Updated: Sep 6, 2022
Starting your own plants from seed (whether you're going for an edible or ornamental garden), should be a rite of passage for every gardener.
For successful seedlings, it's important to have a good seed starting potting mix. One popular option for gardeners is a soilless mix, which is light and aerated so those tiny seedlings can easily emerge.
Your garden may not be a buzz of activity right now, but you can keep that serotonin going by prepping this soilless potting mix for your seeds. Get a head start now with seeds that will be ready to be put in the ground once the weather warms.
Why use soilless potting mix?
● Soilless planting mediums help to control insects, diseases, bacteria, and other soil deficiencies in garden soils.
● Garden soil is typically heavy, which may not support the delicate new root systems of the young seedlings.
● Makes transplanting mature seedlings into their pots easier as the roots will be less prone to damage. Plus - the soft material can shield the roots when they’re first transplanted into soil.
Soilless potting mediums
Soilless potting mixes can be made in several different ways using various soil additives.
Soil additives are already optimized for plant growth. These benefits make them great for starting seeds.
Coco peat or coco fiber - comes from coconut husks & is a sustainable alternative to peat moss. It’s very light, holds water & is beneficial for roots.
Perlite - is a natural volcanic mineral that increases drainage & lightness in soil mixes. It’s also moisture-retaining, so seeds can get the consistent moisture they need as they germinate.
Sphagnum peat moss - is lightweight, retains water so it works great as a soilless potting mix for seedling starts. This medium takes some experience to work with.
Vermiculite - does much the same thing as perlite. It holds water and nutrients and aerates the mix.
Ag lime - is crushed limestone that promotes healthy root growth. Elimite, gypsum and azomite also stimulate root growth & overall health.
Bark - also aids in improved drainage and aeration but not moisture. It is great in mixes for plants with bigger root systems.
Coconut coir - is a coconut fibre by-product that can be a substitute for sphagnum peat moss.
Soilless potting mix recipe
This recipe is a guide for mixing the soilless seed starting mix using your standard garden measurement (one part might equal one cup or one scoop), rather than precise volumes.
The key is for the final mix to have a certain proportion optimal for seedlings to sprout.
This mix can be used for propagating cuttings too. Stem cuttings, leaf props, etc grow well in it because the roots can easily emerge and grow into the soft medium.
● ½ part peat moss/coco peat/coco coir (to provide bulk and support the seedlings)
● ½ part vermiculite or perlite or combination (for moisture retention and soil aeration)
● ½ cup ag lime, elimite, azomite or gypsum (to amend soil pH)
● 1 tsp. bone meal/plant food (to promote growth)
Now that you know what your soilless seed-starting mix needs, choose a great location and start planning for summer planting - but first, head over to one of these black-owned seed companies for the best heirloom stocks.
What do you use to start your seeds? Share your mixes with us!