If perusing seed racks and catalogs is one of your passions, then you already know that there are more exciting seeds available now than ever before. Looking for seeds for that terrific melon your grandpa used to grow, the pepper you ate stuffed in Oaxaca, the medicinal herb your acupuncturist uses, or grasses for basket weaving? Chances are good that you can find them.
Starting plants from seed can be satisfying, economical and exciting, or expensive, frustrating and depressing, depending on how successful you are. But there are steps you can take to increase your chances.
Seeds are amazing little packages that contain all the genetic information to produce adult plants. Every seed contains an embryo and an endosperm wrapped in an outer coat meant to protect the embryo inside.
Genetics are important. Choose high-quality seed for high-quality plants. Buy from reliable dealers or save your own open-pollinated seeds from your best non-hybrid varieties. Hybrid varieties will not come true from seed.
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Commercial seed packets indicate the growing year for which the seed was packaged, the expected germination rate and any chemical treatment the seed was exposed to. Fresh seed is best. If you must store seeds, keep them in a cool, dry place. You can keep laminated foil packets and paper packets in tightly closed canning jars or other airtight containers. Conveniently, a home refrigerator provides adequate conditions for seed storage.
When starting seeds, pay attention to four key factors: water, oxygen, light and temperature.
Seeds must have a continuous supply of water to germinate. A dry period will cause the embryo to die. Seeds need oxygen, too, so use a seed-starting medium that is loose and well aerated.
Some seeds prefer to germinate in the dark, while others need light to stimulate germination. The latter include ageratum, begonia, impatiens, lettuces and petunia. When you sow light-requiring seeds, leave them on the surface of the potting soil. You can cover them with a fine sprinkling of peat moss or vermiculite. If applied thinly, these two materials permit some light to reach the seeds.
Some seeds germinate over a wide range of temperatures, while others require a narrow range. Many seeds have a minimum, maximum and optimum temperature for germination. When a seed packet lists germination temperature, it is usually the optimum temperature, unless otherwise specified. A warm windowsill may be sufficient, or you may need a warming mat to achieve germination. Some seeds really need brisk outside temperatures to germinate successfully.
For germination to occur, seeds must be ready to break dormancy. A dormant seed is just waiting for the right conditions to germinate. Seeds for many fast-growing annuals, such as sunflowers and radishes, are notoriously easy to germinate, while seeds from more extreme climates may require a longer dormancy and more precise conditions.
They may need you to nudge the process along.
Seeds from cold climates may need stratification, a process of exposing the seeds to cold to simulate natural winter chilling. To stratify seeds, moisten some seed-starting mix, blend in the seeds and put the seeds into a plastic box or plastic bag. Leave the bag in a warm place for three to four days so the seeds can soak up the moisture, then refrigerate the bag to simulate winter. Ten weeks is the average refrigeration time needed, but seed packets will often recommend the appropriate time.
Drought-tolerant plants often produce seeds that wait for abundant water to germinate, thus increasing their chances of survival. These seeds benefit from soaking in warm or hot water.
Some particularly tough seeds require scarification to germinate. Seed scarification breaks, scratches or softens the seed coat so that water can enter the seed and launch the germination process. Some propagators rely on chemicals for this process, but home gardeners can scarify seed by using a metal file, sharp knife or sandpaper to crack or nick the seed. For hot-water scarification, cover scarified seeds with hot water (170°F to 212°F) and let soak for 12 to 24 hours before planting.
Seed starting can be simple or complex and a rewarding adventure for all ages. Good gardening books and nursery personnel can guide you in starting seeds, and local nurseries carry all the seed-starting supplies you need.
Workshop: Napa County Master Gardeners will conduct a workshop on “Gardening 101: The Basics,” on Saturday, March 17, from 9:30 a.m. to noon, at the University of California Cooperative Extension office, 1710 Soscol Ave., Napa. The class will repeat on Saturday, March 24, from 9:30 a.m. to noon, at the American Canyon Recreation Center, 2185 Elliott Drive. Learn basic concepts and considerations for planning your garden, including plant selection, planting, watering, fertilizing and composting. Pre-registration required. Class fee is $5. Register on-line (credit card use only) at cenapa.ucdavis.edu.
Napa County Master Gardeners answer gardening questions Monday, Wednesday and Friday, 9 a.m. to noon. Call 253-4221 or (877) 279-3065.