Potting Mix DIY - What to use?

[MrSal]

I am in need of about 6 yds of potting mix/soil and was thinking of just ordering bulk in order to keep price low.

I've Googled a lot of recipes and the most basic ones say something like 1/3 peat moss, 1/3 compost, 1/3 sand/soil.

I went to my nursery and they don't have cow manure nor mushroom compost anymore. They only have compost that came from leaves/branches/bark mulch etc.

My containers will be 10 ft longx 2ft wide x 2.5 feet depth of "soil". These containers are not for veggies or anything like that but to just transfer plants that I bought at nursery like Sky Pencil Hollys, some Boxwoods, etc.

Given this, what should I do? Is it okay to use the compost they have? I really don't want to be spending a bunch of money from big box stores.

And if you have any other recipes available let me know: This is what they have available:

- sand

-top soil

- leaves/branches/bark compost

- bark mulch

I have limestone and fertilizer myself that I would add some to it as well.

Thanks

EDIT - Stores around me don't carry neither vermiculite or perlite



Also, to line these wood containers, would it be best to line them with a good landscape fabric or just plastic sheathing to be impermeable (but maybe some drainage holes?)

Thanks

[Fishindude]

I've got three raised beds built of treated timbers approx. 16' long x 4' wide x 30" deep.   I put about a foot of large gravel in the bottoms for drainage and to take up some space, then filled them up with regular old topsoil dirt.   You can buy this stuff at about any greenhouse but I took the tractor and loader back to the woods and scooped out some good black dirt from a swampy area, then took a couple soil samples and sent them in to see what fertilizers I needed to add.   Never saw any need for a liner, the dirt will close up the cracks.

[MrSal]

I've got three raised beds built of treated timbers approx. 16' long x 4' wide x 30" deep.   I put about a foot of large gravel in the bottoms for drainage and to take up some space, then filled them up with regular old topsoil dirt.   You can buy this stuff at about any greenhouse but I took the tractor and loader back to the woods and scooped out some good black dirt from a swampy area, then took a couple soil samples and sent them in to see what fertilizers I needed to add.   Never saw any need for a liner, the dirt will close up the cracks.

In this case I probably really do need a liner since there's like 1/4" gap between the horizonal boards.



Like this but just out of 2x4s

[Fishindude]

I'll bet those planters pictured have the plants in containers and they are not completely filled with dirt, you can actually see what looks to be the tops of white buckets in the left planter.   If those gaps between the boards are something you like the appearance of, and you want to fill them up with dirt rather than containers, I'd make a sheet metal liner for the bottom and sides to contain the dirt and keep it from contacting what appears to be untreated lumber.

[TomTX]

I need to do a writeup on the "biochar" (natural charcoal) I've been making at home, using the "flame capped kiln" method and a 17 gallon galvanized washtub. Uses up all the sticks and stuff I hate to throw away - made at least 10 gallons of charcoal in about 2 hours.

For my tomatoes this year I mixed up 50% (aged/inoculated) biochar and 50% compost. They did fabulously - better than the ones in the garden. Kept producing all summer, despite having around 60 days of 100+ degree heat.

So, in soil biochar is basically a natural, rigid sponge for water and nutrients and a scaffold for beneficial micro-organisms. Typically you do an ageing/inoculation because it starts out as an empty sponge. Common methods are to mix with compost, manure or urine for awhile before use.