and use fresh potting mix and composted cow manure each year. Many of my plants invariably go down to Fusarium or Bacterial or Tomato Spotted Wilt. Those diseases wind up in the soil, and planting plants in them the following year are inviting disaster.

I think that is why there isn't a one size fits all answer - it depends...depends upon where you live, the winter temp, the condition of the plants in those pots the previous year, etc.

[mensplace]

I bleach all previously used pots and trays. I place any suspect soil in the microwave in a plastic bag with water and give it two cycles of ten minutes but give it time to cool and allow the hot water to spread throughout between cycles. Don't seal the bag totally or open it until thoroughly cool.

[nctomatoman]

mensplace, with the contents of 100 5 gallon grow bags, 20 10 gallon pots and 20 15 gallon pots, I would probably spend as much in electricity as buying the new stuff! (ha ha). Actually, using the used stuff on flowers, herbs and in the garden, cuts down on purchase of soil conditioners and mulch - so it really isn't all that bad.

[dustdevil]

Cooking soil can end up smelling like a manure pit in the house.