Growing plants from seed is one of the most satisfying parts of gardening. In fact, you don't even need a garden, because seeds of many varieties can be started and grown indoors. To watch a large plant grow from a tiny seed is to see one of the miracles of life. And another bonus--it often costs next to nothing.
What Do Seeds Need?
All a seed needs to start growing is something to grow in (such as soil or a seed-starting mix), moisture and light. Most seeds don't need any more heat than normal room temperature.
Seeds cost only a few dollars, but it is important to get high-quality seeds. You will probably get better seeds from a garden center or online than you will from a big-box store or hardware store. A tip: Look for seed packets that have detailed planting instructions printed on the back. Good seed companies do that, while many inferior seed companies don't bother.
Do not use garden soil for indoor seed starting. Much better is what's called a soilless growing medium. You will find this in bags at the garden center, labeled "seed starting mix."
While you are at the garden center, you can buy some containers for your seeds. You can get large flat seed trays, small cell-packs, or round or oval flower pots. Alternatively, to save money you can also use a clean yogurt or cottage cheese container, the cut-off base of a soda bottle, or just about any small plastic container. Whatever you decide to use, make sure it has plenty of drainage holes in the bottom so water can run out easily. Seeds will rot in wet soil.
Spread the seed starting mix in your container so it is at least two inches deep. Sprinkle water on it and mix it around until it is just damp.
Now read the instructions on the back of the seed packet. Different seeds have different requirements, so you need the expert advice on the packet. This will tell you how deep to plant the seeds---it is very important to get this right---and how far apart they should be.
Plant the seeds, following the instructions, then lightly firm the damp soil over them. This is to ensure that the seeds are in contact with the damp soil.
Once the seeds are planted, very gently water them in. A plastic spray bottle is good for this because it gives a gentle spray that won't either wash your seeds deeper or out of the mix.
Over the next few days, until your seeds germinate (begin to grow) you need to keep the surface of the soil just barely damp (not soaking wet--more seedlings die from drowning than from thirst).
As soon as your tiny seedlings begin to poke up out of the ground, they need light. You might be able to give this to them by placing their container in a south-facing window, but if you do this make sure they will not get too hot when the sun shines. Rotate the container 90 degrees every day so the seedlings do not stretch and strain in one direction towards the light.
Another way to give them light is to install a fluorescent shop light on chains (so you can raise and lower it) and keep the seedlings about three or four inches from the fluorescent tubes. Put one warm-white and one cool-white tube in the shop light fixture, and keep it on for 14 to 16 hours a day. An automatic timer will make this easier.
As your plants grow, keep the growing mix damp but not wet. If the weather is nice, you can put them outside for an hour or so (no more, until they get used to the sunlight) and bring them in at night.
As they grow bigger, you might want to give them a plant fertilizer. Be very careful not to mix the fertilizer any stronger than the directions tell you. More is not better. Half-strength is just fine.
Whether they are flowers or vegetables, you can now enjoy the plants that you grew yourself from seed.