Seeds and transplants
Nursery plants are grown from seed under sheltered conditions and are started earlier than you could safely plant the seed outdoors. If you direct-seed vegetables, you must wait for the ground to warm up enough to germinate the seed.
Vegetables produced from transplants are usually ready to harvest earlier than those grown from seed. The vegetables most commonly bought as young plants for transplanting are tomatoes, peppers, lettuce, broccoli, celery, cabbage, cauliflower, and eggplant. You can grow these vegetables ahead of the season indoors or in a hotbed or cold frame.
Always buy seeds or plants from a reliable dealer or nursery. If a neighbor has been successful in growing garden vegetables, ask for advice on where and what to buy. Buy fresh seeds, keep in mind that some seeds, such as onion, parsley, and parsnip, lose viability after about a year. Seed of other vegetables are good for three years or more. Companies date their seed packets and may give germination percentages. If the seed is known to keep for several seasons, it may be more economical to buy it in larger amounts. Write the date of purchase on the seed packets and store any leftover seed in a cool, dry place. Do not use any seed for more than two or three years.
Most vegetable seeds have their best germination potential at the moment they reach maturity on the plant. From that moment they decline in vigor until they can no longer germinate. However, they may continue to germinate well for years if they have been properly harvested and stored.