Fall Alfalfa Seeding Challenges & Completion

Sometimes the stars align, and other times, perhaps even more often, they do not.  Preparing the first fields and completing a fall seeding of alfalfa proved challenging with both time and the weather choosing not to cooperate.

For our area in Kentucky, the ideal seeding time for fall season planted alfalfa is around September 1st – 15th, giving a suitable buffer with an optimal chance of having warm temperatures for germination, emergence, and ultimately crown development.

Farm Selection & Soil Testing

Selection of the farm, site preparation, and soil testing was completed earlier in August.  See the blog post “Alfalfa Hay Production Begins” for more information.

Seedbed Preparation

The fields had previously been cattle pasture for quite some time, so compaction was an issue.  The equipment used combined with vegetation residue after burndown, unfortunately, caused various issues and delays with tillage, preventing a perfect seedbed prior to seeding.

Running subsoiler shanks to break deep compaction, followed by disking to break the top layer and incorporate fertilizer, followed by final passes with an Unverferth Perfecta field cultivator gave way to a drastic improvement, but due to moisture, vegetation residue, and soil conditions, not quite a perfect seedbed.

Seeding the Alfalfa

Even though the seedbed and soil conditions were not exactly what was desired for perfection, the time crunch was real and was nearing the latest planting time recommended by our local UK Ag extension agent.

Using America’s Alfalfa 480HVXRR variety for straight alfalfa, the ideal seeding rate was determined to be 20 lbs per acre.

Seed Drill Calibration

For a small time, the thought of skipping calibration and trusting the alfalfa rate chart seemed like a good idea, but it’s a good thing it was performed instead, as using the recommended adjustment distributed 40% more seed than was noted.

Using the Frontier CS1384 seeder, which is 7ft wide with 16 seed cups, requires calibrating at a distance of 62ft for easy calculation at 1/100th of an acre.

Multiply the seed weight collected from one cup/tube by the number of cups, then multiply by 100 (since our calibration track is 1/100th of an acre) to determine how many ounces of seed per acre.  Dividing by 16 gives pounds per acre.

The first calibration test pass while using the recommended setting from the rate chart collected about half an ounce of seed, which equals an actual rate of 50 lbs/acre — over double what the goal is.

After a few more calibration tests the seeder was dialed into the ideal range to accomplish seeding at 20 lbs/acre.

Germination & Emergence

Immediately following the seeding of fields, near record high temperatures were observed and combined with an abundance of soil moisture and sporadic early fall showers provided a surprisingly well-suited environment for quick germination.

Cotyledon Emergence

Walking the field at only three days post seeding revealed the first signs of germination and emergence, as the alfalfa cotyledons were seen emerging through the top layer of soil.

Checking again a couple of days after emergence was noticed, the beginning of radicle extension and growth downward was very visible.

Unifoliate Leaf Development

Returning after one-week post seeding gave sight to the first true leaf, the unifoliate leaf.

Unfortunately two weeks later we saw our first freezing temperatures of around 30 degrees F, but only for a couple of hours.

So far as of the writing of this post, we’ve received roughly 2 inches of rain, and have accumulated nearly 340 GDD since the early October alfalfa seeding.

Cumulative GDD since October 2nd seeding

Growing degree-days (GDD) for alfalfa are calculated by subtracting 41 degrees F (base growing temperature for alfalfa) from the low & high temperature average for a given day for days where the temperature is above the base.

Although the forecasts are now showing a warming trend moving into November, it will be interesting to see what happens over the upcoming months and into the spring season to determine whether the stand is adequate enough, or needs to be replanted.