Alfalfa Seeding Rate Per Acre: A Complete Guide

Alfalfa seeding rates typically run 12 to 20 pounds of pure live seed per acre, with drilled stands at the low end and broadcast plantings at the high end.

Scatter the same bag across two fields and one comes up thick while the other looks patchy — the difference is rarely the seed itself. It is the rate, the seedbed, and whether the number on the tag matches what actually goes in the ground. Get those three right and alfalfa establishes reliably for years.

What Is The Recommended Seeding Rate Per Acre?

Most U.S. extension guidance lands in the 12–20 lb per acre range for pure live seed, or PLS. That number shifts based on how you plant and how good your seedbed is going in.

• Drilled, good conditions: 12–15 lb/acre
• Broadcast: 20–25 lb/acre, since seed-to-soil contact is poorer
• Midwest and Eastern conditions: Iowa State reports little yield benefit above 10 lb/acre PLS
• With a grass companion: 10–16 lb/acre alfalfa plus the grass rate
• Irrigated straight stands: as low as 7–8 lb PLS/acre in some bulletins
• Dryland: roughly 5 lb PLS/acre in arid regions

Missouri Extension lists 15 lb/acre of certified seed alone, which works out to about 13 lb/acre PLS. Bulk seed blended with grass drops to around 10 lb/acre. The headline point across sources: pushing above the recommended rate rarely improves yield when conditions are already good. More seed is not a substitute for a firm, fine seedbed.

Why Pure Live Seed Matters More Than Bag Weight

Bag weight tells you almost nothing useful. Pure live seed is the portion of that bag that will actually germinate and grow, and it is the number your seeding rate should be built on.

The math is straightforward. Divide your target PLS rate by that index to get the bagged pounds you actually need per acre.

To hit 15 lb PLS/acre, you need closer to 21 lb of bagged seed. That gap is where most under-seeding happens.

Coated seed deserves its own warning. The bag feels heavier, but it holds fewer seeds per pound, so cutting the rate because the weight looks generous backfires.

How To Plant So The Rate Actually Holds

Seeding depth and seedbed firmness decide more outcomes than the rate on the bag. Alfalfa goes in shallow — 1/4 to 1/2 inch on medium and heavy soils, 1/2 to 1 inch on sandy ground.

Test firmness with your boot. A footprint should sink no deeper than 3/8 inch. Deeper than that, and the seedbed is too loose for good seed-to-soil contact.

Calibrate the drill before you plant. Iowa State names calibration as the single step that determines whether you hit your target rate or miss it by a wide margin. Then check the results as you go rather than trusting the setting alone.

If you are broadcasting rather than drilling, bump the rate up. Uniform depth and seed-to-soil contact both suffer when seed sits on the surface, and the higher rate offsets that loss. When you are ready to stock up, our tested alfalfa seed picks for U.S. growers cover variety and tag quality. Extension agronomists also lay out the full alfalfa seeding recommendations if you want the source data behind these numbers.

What Goes Wrong Most Often

Five mistakes account for most poor alfalfa stands, and none of them involve buying the wrong seed.

• Confusing bag weight with PLS. The label is where the real number lives.
• Planting too deep. Seed buried past an inch struggles to emerge, especially in heavy soil.
• Assuming more seed means more yield. Research does not support rates above recommendations under good conditions.
• Using the drilled rate for broadcast. The two methods need different numbers.
• Leaning on a high rate to fix a rough field. Correct the seedbed instead.

Conditions drive the final number more than any chart. Moisture, soil texture, row spacing, inoculation, and companion crops all shift the right rate up or down. Treat 12–20 lb PLS/acre as the working range, then adjust for what your field and your equipment are actually doing. A modest rate in a well-prepared seedbed beats a heavy rate in a poor one every season.