Potting Soil Mixture for Azalea's

Zone 7 - darn it's cold here in Maryland
I'm rooting several azalea's and need to transfer them to larger pots..... so require a good potting mixture. Looking at filling 24 - 1 gallon containers.
The plants will be kept in these pots for another year or two, before being planted in ground..
Am I better off buying a few bags (scotts) or is mixing this soil something a gardner should know how to ?? What type of ingredients are necessary ??
I have plenty of composted soil and leaf mold on hand also some top soil and acid based fertilizer ( there are several other acid based plants in the landscape). Also might have some peat left over from last season.
So, would you buy, or would you make your own? What would be the best mix if you mixed it yourself.
A thought just occurred to me. I have a border of concrete blocks circling a tree. These blocks have holes in them..... would it be a good idea to fill the holes with dirt and keep the plants in them ?? This would be something that gets watered frequently, gets direct morning sun October to May and gets shade from June to the October leaf fall. I think the concrete blocks would wick away excess heat during the summer better than plastic pots would. (If this is workable.... I have a lot of spare hosta's which would thrive under those conditions... instead of the azalea's)
Thanks in advance for your advice !!
Peter
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On 2/24/2009 12:34 PM, snipped-for-privacy@yahoo.com wrote:

See my do-it-yourself potting mix at <http://www.rossde.com/garden/garden_potting_mix.html . However, mixingthis might be more work than can be justified if you are going to plant the azaleas in the ground.

What is your climate? Where are you?
I'm concerned that the holes in the blocks might not be large enough for azaleas, which have extensive surface roots. I have a similar arrangement around a dwarf tangelo to create a raised bed. I planted wax-leaf begonias in the holes.
--
David E. Ross
Climate: California Mediterranean
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On 2/24/2009 2:19 PM, David E. Ross wrote:

Oops! I now see where you are. Some azaleas can take sun; some require shade. Just be careful about the variety you choose.

I would also be concerned about azalea roots having trouble competing with the tree's roots.
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David E. Ross
<http://www.rossde.com/ .
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I'll top post on this one....
Thanks Dave, for making your recipe available..... can't wait to try it out and see what happens... It probably is a little too involved for small batches however, one large basic batch at the beginning of the season can be stockpiled... and the 'add as necessary' ingredients can be added before each particular application.
Zone 7.... Maryland.... Over the past 10 years, the temperature range has been from -5 degrees below zero to high ninties in July and August. Rainfall has ranged from two, multi-year droughts to average spring and fall rains with little snowpack. My backyard is swarming with deer, rabbits, squirrels racoons and groundhogs and unleased dogs (in violation of local laws).
And yet, plants do somehow manage to survive and even thrive. I lose a lot also, due to a lot of conditions.... and manage to trade a few.
So THIS is Eden ?? Could use a few more plants !!
Thx....
Peter

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On Tue, 24 Feb 2009 15:34:42 -0500, snipped-for-privacy@yahoo.com wrote:

Yo, Peter!
How come you put an apostrophe in <azalia's> but not in <scotts>? Gentle hint -- it's a plural, not a possessive...
Now, to business. If you have all that wonderful home-made planting mix on hand, why would you consider store-bought stuff?
My "formula" is about half & half regular soil and compost, with a goodly helping of vermiculite or pearlite to lighten the mix.
I also throw in about 1/5 to 1/4 worm castings. Pure gold.
You might want to hold off on the fertilizer immediately upon transplanting. The azalias have enough work adjusting to their new environment without extra stimulation.
I say wait about two weeks.
What do others think?
Personally, I'm not huge into fertilizer; maybe should be more, but the real health is supposed to be in the soil.
Again, what do others think?
Concrete blocks for the azalias? I wouldn't. Too risky. If it's only for a year, and if you can afford terra cotta pots, I'd go that way. If the expenditure is too much, go ahead & use the plastic, watering regularly in summer.
Do you intend to circle the tree, whether with concrete blocks or pots? In any case, it wouldn't be too difficult, IMHO, to devise a simple shade, perhaps guyed out from the tree, for the worst heat.
Or, better still, is there a shadier area on your property where the azalias would be happier?
Interested in how this comes out.
Persephone
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On 2/24/2009 5:11 PM, snipped-for-privacy@NoSpam.com wrote [in part]:

Actually, azaleas do not need much fertilizer. They prefer a "lean" soil. With a soil containing compost, they likely have enough nutrients for an entire growing season. Wait a whole year.
On the other hand, they do need an acidic soil. If your soil is alkaline, stir a small amount of soil sulfur into the soil. Natural soil bacteria will slowly convert it into sulfuric acid.
--
David E. Ross
Climate: California Mediterranean
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snipped-for-privacy@NoSpam.com wrote:

Yo, Persephone!
Why do you put an i in azalea. Gentle hint, you misspelled it ;)

Sounds good. The most important attribute of a soil mix for azaleas is drainage. The second is the correct pH. So the correct soil mix depends upon your watering habits. If you water frequently like commercial nurseries, you need a special mix such as bark dust that drains quickly. If you are like me and only water when a plant looks like it needed watering a couple days ago, then the soil mixes are good. I like a mixture of top soil and composted peat with some vermiculite or pearlite. I find it is hard to get a plant that has been grown in bark dust to adapt to soil.
--
Pardon my spam deterrent; send email to snipped-for-privacy@earthlink.net
Visit my Rhododendron and Azalea web pages at:
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wrote:

'Zounds! Hoist on my own petard!
Persephone

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On Tue, 24 Feb 2009 15:34:42 -0500, snipped-for-privacy@yahoo.com wrote:

Thanks Persephone and Stephen - your advice was exceedingly helpful providing guidance as to a proper mixture. Azaleas tend to have a surface root system, my thoughts were that it would be important to give them something to hold onto on the surface levels, rather than providing a mixture deeper down where the roots could penetrate and grow. Your points in drainage versus watering habits are well taken.
David Ross covered the components which add acidity to the soil in another post. .
Avast ??? You're being hoisted on a Petard ??? All because you used an " i" instead of an " e " (with only 5 main vowels to choose from). Stephen you're being a hard task master.... I didn't get that treatment even in Catholic grade school when flubbing a word on a paper.
btw the trademark " Scotts " is spelled without an apostrophe.. check it out the next time you're in the garden center. Thanks to corporate america, possessive's now become plurals and plurals become misspelled. My bad.
Peter
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snipped-for-privacy@yahoo.com wrote:

doesn't need to be capitalized, except at the beginning of a sentence;OP

capital "A".

Not really. Most Americans would love to see corporate American CEOs, and CFOs lined up against a wall without blindfolds (So that, at least, they can see what is coming. A courtesy not given to the rest of us.). Cigarettes, though, still seem like an appropriate metaphor to be included in this event.
With due diligence, Peter, we'll have you up and writing, and talking American in no time ;O)
--

Billy
Democrat and Republican Leaders Behind Bars
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