Sudangrass (Piper) Cover Crop Seed

What they do

Pearl millet, Japanese millet and sudangrass are summer grasses that build a lot of biomass fast, smother summer weeds and can be cut for forage.

Sowing

These are warm-season crops: wait until frost danger is past and the soil is 65–85°F (18–29°C). Drill or push-seed 1/2–1" deep, or broadcast at a heavier rate and rake, harrow lightly or roll the seed in.

Seeding rate

Millets: 1/2–1 lb. per 1,000 sq. ft. (12–25 lb. per acre). Sudangrass: 1–2 lb. per 1,000 sq. ft. (30–40 lb. per acre).

Which one where

Pearl millet handles drought, heat and low fertility, and grows where corn or wheat struggle. Japanese millet is the opposite: it does well on low, heavy, wet or poorly drained ground and even tolerates standing water. Sudangrass likes heat, takes drought and grows biggest with good fertility and enough nitrogen.

Light and soil

Full sun. Both millets cope with low pH and low fertility but do best near pH 6.0; pearl millet also tolerates salty soil.

Sudangrass and following crops

Breaking-down sudangrass releases compounds that suppress nematodes, but they can also hold back small-seeded crops sown right after it and tie up nitrogen. Letting it winter-kill and planting the next spring avoids the problem.

Height and mowing

These grasses can pass 8 ft. Mowing keeps them manageable: leave 4–6" of stubble so they regrow.

Cutting

Expect 3–5 cuttings a season. Hay is ready in about 75–80 days, seed in about 105. Mow before working the crop into the soil.

Caution

Do not cut or graze sudangrass for forage after a frost: prussic acid in frosted plants can poison livestock.

Termination

Their size calls for a tractor-mounted flail, sickle-bar or rotary mower; small mowers struggle. All three are killed by frost, which is an easy end for growers without heavy equipment.

Seeds per lb.

About 45,000 on average.