Skip to main content
Phacelia cover crop and bee forage
Photo: "Am Feldrand" by Michael Mueller · CC BY 2.0

Phacelia cover crop and bee forage

Annual · Boraginaceae

Phacelia is a fast cover crop and one of the best bee-attracting flowers gardeners can sow for short windows between food crops. It makes fine roots, quick canopy, and purple blooms that support pollinators and beneficial insects, which is why it is often used as both a cover crop and a habitat plant. It suits gardeners who want rapid bloom and ecosystem services from a short planting. Key facts: 45–60 days to maturity, 6+ hours of sun, 6–12 " spacing. Not recommended for containers.

Updated June 1, 2026 · Backed by 7 cited sources
Overview

At a Glance

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

Days to maturity
45–60 days
Sun
6+ hours
Full Sun 6-8 Hours
Spacing
6–12 "
between plants
Seed start
0 weeks
before transplant
Container
Not recommended
Needs 5+ gal if attempted
Height
0.5–4 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

Watch for these first

Sort
Issue Severity Category Peak window
Damping off Pythium spp. / Rhizoctonia solani / Fusarium spp.
High Disease May–Aug Peak window months: May, Jun, Jul, Aug.

A seedling killer caused by several different fungi working together. It hits vegetables, flowers, herbs, microgreens, and cover-crop seedlings the same way — seeds rot before they emerge, or young seedlings collapse right at the soil line. Wet seed-starting mix and poor airflow in seedling trays are the classic conditions.

Triggers: Wet soil or starting mix, poor drainage, seedlings packed too tightly, contaminated trays or media, and stagnant air all favor damping-off.

On Phacelia: Cold, wet seedbeds or overly dense sowing can kill seedlings.

Prevention: Use clean seed, shallow sowing, and thin dense stands.

Risk fades when: Drying the soil surface and improving airflow slows new spread. Collapsed seedlings don't recover, but the rest of the tray can be saved.

Damping off symptoms
Damping off of coffee seedlings caused by Fusarium sp. — Photo: Scot Nelson · CC0 1.0
Powdery mildew Golovinomyces cynoglossi
Low Disease May–Aug Peak window months: May, Jun, Jul, Aug.

A Boraginaceae powdery mildew supported for forget-me-not, where it causes dense white fungal growth on leaves and stems. Current source support is strongest for forget-me-not specifically — don't auto-add borage unless plant data references and supporting sources are verified.

Triggers: High humidity with dry leaf surfaces, aging or crowded plants, and poor airflow all favor the disease.

On Phacelia: Late-season humidity can coat foliage and blooms.

Prevention: Improve airflow and avoid crowding.

Risk fades when: Pressure eases when weather moves out of mild humid conditions and infected annual foliage is cleared.

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 intensityNone feeder
Timing
Harvest

Terminate at early bloom for easy incorporation and maximum tenderness.

Expected yield0 lbs/plant
Storage Not normally stored; use as mulch or incorporation residue the same day.
Plant relationships

Companion Planting

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

Stay in the loop

Planting reminders for Phacelia

Frost warnings, zone-specific timing, and seasonal nudges -- sent only when there's something to act on. Free, unsubscribe anytime.

Get Personalized Planting Reminders

Frost alerts, zone-specific tips, and seasonal guidance. Free, unsubscribe anytime.

For zone-specific tips
What you'd like to receive (optional):

By subscribing you agree to our privacy policy. We won't sell your data. Unsubscribe link in every email.

What you'll need

Growing Supplies

Hand-picked for your Phacelia, with the extension research behind every recommendation.

Seed starting tray + heat mat

For gardeners who start seeds indoors, this combo improves even germination. Warm-season crops benefit from bottom heat. Look for a rigid tray, cell inserts with drainage, and a heat mat paired with a thermostat.

Source: Utah State University Extension; Iowa State University Extension; Mississippi State University Extension

Our pick

Seedling Heat Mat + Thermostat Combo

Same trusted mat with a digital thermostat so you can dial in exact soil temperature. Peppers want 80-85°F, tomatoes 75-80°F.

paid link ?When you shop on Amazon using this link, SoilStack earns a small commission at no extra cost to you. It's how we keep the site free and the calendar ad-free. Every product on this page was hand-selected based on university extension research. When you shop on Amazon using this link, SoilStack earns a small commission at no extra cost to you. It's how we keep the site free and the calendar ad-free. Every product on this page was hand-selected based on university extension research.
View on Amazon

Mulch / landscape fabric

Nearly every garden benefits from mulch for weed suppression, moisture conservation, and soil temperature moderation. For most home gardeners, quality organic mulch is the better buy over landscape fabric.

Source: Penn State Extension; Wisconsin Horticulture; Illinois Extension

Our pick

Cleaned Wheat Straw Mulch (3 cu ft, ~20 lbs)

Thoroughly cleaned wheat straw at 3 cubic feet, marketed specifically for vegetable gardens rather than animal bedding or decoration. Better per-pound economics than the 1 cu ft option, with the same extension-recommended material. Strong sales volume (2K+ bought past month) supports product consistency.

paid link ?When you shop on Amazon using this link, SoilStack earns a small commission at no extra cost to you. It's how we keep the site free and the calendar ad-free. Every product on this page was hand-selected based on university extension research. When you shop on Amazon using this link, SoilStack earns a small commission at no extra cost to you. It's how we keep the site free and the calendar ad-free. Every product on this page was hand-selected based on university extension research.
View on Amazon

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

Our pick

Complete Garden Drip Irrigation Kit

Designed for beginners with a step-by-step setup guide. Adjustable emitters, both tubing sizes, and all connectors included.

paid link ?When you shop on Amazon using this link, SoilStack earns a small commission at no extra cost to you. It's how we keep the site free and the calendar ad-free. Every product on this page was hand-selected based on university extension research. When you shop on Amazon using this link, SoilStack earns a small commission at no extra cost to you. It's how we keep the site free and the calendar ad-free. Every product on this page was hand-selected based on university extension research.
View on Amazon

Row cover / frost blanket

Row cover adds frost protection, speeds early growth, and physically excludes insect pests without spraying. Look for spun-bonded fabric with a stated weight and frost rating, UV resistance, and enough width for hoops or low tunnels.

Source: University of Maryland Extension; University of New Hampshire Extension; Colorado State University Extension

Our pick

Frost Blanket (10'x30')

Thicker 1.2 oz fabric rated to protect down to 28°F. Covers 300 sq ft — enough for multiple raised beds in a single sheet.

paid link ?When you shop on Amazon using this link, SoilStack earns a small commission at no extra cost to you. It's how we keep the site free and the calendar ad-free. Every product on this page was hand-selected based on university extension research. When you shop on Amazon using this link, SoilStack earns a small commission at no extra cost to you. It's how we keep the site free and the calendar ad-free. Every product on this page was hand-selected based on university extension research.
View on Amazon
As an Amazon Associate I earn from qualifying purchases. These are Amazon affiliate links -- if you buy through them, SoilStack earns a small commission at no extra cost to you. It's how we keep the app free and the calendar ad-free. We only link products that match what the research says you actually need.
Research

Sources

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

university Extension sourceuniversity NC State Extension Plant Toolboxpeer-reviewed SARE, Sustainable Agriculture Research and Educationuniversity Oregon State University Extensionuniversity Oregon State University Extensionuniversity UC SAREP, Phacelia cover cropgovernment USDA NRCS / Iowa State Extension, Phacelia cover crop fact sheet
Internal links

Phacelia cover crop and bee forage Planting Dates by Zone

Jump to your USDA zone for frost dates, start-indoors timing, and a full monthly planting calendar.

Ready to grow Phacelia?

Get a personalized planting schedule based on your exact zone with frost dates, task reminders, and feeding plans.

Start Your Garden Plan