shopping Potting medium / buying in bulk

[jixima]

Hi! I hope this is the right place to ask.
 
I'm in an area where it is very difficult to deter deer, so I'm growing mostly on our fenced-in south facing deck this summer. I have a solid amount of fabric pots, but I am running into an expensive wall when it comes to what to put in them. Buying bag after bag of potting mix is racking up, and I still have a lot of pots to fill and plants that are outgrowing their temporary homes.
 
Today, my coworker mentioned a place near where we live that sells compost by the yard for a really affordable price. He says that this is the reason all the plants in his yard have grown to such a big size, year after year. If I mixed this compost with, say, vermiculite and coco coir, could I use it in the grow bags? Or is there something else I can buy in bulk that would be cost effective?

 

[Bhob Zolokia]

Yep.

Peat and/or coir for the bulk
10%-20% vermiculite and perlite
Compost
Optional: Fertilizer to balance anything the compost is missing
Optional: topsoil ~10%

The peat/coir and compost ratio would depend on the richness and consistency of the compost. 2:1 peat/coir:compost ratio is where I would start.

I use greenhouse megastore for bulk vermiculite & perlite.

 

[jixima]

Thank you so much for your advice!
 
Darn... I was hoping to be able to use a higher compost component, because that is the ingredient I can get cheapest in bulk.
 
I checked out Greenhouse Megastore for vermiculite/perlite, thank you for the suggestion. They do have some coir available too, but it's out of stock until possibly July. I was originally looking at blocks from Home Depot, and I might just have to get more from there.

 

[Uncle Eckley]

Maybe ask your compost outfit. If they can't provide what you want they may be able to point you in the right direction locally.
 
See what you can find out about any coir you find, too.  I put the first lot of coir I bought into service before I understood how important it was to rinse the stuff really well.  I now know there's coir available that doesn't require rinsing, but at the time I just bought what was cheapest.  Caused me some trouble before I worked out what was going on and flushed my plants.
 
Btw, I like your avatar. D was my favorite as a kid.

 

[Bhob Zolokia]

Ask your coworker how they use it, since they are familiar with the compost. If they don't use it in pots, ask how thick they lay it on their beds (how many square feet do they cover with a yard?).

 

[The_NorthEast_ChileMan]

Thank you so much for your advice!
 
. I was hoping to be able to use a higher compost component, because that is the ingredient I can get cheapest in bulk.

 
The best advice I have for  for a "potting" mix is to make sure it's as light & airy as possible - in your case taking the financial issue into consideration. Not  like garden soil that becomes heavy & compacted. I use:
 
 

 
 

 
 

 
 

 
 

 
 
 
 
So your potting mix should look like:
 

 
 
Note how my mix above looks like below commercial mix?
 
 

Edit: Forgot - I don't stress over percentages - I just wing it - see below

So after you're done it should look like this........
 
 

 

[Karpasruuti]

I just do peat and biochar. Peat is least expensive and biochar a bit higher cost but u don't need it much.

 

[Kramer]

I just made my first mix this year, so no authority on the subject but it's working well so far.  I'm also growing on a deck, everything in fabric grow bags.
 
First I made the base mix, which was
 
25% cow manure (any kind, just rake it out and remove stuff you don't want like big pieces of wood or trash sometimes, lol)
25% mushroom compost (from local shrubs place, it was really cheap.  Like $6 for huge 20 gallon bags.  People generally use 25% to no more than 50% of MC in a potting mix)
25% peat moss (forget the brand, cheap though)
15% perlite (buy a huge bulk bag of this, even if if you have some left over...way cheaper in long run.  Think I used the #3 grade, nice and chunky)
10% vermiculite (same deal as perlite)
 
Bonus points if you have something to sift the compost with and make it nice and fine aka fluffy.  I made mine with a 1/4" mesh and leftover 2x4's.
 
Then add amendments.
 
Lime.  Generally rule of thumb is 1/4 cup of lime to 6 gallons (.8 cu ft) of peat moss.  Peat moss is acidic, so this just helps raise the pH a bit into the range peppers like a little more.
Fertilizer.  Whatever you got, just follow the directions.  Especially if it's synthetic, since those can burn if over applied.
 
NECM is right though, you don't have to be scientific about it.  I had to do some planning though just to know what to buy since I was making a lot of dirt.  Some other amendments I used but are not necessary (and will start raising cost) are a bit of epsom salt, azomite, and worm castings.

 

[jixima]

Thank you to everyone who's replied to this, this helps a lot. Now I have a better idea of what I need to aim for. Seeing how you all do yours makes me feel a little better that there's no one perfect scientific formula. I think I'm a little less stressed out now!
 
And those pictures are really helpful, The_NorthEast_ChileMan! I'll be saving them for reference. Thank you so much.

 

[jixima]

Maybe ask your compost outfit. If they can't provide what you want they may be able to point you in the right direction locally.
 
See what you can find out about any coir you find, too.  I put the first lot of coir I bought into service before I understood how important it was to rinse the stuff really well.  I now know there's coir available that doesn't require rinsing, but at the time I just bought what was cheapest.  Caused me some trouble before I worked out what was going on and flushed my plants.
 
Btw, I like your avatar. D was my favorite as a kid.

 
I can't believe I didn't think to shoot the compost service an email... definitely going to be my next step.
 
And thank you!

 

[Karpasruuti]

I just do peat and biochar. Peat is least expensive and biochar a bit higher cost but u don't need it much.

There is reasons why I went this route:
 
1) It's cheap
2) It's simple
3) No added fertilizer
4) Char makes soil pH more suited for chilies and make it more airy