FORT WORTH — With spring break in full swing and temperatures starting to edge into the 80s, some North Texans have fled to the coast for beach parties, and others are itching to get garden vegetables into the ground.After all, the forecast calls for 83 on Tuesday. But nursery managers said hard freezes, which can be fatal for warm-season plants such as tomatoes, squash, cucumbers and okra, are still a possibility.Texas gardening expert Neil Sperry agreed: “It’s way too early to plant tomatoes, corn and beans,” he said Friday.Sperry, who has a radio program and a weekly column that appears Saturdays in the Star-Telegram, has noted that the average date of the last killing freeze in the Dallas-Fort Worth area is March 15-25. The National Weather Service in Fort Worth pinpoints it at March 13.He suggested gardeners who want to get into the yard this week can tend to other chores, such as pruning shrubs and trees, and “scalping” lawns with mowers to rid the turf of winter weeds. He said it is critical to beat crabgrass by applying pre-emergent granules such as Dimension or Halts, between March 5 and 15.“This is the only time to do that,” Sperry said. “And do a booster shot in June.”He said the best time to plant warm-season vegetables is late March and early April. Weather service data shows plenty of freezing days in March; the record so far is 10 degrees on March 3 in 1943. In recent years, it got down to 20 degrees on March 4, 2002, and 30 degrees on March 24, 2006.This year’s March 2 storm dragged temperatures into the upper teens, which was tough even for cool-season vegetables in the greenhouse at Marshall Grain Company on East Lancaster Avenue in Fort Worth.“They did get a little bitten when it got down to 19 degrees,” said Shelly Mercer, assistant manager. “Even in our greenhouse, lettuces, cabbages — anything that was a leafy green — had a little touch of damage.”Cold weather can persist into April and May — it got down to 39 degrees on both May 3 and 4 last year, according to the weather service.“It was ridiculous,” said Kay Matlock, manager at Calloway’s Nursery on South Hulen. “The thing, too, to remember is Texas has the most fluctuations in temperatures. “You can go from 80 degrees to just 14. It certainly has happened several times.”Mercer said “old timers” who visit her store have predicted there could be two more freezes, and she’s concerned one could come later than March. “I’m kind of scratching my head at this,” she said. “I would be real, real skeptical about planting tomatoes anytime soon, but if we don’t do it on time, we won’t have anything in production.”She suggested starting tomatoes, peppers and other warm-season plants in pots and keeping them indoors until temperatures stay warm enough to transfer them outside. Matlock said the threat of a killing freeze will subside “when we have two weeks in a row where nightly temperatures don’t drop below 60.”“When that happens,” she added, “the ground is warm enough to sustain a light freeze.”Meanwhile, Matlock and Mercer said gardeners can prepare for any unexpected freezes by covering plants that are already in the ground, including cold-season vegetables such as lettuce, spinach, carrots, beats and radishes.They both favor “frost cloth,” which is light and porous, but can insulate enough to keep plants 10 degrees warmer.Matlock said frost cloth is inexpensive, about $1 a foot, and can be easily stored for reuse.
Bill Miller, 817-390-7684 Twitter: @Bill_MillerST