Cover Crops

Biological Solutions to Common Problems in the garden

Cover crops have been used by farmers and gardeners for generations to solve common problems like compaction, poor drainage, and low organic matter. So I made a commitment to learn more about cover crops first hand as a biological solution on our farm. In my backyard gardens of the past I’ve grown vetch and spring oats, and on our farm I’ve grown winter rye on a larger scale. I’ve learned there is definitely different techniques in seeding, spreading, and incorporating into the soil. If you are interested in trying cover crops, here are my notes to help you get started.

Let’s start with the basics. Why plant a cover crop?

The technical answer is to help support the 4 Eco-Systems which build soil health. They are:

1.     Water Cycle – how water is absorbed into the soil.

2.     Mineral Cycle – what nutrients are available to plants from the soil.

3.     Biodiverse Community – all the worms and beneficial organisms that live in the soil breaking down organic matter, creating air pockets, etc.

4.     Energy Cycle – think of plants as solar panels, and the soil as the battery. Cover crops charge the soil to grow better plants.

When these 4 Eco-Systems are healthy the soil comes to life. So instead of just tilling deeper, buying more compost, and adding too much fertilizer, cover crops are a great solution but they aren’t as easy to grow as you might think.

Year 1 - August 2018

Enthusiastically, we plowed an entire 2 fields but knew we were not ready to plant the entire field so I only planted ¼ of one field with flowers knowing the rest could be planted with a cover crop. Even though I had a lot to learn about how to properly plant and use cover crops to build soil, I went for it.  

That summer, I ordered a 50lb bag from Johnny’s, a broadcast spreader, and some inoculant.  Mixing the inoculate with the seed, then spreading the seed on the field was the easy part.  But covering the seed with soil felt like I was tripping over my feet.  Do you leave it on top of the soil, or will the birds eat it all? Do you till it in, or will it go too deep and never sprout? The field was too large to rake by hand but I felt like the seed needed covered so I rigged an old gate with a chain link fence to act as my rake. I chained it to the back of our tractor, topped it with a few heavy bricks, and made a couple passes over our field to essentially “rake” soil over the seeds.  All this was thrown together right before the forecast called for rain. I crossed my fingers and did the happy dance when it started to thunder, lightning and pour!  

Fast forward a few weeks and it was dry again.  With no rain in the forecast, and no irrigation out to this section of the field, I used a T-Post, with a sprinkler attachment, hooked up to a really long hose. I watered it a few times to get it going until fall arrived.

By March of 2019, greens were sprouting but nothing substantial. April snow showers followed by warm weather and all the sudden magic happened before my eyes. Before I knew it, the field was waving in beautiful and tall Winter Rye. I wanted it to stay but in a matter of a two weeks the color shifted. It changed from bright green to a shade of gray green and in a matter of days seed heads were starting to form.

Before mulching it with the BCS Flail Mower, I sprayed it with a Biodynamic Field Prep which breaks down cover crop materials making nutrients available more quickly.  The prep needs to be awakened by making a slurry overnight. Simply, add the prep to a jar and stir in a few tablespoons of water. The next day, I added this slurry to a 3-gallon bucket of water and stirred for an hour creating a vortex, an important part of enlivening the preparation and water. After stirring, I used a 15 gallon sprayer to spray the Winter Rye with the Field Prep. We then used the Flail Mower which pulverizes the crop right onto of the soil creating a 2-3” layer of mulch (video of flail mower is at the bottom).

Along the way, I did a few experiments too. For example, how I prepped the field before planting and how I worked the material into the soil afterwards. 

Experiment 1 – Compost or No Compost

Theoretically, cover crops act like compost so you should not have to add compost before planting a cover crop, right? Cover crops are actually referred to as “Green Manures” because they add nitrogen to the soil along with a hefty amount of organic matter. But I wasn’t sure, so I added a light layer of compost to the first field. Let’s call the first field—Field A.  And nothing to the second field—Field B.  The result? Field A (with compost) was substantially thicker, taller, and had better germination.

Experiment 2 –Till or No till

There is a lot of discussion about the No Till philosophy. Entire Podcasts are devoted to the topic alone, but secretly I’m a skeptic. I think something important happens when the soil is tilled allowing it to breath. It always looks better in the fall and spring, and I can almost hear the soil take a huge exhale at the end of the season when I plow up the big clumps, and a huge inhale in the spring when I till and make a nice flat bed for seeds. But, a lot of the experts are challenging the theory, and farmers are having success with No Till so I’m willing to explore. 

After we mulched the cover crop, we tilled Field A (the field with the compost).  The result—weeds. I essential disrupted the seed bed and they all sprouted again. Field B we left untilled. We just let it lay in place and forgot about it all season. The result—no weeds. In August when the weeds were taking over Field A, I looked over at Field B and there were barely any weeds growing. 

Experiment 3 – Cover or Not to Cover the Seed

November 2019, and our second season, I experimented with how to cover the seed. Field A, I drug the old fence over the field and planted in Sept. Field B, I used rotary plow to make trenches then planted seeds in Oct, thinking the trenches would hold more water helping the seeds to germinate. And I accidentally discovered a section where I had to lightly till in November when I was planting tulips. Let’s call this section Field C. Amazingly, Field C currently looks like a carpet of 2” Winter Rye when the other two fields are further behind. Even though it was planted later, the seed is more evenly spread out and the germination is noticeably much better.

Summary of Discoveries

In summary, a little bit of compost was helpful in the size of the crop, planting strategically when its suppose to rain was helpful but really the spring rain was what made it grow, leaving a layer of mulch in place on top of the soil keeps the weeds suppressed, and shallowly tilling the seeds after spreading them helps to cover them with soil for a more evenly planted crop. 

In the future, I’ll continue to do this:

1.     Add compost to the field before seeding.

2.     Sow with a broadcast spreader, when rain is in the forecast if possible.

3.     Till the seed in to cover it with soil and spread it evenly.

4.     Spray with Biodynamic Field Prep when its knee high in the spring.

5.     Mulch with the Flail Mower and leave it in place whenever possible. 

Here is a video we did with BCS Tractors if you want to see the different attachments we use throughout the process.

I hope this blog post was helpful in explaining the many benefits and a practical applications of cover crops. Let me know if you have any questions.

Gina