The Mulch Chronicles- Part 2

Last time we talked about using straw as mulch. Part 2 is all about using cover crops as mulch. I’ve got 2 different scenarios to share with you.

Scenario #1- Raised beds (4x16)- Seeded mid to late November with a mix of crimson clover, greens mix and daikon radish. The greens mix came from my local feed and seed and probably contained mustard, rape seed, etc. I’ve used similar combinations before so knew these would give me good cover for the winter to suppress weeds and add a decent amount of organic matter to the soil.

So that’s where we started. Here’s how it all went- fast forward to mid December and if you pay attention to the weather you know that most of the US was extremely cold around Christmas Day. We got down to around 6 degrees in my field. Unfortunately this killed off most of the cover crop except the crimson clover.

Fast forward to spring and I had a nice crop of crimson clover with it’s deep red bloom - it was beautiful on a breezy day!

Now let me explain one thing about cover crops and why they have always been a bit frustrating to me.

Timing

As you read above, the crop was seeded mid to late November. That’s kinda’ late- we were still at the temps needed to germinate the seed (benefits of living in a warm climate). I can’t seed it any earlier because our dahlia season doesn’t finish until early November and it takes a bit to dig the tubers. This means we don’t get a lot of growth before winter. Most of the growth happens in April. But then the problem arises- I need to plant in May. Most cover crops require at least a month of tarping to decompose. So if I wait until the end of April to get the biomass I need, then tarp for May- I’m not planting until June.

Sometimes this can work out- depends on what varieties are going in there and my current crop goals for the year. This was the process I followed in the 2022 crop year. But I got to mid June and the crop still wasn’t decomposed. So I had to come up with a plan!

I was still using black fabric at the time so we removed the tarp and laid the black fabric on top of the decomposing cover crop. Then we took our hands and just moved the cover crop out of our planting holes. It looked like this:

Then I took an auger bit on my drill and made a hole. A bit time consuming but it was actually very effective. When we removed the fabric at the end of the season, the cover crop was 90% decomposed and the tubers that came from these beds were some of the best ones of our whole dahlia crop.

I was a bit worried about the decomposition and how it would affect the tuber growth but they did just fine.

This year, I’ve modified the process a bit. I’ve eliminated the black fabric from my process. I took a weed eater to the cover crop in mid May and then tarped it for about 3 weeks.

I’m just pulling the cover crop back, drill with my auger bit and planting. I do think I will add a bit of the straw mulch to these beds because there are some inconsistences in the coverage of the cover crop (probably due to losing half of it in December).

This was a very quick and easy process. I’ll probably use it again.

Scenario #2: This field consists of 45’ in ground beds that are 3’ wide and were cover cropped with winter rye. I chose winter rye because I hoped it would break down faster in the Spring. But when it came time to terminate the crop, I took a different route.

The rye made it through the December freeze just fine. (So side note- crimson clover and winter rye are extremely cold hardy cover crops!) It produced a thick stand of biomass. So thick that I decided it would make a great mulch without tarping it. Instead of terminating it by cutting, we “crimped” it.

Crimping is a common practice used in a lot of no-till farming operations but it really requires a bit of equipment (at least on a large scale). Large scale no till farmers have crimper rollers that attach to the front of their tractors that will flatten a cover crop. Well, we don’t have that.

So we did it the old fashioned way- with our feet! We stomped on the crop and used some metal rakes to rein in the rye grass. Here’s how it looked after about an hour (for 6 rows).

You can seed how the rye has just been folded in and laid flat. You want to try to get it going as much in one direction as you can- this is helpful later.

Now here’s where it gets creative…..

I had to figure a way to plant in it because it wasn’t going to spread into nice round holes like the other cover crop. So what did we do- we turned to a little fire power!

First off— proceed with caution if you try this method and it definitely requires two people. One to burn, the other to stand by with a hose! I know it probably looks like we caught the whole row on fire but we actually didn’t require the hose all that much.

You definitely want to use a template of some sort- that helps to control your burn. This is my template from burning holes in fabric. This template is a 9” on center spacing (experimenting with a closer planting on these too!)

Definitely don’t do this on a windy day and preferably a few days after you’ve had a good soaking rain.

The burning helped us break through the mulch layer which was a solid 6-8” thick. We took our hands and spread the mulch apart in the burn holes, used the auger to break up the soil and planted our tubers. They are already starting to sprout. This cover crop is thick enough that I don’t think it will require any extra straw mulch.

So pros and cons of the 2 scenarios. #2 is more time consuming- it took about 1 hr, 45 min to burn and plant a 45’ row containing 171 tubers with 2 people. However, the mulch is very thick and retains a lot of moisture in the soil (which is good because this is an auxiliary plot where I don’t have dripline irrigation on the dahlias. I can use overhead or hand watering if needed).

#1 is faster but requires weed eating which I don’t really like. I enjoyed the foot crimping process much more than weed eating. Also the crimping doesn’t require you to wait to plant— no decomposition time.

Definite pros and cons to each method and I really think that only time will tell. I’ll report back after a few months have passed with how each scenario is progressing.

Next time— mulch methods for the home or small scale grower.