Here's My No Fail, Super Simple, DIY Seed Starter Mix

Here's My No Fail, Super Simple, DIY Seed Starter Mix

Starting your seeds indoors is a great way to get a head start on the gardening season. One key component of successful seed starting is a great seed starter mix. Making your own seed starter mix can be a cost-effective and customizable option that ensures your seeds have the best possible start.

The Recipe

Here’s how we make our seed starter mix—super simple! Only 2 ingredients—compost and vermiculite!

We start with our own compost. Our basic recipe seed starting mix includes our homemade compost and vermiculite. We use a coarse vermiculite, brand name Palmetto from the Palmetto Verminculite Company. 

Vermiculite ready to mix!

Our Compost System

We use a very simple method of worm composting our kitchen scraps and organic waste material from the garden here at Prairie Road. We call it the 'no work' worm composting method. Let the soil microbes and the worms do the work for you. You can watch our YouTube video on how we manage our pit vermicompost system here.

Our compost pit method-- 2 pits side by side (left full; right ready to fill)

I also started a worm bin to create compost in my basement over the winter months. That has been a good experience—one that I'll surely repeat next winter! I have yet to harvest that compost but my worms are happily multiplying and munching away— so stay tuned for updates on that as the spring advances.

Balancing Moisture and Aeration

A good seed starter mix provides a balance of moisture retention and aeration. The nutrients essential for seed germination are present in seed itself—seeds are a self-contained unit with everything that seedling needs to sprout, establish its roots, send out its first cotyledon leaves, and grow its first set true leaves.

So the seed starter mix doesn’t need to be nutrient rich. In fact if the mix is too rich it can ‘burn’ the germinating seedlings. Once the seedlings send out their first ‘true leaves’—it’s time to transplant them into a more nutrient rich planting mix. But your initial seed starter mix doesn’t need to be nutrient rich.

Mixing Your Starter Mix

We screen our mix first to make sure to eliminate clumps or debris that could hamper tender seedlings. Then we mix our starter mix at a ratio of 10 parts compost and 3 parts vermiculite. That’s it!

 It doesn’t matter what you use to measure; use whatever makes sense for the amount of starter mix you need for your plantings. A measuring cup will work for smaller amounts, or maybe a tin can, if you’re mixing a 5 gallon pail amount, or a larger container if you’re mixing a wheelbarrow full. The important thing is the ratio!

We mix it really well to completely blend it in and create a uniform texture. This will make sure to support even moisture distribution and good root development.

Seed starter mix all ready to go at Prairie Road Organic Seed
Seed starter mix all ready to go!


We often use a small wheelbarrow for mixing. To mix smaller batches we’ve used a 5 gallon bucket that is 1/2 to 2/3 full. This allows you to get your hand and arm in there and really mix and blend without too much spillage. If mixing bigger batches, a tarp is advisable!

Other recipe options

There are other options for creating your own starter mix. A common recipe is to combine equal parts peat moss, perlite, and vermiculite, along with a small amount of compost for added nutrients. Or you can substitute coconut core for the peat moss for a greener option.

A good purchased option

If you don’t make your own compost and need a purchased option—this is one that comes highly recommended by a friend of mine, who operates a market garden and CSA. He uses this—Organic Pro Seed Starting Mix.

Your garden coach,

PS. My next post will be actual seed starting tips! Stay tuned!

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