Luckily for most of the Carolinas, warm conditions welcome many outdoor enthusiasts well before the first official day of spring. Wildlife managers should be well underway with preparations for spring plantings. From testing to carrying out an annual liming program, soils need a little TLC this time of year. Many landowners looking to grow 200 bushels of corn per acre are probably growing very anxious to get their seeds set, but planting too early can have its drawbacks as well as its remarkable benefits.
The majority of the corn varieties planted in the Carolinas are full-season hybrids intended to take advantage of the South’s extended growing season to produce very high yields. Commercial and amateur farmers will want to get their corn crops in the ground as soon as possible for several reasons, including less competition, higher soil moisture and a longer growing window.
Higher soil moisture is among the most important factors. An early spring planting will give plants access to critical soil moisture when they need it the most. From germination through maturation, water is the most-important need for plants, and spring is when water is the most abundant during the crop’s life. When mature plants don’t receive enough water, seed yields will be compromised. When young plants don’t receive enough water, the tender root systems will dry out, causing immediate death and wiping out any hope of a staple food source for wildlife later.
During the spring, cool nighttime temperatures and routine rainfall will nourish the soil bed with a consistent flow of moisture that is ideal for germination and early growth.
Early season plantings give corn a head start over the weed army that’s on the way. Most spring weed species that overtake food plots and corn crops do not germinate until soil temperatures reach 65 to 70 degrees, so an early season planting will give plants time to grow tall and shade out some of the impending weed competition. Early season plantings are also known to provide strong stalks and have less insect problems later in the season.
What is the key soil temperature? For most corn varieties, the temperature in the top 2 inches of the soil needs to be 55 degrees in order to get good germination, with 60 degrees being preferred. In the Carolinas, these soil temperatures typically arrive in late March, but the threat of winter weather and freezing temperatures is long from over.
According to more than 30 years of data recorded by the National Climatic Data Center, average high and low temperatures in the Carolinas are in the low 60s and upper 30s in March and in the low 70s and mid-40s in April. It is not uncommon to get a late- season snow or an extended period of freezing temperatures during March.
When seeds are planted early and are subject to a freeze, they become vulnerable to insect and pathogenic attacks. Shortly after planting, seeds will absorb a third of their weight in water. When the soil temperature drops, germination is delayed and gives invaders a chance to destroy seeds.
Even if seeds germinate, growth can be quickly hampered if the soil temperatures drop below 55 to 60 degrees. The first shoot of growth extending from the seed towards the surface is called the mesocotyl. This structure digs through soil particles towards sunlight and will begin to use the sun’s energy to form the first few shoots of green after emergence. A temperature drop during this stage will inhibit mesocotyl growth that can reduce growth potential or cause death.
During these early stages of growth, soil temperature is critical. Soil type and color can affect soil temperature and growth. Light, sandy soils will warm up much faster than heavy, clay soils. And darker soil hues exposed to the sunlight will absorb heat much faster than lighter-colored soils.
Temperature-affected corn crops can be identified when stalk height is abnormal across the field. Groups of plants in clusters shorter than others are a prime indicator of variation in soil temperature during early growth stages. But an entire field can be stunted when soil temperatures dropped below ideal conditions during the growth period.
When landowners want to plant corn, the best yields are produced from early plantings when optimal soil temperatures exist after planting. If corn crops can grow past the dangers of early season planting, the yields can be very impressive that will create a massive food source for deer and migratory birds next fall.