Seed Starting Mix
Seed Starting
Seed starting mix is a lightweight growing medium designed for germinating seeds and supporting young roots. It is usually finer textured than garden soil and drains well while still holding moisture.
How to do it
Choose a clean, fine-textured mix intended for seed starting and moisten it before filling containers. Gently fill trays or pots without packing the material too tightly, then sow seeds at the proper depth. After sowing, firm the surface lightly so seeds have good contact with the mix. Keep the mix evenly moist and transplant seedlings to larger containers or the garden as they grow.
Timing
Use seed starting mix whenever you are germinating seeds indoors, in cell packs, or in small pots. It is especially useful early in the season when outdoor garden soil is too cold or wet for reliable establishment. Once seedlings develop further, some crops benefit from moving to a potting mix with more structure for continued growth.
Tips
Do not use heavy garden soil in small containers because it compacts easily and may drain poorly. Pre-moistening helps prevent dry pockets and makes filling containers easier. Replace old, contaminated, or badly decomposed media rather than trying to refresh it for delicate seedlings.
General guidance for US gardens. Timing depends on your local frost dates and hardiness zone. Page updated Aug 4, 2026.