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The Big Thread on the Uses and Misuses of Pre-Fertilized Potting Soil

G

Guest

Specifically, Miracle Grow, Schultz, et.al. and it's effects on clones, seedlings and overall plant growth in different stages.



Pre-fertilized potting soil is by far the most commonly available medium in which to grow plants inside your home. It makes up well over 90% of the market in the US and is dominated by a handful of very large companies like Miracle Grow, Schultz, and Wal-Mart brand soil. There are other manufacturers that make other kinds of specialized soils, some with food in it and many other kinds without. Some are organic and very costly in comparison. But we will be discusing the most commonly available ones here where I live in the US.

I feel there is a ton of misinformation out there about PFPS (Pre Fertilized Potting Soil), at least in the cannabis growing world, leading to a lot of false rumor and misrepresentation about it. This is unfortuate becasue of how many new cannabis growers use PFPS either either through necessity, availability, cost, or marketing. It is important for us as teachers of growers to learn how to use it properly as well, to better direct others who will be using it when they are new to the scene. We can convince them there are better products out there when they have a sucessful grow or two down. It's just too easy to sit there and say of PFPS, "it burns your plants" or "it makes shitty tasting weed", neither of which is true.

In the best case scenario new growers will do it like we (I) did: Get a halfway decent harvest in and be so freakin inspired they go off on an education binge useen in life since first grade, absorbing everything about the plant, evoloving growing style and room. It is this way that we all develop our individual skills and find out which methods we appreciate more, leading to our unique grow styles. It is our job to get newbies kick started on that education by getting them to harvest once, and it does not matter if they are using PFPS or dirt dug up from under the driveway or Vics Super Soil. We have to get em to harvest to suck them into the light.

I know there are drawbacks to using these soils, I'll get into those as well, but much of that comes from a lack of information on the topic. The drawbacks can be overcome and even taken advantage of with minimal planning and common sense.
 
G

Guest

My apologies, but there will be a TON of pics in this thread, as it is a comparison

My apologies, but there will be a TON of pics in this thread, as it is a comparison

I have several individual experiments going on at once in my room right now. One with clones, rooted in water and transplanted to three different kinds of soil. All soils have been mixed with 1/3 perlite as I normally do for grows. The first kind is the Pro-Mix I use as my everyday medium. The second is the Schultz Organic pictured above and the third is the Mircale Grow. There are four sets of three and I tried to make all cuttings and root development as equal as posible First, the 12 clones with roots







The soil is marked with pipe cleaners. The white is the unfertilized Pro-Mix. the red is the Miracle Grow and the green is the Schultz organic

 
G

Guest

The plants for this experiment. I will simply observe the effect of each soil on root growth into the new soil and report back when each plant has a root hit the side of the clear plastic cup. Not exactly scientific, but the best I could come up with to see if MG is toxic to bare roots





Each are watered with plain water and are placed back under my mother light which is also used for cloning and transition to soil. This means the Pro-Mix has had no food given to it at all.
 
I have used the MG perlite, which is preferted as well, and all the rooted clones Ive used it with seem to take a little bit to get going and developing a healthy rootmass. However there were other "variables" so I cannot say with certainty that the MG perlite was the cause.

I couldn't agree more with ya either, after that first crop, its like you get sucked into a black hole, once your within it pull theres no coming out.
 
G

Guest

I love the way you break things down - put it into pictures & explane your research / very timley post as I feel there are a LOT of new growers here right now = YEA!

The one thing I found so far with all organics is a slower start

Thanks

Ps. Ckeck out "Espoma's" new Soil Perfector - a very nice re-usable soil rock

Also - MGrow has a new all organic soil I am checkng out
 

Joemutt1978

Member
I use the MG, works good for me.

I tried the Organic stuff, without perlite, and killed about 50 seeds. Kept thinking it was PH or Heat or something, turned out it was the soil. Still have a bunch of the organic soil left, if you can convince me, I will use it again, but not for seeds.
 
G

Guest

Sorry for the delay, I have a lot more to write but I had to take care of business.

Welcome folks, hope you feel free to comment on or suggest anything different than what I'm doing. Tell me what you did to make it work or not.

The Organic stuff is new to me as well, but it is a PFPS and I thought it would be good to include it against the Pro Mix and MG. I have no idea what to expect from it, but I did notice it wasn't broken up very well as I was mixing in the perlite. I spent a few minutes physically sifting out and breaking up the balls of some solid-ish material in it. I hope that helps keep the mix more consistent.


The food in most PFPS is chemical and urea based, like the majority of fertilizer used for home gardening. The same stuff in the bottle but used in a time released way in this soil. It's supposed to be close to the same bag to bag and I havent really had problems with it in this respect, though the amount of perlite I use in my mix would mask this to some degree.

Miracle grow is rated at .18-.06-.12


and the organic Schultz is made up of composted turkey litter, hydrolyzed feathermeal and sulfate of potash and is rated at .06-.09-.06



The Miracle Grow has a time relase NPK that is different than it's original NPK.
The time release elements are .12-.03-.07 while I believe the organic compounds in the organic are naturally slowly released and will remain consistent.
 

Rellikbuzz

Active member
Hey Cap - Your threads are always so informative. I'm still trying to get my hands around your LST thread but my plants seem to love it so far. I'll be along for the ride on this one as well. Much props to you, bro! Now, on with the show!!! :canabis:
 
G

Guest

Thanks and welcome!

Adding perlite to the mix is very important for several reasons. It loosens up soil to make roots easier to penetrate into it. It also has a porus surface, being lava rock, and these holes hold lots of oxygen, making it more available to the roots. Last, and specific to PFPS, it dilutes the concentration of soil in your container, meaning less fertilizer overall to wash away. This is a great thing with most PFPS since they usually make a thick and dense soil mass after the first watering dries without it. It's fine to grow without perlite, just remember you'll have to use plain water feedings longer than those who use it. And this brings us right to the heart of the matter: How to feed your plants when using PFPS.

Or more importantly, how to NOT feed them
 
G

Guest

Great thread Cap! :wink: I too cant wait to see how they compare.I use pro-mix bx indoors and have used mg in outdoor plots that i couldnt get to to feed.But this should be very informative. :wave: DWW
 
G

Guest

PFPS has food already in it. It seems obvious when said, and may people who are successful users of PFPS obviously know it, but many others dont or forget or assume it does not contain enough food for cannabis and add fertilizer to the watering can when there is plenty of food still in the soil. This constitutes double dosing your plants and they will show typical signs of stress because of it: leaf damage, discoloration, slowed growth.

In my opinion, this is the primary reason for the school of thought that assumes PFPS burns your plants or is no good for growing cannabis

The 1/3 ratio of perlite I use with Pro-Mix is not typical of my grows with PFPS, and this is the first place to start when figuring out how long your plants can go before feeding when using it. As said before, the amount of additives in your soil reduces the overall amont of soil, and thus fertilizer, in your planter, making the food flush out faster. An equal ratio of perlite and PFPS meant I could begin using my own food in a little under two weeks or two full waterings. A 1:3 ratio of perlite to PFPS meant I was feeding after 3-4 weeks. A undiluted PFPS in a 3 gallon planter held it's water for a full 15 days and went all of veg growth and into the stretch before I needed to feed. These numbers are, of course, unique to me and my situation with many factors like transplant, maturity, seed or clone, etc, not taken ino account. YMMV (Your Mileage May Vary)

It would take unbelievable organization to figure all that out and I just dont have it in me currently. I do have a lot going on in my room and wiith that, it's time to detail my second experiment with PFPS vs not, how established plants do in transplant to organic PFPS vs chemical PFPS.
 
G

Guest

Here are the next plants, the eight you see on the floor between bags. They are fully grown int the cups that rooted them, with many 8" tall and fairly sparse and thin since I left them under the clone rooting light too long. Certainly proof that there is a limit to how little light a plant can receive


Miracle grow is the two pics on the left, before perlite and after. I'm using a 1:3 ratio for everything. Like I said, I had to really work the organic bag to smooth out the mix. I can't tell you how enjoyable a thing it is to mix soil with my own hands. I love the feeling of plunging my hands in and swirling it around. The smell, once you've held your breath through the perlite dust cloud, is intoxicating by itself, beaten only by the smell of my outdoor garden when I'm tilling it. Getting it in the midle of winter is pretty cool, though.

Four plants each went into each kind of soil. I didn't use the Pro-Mix because I'm out of rooted plants and wanted to maintain a four plant minimum per group. I know I dont have a control group here and that's bad, but the comparison between foods in the soil should hold some interest. I trimmed down each plant to a few nodes in order to make the vegetation between each planter more equal. I hope to better observe the new growth from very small branches.
 
G

Guest

Well, ya gotta love it. 24 hours after planting, I have two clones showing roots to the outside of the cup. Problem is, the results are contradictory. One medium sized clone in Schultz organic and one medium sized clone in Miracle Grow show identical development, and pretty darn fast from my exprience. Green is organic and red is MG. The tiny root is right off the end of the light blue cleaner

The Pro-Mix, as I expected, is not showing anywhere, probably because it has no food in it and all were given just plain water.

These are the two groups of three medium sized clones. The small clones and big clones showed nothing yet.




 

Harry Gypsna

Dirty hippy Bastard
Veteran
Nice idea m8....I have trawled through loads of brands and types....now I just use B&Q multi-purpose...mixed in 50/50 with perlite...although I have just started adding some Leca to simulate pebbels i the earth. have you seen those "supernatural Brand" grow pots...theyre bags really, a mix of all kinds, soil...perlite..2 kinds of diatomaceous earth... anyway, they are in layers like the groewund is outside..and thats true coz after reading their speil, i went to do some digging, lol and its true, it is in layers outdoors, anyway, Im trying to simulate this at the moment....but i may give some of those grow pot things(they come filled and layered, u just stick ur plant in and water.) as they can be used for flood and drain tables too. ill take a pic of how im doing my pots at the mo0 when i get ther ein a bit!
 
G

Guest

Thanks John, Harry. Please do and post back your results! The more info we get the better. I dont live in too sophisticated a place for growing, despite all evidence to the contrary. I have never seen a grow bag, ever. Can't even say I've seen ne on the net. Got a link? :D

On day two of my transplant experiment, eight other clones showed roots to the outside of the cup. Twelve hours later, a few minutes ago, I went down and checked and all were rooted.



Results inconsequential for PFPS. All soils handled bare roots just fine, no burning. I give a big win to Pro-Mix, because in my book, in every situation, the less chemicals in your grow the better. If bare roots will strike out without fertilizer, great!





 
G

Guest

Hey zepp, welcome! Feel free to contribute anything you have.

======================

OK, the third experiment is with freshly popped beans. The strain is the mix of seeds I collected off the floor after harvesting seeded females from two strains. I'll do the same thing as before, four freshly cracked beans in the three different kinds of soil and observe the results. (After they pop, I'll be moving them to the flower room to begin the 12/12 sexing experiment)

These have been on the light for 24 hour now. I'll go back and check them shortly. First 12 get planted.



 

zeppelindood

Captain Expando
Veteran
Hi again Cap.... I do try to stay away from the soil until I have germination confirmed.... hints about 2-3 weeks. They seem to enjoy life in their rapid rooter setup I made for them until they hit the soil/perlit with light doses of veggy fox farms. The same pretty much applies to my clones as well. I do know that DeviLock uses a solid lineup of guano during the veg process with great success.
 

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