Cramer recommend Itron (ITRI) as his next featured environmental stock for "green week." Itron manufactures electricity and water meters to help monitor and conserve utilities, which makes it the perfect "green" play, according to Cramer.

In honor of Earth Day, Cramer welcomed Michael Ward, Chairman, President and CEO of CSX (CSX) to the show to discuss his company's environmental side. Ward explained that railroads are the most environmentally friendly form of transportation. He said his company saved over 900,000 gallons of fuel by using new technologies in their trains. He said the use of his railroad is the equivalent of taking one million cars off the road each year.

Trinity, it turns out, has a growing wind power business with a $750 million backlog. And while wind power only accounts for 6% of the company's sales, Cramer expects that percentage to increase to 10% by next year. Trinity is currently building a second wind tower factory in Mexico to help meet its growing demand. At just eight times its earnings, and down 41% from its recent highs, Cramer called Trinity's stock a steal, and recommended investors jump in now, ahead of what he expects to be one more difficult quarter for the company. "The wind story is here," said Cramer.

According to Cramer, Otter Tail's wind power division, DMI Industries, is "on fire." DMI accounted for 27 cents a share of the company's most recent earnings, up 42% from just 19 cents in 2006. Cramer said this 63% growth is hard to find in any industry. Cramer speculated that if Otter Tail were to spin off its DMI division the stock could double in value. DMI, he said, has a solid $289 million backlog and an 18% market share. The company is also expanding its three plants in Canada to help meet its growing demand. Cramer called Otter Tail "the best play for wind power out there," and encouraged the company's management to bring DMI to the forefront of their earnings calls. He called the strong a strong buy under $37 a share.

Cramer told caller Chris in Georgia that he would stay out of China energy companies such as Suntech Power (STP), LDK Solar (LDK) and Trina Solar (TSL). "We are not playing with any of these," Cramer said. "We are staying out of China. We're going to keep out of China until we think that market has finally bottomed, and it hasn't."

Cramer told caller Chris in Georgia that he would stay out of China energy companies such as Suntech Power (STP), LDK Solar (LDK) and Trina Solar (TSL). "We are not playing with any of these," Cramer said. "We are staying out of China. We're going to keep out of China until we think that market has finally bottomed, and it hasn't."

Cramer told caller Chris in Georgia that he would stay out of China energy companies such as Suntech Power (STP), LDK Solar (LDK) and Trina Solar (TSL). "We are not playing with any of these," Cramer said. "We are staying out of China. We're going to keep out of China until we think that market has finally bottomed, and it hasn't."

Caller Matt in Massachusetts said that water is the new oil, and asked about which company Cramer would look at. "Most of the water plays have been a disaster," he said. "I have not liked the pump group." Cramer suggested ITT Corp. (ITT), which has yet to miss earnings.