How to Make the Best Seed Starting and Potting Mix

Sowing seeds in the growing season is incredibly exciting. Think about all the fresh and tasty homegrown produce to come within the next couple of months. To begin the process of seed sowing, you’ll need some good seed starting mix. A good seed starting mix is expensive unless you make your own. The perfect seed starting mix mustn’t be too high in nutrients which could harm delicate seedlings. Overly wet conditions can rot seeds and encourage fungal diseases such as damping off. Mixing your own potting mix blend is easy and it means you have complete control of one of the most critical steps in the growing process. For container gardeners, a high quality potting mix is a must. Making your own potting mix allows you to better cater to the needs of your plants. The results are more stable and consistent and you save a ton of money.

Making the Seed Starting Mix

Here’s a very simple soilless recipe which is beautifully light and fluffy. All the ingredients are natural too, promoting good strong growth and healthy happy seedlings. Begin with 2 parts compost as your base. All parts measured by volume, so it doesn’t matter what you use to measure your ingredients as long as you are consistent. The compost adds slowly released nutrients to the mix, which will help to feed seedlings as they grow. You can use your own garden compost or buy some in. Once you have the compost, break the clumps with your hands and sieve the compost to get a fine even texture.

Now add 2 parts coir or coconut fiber. Coir is extracted from coconut husks making it a sustainable and good alternative to peat or peat moss. Extracting peat can damage fragile ecosystems and it contributes to climate change. So it’s always better to avoid using it. If you bought your coir as a block, rehydrate it first by soaking it in a bucket with water until you can easily break it apart. If you prefer, you may substitute well rotted leaf mold in place of the coir. The coir or leaf mold contribute bulk to the seed mix and are great for moisture retention.

Finally add one part perlite which will improve the air content of the mix. If you prefer not to use perlite, then you may substitute sand though it will give you a heavier mixture. Use a spade or your hands to mix all of the ingredients together. Take your time and be thorough. You need a consistent mix with all of the ingredients evenly distributed. Once you are done, store the seed starting mix in a properly closed container or in a potting soil sack. Don’t forget to store your mix in a dry and cool place until you use it to sow seeds.

Many seedlings need potting on into larger containers at least once before it’s time to plant them out. Most will be happy in the same seed starting mix. But the hungriest seedlings like tomatoes and watermelons appreciate something little bit richer. Adding some worm compost to the mix gives the additional nutritional boost you are after.

Making the Container Potting Mix

Try this potting mix for the plants growing in larger containers. Thoroughly combine 2 parts garden compost with 1 part coir or leaf mold. Then add some perlite for drainage about 2-3 generous handfuls to every 10 gallons or 40 liters of coir compost mix. A similar amount of worm compost can also be added for hungry plants or incorporate a slow release organic fertilizer according to the manufacturer’s instructions.

Plants grown in the same container for a long time need a potting mix that holds its structure and is buffered against nutrient imbalances. Loam or good quality garden soil offers this. Simply combine 1 part loam or garden soil with 1 part garden compost. Then add some slow release organic fertilizer. This is a versatile potting soil for many fruit trees, bushes and perennial vegetables.

Benefits of Making Your Own Potting Mix

If you have a large amount of potting mix to make, you can save money by buying individual ingredients in bulk and mixing yourself. At the same time, if you have concerns about ingredients used in commercial mixes, making your own potting mix is one way to ensure you know exactly what you’re growing in. Except for that, when you can’t seem to find a potting mix that’s quite right for your garden, going DIY allows you to create the exact mix you need.


Whether you want to save money and to opt for a more economical option or you’re not satisfied with the quality of potting mix you bought from the store, it’s a great idea to learn how to make your own potting mix. Making your own seed starting and potting mix is super simple and it allows you to better cater to the needs of your plants. Never use regular garden soil for houseplants in containers because the garden soil does not fulfill the nutrient requirements of the houseplants and compacts in pots. When making DIY potting mixes, use the batch as quickly as possible. But if storage is necessary, place the mix in sealed plastic bags in a cool and dry place.

Potting Mix Facts

  • Potting mix is a blend of materials like sphagnum moss, bark, perlite, vermiculite, compost and coir that’s intended for growing plants in containers.
  • Seeds don’t require fertilizer for germination, so it’s somewhat wasted if you are using it for seed starting.
  • A good potting mix should have the capacity to retain some air and moisture and yet drain well and hold nutrients.
  • Some potting mixes may contain actual soil as one of the ingredients.
  • The best way to judge a potting mix is to see how well your seedlings do.
  • You certainly could use soil right from your garden to start seedlings indoors, but garden soil comes with two major disadvantages including lack of drainage and diseases.
  • The correct degree of acidity for potting mix is between 5.8 and 6.2.
  • A potting mix normally needs about 6 Kg of lime per 1000 L to increase the pH. After adding the lime, it will take a few weeks for the pH to stabilize.
  • Some potting mixes are not suitable for organic gardening because of synthetic ingredients they contain.
  • The main disadvantage of potting mixes is that it can be expensive, while soil from your garden is free.

You May Also Like