To garden or grow vegetables and fruits, most importantly you need a knowledge of how to grow each plant, good garden location, at least 6 inches of soil, sufficient water, sun, a sheltered loation, and and decent growing temperatures (about 90 days or more of frost-free weather).
Plants need water. If water is not convenient, you are likely to avoid watering which will cause plants to wilt (bad) and maybe die. So moving water close to the garden, moving gar den near water or both is advised. Plants get water through the rain (best), drip irrigation, sub-surface water (high water table and vapor rising through soil), hand watering etc. Plants like tomatoes need about 2 inches of water per week.
You can keep a 50 gallon drum of water next to a 4x4 growing bed and scoop out sun-warmed water as needed.
Common mistakes while watering:
Plants need water, but how much do you need exactly, in gallons? Say you had a garden bed 4 feet by 4 feet and you planted 4 tomatoes. Each tomatoe plant needs on average 2 inches of water during the summer per week. To convert this into gallons for the garden, calculate the number of cubic inches. 2 inches water x 48 inches wide x 48 inches long = 1568 cubic inches of water. There are ~230 cubic inches per gallon, so 1568/230 = 6.8 gallons per week. If you watered twice a week, and carried water from a creek to these tomatoes, you would be hauling roughly 3.4 gallons twice a week. Water weighs about 8.3 lbs per gallon. So 3.4 gallons x 8.3 lbs/gallon = ~28 pounds. This is why having water near a garden is important.
If you have a shelter near a garden, and receive decent rainfall, then you can store water in a large tank to use for watering during the summer. You can use formula above (rainfall in inches x width and length of roof in inches, divide by 230 to get gallons. For example, an 8x12 shed with 20 inches of rain per year = 20 x 96 x 144 = 276,480 cubic inches of rain. Divided by 230 cubic inches per gallon gives 1,202 gallons of rainwater. That is a very large tank. Of course, you would be storing water during non-growing months, so say that is 8 months out of the year. Do take 8 months /12 months x 1202 gallons = 801 gallons. So from this, and your plants watering requirements you can figure out if you need to supplement rainfall with a rainwater collection system, and how big of a roof you would need (use tin roof, not asphalt) and what size storage tank it would require).
Plants need soil to grown in, or a "growing medium". Some plants have deeper roots and some less, but always you need 6 inches of soil or more. The most critical nutrients for the plant should be located in the soil within 3 inches of the stem. So that's about a 6 inch diameter. Before you plant a seed, or dig-in a transplant, the 6 inches around that plant should be fertilized and amended according to the plants requirements. For examples, tomatoes like phosphates, and kale likes more nitrogen. Most plants like watered with diluted fish emulsion.
Gardens need sized according to need and experience. If you just want salad ingredients, tomatoes and cucumbers, then a 4 foot by 4 foot (16 square feet) garden will probably be enough for 1-2 people. If you are growing for essential food for a family of four and will be canning for the winter, then you need much larger.
If you're going to invest in a garden, it's wise to choose a place that will profit you the best. You will need light, water, absence of invading tree roots, protection from garden pests and easy access.
Plants need varying amounts of sunlight to grow. Corn loves lots of sun and heat while peas prefer moist cool soils. A garden location that receives 6-8 hours of sunlight for at least 90 days out of the year is important. Remember that the earth has a tilt in relationship to the Sun, so as the days progress the sun rises and falls at different locations throughout the year. Here's a proven method: stake out the potential garden site and go out there in morning noon and evening at different times of year to make sure you are getting full sun for 6-8 hours. Areas that get more sun can be planted with sun-loving crops, and areas that receive some shade can be planted with vegetables that like partial shade.
If you're choosing a garden location in Summer, it's easy to forget that at many latitudes, the sun will dip lower in the sky during Spring and Fall months and especially Winter. That means that when the sun is overhead, a tree will cast shadows east and west, but towards winter, the tree's shadow will be cast to the North. In time, trees grow in height, creating a longer shadow. This needs taken into account so that your garden is not shaded in the future by a growing tree. Also, consider roots from nearby trees. With the natural shade of a tree comes tree roots.
Gardens need to be located away from tree roots. One year I put a garden in my place. I had cut down a tree near it. Throughout the year, I had a horrible time trying to keep the garden watered. And the plants did not do well. When I went to dig at the end of the year, the whole garden was a mat of tree roots from a neighbors tree 50 feet away. If you have a small area, and neighboring trees, then you may need to keep your garden isolated by growing in containers (barrels, buckets, planters).
If you have trees nearby, then what type of trees are they. You can research what types of trees have tap roots and which trees send out roots sprawling 5-10 feet below the ground sideways. How far do your tree roots go? If you are digging in your planned garden area and have to cut out tree roots, then it's very likely those or other roots will grow back right into your fertlized, watered garden soil.
Soil needs cleared of rock bigger than 1/4 inch, tree roots, grass, weeds at least 6 inches deep. The pH of the soil can be checked. Vegetables need nutrients to help them grow. Soil amendments provide the nutrients that the soil needs to be balanced.
Soil needs to have decent drainage so that roots don't rot. In dry areas, that receive little rainfall, you will need to water more. You can also slope the soil around the plant to focus rainwater and runoff towards your garden.
Worms eat food produced by bacteria or fungus that feeds on the decaying matter in the soil. Addind artificial fertilizers destroys the humic acid in the soil and causes the plants to starve when the fertilizer washes out. Worms produce castings (worm poop) that feed plants. Worms also tunnel through the soil, providing paths for the roots of the plants to grow and allows water to go deep into the soil. Worms are very important for good gardening soil.
Compost piles are layers of carbonaceous (think "woody") materials and green materials (like grass, vegetable clippings etc) that decompose. The "finished" product is then added to the garden. Finished compost is the most frequently added soil amendment.
Besides compost, soil amendments are added to gardens to make up for local soil deficiencies. Soil defeciencies are show through soil tests. Most people don't want to pay for a soil test and have "smaller" gardens, so they just add soil amdenments, a "shotgun" approach, hoping to provide plants with whatever their local soil is missing. Here is a list of common soil amendments:
Mulch is used to cover the soil. This protects the soil from UV light from the sun, darkens the earth to shade sprouting weed plants and protects the soil from wind that may dry the soil.