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Only have potting soil on hand please help

Posted by slow73 WA z8b (My Page) on
Wed, Jul 6, 11 at 7:58

Hey folks. I recently bought a palm (washingtonia robusta, i.e. Mexican Fan palm natty habitat coast and inland Mexico/southwest U.S.) and I want to keep it in a large container cuz it won't thrive in ground up here on the "wetcoast". Anyway when I do containers I usually use potting mix. But the other day when I was out with the wife since she is a very confusing person (yeah gotta blame the wife hehe) I mistakenly grabbed the wrong bag of medium and picked up potting soil. I don't want to have to make a trip 20 miles one way back to the store to exchange it and was wondering if it is still useable for my purpose. I am trying to create a mix that drains well but not dries out to quickly. These palms love water but hate wet feet. I want to use what I already have on hand. So what I was planning on using in the potting soil is conifer bark fines and perlite in abundance hoping to get what I want. What do yall think? Am I on the right track? Sorry for the long post.

Follow-Up Postings:

RE: Only have potting soil on hand please help

I personally would not use "potting soil" or other highly-organic, small particle material as the basis for a container mix, certainly not one that will house a plant for more than a few months. It will quickly compress and become waterlogged. Amending with bark fines and perlite will definitely help, but I would suggest that no more than 20% of your mix be comprised of potting soil. A well-draining, somewhat water-retentive mix that's commonly used around these parts is 5 parts pine bark fines, 1 part perlite, and 1 part peat (with some added lime)--the 511 mix. As you can see, that mix is ~15% small particles (peat, mainly); the rest are coarse materials, mostly between 1/8" and 1/4". I'm sure someone else will be along soon with more details. Good luck!

RE: Only have potting soil on hand please help

Great suggestion Strpharia!
Between that kind of mix and the gritty, the failure rate at most anything on containers is at a zilch for me:-)

Garden soils and the like have never lasted for any of my plants I use to pot in them more than a few days at best


RE: Only have potting soil on hand please help

i have noticed some potting soils contain great deal or at least 50% of particle size pine bark, plus compost, and some even got perlite.
Not sure why many here are against using potting soil? You guys actually had bad experience with store bought potting soil or just hard core 5-1-1 fans?:)

RE: Only have potting soil on hand please help

It's been my experience that anything with the word "soil" means mineral soil - ie: very small particles that compact quickly.

Potting "mix" may or may not contain bark, perlite, etc. But all of the ones I can find at the local stores are more like 85% peat. Even the Pro-Mix BRK is only a max of 45% bark. It will be better than most mixes if you can find it but usually that's a trip to a speciality store. I've seen Rhizo suggest Fafard Products and they have a line of medium and heavy weight potting mixes (professional line, not usually available in retail stores) - these can contain high %s of bark if you can find them. I think Rhizo usually suggests Mix 4B which is a medium weight with less bark than the Fafard #51 which is a heavyweight with 65% bark. 51 is the one I would use if I could find it locally.

But I can't. So I make the 5-1-1 which ends up being cheaper in the long run and should also perform better. There is the added advantage that if it doesn't for some reason then you have the materials on hand to adjust it as necessary. When I wanted more wicking for a self-watering container I just dropped the ratio down to 3-1-1. My tomato plants in that mix are over 8' tall now with about 30 fist-sized tomatoes (Early Girls in an Earthtainer).

I wouldn't touch "garden soil" with a 10 foot pole anymore.

RE: Only have potting soil on hand please help

Are you just looking for some one to tell you to use it ? Use it ,you know why you shouldnt.

RE: Only have potting soil on hand please help

Wow, that's interesting. Not knowing about 5:1:1 I planted everything this year in potting soil (mix?) from my local nursery. I've got very happily growing strawberries, lavender, basil, chives, Rosemary, oregano, green onions, shallots, and a few other herbs. All my indoor house plants are in potting mix and they grow ridiculously (I'm tired of buying new and bigger pots). I've left the pots out on the deck all winter, then planted new plants in the summer. I used a tiny bit of herb fertilizer in the spring but otherwise I haven't done a darn thing to them.

Am I just lucky? Or am I misunderstanding this dicussion?

RE: Only have potting soil on hand please help

Potting soil is not the same as potting mix. The former usually has sand, compost, and mineral soil, as redshirt said. The latter is composed of peat, bark, perlite, vermiculite, and other parts that are not considered "soil".

The problem is that the composition of potting mixes, which are the preferred ones for reasons which stropharia mentioned above, differs wildly between companies and stores, even within a few miles of each other. Sta-Green potting mix is decent, composed of bark, perlite, and a bit of sand. Potting mix from Scotts (not Miracle-Gro) is 90% sedge peat, which breaks down in about a month. I've used it as a concrete substitute to hold large trellises steady.

The advantage of the 5-1-1 is that because it breaks down slowly, you know that drainage problems will be eliminated. It's cheaper over the long run than regular bagged mixes and you can experiment and see what percentage of bark versus peat or perlite works best.

Charles and gardeningnewb - you have probably stumbled across one of those rarities called "decent potting mix", which can be used without needing to worry that it will compact the first time you water it. Most everyone else tries to use mixes like Miracle-Gro, which retains moisture too well and has many large pieces of bark, for no good reason, or use mixes with a lot of peat or sedge peat, and give up. Then they try the 5-1-1, see that it works splendidly, and stay with it.

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