Lettuce  has been eaten for over 4,500 years, and was known to the Egyptians, Greeks and Romans. Now, people in some countries start the meal with lettuce as part of a salad. There are hundreds of kinds of lettuce. The main ones include head lettuce, such as iceberg, leaf lettuce,Boston, bibb and romaine. Experts say lettuce is one of the easiest crops to grow in your garden. The best time to plant the seeds is during cool weather. The University of Illinois Extension advises that the best planting temperature is 150C. Lettuce seeds are small, so do not place them too deep in the ground. If you plant some seeds every week or two, you will have crops ready to eat one after another. To start the seeds inside, you can use a seed tray in your home or other shelter. This container should be deep enough to hold at least three centimeters of soil or more. There should be about one centimeter of space between the soil and the top of the container. The container should have holes in the bottom so the extra water can flow out. Drop the seeds over the surface and cover them lightly with soil. If the soil is not already a little wet, give it some water. But do not drown the seeds. Next, cover the seed tray with paper. When the seedlings have come up far enough to touch the paper, take it off. You can transplant the seedlings into the garden when they are about two to three centimeters tall. Do this when the weather is not too hot and not too cold. Take out as much soil as you can with the seedlings, Then dig a hole in the ground bigger thanthe lettuce roots. Water the plants but not too heavily. Harvest leaf lettuces when the leaves are big enough to eat. Pull the leaves from the outside of the planting so the inside leaves will keep growing. Or, you can cut off the whole plant. Leave about two or three centimeters above the ground so the plant will re-grow. Cut off head lettuces at ground level. Lettuce is best when served fresh, so make a salad and enjoy. Experts say lettuce is one of the easiest crops to grow in your garden. What can we infer from the passage?
Lettuce is the easiest crop to grow in your garden. The lettuce is not hard to plant and store. We can plant lettuce in a two-centimeter-high tray. We should water lettuce at least twice a day.