How to Make the Best-Ever Seed Raising Mix

With just a few simple ingredients, you can make your own seed raising mix at home. Discover the best seed raising mix to boost your seedling growth.

How to Make the Best-Ever Seed Raising Mix

Many factors contribute to successful seed germination including light, temperature and moisture. When these conditions are correct, seed germinates readily; when wrong, germination can be patchy at best. 

A good quality seed raising mix dramatically improves the germination of many seeds. To help gardeners with their seed sowing success, Diggers created a special seed raising blend(available in 5lt bags). You can also make your own seed raising mix at home using ingredients from your own garden and local garden supply. 

What makes a good seed raising mix? 

The four key criteria for good seed raising mix:

  1. Has a fine texture to support and surround seeds of all sizes.
  2. Allows ideal drainage while still maintaining adequate moisture.
  3. Provides gentle nutrition to support the developing seedlings after germination. 
  4. Is free from weed seed.  

DIY Seed Raising Mix Recipe

This simple recipe utilises resources from the garden to create a natural and sustainable seed starting mix at home.


  • 2 parts compost (sieved to ensure a fine tilth), 
  • 1 part washed sand
  • 1 part coir, worm castings or leaf mould (sieve to remove large particles)
  • Add an optional sprinkle of rockdust.


Mix all ingredients in a large bucket or tub to combine. Fill punnets or trays and use as you would a commercial seed germination mix.

If you make your own homemade compost, this is the perfect basis for making your own seed starter mix.

Seedlings trials growing in a container - seed raising mix Australia

Are all seed raising mixes the same?

According to our 2022 trials, No, not all seed raising mixes are the same.

In 2022, Diggers tested different seed raising mixes, including their own, to see if there were any differences. The results were astounding. We're happy to report that our Diggers seed raising mix was a clear winner, but the disparity of each mix was disturbing.

The results showed that the quality of the growing mix directly affects seed germination success and seedling development.  

Most seed raising mixes are composed of similar ingredients such as compost, coarse sand or vermiculite, manure or worm castings, coconut coir or peat moss. Obviously commercially made mixes vary in both ingredients and composition, while homemade mixes are entirely up to the gardener.

Seeds contain all the nutrition they need to get started. But as soon as they begin to grow, they draw on the surrounding mix for additional nutrients and moisture. After the true leaves appear, transplant seedlings into a suitable potting mix (if growing in pots) or an improved garden soil. 

Safety precaution: When making your own seed raising mix or when using a commercial preparation, always wear a mask to avoid inhaling fine particles, work in a ventilated room or outdoors to minimise inhalation risk and wash your hands before touching your face. 

Note: Diggers conducts seed germination tests to accurately assess the viability and germination rates of our seed varieties. Interestingly, this test is done without soil or growing media.