The best soils are high in levels of nitrogen. Manure is a great source of nitrogen, and the great news is that often you can even get hold of it for free. You can visit a local farm and offer to collect your own manure. They will often be happy of the help. Ensure that the manure is from a safe and well-kept environment. The last thing you want is to be using contaminated manure that could cause your plants to carry harmful pathogens, which could in turn make you ill.
Another free way of improving your soil is with compost. Compost is made with unused natural waste. Any old fruits and vegetables that are not eaten and have started to rot can be added to compost. This helps lock in nutrients, which feeds nutrients to the soil. By regularly adding more compost to the soil around your plants in your organic garden, you can help your plants to get the nutrients they need to be as healthy as possible when you come to eat them.
An alternative to waiting for compost to develop is to use mulch on the soil. You can usually use any organic products to improve the quality of the soil. Mulch is a great way to lock in moisture and heat to the soil.
You should keep people away from your good quality soil. If people keep on walking over the beds, they will compress the soil and ruin its ability to feed water to the plants. You should enforce paths if you have regular visitors to your gardens. People tend to be good at sticking to paths that are well defined, so use patio stones, gravel or borders to mark out where your paths are. The looser you can keep the soil, the better the plants will grow.