Breaking New Ground

What makes plants grow?(Breaking New Ground)

Maybe you’d like to ask this young gardener, “What’s your secret?” Well, here’s what he’d tell you, “Secrets? Forget it! Growing sweet peppers isn’t a big mystery. Pepper plants need six things. Supply them with these needs and you’ll harvest a basketful of sweet, red peppers!”

Checklist for Growing

As you observed in the Discover Activity, plants grow and develop. Think about your pea plants. They grew from seeds into plants with slender stems, and leaves with curly threads called tendrils. If the pea plants were growing in a garden, they would have formed pods containing seeds. Why a pea plant need to grow? It must have those six things that the pepper grower talked about. To grow, plants need light, water, nutrients, the right temperature, gases in the air, and space to grow.

To produce these tasty peppers, the pepper plants need warm temperatures and plenty of space.

Hydroponics: All A Plant Needs

On hydroponic farms, crops grow indoors in a nutrient-rich liquid.

Plants that grow on farms get most of the things they need from nature. But sometimes nature is undependable. Bad weather may prevent crop plants from getting the sunlight, water, or warmth they need to grow well.

Now scientists and farmers are experimenting with hydroponics, a new kind of agriculture. Hydroponics is the science of growing plants in a nutrient-rich liquid instead of in soil. On hydroponic farms, crops such as lettuce and spinach, are raised indoors in factory-like buildings. The plants are supplied with the things they need to grow well-air, light, nutrients, water, and proper temperature.

Lights

Special grow lights are often used to help plants grow faster. Sometimes lights are turned on for 17 hours a day.

Temperature

Air temperature is carefully controlled so that plants get the warm temperatures they need. Electricity and fuels are used to heat the building.

Nutrients: –

Nutrients nitrogen phosphorous, potassium calcium magnesium and sulfur are added to the water . Hormones are also added to help plant grow.

Water

A system of pipes and sprinkles supplies plants with water . the roots of the crops  hang down into a solution of water and nutrients.

Nutrients from Soil

Unlike plants in hydroponic farms, most plants grow  in soil. Soil is made mostly of tiny bits of crushed rocks. As plants and animals die and decay, their remains mix with the soil, too. The plant-and animal part of soil is called humus (hy mos). This wonderful mix of rock and humus contains nutrients-chemicals plants need to grow. Soil is like a bank. Plants draw nutrient “riches” from the “soil bank” just as people take money from a bank.

Some of the nutrients in soil are minerals such as phosphorus, potassium, sulfur, calcium, and magnesium. Another soil nutrient is nitrogen, the hardest nutrient for plants to get!  But plants can’t use this nitrogen. They must take in nitrogen from the soil. Some soil bacteria change nitrogen gas into nitrogen compounds that plants can use. Nitrogen compounds are also formed when dead plants decay. Plants take in and use these compounds.

The diagram shows how plants use nutrients over and over again in a cycle. In nature, plants take nutrients from the soil. When plants die and decay, the nutrients are returned to soil as humus.

Now look at the diagram on this page. It shows that some nutrients on farmland aren’t cycled, as they are in nature, When farmers harvest their crops, they take away parts of the plants that would die and become humus. It’s a lot like taking money out of the bank but not putting money back. Then you have to borrow money.

When farmers take riches from the soil bank, they must borrow nutrients from fertilizers. A fertilizer is a substance, either chemical or natural, that adds nutrients to soil. Fertilizers are like deposits that replace money taken out of a bank. They allow farmers to keep growing crops on the land after nutrients have been removed.

Chemical fertilizers come in different forms, such as the particles you see here. Natural fertilizers include manure from cattle and other livestock, Legumes, which work with Rhizobium bacteria to make nitrogen, are another natural fertilizer, Sometimes farmers plant alfalfa and then plow the crop into the soil. Crops that add nitrogen to the soil in this way are called green manure.