Cover Crop Calendar: Season-by-Season

By Emma Johnson · October 10, 2026

Why Year-Round Cover Cropping?

Bare soil is dying soil. Without living roots, the mycorrhizal network starves, soil organisms decline, organic matter oxidizes, and erosion strips away the most fertile surface layer. Cover crops keep the soil food web active between cash crop seasons, ensuring your garden beds are biologically ready when planting time arrives.

Early Spring (March-April)

Field Peas + Oats

Sow as soon as soil can be worked. Field peas fix nitrogen while oats provide quick ground cover and biomass. Both are frost-tolerant and can be terminated six to eight weeks later when beds are needed for summer crops. Incorporate two weeks before transplanting.

Mustard (Biofumigation)

Fast-growing brassica that suppresses soil pathogens through glucosinolate compounds released during decomposition. Sow thickly in early spring, chop and incorporate at flowering for maximum biofumigation effect. Wait two weeks before planting susceptible crops.

Summer (June-August)

Cowpeas

Heat-loving legume that thrives when cool-season crops have finished. Fixes 100-150 pounds of nitrogen per acre. Tolerates drought and poor soil. Produces edible pods as a bonus harvest. Terminate before first frost.

Buckwheat

The fastest cover crop—germinates in three days, flowers in 30. Excellent for filling short gaps between spring and fall crops. Attracts beneficial insects with prolific white flowers. Suppresses weeds through rapid canopy closure. Not a nitrogen fixer, but excellent phosphorus scavenger.

Sudangrass

Tropical grass that produces massive root biomass in summer heat. Roots exude allelopathic compounds that suppress nematodes and weed seeds. Mow at three feet height to encourage tillering. Best for large areas with space for summer fallow.

Fall (September-October)

Winter Rye + Hairy Vetch

The classic fall combination. Rye provides erosion control and biomass while vetch fixes nitrogen over winter. Together they produce 3-5 tons of organic matter per acre. Terminate in spring by cutting at soil level two weeks before planting.

Crimson Clover

Six weeks before first frost, broadcast crimson clover into existing crops or onto cleared beds. It establishes slowly in fall, survives winter, then explodes with growth and red flowers in early spring. Fixes 70-150 pounds of nitrogen.

Daikon Radish

Drill-sized taproots penetrate compacted subsoil, leaving drainage channels when they rot. Plant in late summer to early fall. Roots reach 2-6 feet deep, bringing up minerals from subsoil. Winter-kills in zone 6 and colder, leaving ready-to-plant beds in spring.

Winter (November-February)

In mild zones (8+), winter cover crops continue growing slowly. In cold zones, focus on protecting established fall cover crops with row cover if needed. The root systems maintain soil structure and biology even when top growth is dormant.