Since there is no soil, there is less maintenance involved with hydroponics. There is no need for weeding and the worry of pests or soil borne diseases is drastically reduced. Hydroponics is always a soil less culture, but not all soil less cultures are considered to be hydroponics. Many of these cultures do not use the nutrient solutions, which are required for hydroponics. With the advent of high tech plastics and simpler system design, this came about in the late 1970s. The energy saving poly greenhouse covers, the PVC pipe used in the feed systems, and the nutrient injector pumps & reservoir tanks were all made of types of plastic not available prior to the 1970s. Maintaining the proper pH level in the nutrient reservoir is most likely the single most critical factor to successful hydroponic gardening. If the pH factor goes too high or too low, the plants will not do well and will show confusing signs or nutrient deficiencies. Nutrients are a key factor in a successful hydroponic garden. All of these salts must be thoroughly dissolved before being allowed to circulate around your root systems. Micronutrients are also needed for proper growth of your plants. Boric acid, manganese chloride, zinc sulfate, copper sulfate and iron sulfate can be used in minute amounts in the nutrient solution. Plants with plenty of oxygen in the root system will also absorb nutrients faster. The nutrients in a hydroponic system are mixed with water and sent directly to the root system. Hydroponic systems use apparatus that are varied. There are two basic divisions between systems: water culture and media based. Secondly, hydroponics eliminates many of the problems associated with traditional farming that leads to sickly, damaged, or wasted crops. Because hydroponic growers produce their own nutrients mixes, it takes the guess work out of figuring out which plants will grow best in a field and what nutrients need to be added to the soil.