Seed Starting Mix

A note about the links on this page:

If you can’t find these ingredients in your local garden center, everything we use for seed starting is linked here in one place. These links go to our Amazon Affiliate page. If you make a purchase, we get a small commission, at no extra cost to you. This helps us continue to create gardening resources for you, and offer them for free. You absolutely do not have to use the same products we use. We are sharing them because we have been successful with them, and get many questions on them.

What is seed starting mix?

Seed starting mix is used to - you guessed it - start seeds in! The reason this is used instead of potting soil or garden soil is because new roots form better in this mix.

How does seed starting mix differ from potting soil and garden soil?

Potting soil and garden soil often have larger chunks in them, like bark or wood chunks. These chunks can make it harder for roots to move through and grow.

How to Make Your Own Seed Starting Mix

This is the seed starting mix we are using in the greenhouse this year. If you need a larger quantity of mix than you would get in a bagged mix, or just want to make your own, mix together:

4 parts peat moss

1 part perlite 

1 part vermiculite 

1 part worm castings 

✔️ Peat moss (sphagnum moss) provides a good base the roots can easily grow through. Coconut coir is a more sustainable option, and will offer the same benefits. 

✔️ Perlite (volcanic glass formed through the hydration of obsidian) is porous, so will retain some water, allowing excess water to drain, while providing aeration to the mix.

✔️  Vermiculite (aluminum-iron magnesium silicates) retains some water and minerals, and will release them over time. Vermiculite will also aid in aeration. 

✔️ Worm castings (composted worm poop) provide essential nutrients to the roots over time. 

🔥 Bonus tip - Using water that is warm to hot will help the seed starting mix absorb the water more quickly.