Are you reading seed catalogs and dreaming of what to grow in your spring garden? Starting flowers and vegetables from seeds is a good way to save money and give your garden a head start. An indoor seed-starting project lets you choose from a wide variety of resources and costs less than purchasing seed starts. You control the temperature, light and humidity for successful germination (the development of seeds into seedlings).
Germination begins when the seeds become active and seedlings appear, triggered by the availability of water, oxygen and light. Nutritional reserves in the seed itself provide the resources for the initial development. A seed’s ability to germinate and establish a new plant is known as viability. Each seed has a set range of time during which it is viable, some mere days, and some for many years, depending on the storage conditions and the type of seed.
Before planting, read your seed packet. Look for the date the seed may expire. Note the times to plant, sun or shade requirements, planting depths and how far apart, the days to germination and the days to maturity. Learn if you need to soak or scarify (seeds that need to be nicked) to speed up germination or stratify (seeds that need to be chilled to mimic the effects of dormancy) before planting.
Many seeds have a top and a bottom where the roots come out. If in doubt, plant horizontally. Sowing depth is usually two to four times the diameter of the seeds. Sow two to three seeds per unit and later thin the plants, allowing the strongest to survive. You can use recycled containers like egg cartons or 4-inch pots. Recycled containers like milk cartons should be washed thoroughly and soaked in a solution of one part chlorine bleach to nine parts water to prevent diseases. Heat mats and grow lights are optional, depending on the location of your seedlings. The ideal temperature is 60 to 70 degrees during the day and 50 degrees at night. It is crucial to keep the seeds moist and always label what you sow.
Selecting the right soil medium, such as a soilless mix or various mixes amended with vermiculite or perlite, is essential. The ideal soil is lighter, free from disease and provides good drainage. Do not use garden soil as it is too heavy, not sterile and will not drain well. With experience, you can find out what works best. You may also need to “up-pot” your plants to larger containers before planting them in the garden.
Before transplanting your seedlings outdoors, check the soil temperature for favorable conditions. Seedlings can be fragile and benefit from gradual exposure to outdoor temperatures. This is a “hardening off” process, slowly acclimating them to outside conditions a few hours a day. The Master Gardeners recommend the “no-till” method of planting by digging a small hole in the ground, gently spreading the roots and taping the soil lightly. After planting, water the soil thoroughly.
Later in the season, direct seeding and planting directly into the soil eliminates the need for raising in pots or trays, as seeds are planted at the right spacing and depth where they are intended to grow. Some crops have taproots (like carrots) that are sensitive to disturbance and are better suited to direct seeding. Direct seeding requires the right soil preparation, soil temperature and irrigation.
Planting seeds is a means to getting the right plants in the right place at the right time. Remember to nurture the soil by adding compost and mulch and minimizing soil disturbance. Whether cultivating plants for food or fostering habitat for pollinators and beneficial insects, protect the environment using the least toxic methods to solve garden problems for an Earth-friendly garden. For more information, go to marinmg.ucanr.edu/EDIBLES/PLANTINGCALENDAR.
Sponsored by UC Cooperative Extension, the University of California Marin Master Gardeners provides science- and research-based information for Marin home gardeners. Email questions to helpdesk@marinmg.org. Attach photos for inquiries about plant pests or diseases. Please call 415-473-4910 to see when a master gardener will be at the office or drop off samples 24/7 in the sample box outside the office. To attend a gardening workshop or subscribe to Leaflet, a free quarterly e-newsletter, go to marinmg.ucanr.edu.
