Soil Moisture – The Critical Component for Alfalfa Summer Seeding in 2021

As we approach mid-summer, it’s time to begin thinking about late summer establishment of alfalfa. Summer-seeded alfalfa allows a producer to plant immediately following the harvest of small grains and for the alfalfa stand to be fully productive right away the following May.

The two most important factors affecting summer seeding are planting date and soil moisture. Due to the current soil moisture deficit across much of the Dairyland Seed territory, it will be critical to consider your areas extended weather forecasts and historical rainfall in drought years against forage inventory needs since alfalfa depends on adequate moisture in order to germinate.

Although they may work in some areas, cover crops for summer alfalfa planting are not recommended because they will compete for moisture and can smother small alfalfa plants going into the winter season. And unless manure needs to be incorporated into the soil, minimum till or no-till systems are recommended to avoid additional soil moisture loss.

Ideally, we want at least 6 weeks of growth before the first frost. In the upper Midwest, this time period is August 1st – 15th in a typical year. As you move south into the corn belt states the planting window can be pushed another 1 – 2 weeks later.

Additionally, a firm seedbed with seed placement from 1/8 to half inch deep is best with a planting rate of 18-20 lbs/acre to provide maximum yield potential.

Advantages of summer seeding:

• More yield in the first full production year than a spring seeding stand harvested during the establishment year.
• Less weed competition because annual weeds will be killed by the first frost
• Less insect pressures
• Less disease incidence like root rots because the soil temperature is much higher in late summer vs. spring
• Opportunity to apply manure before the fall harvest of other crops.
• Removes some of the workload from spring planting season.

RISKS OF SUMMER SEEDING:

• Lack of moisture can result in poor germination and emergence.
• Early frost can cause alfalfa plants to enter dormancy before adequate root establishment, which increases winter injury risk
• Herbicide carryover can cause poor germination or early seedling death.

A summer seeding alfalfa decision requires careful consideration of many factors. If crop rotation and moisture allow for this opportunity, it is an efficient and productive option for establishing healthy alfalfa stands. Work with your Dairyland Seed District Sales Manager, Dealer, or Regional Agronomist to help decide if summer seeding alfalfa is the right decision for your farm.