by Susanne von Rosenberg, UC Master Gardener of Napa County
Starting plants from seed can save you money, allow you to try more interesting varieties and be a lot of fun. Although it can seem intimidating, starting plants from seed isn't hard. To grow plants from seed successfully, you need to plan the timing (so the plants are ready to set out into the garden at the correct time) and follow a few basic rules.
To know when to sow your seeds, consult the seed packet for information on when the plants should be planted in the garden. Both vegetables and flowers are commonly divided into cool-season and warm- season plants. You can start seeds for cool-season plants now. For warm-season plants, you need to know how long they typically take to grow to transplant size.
For example, pepper and eggplant seedlings grow slowly and should be started in early February for transplanting in mid-April. Tomato seedlings grow much faster and should be started in mid-March for transplanting in mid-April.
Seeds can be started indoors and transplanted outdoors when ready or they can be started directly in the ground. It's too early to start seeds outdoors right now; the soil is too wet and cold.
When you start seeds indoors, you control the temperature and the amount of water they receive. You can provide a sterile environment and protect them from hungry critters. You can nurture the seedlings indoors until they are large enough to fend off damage by insects, birds and other predators.
To grow successfully, seeds need the right temperature, consistent moisture, adequate air circulation and, in some cases, light. Start seeds in a soil mix designed especially for that purpose. Seed-starting mixes are finer and lighter than regular potting soil. Using a soil mix will also ensure that the seeds have adequate air circulation. Seeds are likely to rot if the soil is too heavy or wet.
Germination begins when the seed takes up water from its surroundings. Once a seed begins germinating, a dry period can be deadly. All seeds have an optimal temperature range in which they germinate most reliably. Generally, 65°F to 75°F is best for most seeds. A seedling heat mat that gently warms the containers from the bottom will make your seeds germinate much faster and more consistently.
Buy seeds from a reputable source to make sure you get good germination and, more importantly, the correct seed. Fresh seed will yield the best results; older seeds may still sprout but the plants are typically less vigorous. After years of starting plants from seed, I've learned to recycle (feed to the birds or use for micro greens) seeds more than two years old.
Seeds can be started in almost any container that has drainage holes in the bottom. A used container should be sterilized (1 part bleach to 9 parts water), rinsed carefully and allowed to dry. Moisten your seed-starting mix until it is as damp as a wrung-out sponge, then fill your containers to within one-half inch from the top.
Decide how many plants of each variety you want. It's a good practice to plant two seeds for each plant you want, just to be safe. I also recommend preparing your labels before you start planting.
Plant seeds at a depth of about twice their diameter. The seed packet will specify how deep to plant them and whether they have any special needs. Some seeds, such as lettuce, need light to germinate so they should only be covered with a dusting of soil mix. Keep seeds moist until they germinate. The easiest way is to loosely cover the containers with a clear plastic bag until the seeds sprout.
Once seedlings have emerged, move the containers off the heat meat and into bright light, either underneath full-spectrum fluorescent lights (grow lights) or outside in a protected area. If using grow lights, keep the lights approximately six inches above the seedlings.
If you put your little seedlings outside during the day, bring them back in at night so they don't get too cold. Also, put them in a partly shaded area first and then gradually move them into direct sunlight.
You may want to cover seedlings with floating row cover to protect them from birds. All seedlings should be watered regularly; do not allow them to wilt. Fertilize with half-strength fertilizer every other time you water them. Prior to planting indoor-only seedlings in the garden, expose them to the outdoors a little bit more each day, a process known as hardening off.
If you have questions about seed starting, contact the Master Gardeners. You can e-mail, call or come into the office during our office hours.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County (http:/napamg.ucanr.edu) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.