Excellent points!

You may wish to warn not to overmix. If you get carried away you can break the peat particles down into smaller sizes which would mean a less porous mix.

Thinking I collect potting-soil recipes like most would collect food recipes. By putting together way too many different mixes, I've found the key (and failure) is aeration. Good thing I like to experiment!

If pumice or 1/4 inch lava were reasonably available here, that would be used in place of perlite
My media mix de jour is:
1/3 Lowe's Pathway Bark,
1/3 perlite and
1/3 coir (An eco-friendly peat alternative! Breaks down slower than peat too)

With 0.25 cups Apex CRFertilizer and 1TBS Micronutrient powder added to each cuft. Still trying to decide if it needs gyp or lime.

Living in an agricultural area with wholesale nurseries too, many of these ingredients are easily obtained from their distributors or our AG Chemical dealers...which makes me one happy girl!

Barbara

i said to barb:

you are really playing with fire with the fert.. but maybe you farm peeps know how to handle it .. ken

for us fert novices .... i would prefer you use a diluted liquid fert.. rather than mixing it into the soil ...

this is VERY important for peeps who have to deal with a real winter ...

e.g. my plants have to start slowing down in september ... if i use something like osmacote.. and i use the wrong time formula.. you might be releasing fert in october ... and you will have dead plants come spring ... becasue they will go into a lush growth phase instead of hardening off ... barbs plants.. probably barely harden off compared to mine ...

if you use it in water.. you can know exactly what you are putting in.. and when ...

as for pasadena .. i get the 2 x 3 foot dry bales.. and break the peat completely ... i get coarseness from the mini chunks ... whatever works is all that matters ...

also ... zone matters ... so it wouldnt surprise me if recipes differ.. zone to zone ...

i use the garbage cans for storage .. because all the stuff makes great nesting material for vermin ....

ken

"words mean things ...

and each of these 3 things are VERY VERY different ...."

Soil: stuff that roots grow in.

Media: communications businesses (newspapers, TV, etc.).

Dirt: pollution.

Resin

Ken, Osmocote is temperature release, shuts down below 70 degrees.

Frank

i was wondering if anyone would pay attention to that.. lol ..

a black pot in the sun.. on a 70 degree day .. in sept ....it wouldnt surprise me if you couldnt get a fert dump then ...

i learned the hard way.. there is a 4 month formula.. and a 3 month.. and probably others...

in my zone 5 .. frankly.. we dont have 4 months of growing season.. if you count june/july/august ... i dont fert in may .. since i can have hard frost thru 6/1 .. and i wouldnt fert in september.. for the same reason ..

so i lost a lot of hosta [read that 300] with a 4 month fert ...

a 3 month would probably work ... but i am too gun shy now ... its just not worth the risk... unless you are in production and are trying to zoom plants for quick sale ..

mixing and using it diluted.. is good enough for me.. and it goes on.. dumps its fert.. when i want it too ...

the MAIN POINT would be.. to know how it releases.. and when it releases ... not just throwing it in the pot.. because you see it in pots .. or because some guy told you he does it that way ... you alone are responsible to know how each of your media amendments work ...

one reason mass producers can do that.. is they flood their pots every day or so ... so they need all that food.. all the time ... a properly watered pot.. would not have that high flow of water.. and ergo.. would not need all the fert ...

ken

ps: a 4 month release would probably be moot in higher zones where they have longer seasons ...

Soil - the upper layer of earth that may be dug or plowed and in which plants grow.

Media - plural form of medium. Medium - a surrounding or enveloping substance; a nutrient system for the artificial cultivation of cells and organisms.

Dirt - loose or packed soil or sand; a filthy or soiling substance (as mud, dust, or grime).

Container potting mixes generally contain NO soil, or that mix of finely ground minerals and organic matter that is found out in the garden, and are typically referred to as soil-less mixes for that reason. And when making your own potting mix, it is best to avoid adding any, as it has neither the necessary pore space or texture to promote the proper aeration and drainage required for good container health.

As to everything other than the three materials Ken outlined being superfluous, it's all a matter of opinion, preferences and the needs of the specific plants you are growing. I try avoid absolute statements when it applies to gardening/horticulture whenever possible as there are nearly always exceptions :-)

I would encourage the use of some sort of controlled release fert in the initial potting process simply for the reason that all types of container media tend to lose nutrients rapidly, both because of their restricted availability of not very organic material in a very confined space and the need for frequent watering, which leaches out whatever soluble nutrients that may be present. And most CRF's - like Osmocote - are both moisture and temperature sensitive, as Frank notes. They will not encourage growth at inopportune times. For long term plantings, like conifers or other woodies, I reapply annually in spring.

"Osmocote is temperature release, shuts down below 70 degrees"
Frank,

That is not correct, Osmocote will cotinue to release at even 40'F or lower...the term in the trade is it "leaks" all winter long. The other primary controled release fertilizers on the market in the USA, "mostly" shut down or have minimal release under 50-55'F

"And most CRF's - like Osmocote - are both moisture and temperature sensitive"

Gardengal,

Also incorrect..while Osmocote has an aspect where moisture can influence the release (the true Osmocote coating releases via small cracks in the coating...ever notice it is the only one that swells up when hydrated...none of the others change size or shape), the other's release because of temp....moisture level, pH, etc. do not influence the release.

"NEVER, EVER use dirt in them .... it wont work"

Ken,

While I agree with what you are trying to convey, if you want a challange and possibly head aches, you can use soil.....people have done it longer than you or I have probably been on this globe. You can grow in gravel, sand, styrofoam beads,muck,compost, etc......'IF" you want to spend the time figuring out how to do it. I am sure many dead plants will be involved...just like you can grow plants with any kind of fertilizer...compost, fish, liquid , granular, controled release, etc. ...to each there own with what they have and where they live.
BUT...more plants will live, survive and thrive if you dont put soil in a container...much more user friendly for most people.....

Schmoo

This thread is funny.For orchid i used various mixes Sunshine Mix promix.The secret to growing in pots is not so much what material you use but learnig how to grow in that material.Take watering some material drains fast some not so fast so you adjust your watering to compensate.However you don't want a mix that is soggy so additives maybe necsesary,such as sand perlite or vulanic pumice.Same with fertilizer.On orchids i used Dyna gro 7-7-7 at 1/4 strenth every watering,and of course each plant has differnt watering and fert.schedules.Also hearing about hardenigoff what i learned from some Rhodo growers is use a little super phosphate around august or early september i have neve given a plant growing outside(except my lawn)nitrogen in the late sumer or early fall.

Just one more thing ,I don't take anything i say as my own but what i have leared over the years form so called pros.If you read 30 differt authors you will get 30 differnt examples.However, the basic principles are all pretty much the same. Joe

"The secret to growing in pots is not so much what material you use but learnig how to grow in that material"

Joe,

Well said/written on both posts....we all learn from those who came/learned before us......

Schmoo

It also depends on how long the plant is going to be in the pot. I usually try to grow a plant in a pot for one season before repotting or planting out. I can use good topsoil mixed with aged woodchips, and cow manure with no problems.
As mentioned above, drainage is the main issue accompanied with a proper watering regimen tailored to your conditions.
My little backyard nursery just supplies my garden so I don't have to fine tune things like a commercial production nursery would. I haven't bought commercial fertilizer in over 20 years. I just don't see the need after amending my soil on a constant basis. I treat my whole garden as a compost pile........with worms and moles doing most of the turning. ;-)

schmoo - I'm not sure where you're getting your info but according to the manufacturer of Osmocote:
Osmocote® fertilizer is composed of resin-encapsulated N-P-K granules, which provide nutrient release over various climatic zones. Water vapor penetrates the permeable shell and dissolves the nutrients, which are released evenly through the coating at a rate determined by formulation and soil temperature.

So how exactly is that not moisture and temperature related?

And I'm sorry but comparing growing orchids to conifers is like comparing fish to horses - other than them both being plants, there is no similarity, especially when it comes to container culture. Most orchids are epiphytes and do not even require any potting medium - other than some sort of root anchorage - to grow at all. I've seen them potted up in lava rocks. Try that with a conifer! A proper growing medium for any kind of terrestrial plant in a container is essential for their long term health and viability.

i am trying to break this down for the newbie.. someone who is THINKING about pots ... so i try to simplify to the max ... and then RELY on you guys to spice it up .. and add variables ... GO TEAM!!!!

when i said that everything else was superfluous... from the basic three ingredients... i was trying to say ... that my proposal is the basis .. the starting point...

once you master water, air, and fert movement through the basic product ... then you can start adding other things.. that are more specific to what you are growing ...

and that basic premise would bring me full circle back to marketing methods.. and foo foo premixed potting media ... that have all kinds of mysterious additives... which frankly .. are just marketing tools.. to charge you 10 times the actual cost of the ingredients... for what amounts to a bunch of stuff.. you most likely do NOT need ... or might harm your plants in the long run ...

as to the osmacote disagreement ... you guys knock yourself out.. my simple point is... professionals use that FERT.. because it fits in their watering method .. in their media ... its a science.. they have worked it all out based on what plant they are propagating[probably by losing hundreds of plants over the years experimenting].. and how they care for it [pot flooding] ... it is NOT necessarily a handy dandy easy no brain idea for the homeowner to throw in pots.. simply because you see it in all the potted plants you get ...

and frankly.. spreading it on mother earth is simple a waste of money ... google says the cost for 50 pounds is around $104 ... for the same 14-14-14 basic granule fert ... $18 .... thats a big mark up for a product that is engineered for pots .... even if you consider that you would need 3 applications of the grans to be equal to the three dumps the pellets make... in theory ...

yeah.. i have a bucket in the barn ... going on 8 years now .... i burned a bunch of stuff with it way back ... and now it just sits there .... live and learn ...

ken

PS: i think of the time release as a very small jawbreaker .... layers of heat and water resistant coverings.. with fert in between the layers .... as heat and moisture build ... the first layer releases the first amount... then exposes the second layer.. which has to take up more water and heat.. etc ... no clue if i dreamed that up .. or if it is a proper explanation ...

i would not expect if you wetted some and put it in the freezer.. it would release.. nor would i expect that if you went out to death valley and laid some out.. it would release .. ergo .. i like the theory that it needs both moisture and temp to work ... otherwise... my 5 gal hermetically sealed pickle bucket full of it in my barn would be all released .... and its not ... and it gets hot in my barn .... in august ...

gardengal,
"So how exactly is that not moisture and temperature related?"

Moisture is needed for the disolving of any solid fertilizer, but with controled release fertilizer, it does not have a direct effect on the release rate or curve of that fertilizer...indirect yes since it is needed to dissolve the fertilizer. This is true for any polymer or resin coated product...Osmocote is old school technology compared to the others available in the USA.
My knowledge of controled release fertilizer comes from using, being around many types in commercial nursery operations over the past 15+ years....and you??

Similar to Ken and his comments on components in growing media....the website you reference is simplfied to make it easier for many to understand.

Schmoo, if you find it necessary to flaunt 'credentials' to give any credence to your opinions, you're not the only with a professional background......mine is quite extensive as well and includes many years of both retail and wholesale nursery experience in addition to teaching classes and seminars at various levels on soils, fertilizers, container culture and whole range of other horticultural topics. Is that sufficient for you?

So the website has simplified the process - big deal.....it is still a combination of moisture and temperature that activates the product. And since this forum tends to attract mostly hobby gardeners rather than professional horticulturists, delving into the specific technicalities of exactly how a CRF works are unnecessary.

btw, if you are that familiar with Osmocote, you are well aware that while it may have been one of the first CRF's on the market, it has gone through various changes and improvements over the years and the current formulations bear little resemblance to the original product and are much more sophisticated in their presentation.

Gardengal,

You asked where my info came from, I was answering (and it sounds like you have been around fertilizer also). While the formulations have changed, the resin coating is still the same resin coating.

Schmoo

One HUGE aspect of this stuff-used-to-fill-containers-to-grow-plant-in discussion that has not been addressed well enough in this thread is change, or breakdown, over time. I am in the process of writing a semi-technical brochure about soil drainage for the arboretum, and, in the process of reviewing what others had said, ran into this post here on Gardenweb. It would probably be well worth reviewing the link below for anyone not thoroughly familiar with the physics behind drainage and the different soil additives available to ensure proper drainage over a relatively long period of time.

Here is a link that might be useful: Container Soils - Water Movement & Retention VI

I agree with Brandon. I've learned a great deal from the container forum. I use Dynamite from big box stores which I believe to be a superior product than Osmocote products sold at big box stores. The better Osmocote products are hard to get locally if you're not a commercial grower. You have to read Plant Production in Containers II by Dr. Carl Whitcomb who had done many years of research in this stuff. You'd learn a lot from it. My mix for roses and trees looks like this

3 parts screened pine bark fines
1 part expanded shale
1 part peat

I spread Dynamite on top of the container.

Works great for me so far...

if i were to grow things in pots .... i would re-pot every other year or so .. to avoid the issues brandon raises ...

if i were to be working with large containers ... say as an entry way ... WILL ... i would use a pot in a pot .... so that i could remove the plant every second year.. for a root pruning and new media ... avoiding.. in its entirety ... the variable of decomposition of the media ...

in my z5 ... pots are extremely problematic in winter ... i prefer to un-pot.. and stick them into the garden for mother earth to protect them.. and then repot in spring ...

if a variable is a problem ... remove the variable.. lol ...

and if i use fresh media each year .... then there is no real reason to use all that much fertilizer ...

that would be the other key to this post...

if you know the variables ... you can be proactive in manipulating them ... ignore them at your own peril ...

ken

Schmoo - I'm sorry if I misread your intent :-) But the statement did come across as rather confrontational.

Brandon - that topic, and in fact the link that you posted, were addressed and discussed rather well in the thread that prompted THIS discussion :-) And just so there's no misunderstanding, drainage as it applies to container culture is vastly different from drainage as it applies to inground plantings, other than the soil interface issues.

Here is a link that might be useful: what got all this started

Wow, it's a small world (or internet in this case). I don't keep up with the conifer forum as well as I do some of the other forums, so I didn't realize this thread was a spin off of another one, but it's still a good idea to have the link to the above article as a reference for any future searches.

I agree with Ken, that frequent replanting would go a long way towards solving the issues relating to soil decomposition, except for four things. First, even if you change your soil every other year, most soils will still have some drainage deterioration towards the end of the two year period. Second, if you use your old soil and mix it back in as many people do, that has the potential to cause problems. Third, it's good for everyone to understand how drainage works so that they are better able to decide what ingredients are best for particular plants or circumstances. Different species have different moisture and drainage requirements, and different circumstances (climate, amount of supplemental watering available, etc) require adjustment. Fourth, and maybe most importantly, many people (we know who we are) won't replant frequently enough even though this would be best.

As for drainage, as it applies to container culture, being vastly different from drainage, as it applies to in-ground plantings, I'm not so sure. The physics is the same! Only the variable, or circumstances, change. A true understanding of one is a true understanding of both.

Well said, Brandon.

Ken - if you use a soil that is appropriately durable, you can repot based on the condition of the plant's roots, rather than being dictated to by a timetable of 1-2 growth seasons. You can also construct a durable soil and use a much larger container than you normally would if you pay attention to particle size and construct your soils with a smaller organic component (You said that "if you use fresh media every year, there is no real reason to use all that much fertilizer .....", but I think that from a practical perspective and because soilless media provide so very little nutrition, it's wise to treat our container plantings as if soilless media offers no nutrition, and to shoulder the entire responsibility for insuring our plants get it through our own efforts. If we allow that container culture is much closer to hydroponics than it is to garden growing, it's easy to see where I'm coming from on this point.

Al

and if i use fresh media each year .... then there is no real reason to use all that much fertilizer ...

Doesn't make that much sense. Al knows what he's talking about. Dr. Whitcomb covered that in his book. Very informative. My trees grew much better after reading what Al had to say and reading Whitcomb's book. And yes you do need fertilizer. I noticed A HUGE DIFFERENCE....

i only pot things for one season ...

i plant in april or october... but they sell the stuff all summer long ... i do NOT plant in the heat of summer .... i have increased my success rate to near 100% by planting ONLY at the proper planting times ...

in a perfect world .... EVERYTHING will be planted by october .. since mother earth can protect them much better than i can in pots ...

in an imperfect world .... whatever doesnt get planted by october ... gets stuck in the ground.. pot and all ... and planted in april of the following year ...

ergo .. no need to ever fertilize ...

when i moved from the city to the country ... i potted and moved 1500 hosta.. and another 250 pots of various other things.. and ended up moving in january ...

i lost about 120 hosta.. and 30 or so other things... to this day .. i wonder how much was lost fooling around with fertilizer in the pots ... WHEN THERE WAS NO NEED FOR IT ...

if you wish to err... err on the side of NOT fertilizing your pots...

if you wish to grow things in pots forever [or more than one year] .. well surely .. you must learn to fert the pots ... due to the leaching effects of watering running out of the bottom of the pots ... which is the whole point of a proper media when dealing with conifers and trees in pots ...

ken

ps: no comment on success rates of the pots i forget to plant the following year.. lol ...

I don't ever use any native soil. That's a rule I abide by.
Composted material - AWESOME! Leaf mould, etc-

I also don't wish to pay a lot.

For potting up grafts, It's June here. That way I've given the new "liners" a chance to chill out before I hack into the roots. Of course I have a shade structure. That's very important for a few years for new grafts or conifer seedlings! You won't as many this way, it's a guarantee.

Right now I'm potting up dormant seedlings in my greenhouse that I didn't get to last fall. Just a few.

I use Anderson Tree Band Pots.... because I like 'em.

Plugs over bareroot anyday in my opinion for the little starter understocks or little seedlings planned not to be used for grafting. They get graduated from these the next year after a full one-year cycle to gallon pots.

Osmocote.... very commonly used. No problem there, really. I hope I don't start any controversy.

Did you guys know that Monrovia Nursery's potting mix is either 100% composted scraps or near too? They're #1 for their recycling in the industry. My hat is off. American Nurseryman Magazine ran an article a while back about Monrovia.

Here's a simple recipe where the peat can be replaced with composted material:

three 4 cu. ft. bags of perlite
one 4 cu. ft. bag of peat
and mix in 6 lbs. of Osmocote plus 1/4 lb. of Micromax

Dax

osmacote has a number of different formulas and time release spans...

if you decide to use it.. use one that is made for the length of your growing season ...

ken

I enjoyed this very informative thread. Two things I was thinking as i read through were:
1- Whitcomb mentions using native soil with good success in bottomless containers. Anecdotally a friend who traveled to Japan with the Maple Society last fall reported that Japanese Maples in nurseries there were potted in native soil with mostly open bottomed containers.

2- I grow trees in large pots and have been root pruning and refreshing soil for years. Last year I potted trees using a mix that is peatless and heavy on coir. I added a percentage of bio-char. I hope to get 2-3-4 years out of this mix. I add espoma bio-tone and 1/2 dose of nutricote total w minors.

Thanks for all that thoughtful discussion.

Here is a link that might be useful: Local potting mixture

There are a million types of native soils .Some are naturally fertile and well-textured...and some are like moondust.Best to avoid these! Thanks for the link. T.

herman_neutics...where did you find the Biochar? My last attempt to find a source of charcoal ended with a mush of barbeque briquettes.

Have you seen positive results using Espoma Bio-Tone? What is it's effect on plant growth?

Coir is a major component of my current potting media also, though my usually source has quit carrying it. And...I just returned from Lowe's where 6 to 7 cu ft of perlite cost $3.24 in a sale of broken bags. Felt like I'd just won the lottery!

Barbara

Hey Barbara,

Last year there was a vendor on ebay selling bio-char and i bought a bunch there. When that ran out I used hardwood lump charcoal from wholefoods that i pulverized. I can't say I've seen any improvement from the char but it does help with aeration, it makes large pots lighter, and it's very stable.The proponents say that you only see results when the char is completely colonized.

I am using biotone for the first time. I potted up a few smaller plants with biotone in the mix and i gave a light dressing to seedlings that haven't surfaced yet.

I look for those broken bag deals all the time.