Great tip, Patricia!

So many potted plants have different needs from one gardening area to the next, that it's difficult to choose a one-for-all pre-made mix.

I've mixed my own media for years as the commercial mixes are not right for the plants I grow. I like being able to tailor my mix to the plants I'm going to pot up. Years ago I purchased a small cement mixer (plastic drum, not metal) and that mixer has never seen a bag of concrete, ever. It has been used only for mixing my soil media.

LariAnn

I make my own too. I usually can smile sweetly at the nice man at the local ready-mix concrete place when I ask him "how much" for some sand. He asks "how much do you want?" I say 4-5 gallon pails. He waves his hand at me and says "take it". :>)

My mix is 2 parts peat moss and 1 part each of sand and compost.

I like conifer bark to improve drainage and reduce cost (around $2 per cubic foot for clean dry bark mulch). Then I screen it myself.

If it is held back even briefly by 1/2" mesh, I use it as top-dressing mulch outdoors (but I could grind it up if I wanted to).

Then from the rest, I remove dust and powder. If it passes too easily through 1/8" hardware cloth, it's too much like peat moss and kills the aeration & drainage. I use bark powder and fine fibers to lighten clay soil for filling raised beds (I mix it in well).

If it won't pass pretty easily through 1/4" mesh, it might be too coarse for seedlings or small pots, but be good as the coarse component for 5-gallon buckets.

In-between .1" and .2" seems right to me as the coarse component in potting soil, depending on pot size.

Does anyone like to add vermiculite or lava sand? I think it adds drainage and moisture control...but maybe wrong

I started using a lot of vermiculite after I submitted this tip, and it really helps with moisture retention. Seeds sprout well in vermiculite or a mixture of half peat and half vermiculite. I actually put vermiculite in all my soil mixtures now!

Do you use perlite also?

This is a nice tip indeed So as you make your own potting soil, do you mix in the old soil with the new one right away or bake the old soil before mixing in with the new potting soil?

Old mix that I am reuse may have some perlite in it, but I have not been adding it to new mix since I discovered vermiculite.
I don't sterilize peat and vermiculite mixtures, but if I add top soil to a mix for seed starting, I sterilize the top soil in an old microwave prior to mixing. Mostly, however, I am using peat and vermiculite mixtures for seed starting, and the plants seem to approve.

>> Mostly, however, I am using peat and vermiculite mixtures for seed starting

Can you teach me your magic touch for avoiding overwatering?

I've been making my mixture so open I can top-water my mix until it comes out the bottom, and still have an aerated medium.

But that does not Not NOT work with peaty commercial mixtures. They just get saturated and hold far too much water until the seeds or roots rot.

How large are your vermiculite grains?

I use coarse vermiculite. I live in the middle of nowhere, so I ordered vermiculite from Greenhouse Megastore, and coarse is what they had in the big bag. I soak the vermiculite or vermiculite/peat mix and then pour off all the water I can, pressing the mix down with a coffee filter to drain as much excess water as possible. I just mist the surface daily until seeds sprout. I use about half vermiculite and half finely sifted peat for most seeds and dust over the seeds that want to be covered with very finely sifted peat.

>> pressing the mix down with a coffee filter to drain as much excess water as possible.

Wow, squeezing it like a sponge?!?

>> just mist the surface

Me, too.

I've started putting a "capillary pad" under my seedling pots and trays. It touches the soilless mix through the holes and wicks away some of the excess water. It also makes it easy to bottom-water uniformly without pouring an inch of water in to the trays. If I get the cotton flannel good and wet, there is a little excess down in the grooves of the tray, and every cell can wick up as much water as it wants without drowning.

I killed whole trays full of seeds my first two years, and now I have a fast6 drainage/aeration fetish.

PTSD: Post Tray-Saturation Disorder.