Weed early, often and everyday.
Weeds only get out of control if you let them. I try and weed every morning first thing and then pick at weeding all through the day. If you can get the weeds before they have a chance to establish themselves then they are easier to remove and do not have a chance to set seed and spread. Weeds compete for moisture and nutrients with your veggies and flowers, the sooner you remove them, the less competition. I can not stress this enough and constantly read this in gardening literature. Weeding can be hard work, staying on top of it reduces the total time spent digging and pulling. Time spent weeding is time well spent and greatly pays off in the long run.
Work in compost, fertilizer or really well rotted manure prior to planting.
If you are using the same garden plot year after year, it only makes sense that you need to replace used nutrients. Compost works to add nutrients to the soil and retain moisture. If adding manure in the spring it needs to be really well rotted and preferably composted. Manure that is too fresh can contain weed seeds, potatoes and carrots will not grow well in it and it can contain too much nitrogen, causing rapid plant growth but little fruits or even 'burn' the plants. We allow our chicken manure to break down for two years since it contains so much wood shavings before composting and then pasteurizing it in the cold frame on a really hot day to kill any weed seeds. Often manure is added to the garden in the fall to avoid potential problems with potatoes and carrots.
Mulch around seedlings and transplants.
After your seeds have sprouted and reach a good size, mulch around the plants to conserve moisture, suppress weeds and add a slow release source of nutrients. Seaweed, compost, grass clippings and leaf mould make great mulches. Leaf mould is simply well decomposed leaves, usually obtained from piling leaves onto themselves in the fall and allowing them to rot through the winter. Do not place the mulch directly around the stalk of new seedlings and transplants, you can add more closer to the plant after it becomes established. I use straw to suppress weeds around the perimeter of the garden but not around plants as it uses too much nitrogen while breaking down. Wood mulches use the most nitrogen while breaking down and I find they encourage slugs, two reasons not to use it at all. The other mulches I mentioned do not use as much nitrogen as they break down.
Water if needed.
The last few years around here this really has not been a problem, too much rain was a problem last year, however if you suffer a dry spell, water accordingly.
Rotate your crops.
Crops should be rotated on an at least three year schedule. This helps reduce pests and diseases, reducing the need for pesticides, and different crops have different nutrient requirements. If you grow tomatoes in the same spot every year the soil will quickly become nutrient poor as tomatoes are heavy feeders. Legumes can fix nitrogen from the air into the soil, making them less dependant on soil nutrients and lighter feeders. Crops are rotated by family, as the same pests and diseases affect members of the same family. For example, the carrot family consists of carrots, parsley, celery, celeriac and parsnips. Usually the families are referred to as the brassicas, legumes, cucurbits, carrots, the potato, amaranth and alliums although you will find variations and more proper versions of this, this is just what I have stuck in my head and will give you an idea to work with.
Brassicas or the cabbage family contains, cabbage, cauliflower, kale, brussel sprouts, kohlrabi, turnips, mustard and radishes.
Legumes consist of all beans; soybeans, green and yellow beans and runner or pole beans, peas and even peanuts.
Cucurbits encompass cucumbers and squashes like pumpkins, butternut and others.
The potato family consists of the nightshades, potatoes as well as tomatoes and peppers.
Amaranth has spinach, swiss chard and beets as a family.
Lettuce and endive are on their own.
The allium family holds all the onions, leeks, scallions, garlic, shallots and chives.
Chives are perennial and usually kept outside on on the outskirts of the main veggie plot with asparagus, berries and rhubarb. Rotation is not possible as you will not be moving these plants, however if removing an existing bed of any of these and planting another it should be moved to a new, different location.
It only makes sense to follow heavy feeders with light feeders, even if you add soil amendments each year as roots travel deep into the soil. Crop rotation is often referred to as the single most important tool for organic gardening. Promoting healthy plants that grow well and quickly is the best way to defend against pests and diseases. Many pests depend on soil to live and reproduce. A hardy, healthy beet green can take a few nibbles from flea beetles, aphids and leaf miners and still be well enough to eat.
Protect peppers, beans, tomatoes and other affected plants from cutworms.
Cutworms can take a healthy transplant down in one night. Placing three nails, toothpicks or a collar of some sort firmly into the soil close to the base of the plant will prevent the cutworm from being able to wrap themselves around the stalk and nibble it down. Better safe than sorry in this case. I put collars around all my tomatoes, ground cherries, peppers and beans just to be sure.
Hand pick slugs at night and in the early morning.
Slugs can be a gardener's worst enemy. Slugs usually attack tender greens like lettuces, however they do not stop there. They can eat berries, flowers and all kinds of crops. We allow our chickens out to free range for about an hour at night to help clean up on slugs. When I have the garden planted, I usually pick the slugs first thing in the morning while I am weeding and checking on crops. As with the cutworms, it is better to be safe than sorry when it comes to slugs and prevent them from being able to nosh on plants. If they are a huge problem you can also set up various traps containing beer, wine, yeast and water and many other proven concoctions. Slugs particularly like to eat marigolds. I use a very thick barrier of crushed eggshells and sand which seems to work well. The slugs do not enjoy crawling over the sand.