Organic gardening
Organic gardening can be as simple as pledging not to use pesticides and chemically produced fertilizers. It can be as complicated as carefully planning the garden so that each plant has the light, soil, water and companions it likes best. It can also support native ecology.
In a veggie garden, you can avoid the buildup of pathogens by rotating crops each year. For instance, if you grow potatoes in the flower beds you'll have to find a new sunny spot every other year to sneak them in.
Probably the most widely acknowledged practice is composting. By recycling the nutrients created by previous season's plant growth back into the beds, we're being very sustainable indeed! Compost not only contains macronutrients (NPK), but micronutrients that enable plants to use the NPK. Compost is a marvelous soil conditioner, that can be dug in or simply top dressed (spread a couple inches thick over the soil). It is full of microorganisms that enhance the soil ecosystem, in turn constantly feeding plants.
Mulch is another popular organic gardening technique. Mulch mimics nature's way of conserving soil moisture, inhibiting weeds, providing homes for good bugs like ground beetles (there is a native beetle that predates on slugs and snails!) and slowly turns into compost. Mulch can be any material that isn't totally decomposed, such as bark mulch, grass clippings (sans dandilion seeds), straw, or chopped up leaves. If you are mulching a path, use cedar bark mulch as it contains a chemical that inhibits plant growth, but don't use cedar mulch on garden beds for this reason.
Water, in the dry season, is best applied deeply rather than shallowly. To accomplish this, water less frequently but for longer duration. That said, some fantastic gardens get watered daily. It is important to water daily if you are growing from seed. For established plants and lawns, a deeper watering will encourage deeper roots that are better able to handle dry spells and hot days.
For those of us who want to support the native ecology, staying clear of pesticides is very important. So is growing native plants. The idea is to actually provide native food for native BUGS so that native BIRDS have the food they look for. June Pretzer at the Swan Lake Nature Sanctuary recommends the book Bringing Nature Home, which elaborates on this idea. Organic gardening, and naturescaping, allow wildlife, especially birds, to continue using the vast area of urban gardens as habitat, where they can find food, water, shelter and breeding grounds. In return, they enliven the outdoors with such a variety of songs and calls.