Cover Crops Fall gardening

2 Cover Crops and Notes on Nitrogen

The cover crop seed I have on hand I purchased a good many years ago. But since then,  with the exception of a few beds planted with winter rye, I’ve not planted cover crops because of various set backs.

This fall — although later than what I had hoped —they’re planted over much of the garden.

In years when none were planted, basically the same benefits they provide were derived from select wild and cultivated plants that I allow to volunteer in the garden.  I’ve explained this in letters to “subscribers only” and in various TMG posts.  You’ll recall titles such as “Don’t Waste Your Weeds”.

These “weeds” (as some folks call them) when cut or pulled and laid on top of the beds also serve to  provide the same benefits as the purchased covers do. They hold the soil in place, increase soil health, add nutrients,  add organic material and thus increase soil life, allow the soil to hold more water,  and can aid in breaking disease and pest cycles.

So why did I use purchased cover crops?

One reason of course, is I had the seed.

But one main reason was to add some biodiversity. Each plant makes its own unique contribution to the soil. And. the more diversity you can add to your garden, the better it’ll be.

In addition sowing the covers gives uniform coverage and therefore benefits more of the soil than random growth of various plants scattered here and there.

And beds filled with covers seem easier to work in the early spring. (That might just be a mental thing for me.)

In the picture below are seven beds with either oats or a mixture of oats and field peas.  The ones showing the most growth were planted first.  The others with only sparse vegetation were planted much later. 

Seven beds on the far side of the garden planted with cover crops.

How About the Paths?

If there had been enough seed,  paths would have been planted as well.  As the covers grow in the path you can cut or weedwack them to the ground  if they get in the way.

You’d miss out on a little organic material (depending on the amount of growth before you cut them), but you’d get all the  benefits the roots offer. (Whatever you cut, leave it where it was growing to get its benefits.)


You’ll notice that leaves have also been added to the beds.

Bed First Planted – Oats and Field Peas – A Closer View

Close up of oats and field peas. This was the first bed planted.

Field Peas and Oats Winter Kill 

However, the first year I planted oats I didn’t think they would —even though we’d had many nights below freezing.  (I’ve read that they winter kill at 15ºF.)

Thankfully they finally died back. But it was very late winter before it happened. 

When I was ready to use that bed for lettuce in the spring, I just pulled out the oats and laid it on the remaining empty spots of the bed to finish decaying.

Had I been using the bed for transplants like cabbage or a warm weather crop, I’d have made a space for the transplant and left the remaining oats where they grew to finish decaying.

Your field peas can be handled the same way. 

Legumes (like field peas, garden peas, beans etc) and Nitrogen

Although legumes can add nitrogen to the soil, they will use almost all that nitrogen when they set seed. That’s why your peas and beans grown to eat don’t leave much nitrogen in the soil. Most is stored in the seeds (fruit) the plant produces.

With legumes used as cover crops (that are not allowed to seed) you can check the roots and tell if they’ve been fixing nitrogen. If they have, the nodules on the roots should be  readily visible.

A Main Job for Oats as a Cover Crop

Oats scavenge, collect, and hold nutrients. 

Why You Might Not Want to Grow Field Peas – at least not every year.

Since oats hold onto (mop up or collect) nutrients in the soil the combination (oats and peas) could keep concentrated levels of nitrogen in your soil. (I’ll give an example further down of why you might not want that.)

If you’ve gardened for a while as I recommend you can assume a carryover of nutrients (including nitrogen) when you mulch and when you continually refurbish your soil with organic materials.

Mr Robert Parnes, noted soil scientist, stated that in his book as I elaborated on in the post Nitrogen – Do You Need to Add it to the Soil —

As I pointed out in another post here – “The chemical companies have done a good job “selling” the need for added nitrogen.”

If you’ve gardened with nature for a while you just don’t need to add any.

What About Seedlings?

Even with growing seedlings that I start in containers they seldom if ever need extra nitrogen. Years ago I purchased a bottle of liquid seaweed and I may have used  a total of 6 cap fulls over the years.  I’ll probably have it the rest of my life – which I’m hoping will be at least 20 more years.

How Do Our Gardens Get Nitrogen?

Nitrogen and other nutrients are added to our soil through decaying/decayed organic materials. (Mulch, crop residues, cover crops, etc.)

As I mentioned near the beginning of the post I used wild plants and domestic plants that I allowed to grow up in my garden to get the benefits of cover crops when I was not able to plant purchased cover crops.

Some I laid onto uncovered beds. Others I formed into a roll or a tight pile and put them in an unoccupied spot to decay.

One such pile I had placed next to my best asparagus plant to provide an extra boost of nutrients.  It was already decayed when I planted a pepper plant into the pile which had turned to black dirt already.

The plant grew. But didn’t have even one pepper on it until into September!! As it turns out – unbelievably – I harvested over 150 peppers from that plant by late November. (Shown below.)

Pepper plant growing my decayed weed pile.

Any of you who are seasoned gardeners may have already guessed the possible cause:  That tall pile of decaying weeds held a lot of nitrogen.  And it produced a lot of green but no peppers until September.

That’s what many fruiting plants do when they have too much nitrogen.  They produce more foliage than fruit.  It was sheer luck to get as many peppers as I did!

How I’ll Use Beds in the Spring That Have Field Peas (and Oats) in them now

In those beds I’ll plant things like lettuce, chard, kale, beets, cabbages, potatoes, parsley, onions,  and anything else that can use that much nitrogen.

For sure it won’t be my first choice to put fruit producing plants like peppers, tomatoes, cukes, melons, squash, etc. in them. Although if I have extras of those plants that would go in late – I’d try it.

An Excellent Reason to Use the Combination of Oats and Field Peas

I have one reader that I know of that is working on bringing her soil back to life with the use of cover crops such as oats and peas. And of course leaves.

I’m very excited for her and can hardly wait to see how her garden will begin its transformation as she works hand in hand with nature.

Posts on the 3 Keys

There are many posts on the 3 Keys to Successful Gardening on TMG.  Here’s an easy one you might want to review

If you’re new to TMG and want to know more, just click “Home” at the top of the page. Then put “3 keys” into the search box. Numerous posts will come up.

Final Thoughts

I hope your fall/winter garden is thriving.

Hopefully you’ll have some time at the end of December to think about starting onions, what you’ll plant in 2024, planning what goes where, what cover crops you might use when beds are empty, what cover crops you might combine in beds with growing vegetables, and in general what easy thing you can do to enjoy your garden more and make it even better.


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  • Always a pleasure to read your posts. If new, you learn, if longtime they help keep the brain in grow gear. Thanks

    Ray Kent

  • We used cover crop last year for the first time. Grew the best tomatoes ever. We wait unti spring or when we are ready to plant then weed wack and plant and heavy mulch. Worked perfectly.

  • Thank you Theresa for another post packed with information.
    It was good reading the old posts you linked to also!

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