By Grace Mahannah
The beauty and order of the earth's natural rhythm bring us once again to spring—seedtime-- and the promise of new life embedded within each seed. For those who disbelieve in miracles, take a closer look! Each individual seed contains a tiny embryonic plant, with root, stem and leaf, a food source to nourish its growth, and a protective covering to safeguard the seed until growing conditions are right.
The plant kingdom is incredibly diverse, but most flowering plants (angiosperms) familiar to farmers and gardeners fall into two categories: monocotyledons (grasses, palms, lilies and orchids) and dicotyledons (all other flowering plants). Monocotyledons (monocots) have one seed leaf: for example, a kernel of corn sprouts one single blade; while dicotyledons (dicots) have two seed leaves, like a tomato or squash seedling. The seed leaves (cotyledons) nourish the young plant until the first true leaves emerge and photosynthesis begins.
To nurture a plant from “seed to harvest” is to witness the miracle of growth in real time. Some seeds, like snap peas in early spring and corn, beans or squash in summer, can be planted straight into the ground, while others are best started indoors. When starting seeds in trays or pots, allow 6 to 8 weeks for the young plants to mature before you plant them outdoors. In Zone 9b where many of us live, a lot of gardeners favor mid- to late-April (depending on the weather) as a good time to plant their seedlings in the ground for summer crops. The soil needs to be warm (above 55 degrees) with all danger of frost well past. If the soil is cold, young plants will grow slowly, if at all.
Research your best local date for transplanting seedlings outdoors, and then count back the number of weeks indicated on the seed packet; six to eight weeks is often, but not always, the amount of time needed to grow sturdy young plants. The UC Master Gardener website provides helpful vegetable planting dates for the Chico Valley Area and the Foothills. Starting seeds too soon results in seedlings that stay too long in their pots. They can become leggy and rootbound and more likely to exhibit stunted growth and poor health when finally transplanted.
Because seeds contain their own nourishment, the best planting mixes used to start seeds indoors contain no soil but rather a potting mix that includes some combination of peat moss, sphagnum moss or coconut coir; vermiculite, perlite, or sand; and perhaps compost. The mix should provide a good balance of water holding and drainage capacity, and it should be airy, fine and uniform (to foster the growth of delicate roots).
If you don't plan to transfer your seedlings to bigger pots, include some nutrition in the seed starting mix in the form of organic compost. A good, basic DIY seed starter mix might be one-third peat moss, sphagnum moss or coconut coir; one-third vermiculite, perlite or sand; and one-third good quality organic or natural sifted compost.
Pots for starting seeds should be clean. If not new, the pots should be free of old soil, washed in soapy water, then soaked for several minutes in a solution of one part chlorine bleach to nine parts water (to eliminate pathogens) and rinsed well. Fill pots with moistened seed-starting mix and flatten the surface with your fingers or a piece of wood or cardboard.
Fresh seeds are best, planted according to the packet instructions and kept warm inside a greenhouse or on a heat mat until they sprout (if they are warm-season crops). Temperatures of sixty-five to 70 degrees during the day and 55 to 60 degrees at night are optimal for growth. Keep seeds uniformly moist (pots can be tented with plastic until seeds sprout), and give them plenty of bright, indirect natural or artificial light. Fertilize your seedlings as they grow, and be sure to “harden them off” by gradually introducing them to living outdoors.
To harden off young plants, start two weeks before your transplant date, when plants are two to four inches tall. For the first week, set plants outside in their containers in a shady spot, and take them inside each night. During the second week, begin leaving plants outside both day and night, gradually increasing the amount of sun they receive each day. During hardening off, remember to protect plants from too much wind or heat that might burn tender leaves. After two weeks, your seedlings should be ready for transplanting in the garden.
Many gardeners buy plants each spring, but starting your own seeds is considerably less expensive, and it's also fun! Enjoying an abundant harvest from plants you grew from seed is one of life's real pleasures. By the time summer rolls around, the tomato seed planted in early spring becomes a large vine full of ripe tomatoes ready for the table. You may even want to save the seeds of a favorite heirloom tomato for next year; thus, the miracle of seed-bearing plants can come full circle once again.
The Master Gardeners' Spring 2025 Workshop Series has begun, and will run through early June. Coming up in March are workshops on Post-Fire Soil Recovery, Healing Gardens, and Salvias & Companions. For more information about the series, which runs through early June, and to register for the upcoming workshops, visit our website. All workshops are free, but registration is required.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at 530-552-5812. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.