Nitrogen Fix Mix Green Manure Seeds

NITROGEN FIX MIX — Green Manure Seeds

Botanical names: Crotalaria juncea (Sunn Hemp), Helianthus annuus (Sunflower), Vigna unguiculata (Cowpea), Lablab purpureus (Lablab)

Nitrogen Fix Mix is a high-biomass, warm-season green manure blend designed to rapidly build organic matter and fix substantial volumes of nitrogen. Combining fast-growing Sunn Hemp and nitrogen-fixing Cowpea/Lablab with deep-rooted Sunflower, this mix produces abundant biomass, improves soil structure, and supports soil microbial diversity. Ideal for gardeners, market growers, and broadacre rotations seeking a powerful seasonal nitrogen boost.

• Designed to enhance biomass yield and fix high levels of nitrogen using complementary legumes (Sunn Hemp, Cowpea, Lablab).
• Sunflowers add deep taproots for soil loosening, organic matter and pollinator habitat.
• Rapid canopy cover suppresses weeds and reduces erosion while building soil carbon.
• Supports beneficial insects and an active soil food web.
• Suitable as a green manure, cover crop, forage or fallow break in warm seasons.
• Produces abundant chop-and-incorporate material for nutrient-rich soil amendments.

Plant Details:

• Mix Type: Multi-species warm-season nitrogen-fixing green manure
• Dominant Roles: Nitrogen fixation (Sunn Hemp, Cowpea, Lablab), biomass & rooting depth (Sunflower, Forage Sorghum alternative)
• Benefits: High biomass, fast N accumulation, improved structure, weed suppression, pollinator support

Sowing Information:

• Sow When:
  Temperate Regions: Late spring–early summer (October–December).
  Subtropical Regions: Spring–early summer (September–November).
  Tropical Regions: Early wet season (November–January).
• Germination: 5–14 days (species-dependent)
• Depth: 1–3 cm depending on seed size (legumes shallower, sunflower deeper)
• Position: Full sun for maximum biomass and nitrogen fixation
• Sow Where: Direct into garden beds, paddocks, fallow blocks, or prepared seedbeds
• Soil Type: Tolerant of a range of soils; prefers well-drained soils. Adjust pH if extremely acidic or alkaline.
• Mixing & Rate: Example blend by weight — 30% Sunn Hemp, 30% Cowpea/Lablab (combined), 30% Sunflower, 10% filler/forage. Adjust ratios to prioritise nitrogen or biomass as required.

Management:

• Keep evenly moist until established; legumes and sunflowers both establish faster with consistent moisture.
• Monitor for flowering — cut or incorporate legumes at early bloom to maximise nitrogen return and avoid heavy reseeding.
• For maximum biomass, allow sunflower to reach early anthesis and Sunn Hemp to approach peak vegetative growth before chopping.
• Use shallow incorporation or chop-and-drop depending on your tillage system; allow residues to decompose before the next cash crop.
• If used for grazing, rotate carefully to avoid overgrazing and to retain ground cover.

Harvest and Incorporation:

Mow or flail when the tallest species begin to flower (legumes at early bloom; sunflower at early head formation). Incorporate by shallow tilling or leave as surface mulch (chop-and-drop). Decomposition typically 3–6 weeks depending on climate — allow adequate time before planting sensitive seedlings.

When to Sow Nitrogen Fix Mix in Your Climate

Quick Growing Guide