The DE we discuss here for soil applications is calcined (fired at high temps) and fused together by the heat, so it's in the form of something like a soft pebble or nugget.

I don't reuse my soils, but if I did, I think I'd still start with a large fraction (>80%) of bark and some perlite, and use the old soil to adjust the water retention I want/need. Altogether, I doubt it would make up more than 10% of the fresh batch.

If you live somewhere there's a source of pine bark fines that can be used as mulch or soil conditioner, you should be able to make your soils for less than half of what a commercially prepared soil might cost. Let me know if you want more info.

Al

Hi Al!
I've seen you in quite a few threads and you really know your stuff so thanks for responding!!
I can get 4qts of pine fines at Home Depot @ $10 a bag, which may not be economical if it's to make up 80% of my mix. They also have perlite- but it's by Miracle Gro, which I know to be iffy; does the brand matter? They also have some by Thermorock but that bag is much bigger (20qts) than what I can easily store.
Home Depot and Walmart are, unfortunately, the two places where I have gotten most of my gardening supplies. Lowe's never has anything. There are two other local places w/o detailed websites so I'll call to see what they have.

In the meantime, I have to find somewhere to dump my used soil which I was hoping to avoid. However, I will definitely give this a shot when I start getting stuff together for spring.
Thank you!

Where do you live? Usually, you can get 2 cu ft of pine bark, where it's available, for under $5. What you want should look like
{{gwi:20507}}

and the finished soil after adding a little perlite and peat or your old soil, would look like
{{gwi:20508}}

The older a soil is, the finer are the particles it's made of and the faster it breaks down ........ and it follows, the more water it retains. An overwhelming % of the problems people come to the forum seeking help for are related to excess water retention. It's easy to shift the blame to 'over-watering', but if you try to water in small sips to prevent the soil from staying soggy for extended periods, that opens up another whole topic related to not being able to flush the soil of accumulating salts at regular intervals.

Al

Hi
I use a brand by Timberline . Under 3 bucks for 2CF!!
I get mine from Walmart but many of them don't carry it
So check out your local site on the web . They make 3 sizes the smallest in a purple bag All the bags say mulch on the label so check carefully The backs are transparent so you can see inside I've also been using the "top soil " also Under 1.25 very consistant for such a cheap product was impressed with the quality gary

Al, I'm in the Parkville area of Baltimore County in MD.
I can go look at Valley View Farms in Timonium or Watsons in Lutherville but I don't head that way often and it would be solely to see what they actually have.
Gary, Walmart has 2cf of pine bark mulch; how is that different from pine fines? (Says it's available only in store but of course none of my local stores carry it....) And the only prices shown are ridiculous. Depot had both mulch and fines and pine bark nuggets, as well. Their pine bark mulch is, as you said Al, 2cf for about $3.

I think if I can nail down what is what- bark mulch or pine fines- I'll be off to a good start.

Some parts of the country end of having more diseases in their plants than others. High humidity (as example) is a killer for tomato plants quite often. Rainy periods wreak havoc. Where I live it is fairly easy to re-use potting mixes, as long as you avoid diseased medium. I do add some fresh medium to the old. Just pay attention...

If you use part of the soil again, I would make sure you switch it up. If you grow melons and peppers again, put the pepper in the soil the melon was in, and the melon in the soil the pepper was in.
All the other advice given here is really good. I would follow it. I grew 8 different melons this year and about 21 peppers. Way too many! Most in pots. I was testing mixes, so grew a bunch. Good luck! So how did the plants do this year? Using a soil mix for 2 years is usually OK. I recycle mine by adding it to raised beds.
Since I have over 40 pots, making new soil every year is expensive and time consuming. So I use mine for 2 years. Sometimes longer. Depends what it looks like. The pots that I keep outside dry quickly, so water rentention is not a problem. It's actually nice once the soil begins to breakdown and stays moist longer.
I use DE, not the kind you have, the pebbles, it helps keep structure in the soil even after breakdown occurs.

"I use DE, not the kind you have, the pebbles, it helps keep structure in the soil even after breakdown occurs."

Sorry, it doesn't keep, add, or help the soil's structure unless it a very large fraction of the medium (like 80%+) and has been screened.

Al

I went to walmart and home depot today looking for pine bark mulch/fines. The bags they had are all way too big for what I currently need so I'll just wait for spring. (Also, the guy who was helping me was very skeptical of growing things in a mix of just mulch, perlite, and peat moss. He kept asking "what are trying to grow?")
Also... I've been leery of peat moss because I seem to recall hearing that it gets hydrophobic....?

Instead, I got 2 small bags of organic potting mix, not MG affiliated as I keep getting the present of gnats with MG potting mixes. No reusing container mix this year.

You might find the link below helpful.

Al

Here is a link that might be useful: Click me when you have some time ....

Awww man! I've been meaning to start reading that thread. It's just soooooooo long and it is an ever growing document......

I'll get into it though. I just never saw myself as a serious gardener that would need to know that stuff but I guess I'm growing into one. The look my fiancee gave me when I told him I want to try making a potting mix was priceless.

Thanks for all your help, Al! I'm reading it now.

I honestly think that the single largest step forward you can take at any one time while on your container gardening journey comes by gaining an understanding of how water behaves in soils. Most of the problems people come to GW's Container Gardening, Houseplants, and related fora seeking remedies for are related to excess water retention; so an understanding of how to avoid those issues, or at a minimum how to deal with them, plays a big part in how much reward you get for your efforts. IOW - it's worth learning. ;-)

Best luck!

Al

MeaWea, any decent potting mix is actually soiless. Most of them are mostly peat, coir, or peat-coir, with a smaller portion of perlite and/or bark fines. So don't worry about the guy who was flabbergasted at the idea of a soiless potting mix.

Lots of soiless mix ingredients, including fines and coir, get "hydrophobic" if they are left to dry out. Turface can get that way as well. I've never had trouble with peat getting hydrophobic in a potting mix, as long as I wet it well before mixing it in and didn't let it get too dry in the pot.

Compost in potting soil is not a good idea. It's great for conditioning soil - but the best container mixes are soiless. It's its own little microcosm, and when its healthy, it's just totally different than healthy soil-in-the-ground.

Currently I'm trying a pumice-peat mix. My preferred potting soil was peat-vermiculite for about 30 years, but in the last 15 years, I've not been able to lay hands on the really coarse vermiculite, not even by special order. You don't even want to know what I've been using instead. Lets just say I made it work for me but it was far from ideal. I would not expect it to work in the desert environment to which I have recently moved without far more trouble than it is worth.

Here, I can get pumice reasonably inexpensively and very easily. It has other properties that might make it useful in a desert environment. I don't know that it would be as useful in your climate, or whether you could find it all the way over on the other coast.

If your potting medium is mostly peat, you can probably get away with using it for 2 or 3 years. However there are issues of sterilization as well as breakdown of components involved. I used to reuse potting mix for one season (eg 2 total seasons of use) and after that it went into the compost. I did not mix in new stuff with the "old" because that never seemed to accomplish anything noticeable. For houseplants, it went straight into the compost whenever I repotted.

If you're going to try the 5-1-1 mix, try to find the coarsest perlite you can lay hands on. Home Depot carries some under the Thermorock label that is SUPPOSED to be coarse. People on these forums don't seem to like it, but at least it can be found almost anywhere across the country.

Perlite, at least, is easy to stuff into several large plastic bags (I'd double layer them) - but no more than you can flatten out after tying it off so you can stuff it under your bed. I'm big on using wasted space. It's light weight so as long as you don't overfill the bag it'll be out of sight when you don't want it, but easy to get when you need it.

Bark and peat - not so easily stored.