Managing Over-Wintered Rye Cover Crop in Spring

Winter Rye (Secale cereale) is a commonly used cover crop in backyard grower, community garden and urban farming operations.  It is cold hardy and can germinate in as low as 34 degree soil temperatures making it useful to plant after a fall harvest of summer vegetables that last until the frost date.  Once established it can tolerate sub-zero temperatures over the winter to start rapid growth in the spring.

 

Winter Rye does many things well:

  • Seed is inexpensive and easy to obtain
  • Establishes quickly and easily
  • Suppresses weeds
  • Prevents erosion
  • Can create large amounts of organic matter
  • Assists in suppressing pests
  • Scavenges nitrogen

 

Winter rye however can present a management challenge as it can regrow depending on what stage of growth it is terminated in and how large it is allowed to get before management methods are implemented.

 

There are several  different types of management methods that can be used to terminate winter rye.  Each has its place depending on what the need is for the cover crop, what management tools are available,  as well as what is the production plan after the crop has been terminated.  Management Methods:

  • Herbicide
  • Tillage
  • Rolling/Crimping

Herbicides can be used to effectively terminate rye at any stage of growth.  Tillage can have spotty success due to regrowth of clumps if the rye is less than 12 inches tall, and multiple passes may be needed.  Rolling or Crimping is more effective if the rye has gotten about 4 feet tall.  Keep in mind that rye at that stage is very large with woody stems and may be difficult to manage unless the producer has heavy duty equipment.

Rye regrowth after tillage. The rye was tilled 14 days prior at 10 inches tall then followed by rainfall which facilitated regrowth. Will need additional tillage or herbicide application

 

Rye was terminated in early April at 18 inches tall with herbicide (glyphosate) then compost was added prior to summer vegetables in May

 

Rye was crimped at four feet tall to terminate growth and left in place, then tomatoes were planted through the rye mulch

 

Each method of rye termination has benefits and concerns.  A careful consideration needs to be made about what benefits are needed and how that will impact production.  A few things to keep in mind when planning around spring management of winter rye cover crop:

  • Rye suppresses germination of seed after termination due to allelopathy.  It can take up to 3 or 4 weeks for that effect to subside.  Make sure to plan termination if early spring seeding is planned.  Incorporating the residue after termination can speed up breakdown of the rye to allow earlier seeding.
  • The smaller and younger the rye, the more Nitrogen is present.  Older rye with more stems has more Carbon present.  A ration of 25:1 (roughly the same as well made compost) strikes a good balance of preventing nitrogen loss and preventing nitrogen tie up to break down the rye. (Nitrogen Release from Cover Crops – SARE)  While this can be difficult to accurately predict or measure in rye, it occurs when the rye is starting stem elongation but before it gets to the boot stage. (Purdue – Small Grain Growth Stages)
  • The taller the rye gets, the more difficult it gets to manage.  Large scale equipment may be needed. Herbicides such as glyphosate may be less effective the taller the rye gets.

SARE Winter Rye Fact Sheet

Cereal Rye for Cover Cropping in Organic Farming – eXtension

10 thoughts on “Managing Over-Wintered Rye Cover Crop in Spring

    • You could probably do that. It may take awhile for it to die. I found that spring planted rye that I mowed all season persisted for a full year and then took two rounds of tillage to kill it.

      • I never had enough rye to germinate in the spring to do anything. It was a total waste of seed.
        I’ll use oats this year to fill in the empty spots.
        Just mowed the cereale rye for the 1st time 3 days ago.
        Guess we shall see, I also have a small 30×30 plot I plan on letting grow taller between mowing.

        I’m using it to restore a utility right of way that has a bad case of ponding and ruts and the soil is your typical nasty ohio heavy clay.
        Once/IF the rye dies, or not I’ll plant Buckwheat for the summer then this fall plant with a mix of rye, radish, peas & oats.

  1. I cut rye that was about 2 feet tall with a sickle in March, dropped it, then covered it with black plastic for several weeks to terminate and accelerate decomposition. I planted seedlings into it in May. It took a grass knife to cut through the roots at that point to create planting holes.

    Now the roots are broken down and there is black fluffy soil that can be dug with a trowel, in June. The seedlings planted when roots were less broken down have not really taken off, maybe because nitrogen was tied up to break down the roots? What should I have done differently and how could it be timed better next year? Does crimping or cutting and dropping change the timing?

    Re: the current seedlings, I had added some aged manure and bone meal to the planting holes and applied an organic fish fertilizer recently. Is there anything else that can be done to help those plants become more established at this point?

    I really like the benefits to soil structure and the weed suppression but also want my tomatoes and peppers to grow. Thanks for any advice!

    • Rye does have some allelopathy that may have affected the transplants. Also, a cover can keep the soil temperature lower than what they like at transplanting. Check soil temps before transplanting peppers and tomatoes.

    • Next year cut it a couple weeks sooner and cover with some aged manure. The dark manure will help with solar heating as well as its nitrogen in speeding up the composting of the rye. It will also give more nitrogen to start off the transplants. Fork aeration could also speed up the break down but the starting the cut down sooner will help a lot as it will decrease the allelopathy by the time you plant. You could also do a compost tea after the cut down a couple times a week till planting. Have similar effect as the compost addition.

      I think the biggest deterrent ho,e gardens have to winter rye is they wait too long before killing it and thus have that massively dense root structure still in place when they go to plant. But it’s also that same root structure if cut early enough that gives that awesome loamy loose soil when its broken down.

  2. We planted bush beans into a garden plot where two-year-old winter rye was rototilled into the soil. Our bean germination rate was zero percent. I wonder how low before this allelopathy contamination will last.

    • I do not think it lasts more than weeks to months so I suspect it is not allelopathy for the germination. Could be wildlife, soil moisture, seed viability, seed to soil contact, soil temperature, etc.

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