How to Start Seeds in Peat Moss or Potting Soil
Starting seeds in containers with peat moss or other appropriate medium will allow you to start the growing season early and offers you greater control over the germination and seedling environment. Selecting and preparing the containers and medium for sowing the seeds is very important and greatly influences the degree of success you will have with sprouting and young plant development. The ideal germination medium should offer a fine texture, excellent drainage, good aeration and low fertility. It will also not contain weed seeds, pests or disease pathogens.
Select and disinfect, if necessary, a flat or other shallow containers that offer plenty of drainage holes. New, never-used containers are typically sterile, but previously-used trays or pots could contain debris that is hosting pathogens or pests. Wash all debris off of the containers and immerse the container in a solution that contains 10 percent bleach for five minutes. Let the container air dry before using it.
Choose or prepare an appropriate germination medium. Sphagnum peat moss alone can be used to start seeds or you can blend it with vermiculite, sand or perlite. Potting soil or loamy garden soil by itself is often too heavy for seed starting, but a mixture of two parts soil, one part peat moss and two parts sand or vermiculite is acceptable, especially for large seeds. Use only sterilized potting soil to avoid problems with diseases, pests and weeds or sterilize soil prior to using it by placing damp soil no more than 4 inches deep in an oven-safe container covered with aluminum foil and heating it to 180 degrees Fahrenheit. Keep it at that temperature for 30 minutes, then let it cool and keep it covered until you are ready to use it.
Fill the flat or other sterile containers most of the way with the chosen or prepared germinating medium. Gently firm the medium down as you place it in the container and fill the container to about an inch from its top.
Moisten the germinating medium thoroughly and evenly. Wet the medium enough so that excess water begins to exit from the container’s drain holes.
Sprinkle the seeds over the surface of the prepared medium or press them lightly into its surface. Recommended spacing between seeds varies depending on the plant species. In general, sowing seeds about an inch apart in rows about 2 inches apart is often acceptable. Thinning later can address any overcrowding.
Cover the seeds lightly with germinating medium. The appropriate amount of medium to apply varies between seeds. Do not cover very fine seeds like petunia with any medium. Otherwise, as a general rule, cover seeds with an amount of medium equal to about two times their diameter.
Mist the newly-planted seeds lightly but thoroughly. Cover the container with a clear glass or plastic lid or enclose it in a bag to maintain a high level of humidity around the seeds. Mist the surface of the medium as needed so that it remains constantly moist but not wet.
Place the container with the germinating medium and seeds in a warm spot that receives bright, indirect light. Most seeds germinate best when temperatures remain between about 65 and 75 degrees Fahrenheit.
- Purdue University Cooperative Extension Service: Starting Seeds Indoors
- The University of Arizona Master Gardener Manual Reference: Starting Seeds
- University of Minnesota Extension: Starting Seeds Indoors
- North Carolina Cooperative Extension Service: Starting Plants from Seeds
Angela Ryczkowski is a professional writer who has served as a greenhouse manager and certified wildland firefighter. She holds a Bachelor of Arts in urban and regional studies.
How to Start Seeds in Peat Moss or Potting Soil. Starting seeds in containers with peat moss or other appropriate medium will allow you to start the growing season early and offers you greater control over the germination and seedling environment. Selecting and preparing the containers and medium for sowing the seeds …
How to Start Seedlings With Peat Moss
Seeds germinate best when provided with optimum light, temperature and moisture. Starting the seeds indoors gives you control over the climate, unlike when you try to grow seeds outdoors in fickle spring weather. The growing media gives you further control over moisture. A peat-based media supplies drainage that combats sogginess and compaction while retaining enough moisture for healthy germination and growth. Peat isn’t suitable on its own and requires the addition of other elements to provide an optimum growing base.
Combine one part peat with one part vermiculite and one part perlite. Use a fine-textured peat because large pieces may block tender roots and sprouts from spreading. Vermiculite and perlite are inorganic volcanic compounds that provide aeration and further drainage to the organic peat mix.
Fill the seedling containers with the peat mix to within 1/4-inch of their rims. Water the peat until it’s thoroughly moistened and water drains from the bottom of the container. Empty the drainage tray under the containers and allow them to set for approximately one hour so the peat can absorb the moisture adequately.
Sow the seeds on the soil surface. Plant two seeds per container, or sow the amount of seeds recommended on the seed packet.
Cover the seeds with moistened plain peat moss. Most seeds require a covering 1/4-inch thick or equal to twice the width of the seed, but planting depth requirements vary between plants so refer to the seed packet for exact planting depths.
Cover the containers with a sheet of clear plastic to help maintain the moisture in the soil during the germination period. Place the covered containers in a warm 70 to 75 degree Fahrenheit location. Select a brightly lit location for seed varieties that require light for germination.
Remove the plastic after the seeds sprout. Provide the seedlings with eight hours of sun or fluorescent lighting each day and keep the soil moist but not soggy.
How to Start Seedlings With Peat Moss. Seeds germinate best when provided with optimum light, temperature and moisture. Starting the seeds indoors gives you control over the climate, unlike when you try to grow seeds outdoors in fickle spring weather. The growing media gives you further control over moisture. A …