You can save a lot of money by starting your own bedding plants from seed rather than buying individual plants. Check the seed packet instructions, but it's usually best to start them about 6 weeks before the last frost date in your growing region.
Saving and storing seeds: some seeds can remain viable for many years, but sometimes the germination rate (how many will germinate vs. how many seeds you have) will vary over time. I keep mine in their original packages when I can and store them in a cardboard box under my bed where the temperature and humidity remain relatively contant. I save seeds from plants and herbs that I grow if they are non-hybrid/heirloom garden fruits and vegetables. If you use seed from a hybrid plant, you never know what the end result will be. I package them in brown paper bags to prevent moisture from collecting, which is key to keeping them viable. Some of these seeds are going on 10 years old.
I always start with a plan. What I want to plant, how many, and how I want to arrange my plants. I usually arrange the flats by plant family so that they will likely germinate at the same time and have
the same environmental requirements.
I first spread the flats out and add a good organic seed starting mix.
I spread the mix evenly and tap the tray a few times to make sure everything is settled well.
This year I used a coconut coir planting medium. Most seed starting mixes are peat-based. Peat bogs are important wetlands and are like nature’s kidneys where they purify water and contribute to healthy watersheds and ecosystems. They are not sustainably maintained because they are not a renewable resource. Coconut husks (coir), on the other hand, are a byproduct from the food industry and is usually a more sustainable and renewable use of our natural resources. The peat trays in the background are a few years old (before I knew better : )
Start with moist potting mix: It is important to moisten the potting mix before you get going. Dry mix will not take up water well. It is best to add water from below, so that the cells wick the water by capillary action. If you wait to add water from above when you add seeds, you might disturb them too much or even wash them out. You can water them this way until transplanting.
Planting depth: The general rule of thumb is to plant the seeds 3 times their width in depth. For example, this pea seed is about a 1/4 inch in diameter, so I pushed it down about 3/4 inches into the potting mix and covered with the potting mix. Small seeds, like lettuce or broccoli are very tiny and often just barely need covered with soil and some just need sown directly on top. Be sure to read the seed packet instructions for proper planting depth.
After planting all seeds, make sure the trays are fully saturated with water, cover with clear plastic covers and put in a warm place to germinate. They need to stay moist until they germinate, but don't let them soak in standing water or they will rot. This late winter/early spring has been unusually mild and they are germinting well outside. If you decide to do this outside as I am, keep in mind that these little greenhouses can get quite hot and you may need to vent them. At this point, they do not need light, just warm temperatures. When they germinate, they will need sunlight or artifical lighting (flourescent tube lighting set on a timer) to begin photosynthesis. You can build your own, or buy one and may wish to buy heating mats as well to hasten germination: http://www.amazon.com/Hydrofarm-
I'll add details throughout the germination process so you'll know what to expect.