I recently saw an old school video of Ruth Stout speaking about her no-work gardening method. In it, she describes a way to garden without ever tilling, hoeing, or weeding... she just throws out the seeds and lets them grow. What is her secret? Mulch. While I've personally never attempted the no-work method (I don't feel like I'm really gardening if I don't break a sweat!) I can vouch for the many benefits of mulch.
All mulches help suppress weeds. This will indeed reduce your garden workload in the long run. In addition, depending on which type you use, mulch can also improve soil structure, retain soil moisture, protect roots from sudden changes in temperature and moisture, and create a welcoming environment for some pest predators. Many mulches also look nice.
You can apply mulches wherever you need them, in garden beds, on paths, or on barren soil where you don't want weeds to take over. However, different types of mulch are better for different jobs. The following are the three main categories of mulch, and the best uses for each.
Loose mulch is good for paths, food gardens, and ornamental gardens. Use fresh wood chips for paths, composted bark and wood chips for gardens or paths. Layer 3-4 inches deep. These can last 2-3 years. Straw and hay is good for gardens and should be layered a half-foot deep (it will compress with time) and will last one season. Other mulches include gravel (good for heat-loving plants), leaf mold (abundant and free, but short-lived like straw), and cocoa shells (re-purposed industrial waste).
When applying, first pull weeds and make sure the soil is sufficiently moist. If it's dry, give it a good watering. Next, apply the loose mulch. This will provide effective weed control and confer many other benefits. Use less loose mulch if you're using it in conjunction with sheet mulch. Also, don't clump loose mulch around the base of your plants as it encourages stem rot.
Use sheet mulch as a weed suppressor on open soil. Cardboard and newspapers are readily available and good one-season options. Lay out newspapers about 8-sheets thick. You may have seen plastic used on a neighbor's yard in preparation for a new grass planting—it will wipe out all weeds. But make sure you remove it after one season, as the soil needs to breath. You can also use plastic around the base of tomato plants. Water the soil well, lay out the plastic sheet, cut holes and plant young tomato plants. This way you shouldn't have to water at all for the rest of the season. I've heard that tomatoes like red plastic better.
Landscaping fabric works well for suppressing weeds while letting water and air circulate. Cut holes to let your plants grow through. If you're using landscaping fabric with ornamental plants, you'll probably want to cover it with a layer of loose mulch to make it look nice. If working with annuals, it's easier to lay out the sheet and then cut holes where your plantings will be.
Green mulches, also known as living mulches, restore nutrients and organic matter to the soil while protecting otherwise barren ground from compaction. In the garden, use them during the winter or when letting an area lie fallow. Nitrogen-fixers like vetch make excellent green mulch, and add nitrogen into the soil at the same time. Winter rye improves soil structure. You can also plant these mulches in barren spaces between vegetable crops, or at the base of tall crops like corn in order to smother weeds.
A few weeds will still find a way to come up around mulch edges or in the holes where your plants are growing. These can easily be plucked. While mulch is not a panacea, its use is certainly easier than taking a hoe to the soil every few days.