Squash is a warm-season crop whose successful growth in Arkansas depends entirely on precise timing. It is extremely sensitive to cold temperatures and cannot tolerate any frost. The key to a good harvest is ensuring both the air and the soil are sufficiently warm before planting seeds or transplants. This careful timing is important because Arkansas features a varied climate, ranging from the cooler Ozark highlands to the warmer southern Delta regions.
Understanding Soil and Temperature Needs
Squash seeds require warm conditions to germinate successfully, making soil temperature a more reliable indicator than the date on a calendar. Planting is not recommended until the soil registers at least 60°F, measured four inches below the surface. Optimal germination and seedling growth occur when the soil temperature consistently reaches 65°F to 70°F.
Planting in soil colder than this minimum threshold can cause the seeds to rot before they sprout. Cold soil can also stunt the young plant’s growth, making it more susceptible to disease. Gardeners should wait until the danger of the last spring frost has passed and the ground has retained enough heat to support the developing roots.
Planting Windows Across Arkansas Regions
The state’s geography dictates three distinct planting windows, requiring gardeners to adjust based on their location’s average frost data. These timelines are based on the need for consistently warm soil conditions well after the last potential freeze.
Northern Arkansas
The cooler, higher elevations of Northwest Arkansas, including the Ozark Highlands, have the latest planting window. The average last frost date here typically ranges from mid-April to early May. Gardeners should plan to direct-sow squash seeds starting mid-May, or slightly earlier if soil thermometers confirm a consistent 65°F reading.
Central Arkansas
Central areas, including the Arkansas River Valley and the Little Rock metro region, experience a moderate spring warm-up. The average last frost date usually falls around the end of March or the first week of April. The ideal window for planting squash in Central Arkansas begins in mid-April.
Southern Arkansas
The southern and eastern portions of the state benefit from warmer Gulf air masses and have the earliest planting window. The average last frost in this region typically occurs in late March. Direct-sowing can reliably begin in early to mid-April, as the soil warms quickly.
Adjusting Planting for Summer and Winter Squash
While the regional windows provide a starting point, the specific type of squash determines planting. Summer squash, such as zucchini and yellow crookneck, mature rapidly, typically within 50 to 65 days of planting. Winter squash varieties, including butternut and acorn, require a much longer growing period, often 90 to 110 days, and must reach full maturity before the first fall frost.
For summer squash, gardeners can utilize succession planting by sowing new seeds every two to three weeks until mid-summer. This practice ensures a continuous supply of tender fruit throughout the season and helps manage the inevitable decline in plant vigor from pests or disease. The final planting of summer squash should occur no later than 60 days before the projected first fall frost to guarantee a harvest.
Winter squash requires a single, earlier planting to utilize the entire summer for development and ripening. In Northern Arkansas, where the first fall frost can arrive in mid-October, winter squash must be planted by the end of May to ensure the 110-day maturity is met. In the warmer southern regions, where the first frost may not arrive until early November, planting may be delayed until mid-June. Timing the planting so the harvest occurs just before the first frost allows the tough rind to fully develop for long-term storage.
Preparing the Planting Site and Soil
Once the optimal planting time is determined, site preparation is the next step to ensure robust plant growth. Squash plants require a location that receives a minimum of six to eight hours of direct sunlight each day. This sunlight is crucial for photosynthesis and maintaining the necessary warm soil temperatures.
The soil itself should be rich in organic matter and well-draining to prevent waterlogging. Incorporating several inches of high-quality compost or aged manure before planting will provide a steady supply of nutrients and improve soil structure. Squash are heavy feeders and benefit from a slightly acidic to neutral soil pH, ideally between 6.0 and 6.8.
Seeds should be planted about one inch deep, either in traditional rows or in small mounds, often called hills. Planting in hills, with three to four seeds per mound, can slightly accelerate soil warming and improve drainage around the roots. Once the seedlings emerge and develop their first true leaves, they should be thinned to the strongest one or two plants per location to prevent overcrowding.