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Choosing the Right Soil for Seedstarting

If you plan to start seeds indoors — under lights, on a windowsill or in a greenhouse — don’t use regular potting soil. It's too heavy and dense for the delicate, hair-like roots of a newly-germinated seed.

The best soil mix for seedstarting is not really soil at all. It's a growing medium comprised of sphagnum peat moss and small amounts of vermiculite and/or perlite. This blend helps ensure a consistently moist environment to encourage good germination. It is also light enough to provide lots of wiggle room for tiny roots. Just as importantly, it has been sterilized to eliminate bacteria and fungus which can cause problems such as “damping off,” a disease that kills seedlings.

Eco-co Coir™ Seedstarting Mix

This coir-based mix is an effective, economical and earth-friendly medium for starting seeds. Derived from recycled coconut husks, Eco-co Coir passed our extensive seedstarting trials with flying colors, providing excellent germination rates and producing healthy, sturdy seedlings. Unlike other blends, our coir is processed to remove salts and balance the pH for optimal plant growth. Then it's finely ground to provide the perfect environment for seedling roots. Eco-co Coir has excellent water-holding capacity yet drains well — so important for healthy root growth. Simply add water and each compressed brick expands to 10 quarts of fluffy planting mix. Recommended for all of our seedstarting systems.

Learn more in the article Coir: A Better Way to Start Seeds.

Professional Germinating Mix

Professional Germinating Mix is a great choice for starting seeds — especially very tiny flower seeds like those of petunias, snapdragons and flowering tobacco. It has an ultra-fine texture because the sphagnum peat moss has been milled to remove all clumps and lumps. This mix is also a must for the APS seedstarting system because it doesn't get waterlogged when it's used with capillary matting.

Organic Seedstarting Mix

Organic Seedstarting Mix: Can the best seedstarting mix get better? Our tests say yes! This 100% organic blend is the new gold standard for starting plants from seed. Sphagnum peat and perlite give it the same fine texture and superior moisture-holding characteristics as our original Germinating Mix. The addition of compost, protein meal and trace minerals puts this organic seedstarting mix in a whole new league with results that impressed even our most experienced gardeners: faster growth, heftier root systems, and beefier plants. Recommended for all of our seedstarting systems.

Transplant Mix

Transplant Mix contains essentially the same ingredients as the Germinating Mix, but it has a more coarse texture. It is the right mix for starting larger seeds such as cucumbers, zinnias and marigolds. It’s also the right choice when it comes time to transplant seedlings into larger pots.

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