How to Make Your Own Seedling Soil

How to Make Your Own Seedling Soil with the LED Indoor-Herb Garden

How to Make Your Own Seedling Soil

Posted by: Jake Moss Category: How To's, Plant Talk Tags: , , ,

Seed starting indoors begins with having the best seed starting mix. Luckily, you can make a DIY seed starting mix right from home. Making your own is recommended over buying a store-bought seed starting mix, as you can control what ingredients go into your mix. Not to mention, it is so much cheaper this way! And you can make a large batch and store it for next season.

The Recipe

Supplies Needed

  • Ingredients above
  • Large bucket for mixing
  • Spade (or you can use your hands, if you are not afraid of some dirt!)
  • Seeds! (We have great success with Rennee’s Garden Seeds)
  • Seedling Trays or Cow Pots
  • Optional: Food Safe Bucket for storing afterwords
Supplies for DIY Seed Starting Mix
As you can see, the ingredients for our seed starting mix make for a refined and ultra-fine mixture- perfect for germinating seeds!

Keep in mind, the best seed starting mixes are fine and loose. This fine mixture allows seeds to germinate and grow with ease.This is a soilless, fluffy recipe and includes only organic ingredients only- making it ideal for seedlings.

The Ingredients Explained

Coco Coir

For our base, we chose coco coir instead of peat moss- making it a peat-free and soil-less mix. We are firm believers in the notion of peat-free gardening. Peat moss is an active ingredient in many gardening soils, compost and much more. However, extraction of peat moss has detrimental effects on the planet. Fortunately, coco coir is a sustainable alternative to peat moss and has excellent water retention properties. Read about peat-free organic potting mix here.


For just a bit more moisture, we added vermiculite. This soil amendment is used universally by growers for seed germination and rapid root growth. Read more about the uses of vermiculite here.

Organic Compost

Next, we added compost. You can either make your own from home or you can purchase some from your local garden store. Why is compost important for seed starting mix? It slowly releases nutrients to the seedlings, which will assist in the growing process. The key is to not oversaturate your seedling mix with nutrients, especially during the germination process. Do make sure you break up the compost, so that that your mix is free of large chunks of substrate which can impact the growth of your seeds! Once your seedlings have developed, you can then start to think about fertilizer.


Then, we added some pumice for drainage. Pumice will help lighten the mix and provide some drainage for your seedlings, so don’t leave this stop out! Perlite can be substituted for pumice if needed. Vermiculite is another component we like to add to our seed starting mix. It retains moisture and is essential for seed germination!

Finally, use a spade or your hands to mix all the ingredients. Make sure the mixture is evenly distributed. If you have some potting mix left over, we recommend storing it away for next season!

DIY Seed Starting Mix
The best seed starting mix is a soilless, fine mixture. See above.

Regular Potting Soil vs. Seed Starting Mix

What is different about seed starting mix is that they often times they have have less nutrients than regular potting soil. Why is this? The experts affirm that seedlings are not to be exposed to an abundance of nutrients- just ask the editors at the Old Farmer’s Almanac. Another key difference is that, potting soils are more dense, making it more susceptible to mold buildup and damping off. Furthermore, this disease often times occurs during the process of germination,  when there is a fungus in the growing medium. But, you can prevent damping off with a well-draining seedling mix!

Why make your own seed starting mix?

There are so many reasons why!

  • It’s cheaper!
  • Better for the environment
  • Make a large batch and store away for next season
  • You can control what ingredients your seedlings receive

Final Note

We are a strong advocate for the power and art of DIY. There’s just something so mundane about going to a local store and hand choosing all the supplies you need for a project. Just like our DIY indoor potting mix recipe, this seed starting mix  is a peat-free  mix which can be made with just a few ingredients! For best results with seed starting indoors, consider using an LED light set up to ensure your seedling are getting proper sunlight. See our LED Grow Garden below.


seed starting indoors with Tabletop LED Garden
LED lights are highly recommended for starting seeds indoors

Happy Growing!



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