Winter-Killed vs. Overwintering Fall Cover Crops

Ashleigh Smith + photo

Ashleigh Smith

Jul 12
6 min read
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pea blossom cover crop

How to Plant Cover Crops

Cover crops are a fantastic tool to keep your garden in tip-top shape. But how should a cover crop be planted? The most common way of actually spreading the seed is by broadcasting. Broadcasting means you sprinkle the seed over your garden area without needing precise seeding distances. Occasionally a seed may be planted with the drilling method if you are seeding an entire field. How much seed is spread over a given area depends on the type of seed. We have included a guide at the end of this article to show you the seeding rates for each recommended fall cover crop.

As we mentioned in “Fall Cover Crop Planning” the first step in restoring and preserving soils is to select the best seed for your needs. If you want to address a specific problem, select seeds based on the benefits they provide. If you aren’t sure what problems need to be addressed, we highly recommend growing our All-Purpose Garden Cover Crop Mix. This mix includes plants from each cover crop category for the maximum number of benefits. Below we have matched up the benefits and route of action for each popular fall cover crop. Once you have selected the type of seed that will best help your garden, we recommend following the planting guide supplied below.

Benefits of Overwintered Fall Cover Crops

Overwintered crops are planted in the fall and left to overwinter in the garden. These plants are not killed by the winter weather. Instead, they may go dormant and come back in the spring. These varieties require maintenance, such as mowing, when they put on vertical growth in the fall. To kill them in time for your spring planting, till into the soil to break up the root structures at least 2-3 weeks before planting cash crops in the late spring. You may till them into the soil before winter sets in; however, any seeds that have developed may sprout in the spring. If they do, you should till them back under to terminate before planting. Some perennial cover crops, such as White Dutch clover, can be grown as an intercrop groundcover. This means it is not tilled under. Instead, it grows in place to prevent erosion, supply nitrogen, and improve soil over time. This application is most popular for long-term crops like fruit orchards or growing on walking paths between crop rows.


Overwintered Rice Field

Overwintering rice with a fall snow

Wheat Sprouting in the Spring

Wheat sprouting in the spring with an early frost


Hairy Vetch

Organic Hairy Vetch

  • Sow 4-6 Weeks Before the Fall Frost
  • Perennial, Hardy to -40F
  • Plant seed: 1/4-1/2 inch deep
  • Seed Rate: 30-40 lbs/Acre
  • Days to maturity/seed production: 60-300 Days (single season or overwinter)

Green Manure Benefits: Organic Matter Builder, Nitrogen Fixation, Weed Suppressant

Overwintering Benefits: Organic Matter Builder, Nitrogen Fixation, Ground Cover

Medium Red Clover


  • Sow 4-6 Weeks Before the Fall Frost
  • Perennial, Hardy to -30F
  • Plant seed: 1/4-1/2 inch deep
  • Seed Rate:20 lbs/Acre
  • Days to maturity/seed production: 70-300 Days (Single Season or Overwintering)

Green Manure Benefits: Organic Matter Builder, Nitrogen Fixation, Weed Suppressant

Overwintering Benefits: Organic Matter Builder, Nitrogen Fixation, Ground Cover

Winter Rye

Organic Winter Rye

  • Sow 4-6 Weeks Before the Fall Frost
  • Annual, Hardy to -40
  • Plant seed: 1/2 inch deep
  • Seed Rate: 100 lbs/Acre
  • Days to maturity/seed production: 330-345 Days

Green Manure Benefits: Organic Matter Builder, Weed Suppressant, Early Weed Suppressant (Plow before maturity in Spring)

Overwinter Benefits: Organic Matter Builder, Ground Cover, Erosion Prevention

White Dutch Clover

  • Sow 5-7 Weeks Before the Fall Frost
  • Perennial, Hardy to -30F
  • Plant seed: 1/4-1/2 inch deep
  • Seed Rate: 5-9 lbs/Acre Drilled 7-14 lbs/Acre Broadcast
  • Days to maturity/seed production: 60-75 Days

Green Manure Benefits: Nitrogen Fixation, Pasture Forage, Can be undersown, Weed Suppressant

Winterkill benefits: Biomass Builder, Organic Matter Builder, Nitrogen Fixation


Field Covered in Snow

Field Covered in Snow


Benefits of Winter killed Crops

Winter killed crops are those that die under natural cold winter weather conditions. These crops are ideal for those who want to plant a fall cover crop and start their gardens as soon as possible the following spring. The seed is planted in the late summer to fall months, grows, and is naturally killed by winter temperatures. Tilling is not required if your frost will arrive before seeds develop. Otherwise, consider tilling before seeds mature to prevent volunteers from sprouting the following spring. If you use no-till or limited-till practices winter-kill crops are your friend. Like overwintering crops, winter-kill types can also be grown in the early spring. If grown in the spring, allow 2-3 weeks of rest after termination before planting your spring garden.


Peas cut for a green manure

Peas cut as a green manure in the fall

composted cover crop

Naturally composted plant material


Crimson Clover

Organic Crimson Clover

  • Sow 6-8 Weeks Before the Fall Frost
  • Annual, Hardy to 0F
  • Plant seed: 1/4-1/2 inch deep
  • Seed Rate: 20 lbs/Acre
  • Days to maturity/seed production: 70-90 Days

Green Manure Benefits: Nitrogen Fixation, Can be undersown, Attracts beneficial Insects

Winterkill benefits: Organic Matter Builder, Nitrogen Fixation, Ground Cover

Austrian Field Pea. Dundale Pea, Arivka Pea

Organic Dundale Pea

  • Sow 6-8 Weeks Before the Fall Frost
  • Annual, Hardy to 0-15F
  • Plant seed: 1.5-3 inches deep
  • Seed Rate: 200 lbs/Acre
  • Days to maturity/seed production: 52-75 Days

Green Manure Benefits: Nitrogen Fixation, Edible Tendrils, Pasture Forage, Weed Suppressant

Winterkill benefits: Biomass Builder, Organic Matter Builder, Nitrogen Fixation


Organic Oats

  • Sow 8-10 Weeks Before the Fall Frost
  • Annual, Hardy to 15F
  • Plant seed: 1 inch deep
  • Seed Rate: 100-140 lbs/Acre
  • Days to maturity/seed production: 100-120 Days

Green Manure Benefits: Nurse Crop for Clover/Peas, Weed Suppressant

Winterkill benefits: Biomass Builder, Organic Matter Builder

Organic Daikon Radish

  • Sow 4-10 Weeks Before the Fall Frost
  • Annual, Hardy to 15F
  • Plant seed: 1/2 inch deep
  • Seed Rate: 8-10 lbs/Acre
  • Days to maturity/seed production: 60-90 Days

Green Manure Benefits: Nutrient Miner, Pasture Forage, Weed Suppressant

Winterkill benefits: Biomass Builder, Breaks Compaction


Planting Months
Crop Jul Aug Sep Oct
Hairy Vetch x x x
Medium Red Clover x x x
Winter Rye x x x
Crimson Clover x x x
Mustard x x x x
Organic Oats x x
Pea x x
Radish x x x
White Clover x x
Yellow Blossom Sweet Clover x x

Mustard

  • Sow 5-8 Weeks Before the Fall Frost
  • Annual
  • Plant seed: 1/4-1/2 inch deep
  • Seed Rate: 5-12 lbs/Acre Drilled 10-20 lbs/Acre Broadcast
  • Days to maturity/seed production: 80-95 Days

Green Manure Benefits: Nutrient Miner, Suppress Pests, Weed Suppression

Winterkill benefits: Biomass Builder, Organic Matter Builder, Breaks Compaction

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5 comments

Jen

Super helpful article – thanks! Especially appreciate the chart, really helps me plan.


Christy Gentry

Hi! Thanks for the information. Just wondering though, I purchased the Cover Crop Mix from True Leaf Market. Just wondering if it is considered a Winter-Killed or Overwintering Fall cover crop. Thanks for your help!


Kenneth K Brodak

Can you mix cover crops and plant in same area ?


True Leaf Market

In response to our comments: Yes, you can create a mix of various cover crop seeds and plant them in the same area. For a complete mix of our best-selling cover crop seeds try our Garden Cover Crop Mix. It does contain both overwintering and winter-kill seeds so plan accordingly.


Louis Paff

As a first time cover cropper ,I broadcast your garden mix ,pressed the seed into the surface-loosened soil with the back of a long handled square end shovel, then spread enough compost to cover all seed. This resulted in a fairly good stand, but I think that at least some larger seed (peas etc) not placed deeply enough either did not germinate or soon died .Is there a better method to deal with this ? Maybe directions included in the future? Thanks for a good product.


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