It’s time to start getting ready for spring! If you don’t have space for a garden, or just like to have a few plants closer to or in the house, you’re going to have to pot your plants. One thing people don’t always consider is the cost of dirt, a quality potting soil can be a little pricey if you have more than one or two plants. You can get away with cheap stuff, but it is usually either poor in nutrients or filled with weed seeds or chemicals, so why not mix your own?  A good potting soil needs to be light so you can move it,  rich in nutrients,  and have the right drainage and water retention properties based on what you want to grow.   Let’s cover the basic components of potting soil and what they do for you

Dirt(top soil):
It’s pretty straightforward,  you can buy sterilized potting soil (no weed seeds) from the store,  or dig some up dirt from your back yard.  This is a base to start from with nutrients for your plants. Compost is better,  but dirt will do.

Compost:
Decomposed organic material,  the gold standard. You should always use compost if you can get some.  This is one thing where local is better; the best part of compost is that it’s literally alive. If you make your own or buy local,  chances are there are still microscopic organisms that your plants will benefit from.  Store-bought will still be rich in nutrient,  but will be completely dead. You can get around this by mixing small amounts of finely shredded vegetable scraps or paper if you can’t find quality compost, it will break down in your pot and act like tiny compost nuggets over time.

Manure:
AGED manure (partially composted) is a great addition,  and acceptable substitution for compost. Do  NOT use human or pet manure,  our diets leave behind too many toxins to be safe to use. Instead look for a local farm with horses or cows.  If it didn’t just come out of the back end,  you’d be surprised how little it smells.  I spread two trailers full of horse manure for my garden in the back of an 1/8 acre lot and nobody would believe there was so much horse poop in my garden.

Worm Castings:

Aka worm poop, is somewhere between compost and manure, and is very high in minerals and nutrients, but are pretty expensive if you try buying from a store instead of producing your own. If you are buying it, I recommend you use small amounts as a soil amendment instead of as a base for your potting soil.

Perlite:
This white stone “popcorn” increases aeration and drainage for the health of your roots. It is covered in microscopic pores, which provides excellent habitat for microscopic organisms and keeps your pots nice and light

Vermiculite:
Frequently confused with Perlite, Vermiculite is similar in that it improves aeration and drainage.  However,  Vermiculite is more of a brownish mineral-based sponge which is better at retaining moisture in the soil, and less efficient at aeration than Perlite.   Which one you prefer depends on the needs of your plants.

Mulch/wood chips/bark:
Relatively light weight and in large pieces,  for most plants you want to use small amounts of this to help with texture, aeration and drainage. Cedar or pine bark/chips, or pine needles,  are a good choice for acid loving plants.  Instead of mixing it into your top soil,  you can also cover the exposed soil after planting to help prevent evaporation and reduce the amount of watering needed.

Peat Moss/Coconut Coir:

It’s really a crapshoot in my opinion, because peat moss, while being very light, is both hydrophobic (nearly impossible to get wet) and a great amendment to help keep your soil moist.  If peat dries out too much, it will be nearly impossible to get it to absorb any water.  If you are eco-conscious, definitely go for the equivalent coconut coir, it’s derived from shredded coconut husks and is much more environmentally friendly than depleting peat bogs, which take centuries to milllenia to replenish.

Those are your basic ingredients for a potting soil,  the ratios of which can vary greatly based on what you want to accomplish.

A generic potting soil can be made from two parts of compost/dirt, one part Vermiculite/Perlite based on if you want drier or wetter soil, and one part peat/coconut coir. You can add in a little mulch, bark,  or leaves for more aeration and organic material, most plants can tolerate a wide diversity. Just make sure everything is very will mixed, and for the love of god don’t listen to those people who tell you to add rocks or packing peanuts to the bottom of a pot. This barrier between layers of materials with different sizes and textures raises the level where water will sit and collect, causing your roots to rot.

If you want to get more detailed, any quick google search should point you in the right direction if you are looking to accommodate a unique plant like succulents or ornamental bulbs.