How To: Make Seed Starter Mix at Home

Growing your own starter plants from seed is a great way to save money in your garden. But, it can get expensive fast if you’re starting a lot of seeds. And you don’t really know what chemicals could be lurking in the mass produced, big bag mixes. Luckily, it’s pretty easy to make your own all-natural, organic seed starter mix at home. This is the recipe we use at Sunnyside Soil for our mixes, and we love it.

This recipe makes about 8 quartz of seed starter mix. You can easily double or triple it if you need more. We usually mix it in a mortar tray, but you can use whatever clean bucket or bin you have at home.

Step 1 – Coconut Coir

Start by adding three quarts of shredded coconut coir to your bucket or bin. Coconut coir is made from the fibrous husks of coconuts and it’s a great base for seed starting because it both retains moisture and is also rot resistant. Coconut coir usually comes in large hard blocks. To use it you’ll need to soak it in water to loosen it up. Just follow the directions on the packaging for how much water to use for the specific coir you have.

Coconut Coir Affiliate Link: https://bit.ly/4hz5NY0

Step 2 – Peat Moss

Next add in three quarts of peat moss. Peat moss adds hummus to the mix. Hummus is a carbon, which is the main fuel for seed life.

Peat Moss Amazon Affiliate Link: https://amzn.to/4iX4lzV

Step 3 – Worm Castings

Step three, add one quart of worm castings. This is our favorite ingredient because this is what adds life to the mix. Worm castings are full of micro life and nutrients, so once your seeds start to grow they will have these minerals and nutrients to feed on.

You can buy castings from us: https://www.sunnysidesoil.com/shop/p/worm-castings-1-gallon

Step 4 – Azomite

Next add one tablespoon of Azomite.  Azomite is a natural mineral powder that’s full of good minerals and nutrients for your garden. And it’s another added nutrient boost for your seeds to feed on as they grow.

Azomite Amazon Affiliate Link: https://amzn.to/4iia9DO

Step 5 – Rice Hulls

Step five, add one quart of rice hulls for aeration. Traditional seed starter recipes will tell you to add vermiculite or perlite instead of rice hulls. Perlite is derived from volcanic rock and vermiculite is magnesium-aluminum-iron silicate. Both are non-renewable resources and both will literally take millions of years to breakdown in your garden. 

With rice hulls you still get all of the aeration your seeds need, but the hulls will breakdown much faster in your soil. And they add food to the micro biology of your soil which make them a win-win.

Rice Hulls Amazon Affiliate Link: https://amzn.to/4iZHsff

Step 6 – Mix

Finally, fluff it all together.  You want your mix to be spongy and damp. If it’s too dry (and odds are it is) add water and mix again. You’ll know you have the right moisture level when you squeeze a handful of the mix and it bounces back in your hand. 

And that’s it. You can use this right away, or pack it up and store it in a cool, dark spot. As long as you keep the mix moist, it will last for months. If you’ve read this and love the recipe but don’t feel like making your own, we sell this exact mix in our store and we are happy to do the mixing for you.

You can buy seed starter mix from us: https://www.sunnysidesoil.com/shop/p/seed-starting-mix-8-qt