ST. LOUIS — As Midwestern farmland bakes under days of relentless heat, farmers are doing something they are well accustomed to: hoping.

But as crop growth slows and grazing pastures turn brittle, many are looking to the rainless skies with a building sense of dread, while watching a growing season - expected to be one of the best on record - evaporate in the blazing sun.

“Everybody’s pretty bummed out right now,” said Brenda Stanberry, who sells insurance to farmers across the Midwest. “They’re all really down.”

Rainfall across parts of the Midwest is well below average, giving little relief to already parched soil that saw little moisture over the mild, virtually snow-free winter. April, May and June are among the warmest months on record, with little cooling air in sight. Parts of southern Missouri, Illinois, Kentucky and Indiana are under “extreme” drought conditions.

Corn is curling and too short. Soybeans are struggling to emerge. Dairy cows aren’t producing milk because it’s too hot to eat. Cattle are being sold off in record numbers because their owners can’t afford, or find, hay or pasture.

“I’ve seen tough times. I’ve seen floods; I’ve seen droughts; I’ve seen diseases in crops. Pretty much everything,” said Tim Johnson, a salesman at Wm. Nobbe & Co., a John Deere dealership in Scott City, Mo., where drought conditions are among the state’s worst. “But as far as drought, I’ve never seen one this early, and I’ve never seen it this bad.”

For the nation’s corn crop - worth roughly $76.5 billion last year - the weather is especially troubling. Because of the mild spring, many farmers planted their corn weeks ahead of schedule on a record-high number of acres. Now, the crop is being whacked with extreme heat at a critical pollination stage when the plants set ears. No ears mean no harvest.

“The theory is, you plant as early as you can, then it tassels and sets its ears before the heat of summer,” said Greg Guenther, a corn and soybean grower from Belleville, Ill. “I planted around the 15th of April, and it’s about six feet tall. In a normal year, it’d be 10 feet tall.”

This year, taking advantage of the early spring, corn growers across the country planted across a near-record-breaking 95.9 million acres - to capitalize on high prices and high demand. The U.S. Department of Agriculture predicted yields of about 166 bushels an acre - a record - but the weather is throwing that into question.

“I think we’ve lost significant yield potential in the hardest hit areas, and that’s probably brought our national yield potential down,” said Darrel Good, an agricultural economist with the University of Illinois. “People are beginning to think sub-150” bushels an acre.

Dry conditions and drought last year, particularly in the Southwest, meant that cattle ranchers there were forced to scramble for hay - much of it from Missouri, which ranks second in the country in forage production. But now, with pasture land here burning up, producers are turning to their hay stores - normally reserved for winters - if they still have them.

“To be feeding hay in June when that hay is meant for winter - that exerts a tremendous pressure,” said Eddie Hamill, the executive director of the state’s Farm Service Agency.

The rise in corn prices also means livestock producers will pay more for feed. The combination of rising corn prices, scant hay and burnt-up grass has prompted livestock farmers to sell off their animals at a worried pace. Some cattle are worth half what they were just three weeks ago as animals flood the market.

“Ozark Regional Stockyards has had record receipts because it’s so dry down there,” said Corbitt Wall, a market reporter for the agriculture department. “They’ve sold a world of cattle down there.”

Dairy farmers, too, say they are selling some of their milk cows to slaughter because feed or forage is so scarce and expensive.

“The dairymen are very concerned. They’re unsure where the hay is coming from and they’re watching corn prices go up,” said Larry Purdom, chairman of the Missouri Dairy Association and dairy farmer. “Some are selling. The worst is probably ahead of us.”

Weather experts agree.

“Things are going to get worse before they get better,” said Pat Guinan, a state meteorologist with the Missouri Climate Center. “May and June are typically our wettest months.

“There’s no good time for a drought, but when it happens this early in the season, it’s very worrying.”

The outlook for July, Guinan said, doesn’t suggest much relief. “We need a pattern change and we need it now.”

So far, consumers aren’t feeling the drought’s impact on corn and other vegetables, said Paul Poe, the general manager at Sappington Farmers’ Market in St. Louis. Price and supply haven’t been affected, but that could change before the heat wave ends.

“What we’re hearing from the farmers we deal with is that a lot of the garden-variety vegetables - tomatoes, and things like that - are pulling through as long as they get lots of water,” Poe said. “The heat is having the biggest impact on things like herbs that are just getting burned up.”

But Poe said there’s a bright side of the heat wave, at least when it comes to produce that thrives in the hot weather. The market’s watermelon and cucumber suppliers seem to be enjoying a bumper crop.

Henry Lehmann, the director of produce procurement at Dierbergs, said he kept in daily contact with farmers in the region that supply the grocery chain.

“Right now, they’re telling me they’re in decent shape, but there are going to be problems if this heat lasts for another week or more,” Lehmann said.

Lehmann said this year’s local-produce season likely will be shorter than usual. In a typical year, Dierbergs stocks local produce through Labor Day.

Except for a brief gap in local blackberries, the weather hasn’t disrupted Dierbergs’ supply of local produce - but that could change soon. Even at farms where crops are thriving, the heat likely will mean a slowdown in how much fruits and vegetables can be brought to market.

“When it’s this hot, they’ve got to look out for the safety and welfare of the pickers,” Lehmann said. “They’ve got to take more breaks, and that’s going to make for slow going.”

In the Missouri Bootheel, where counties are under extreme drought conditions, many row-crop farmers have irrigated land, which is unusual for the state. So despite the conditions, crops there are actually faring well, farmers say.

“If it’s been irrigated, it looks pretty good,” said Jim Stuever, who grows corn, soybeans, rice and cotton near Dexter, Mo. “But I’m already been through most of my irrigation budget for the year.”

Stuever said he has spent twice the amount on irrigation so far this season than he does in an entire typical year. “That’s mainly because of fuel costs,” he said. “But also labor and time.”

The costs of coping with the drought will hit sales of equipment and supplies, too.

At Wm. Nobbe & Co., sales are half what they would be in a usual year.

“We know our customers, we know how they like to buy and when,” Johnson said. “But we’ve got guys we know are due to buy, and they’re saying they have to spend a couple thousand on fuel. The money just isn’t going to be there.”

The possible hit to state economies has lawmakers worried as well. Earlier this week, Gov. Jay Nixon called on the Farm Service Agency to conduct a damage assessment of the state’s crops - a precursor for declaring a disaster area, which would trigger federal aid.

But the agency says it’s too soon to say how extensive the damage actually is.

“This drought and heat is coming so early,” Hamill said. “There’s really no crop there to evaluate at this time.”

Farmers are fearing the worst.

Insurers are reporting a flood of calls from farmers, checking on their policies to see how extensive their coverage is and when they need to file claims. “A lot of them are checking their file cabinets to see what kind of policies they have,” Hamill said.

In the meantime, farmers are relying on nature and a little bit of optimism to save the season.

“That’s the nature of farming,” Stuever said. “You always start the year hopeful.”