About Sunn Hemp
Sunn hemp is a tall-growing warm-season annual legume that fixes more atmospheric nitrogen than almost any other legume and improves soil organic matter significantly when terminated, making it as valuable for soil health as it is for deer forage. The leaves contain roughly 30% crude protein and deer use varies considerably by region — some herds browse it heavily throughout summer while others largely ignore it. Sunn hemp is one of the most tolerant food plot species for poor, low-fertility soils and requires only 8–12 weeks of frost-free conditions to complete a productive growth cycle.
How much Sunn Hemp seed per acre?
The standard broadcast seeding rate for Sunn Hemp is 30–40 lbs per acre, dropping to about 18 lbs per acre when drilled. 30–40 lb/ac broadcast; 15–20 lb/ac drilled per NDA species profile. Grows 6–12 feet tall — plan for this when locating the plot. The calculator above scales this to your exact plot size and converts it into the number of retail bags to buy.
When to plant Sunn Hemp
Sunn Hemp is a warm-season crop. In the northern US, plant in May–Jun (after soil temps reach 65°F); farther south, plant in Apr–Jul. Sow it 3/4" deep and plan on 60–90.
Soil, pH & fertilizer
Aim for a soil pH near 6.5(don't go below ~5.5). No N (nitrogen-fixing legume; one of the highest N-fixing legumes available). No special fertilizer needed on moderate soils. Tolerates poor, low-fertility soils better than most legumes. Not sure where your soil sits? Read our soil test & lime guide.
Sunn Hemp blends well with cowpeas, lablab, soybeans, grain sorghum if you want a more diverse, resilient plot.
Sunn Hemp FAQ
- How much Sunn Hemp seed do I need per acre?
- Broadcast Sunn Hemp at about 30–40 lbs per acre, or 18 lbs per acre if you drill it. 30–40 lb/ac broadcast; 15–20 lb/ac drilled per NDA species profile. Grows 6–12 feet tall — plan for this when locating the plot.
- When should I plant Sunn Hemp?
- In the northern US plant in May–Jun (after soil temps reach 65°F); in the South plant in Apr–Jul. Expect 60–90.
- What soil pH does Sunn Hemp need?
- Sunn Hemp does best at a soil pH around 6.5 (minimum ~5.5). No N (nitrogen-fixing legume; one of the highest N-fixing legumes available). No special fertilizer needed on moderate soils. Tolerates poor, low-fertility soils better than most legumes.
- Do deer like Sunn Hemp?
- Deer preference: medium — highly variable by region; leaves 30% protein; some herds use it heavily, others ignore it until other food sources decline.