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Alfalfa Cover Crop

Standard · Fabaceae

Alfalfa is a deep-rooted perennial legume used as a high-value soil-building and forage cover crop in well-drained beds. It develops a dense crown and taproot system that can mine nutrients from depth, improve soil structure, and fix nitrogen when properly inoculated. Because it dislikes wet feet and has strong autotoxicity, it is best used where a longer cover window and excellent drainage are available. Key facts: 60–70 days to maturity, 8+ hours of sun, 6–10 " spacing. Not recommended for containers.

Updated April 19, 2026 · Backed by 4 cited sources
Overview

At a Glance

The essentials first: timing, light, spacing, seed-starting, container fit, and overall size.

Days to maturity
60–70 days
Sun
8+ hours
Full Sun, 8+ Hours
Spacing
6–10 "
between plants
Seed start
0 weeks
before transplant
Container
Not recommended
Needs 7+ gal if attempted
Height
2–3 ft
at maturity
Planting window

Zone Planting Guide

Switch zones to see whether this plant is a strong fit, what frost timing looks like, and any extra notes worth planning around.

This card updates instantly with viability, frost timing, and any planting notes for your selected zone.

Resilience

Plant Health

Stress tolerance, resistance notes, and the most common problems to watch for as plants mature.

Tolerance
Heat: Moderate Cold: High Drought: Moderate

Common Issues

Autotoxicity

Cause: New alfalfa sown into old alfalfa ground germinates poorly and forms weak roots

Prevention: Do not reseed directly into existing or recently terminated alfalfa

Poor Drainage

Cause: Wet soil stresses roots and crowns

Prevention: Choose only deep, well-drained beds

Weed Pressure

Cause: Slow canopy closure on weak seedings

Prevention: Prepare a clean firm seedbed and seed shallow at adequate density

Feeding & picking

Nutrition & Harvest

How hungry the plant is, what ripe harvest looks like, and how long the crop keeps after picking.

Feeding
Nutrition
Feeding intensityLow feeder
RecipesWorm Castings Topdress, Compost Tea
Timing
Harvest

Terminate at late bud to early bloom or take a first cut once the stand is vigorous and well rooted.

Expected yield0.1–0.25 lbs/plant
Storage Use immediately as mulch, compost feedstock, or green manure.
Plant relationships

Companion Planting

Helpful neighbors can support growth or deter pests. Keep antagonistic plants separated to reduce stress and competition.

Avoid planting near
Herb Fennel
What you'll need

Growing Supplies

Based on Alfalfa's growth profile -- recommendations matched to this variety's specific requirements.

Drip irrigation / soaker hose kit

Every gardener benefits from putting water at the root zone instead of on the leaves, because drip and soaker systems reduce foliar disease pressure by limiting leaf wetness and soil splash. A quality kit should include a backflow preventer, filter, pressure reducer, and UV-resistant tubing.

Source: Iowa State University Extension; Colorado State University Extension; UMass Extension

Soil test kit

A soil test gives a baseline for pH and nutrient status so gardeners can add only what the soil actually needs. Prioritize a mail-in or lab-affiliated kit whenever possible because extension guidance notes that laboratory testing is more accurate than instant readers.

Source: University of Maryland Extension; Purdue Extension; Montana State University Extension

Quality bypass pruners

Extension guidance favors bypass designs because they make cleaner, closer cuts on living tissue than anvil types. Look for hardened steel blades that can be sharpened, a comfortable grip, and a cutting capacity matched to real home-garden stems.

Source: University of New Hampshire Extension; Iowa State University Extension; Purdue University Extension

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Research

Sources

Reference material and extension guidance used to build this growing guide.

seed_catalog Seeds Nowuniversity University of Minnesota Extensionuniversity University of Nebraska CropWatchreference SARE cover crop resources
Internal links

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