I make potting mix every year for my greenhouse seedlings. I also make mixes for my mom’s raised garden beds, (at home I grow in the ground and do things a bit differently for that). I have written about making potting soil many times here & here, but every year I refine it, learn more, change things, or get my hands on something new.
I gather my materials from my yard and pre- sift everything so I have it ready to make mixes when I want to. I sift it because little plants need readily available nutrients and fine tilth so their roots have an easy time growing. Any big chunks sifted out can go back into the landscape under big trees and around perennials.
Sifted Compost from your own pile (or another source if not is available)
Sifted Soil from your garden
Sifted Sand from your arroyo
Moistened Coco Peat ( this is the only thing I buy and I get it locally at Agua Fria Nursery)
I get all this stuff in advance and store it in bins so everything is ready to go when I need to mix.
Once I have everything gathered I get my
a 5 gallon bucket,
a shovel and
Here is my the recipe I use, adapted from my Alma Matar, CASFS.
It is a parts recipe, but if you use a 5 gallon bucket as your measuring cup and follow this recipe you will get a full wheel burrow, which will be enough soil for 10 flats of 2 inch pots or 6 homemade wooden 2x1ft seedling trays.
Mix into wheel burrow
1 Bucket-Shifted Compost
1Bucket- Shifted Garden soil
1 Bucket Coco Peat
This is the base recipe from here you can add all sorts of fancy things if you have them:
Ground up egg shells
Oh there is so many thing you can add to soil mixes and that is really determined by how much money you have, what you are trying to grow. I keep things pretty simple around here, but have fun with what you decide to add to you soil, (or ask me for more advice!)
Mix everything well with a hoe and sprinkle occasionally with water.
The moisture level is key, not only does it cut down yucky dust, but you want a nice moist mix in your flat before you seed.
If it is too dry it will actually repel water and you tiny seeds will float away in the run off.
Give it a squeeze and release
If it stays in a loose ball and breaks apart when you bounce it in your palm you have got it. Now store it in a bin with a lid to keep that perfect moisture, or put it directly into you flats and sow away!
And that is that. Once you have your flats made & potting mix made, now all you have to do is decide what to grow. Go here if you are ready for the next step!