Seedybeans Blog

Celebrating the Humble Harvests of High Desert Homesteading

Making soil mix

One of my favorite activities is making dirt– It feels like a miracle when you do it and really connects you to the components of what is in soil that makes it so fabulous to begin with.  If you never have done it, I highly recommend it.  You will need to gather a few materials if you want to make a soil mix that is good for seedlings, some store bought, but you will save money in the end if it is your habit to just buy seedling mix.  Making it yourself also gives you options to make mixes that are appropriate to the job at hand; you can make a fine mix for seedlings, a richer one for potting up and even a grittier one for cactus and such.

If you are a teacher or doing gardening with kids, it is a great activity because it is a lot like cooking, only you don’t have to wash your hands till after!!  A bunch of kids gathered around a wheel burrow, mixing and shifting is a great sight, though keep in mind– (FINE DUST FROM SOME OF THE INGREDIENTS CAN BE DANGEROUS TO YOUR LUNGS AND THE LUNGS OF LITTLE ONES…..VERMICULITE, PEAT MOSS AND PERLITE ALL HAVE FINE DUST TO BE AWARE OF)

Now if you feel so bold– here is how I do it

Gather your Materials

Peat Moss or Coir Fiber- Peat moss is made from the remains of dead plants that have decayed over hundreds of years.  Sphagnum moss is specifically moss that grows in peat bogs in Canada and other northern regions.  These are common in soil mixes because they are so fine and hold moisture incredibly well.  Coir Fiber is made from the husks of coconut and much more renewable and eco-friendly than Peat Moss, which take hundreds of years to form and is getting very rare.  These two are interchangeable in soil mix but Peat holds nutrients better, where as Coir Fiber holds water better. Coir fiber is also not as acidic as Peat Moss.  They both are highly compressed in packing so it is good to open them up and put them in a wheel burrow or container and pre-moisten them a day in advance of making soil mix.  They will absorb the water and become fluffy and expand quite a bit.  You can should break up any clumps before using in mixes.

Peat Moss

Fine Sand– Gathering Sand from the arroyo and sifting it through an old window screen is perfect.  Store bought is fine as well, but never use sand from the seashore.  Sands main role is drainage and aeration in soil mixes but can create a cement when mixed with heavy clay soils so keep that in mind.

Arroyo Sand

Garden Soil– Sifted through a 1/4 inch sifter for finer mixes.

Compost– From your pile or  from the store is fine–Sifted through a 1/4 inch sifter for finer mixes

Worm compost-before sifting


Vermiculite – Exploded Mica that is good for drainage, but does have a fine dust that is harmful when inhaled. Pre-moistening can cut down on dust


Perlite– Exploded volcanic rock that is good for drainage, but also has a fine dust that is harmful when inhaled. Pre-moistening can cut down on dust.


Once you have all your ingredients you will need a wheel burrow, mixing hoe and shovel.

Wheel Burrow and hoe

Mix— Now when you are following the recipes below, it is important to think about the qualities of your ingredients.  You basically want a balance between materials that are nutritious, hold moisture and drain moisture.  These characteristics will of course vary depending on what the mix is for (Ex: cactus want more drainage than seeds) but before you simply follow a recipe it is good to understand what each element brings. Now–Follow the recipes and mix all the ingredients together, making sure to mix well and get everything hiding in the corners, you don’t want pockets of unmixed material.  This is a great job for taking turns, especially with kids.


It is good to have water on hand as well, and I of course prefer a watering can or nozzle with a very fine spray, as it is disperses well in your mix and cuts the dust down considerably.  It is nice to have someone else help sprinkle water as you are mixing, not too much not too little.

A fine sprinkle is ideal

You want the mix to be ‘as moist as a rung out sponge’ when you are done. It should feel moist to the touch but when you squeeze it into a ball you are not able to squeeze drops of water out. When you go to use it, if it isn’t the same day, you will want to make sure this moisture level is the same.  Storing the mix in Tupperware can help with this, or just add water when the time comes.


Squeeze in a ball

release you should have a ball that breaks up easily

A note on Sterilized Soil–Many farmers and greenhouse owners buy seedling mix because it is sterile, and thus free of diseases that can be carried in soil.  Though we talk a lot about the life of the soil, when it comes to indoor conditions of seed starting, having too much life can create imbalances that nature can’t manage because greenhouses are human controlled environments.  Diseases can really set you and seedlings back so if you know diseases are present, you may want to sterilize your soil.   I have always used soil and compost from my garden without sterilizing, and have had no problems.  I have also been to farms gardens where the gardeners sterilize their own soil by baking it.  I have seen this done in the oven as well as in steel drums over a fire.  The soil only needs to get to 180 F degrees to kill most harmful things.  If you get it too hot it can start to release other toxins, so beware.  Cooking soil stinks so consider yourself forewarned.  It will create a ‘dead soil’ but when seedlings are small the don’t need as much biological activity as when they grow up.  If you choose to sterilize your soil let me know how it goes.

Below are the soil recipes I like to use, published from the University of Santa Cruz Center for Agro-ecology– where I learned all my tricks.



3 parts compost (sifted .5 inch screen)

2 parts soil

1 part sand

2 parts coir fiber (premoistened)


2-1/2 compost (sifted .5 inch screen)

1 soil

2 coir fiber (premoistened)

1/4 gallon kelp meal (*1 tablespoon)

*Use 1/4 gallon when one part is equal to one

wheelbarrow. Use 1 tablespoon when the measure is

a shovelful.


1-1/2 compost

1-1/2 partially decomposed duff

1 used mix

1 sand

1 perlite

1/2 soil


3 potting mix

1 sand

1 perlite

Hope this was helpful and have fun playing in the dirt!!!


  Pablo Navrot wrote @

There are two things about the soil mixes that I find quite refreshing. First, the formula calls for garden soil – sand, silt, and clay. I find that this helps retain moisture quite well. Although it is usually discouraged because it fosters root ball shrinkage, it is not much of an issue unless it is used in much greater proportions. Second, you are not proposing the use of a sterile mix. I have never seen healthy seedlings have trouble in such conditions. Rooting stem and leaf cuttings, performing layering techniques and maybe transplanting desert succulents is really the only reason to use a sterile media from what I gather.

  Planting into pallets | Seeds & Stones wrote @

[…] you are ready here is a link to how to make potting soil for the flats and one on how to plant into them properly.  Let the sowing […]

  Homemade Potting Soil | Seeds & Stones wrote @

[…] make potting mix every year for my greenhouse seedlings.  I have written about it many times here & here, but every year I refine it, learn more, change things, or get my hands on something […]

  Seeds Starting Recap | Seeds & Stones wrote @

[…] and moisture to germinate, that is sprouting before photosynthesis.  Once you sow seeds (in a moist sowing mix) you MUST keep them moist at ALL times.  Yep, Always!!!! that means watering many times a day if […]

  Jere wrote @

Hi there! This post couldn’t be written any better! Reading tnrough
this post reminds me of my old room mate! He always
kept chatting about this. I will forward this article
to him. Pretty sure he will have a good read.
Many thamks for sharing!

  seedybeans wrote @

So glad you like it!! Thanks for letting me know!

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