Reading 1

Unit 9- Reading 1

Page 130

Hydroponics

Hydroponics is a way of growing plants without soil. Instead, the plants grow in water. The principle is simple. The water is mixed with nutrients, vitamins and minerals , that plants require in order to grow.

The roots of the plants grow in the water mixture and absorb the nutrients. Hydroponics is one strategy to help provide food to the billions of people on our planet.

WHAT PLANTS NEED TO GROW

Plants naturally grow in soil. The soil holds the water and the nutrients that plants need. The soil surrounding the plant roots helps the plants maintain a vertical growth pattern.

Plants naturally grow upwards toward the sun. If plants cannot grow straight up, they receive less benefit from the sunlight. However, soil is not required for plants to grow. Soil is not required if the plants can get water and nutrients another way. Soil is not needed if another method is used to maintain a plant’s vertical growth pattern. A hydroponic system provides water and nutrients to plants.

It provides a way for plants to grow straight up.

HYDROPONIC SYSTEMS

There are many different kinds of hydroponic systems. The kind of system used depends on several factors. One factor is the kind of plant that will be grown. Nearly any plant can be grown in a hydroponic system, but the methods will vary according to the type of plant and its size.

Another factor is how many plants will be grown. Some people use hydroponics to grow a few vegetables in their own garden. They want to grow just enough to supply their families with fresh tomatoes and carrots, for example. In contrast, a commercial farm might use a hydroponic system to grow thousands of tomatoes and carrots that will eventually be transported to nearby markets and sold.

Commercial farms usually set up a hydroponic system in a greenhouse— a building made of glass or heavy, clear plastic. The greenhouse will protect the plants from insects, rain, and too much heat from the sun. Long rows of tables fill the greenhouse. Each long table has a water pipe down its center that will deliver a nutrient mixture to the plants. Large plastic trays are lined up on the tables.

Each tray has a cover that has rows of holes cut out. A tiny carrot plant grows from each hole. The hole helps keep the plant vertical. Each tray is connected to the water pipe and to a drain. An automatic timer regulates the watering schedule. Several times a day, the roots of the plants are sprayed with a nutrient mixture from the water pipe.

The extra water drains out of the tray and back into the water pipe. The carrot plants have everything they need to grow: water, nutrients, and sunlight. When the carrots achieve the right size, they will be removed, packaged, transported, and sold.

The environment inside a greenhouse can be changed according to local conditions.

For example, in areas that have few daylight hours or many cloudy days, farmers can add a lighting system to provide the light that plants need to grow.

The theory of hydroponics is not new. A book written in 1699 described experiments to grow plants without soil. In one description, the author maintained that plants grown in dirty water grew better than plants in pure water.

Today we recognize that the “dirty water” probably contained nutrients that helped the plants grow.