Could I make absolutely FREE quality potting mix from what's around?

I'm wondering if I could make quality potting mix from what's naturally around. The natural resources I have in my area are:

1. Lots of pine needles and rotted pine compost beneath them.
2. Homemade compost.
3. Worm castings (my worms don't produce much though).
4. Fallen deciduous leaves, and the leaf mold beneath them.

The following are a bit of a drive but doable:

5. Horse manure
6. Seaweed/ seagrass.
7. Beach sand. I'm trying to find river sand.

Could I make a decent potting mix out of all these? Or do I really have to go buy stuff?

to me potting soil is compost and all the above you listed mixed in to make the compost.....lol
I would be very careful of the pine. tends to be more acidic.

The store bought potting soil had been cooked. They do this so that it's sterile and won't infect your plants with fungal or other deleterious organisms. Or let volunteer seeds grow.
The bad thing about this is that it's sterile... it's dirt (dead), not soil (living).
Here's a video on making potting SOIL at home:

1 part compost to 2 parts coarse sand makes fine potting soil.

If you make biochar, it's a great addition. Also free.  

Most of my potting soil is compost made from chicken litter, wood chips, and biochar. If the wood chips aren't all the way broken down, I don't even add sand because the wood chips make it drain well.

With the addition of bark, gravel and charcoal, you probably have all the ingredients for a few types of potting mix: acid/alkaline loving plants, orchids, bulbs, seedlings, even cacti and bonsai.

It's just about using the correct recipes.

Manures should be composted, fresh manures in potting mix will likely kill plants. Though I have placed 1 or 2 dry nuggets of chook poo on the tops of pots just as slow release fertiliser.

Seaweed is a conditioner and should be laid on tops of gardens, not buried. Never heard of it being used in pots.

Beach sand, like seaweed, should be well washed before use, though it's often too fine for most mixes except perhaps seedlings.

hau Tim,  I think the key to your question is "your definition of Quality Potting Mix".

It is very possible to make a great potting mix with the components you listed, but you would possibly run into a soil drainage problem as in, not enough drainage, but that is really a rather small concern since containers hold small amounts of soil.
Pine needles will give more acidity than the rotted pine "compost"( detritus ), I'd hold back the needles to be used as a mulch to keep the containers from drying out too fast.
Worm castings are great, they will provide members of the microbiome we want in quantity and they provide minerals.
I would stick with the leaf mold and leave the fallen leaves behind so they can become leaf mold.
To all of the above, you will still need some soil, not a lot but you do want to have some since the microbiome lives in it.

Others have mentioned many great amendment items, of them all, the char is the one that would give you multiple benefits and your plants would like that too.

With the addition of some char along with a well rotted or well composted manure, you would have a mix that provides everything a plant wants to thrive.

Redhawk

i like using %20 local soil.
most of it i use has had lots of organic material in it over a period of a few years
and the underlying soil is fine sand with a little silt+clay.
sugar sand (large particle sand) like most beach sand, is excellent IMO, its a great size for roots.
i would make sure its washed if it came from a salt-water beach.

composted leaf mulch is excellent, feeds the plants, and adds lots of microorganisms...

i get 100lb of coffee grounds from starbucks every couple of weeks.
(sometimes they will save it for you, if you ask nice), or just stop by often.
used-coffee-grounds (UCG)  usually need to be dried, if not fully composted (best)
%20 max on the UCG (%10 to %15 is better IMO)

lava rock on the bottom of containers helps drainage... the roots will actually hold on to the rocks getting into the pores.
i use lava rock and leaf mulch on the top also to prevent water loss.

Beware herbicides, antibiotics, worming compounds and other substances in manure!

I know it’s already been said but I didn’t notice it here, be cautious about utilizing manure from horses and cattle and other ruminants commercially raised or no.  The worming mania continues, with many people worming their stock on a regular basis.  The toxic compounds are not usually destroyed by the digestive process, and are toxic to the very organisms we want in our soil.

This also happens with herbicides used to grow hays and grains, they are not destroyed by digestive processes in ruminants.

Some animal feeds (hog pellets for example, probably the feed for fattening cattle in feedlots) have antibiotics added.

These compounds slow composting processes, and can be harmful to plants.

I'm working on trying this myself.

Currently I'm using
1. Fine shredded leafmold/degraded wood chips.
2. Biochar (I'm using it as an aggregate in place of vermiculite or perlite)
3. Worm Castings


I currently also have incorporated coir because I have not built up a substantial amount of leafmold yet to pull from as I live on a 1/3rd of an Acre and last year utilized a lot of fallen maple/box elder leaves for garden pathways which fungus has just absolutely went to town on. I have sense added a layer of elm/pine woodchip which also has been degrading into some fine material.

I hope after this fall, I will remulch the garden pathways with more leaves and next year go through and dig up some gold before relaying a layer of new chip. (I have a long forsythia hedge I hope to thin out significantly and hoping that chipping it will turn into some more fungus food.)

I too have been working on creating a 100% locally sourced potting mix. Drainage is my single largest issue. I sourced some very coarse sand from a local commercial pit that is up to 1/8" and it works, but the resulting mix is physically too heavy in large pots.

The following is not 100% local because of the perlite, but O my, can it grow seedlings.

2 parts composted shredded hardwood arborists chips. See note 1 below.
2 parts high quality compost (mix of Johnson-Su, hot and vermicompost)
1 part coarse perlite. See note 2 below

Note 1: These wood chips were left in a wire cage for two or three seasons (winter snows and summer rains) until quite dark, then I put them through my chipper. The resulting product looks much like peat moss in texture. I've made MANY different kinds of compost, including Johnson-Su, but I've never seen any product (under my microscope) with such a healthy spectrum of soil biology.

Note 2: I'm working on replacing the perlite with biochar (well activated), but I've encountered two issues. First, too much char (10%) keeps it too wet... I think about 5% will be best. Second, two out of three attempts to effectively inoculate the raw char have failed, and thus the plants fail to grow. Seems the char is still inoculating and sucking all the nitrogen out of the soil to the detriment of the plants. I've tested this by transplanting stunted plants into biochar free soil and they thrive.

I made my own potting mix a few years ago.

I was growing tomato starts, and the last frost comes LATE.  Most locals just keep their seedlings in a 2” cube sized container.  And so you get a tall spindly thing with a tiny root system.  Hardening them off becomes a major undertaking, getting them established another.  

I wanted to put the seedlings with their developed 2 inch root system into USA nursery “gallons”.  Then I could have them outside (and cover them when frost is expected), and when summer finally arrived they would be sturdy, accustomed to full sun and our arid conditions.

And I did not want to buy that much potting mix… and then do the thing where you create a transition zone between commercial mix and local soil. (I have no till leanings)

I mixed semi composted goat bedding straw (had been impregnated with urine) with manure, composted goat bedding, dirt and wood chips.

Some of the chips were more like sticks.  I was trying for living mix with texture to encourage rampant root growth, food for the soil community, food for the growing plant.

It wasn’t that pretty, and sometimes I had to dump the pot out to get the sticks in first, then plant the plant.

I ended up using the very coarsest mix in the bottom and perimeter of the pot, finer grained stuff next to the root ball.

I had a friend whom I grew these plants with.  She did not like the look of this stuff at all… it not being all pretty and like commercial products or magazine pictures.  I said if the plants grew robustly, people would want them, and that we would be inoculating gardens all over the valley where we lived.

She also worried that they would take the plant home to plant it and be scandalized at the gaps and the composition of the mix.  If it’s all held together by a vigorous root system, what’s to complain about?

And thrive the plants did.  People bought them and there were no complaints.  People raved.

If you’re starting seeds then I guess you do want finer grained substrate, but I don’t think the plants are as fussy as the people selling products say they are.

Seems like coarse thoroughly composted wood chips (but not those sticks) would be fine for most purposes.  I’d try it😄

Thekla McDaniels wrote:I made my own potting mix a few years ago.

I was growing tomato starts, and the last frost comes LATE.  Most locals just keep their seedlings in a 2” cube sized container.  And so you get a tall spindly thing with a tiny root system.  Hardening them off becomes a major undertaking, getting them established another.  

I wanted to put the seedlings with their developed 2 inch root system into USA nursery “gallons”.  Then I could have them outside (and cover them when frost is expected), and when summer finally arrived they would be sturdy, accustomed to full sun and our arid conditions.

And I did not want to buy that much potting mix… and then do the thing where you create a transition zone between commercial mix and local soil. (I have no till leanings)

I mixed semi composted goat bedding straw (had been impregnated with urine) with manure, composted goat bedding, dirt and wood chips.

Some of the chips were more like sticks.  I was trying for living mix with texture to encourage rampant root growth, food for the soil community, food for the growing plant.

It wasn’t that pretty, and sometimes I had to dump the pot out to get the sticks in first, then plant the plant.

I ended up using the very coarsest mix in the bottom and perimeter of the pot, finer grained stuff next to the root ball.

I had a friend whom I grew these plants with.  She did not like the look of this stuff at all… it not being all pretty and like commercial products or magazine pictures.  I said if the plants grew robustly, people would want them, and that we would be inoculating gardens all over the valley where we lived.

She also worried that they would take the plant home to plant it and be scandalized at the gaps and the composition of the mix.  If it’s all held together by a vigorous root system, what’s to complain about?

And thrive the plants did.  People bought them and there were no complaints.  People raved.

If you’re starting seeds then I guess you do want finer grained substrate, but I don’t think the plants are as fussy as the people selling products say they are.

Seems like coarse thoroughly composted wood chips (but not those sticks) would be fine for most purposes.  I’d try it😄

Wow this is really cool to hear how your outside-the-bag method worked and even worked for plants you sold. That’s inspiring to me.