Can you dig a swale (and heap a berm) in the fall?

Howdy!

First post here, so hopefully I'm not doing anything wrong here.

I just moved into a new home on four acres. About 2/3 of an acre is clear and I got all anxious and started digging swales. As I was about to plant some apple trees in the berms, I had a "wait a minute..." moment. I remembered reading somewhere that plants need to be planted immediately after heaping the berm to prevent erosion. But, since I'm planting in the fall, I don't expect the roots to expand all that much, and so I don't see how they'd help much with preventing a collapsing berm.

So, is a collapsing berm inevitable if it's heaped in the fall? Should I backfill and wait until spring to finish my berming?

Can you take other measures to mitigate erosion?  If you've already put the hard work into this project, I wouldn't back-fill, but find another way to keep that freshly moved soil from moving down the hillside in a big rain.  I don't see the risk of a collapsing berm, as you put it, any less severe in spring than it would be in the fall.  Most places, you get heavy rains in spring just as you do in the fall --- perhaps even heavier.

A couple of thoughts how you might do that:

1.  Mulch.  If you have access to large quantities of carbon, like wood chips, lay that down and let it begin to mat down into a protective soil blanket.  Water will move through it easy enough, and hopefully, it will help to open the soil profile so that infiltration happens quickly.  Branches from trees can be integrated into your mulch layer, giving it a bit more structure.  If you were able to get a couple of round bales of spoiled hay, that could be unrolled and put down like a big blanket.  I've used the 15 foot-long palm branches of queen palms to stabilize loose soil on hillsides.  If you have access to any of these materials, they will offer a multi-purpose solution to your situation (erosion controling, soil building, fungi feeding, earthworm hatching, water retaining, weed suppressing, soil protecting . . .).

2.  What about using some sort of erosion control fabric?  I see highway maintainence crews use this stuff on the sides of the freeway after they have graded the slope and left bare dirt.  It's like a really rough-weave, burlap kind of fabric—made of jute.  They roll it out in wide courses and stake it down.  Plants grow right up through it.  Check these out:

https://www.onlinefabricstore.net/jute-erosion-control-cloth-.htm?gclid=CIXN0rGMhtACFVBcfgodRXIH9A

http://www.benmeadows.com/jute-erosion-control-blanket_s_60920/?gclid=CPH6n8OMhtACFYWJfgodv-0Alw&CID=BMPL10&s_kwcid=AL!3210!3!55826733898!!!g!130343984938!&ef_id=WAEyUAAABO2pk@Kq:20161031223228:s

3.  Is there a quick-sprouting cool season cover crop you can get down right now?  Oats or rye or something that quickly sends out a lot of roots?  Where do you live?  If you don't have frost concerns, just get something growing ASAP.  Where I live (Southern California), I can start a cover crop any time of year ---- so I do.  Where do you live?  Some plants have the ability to stand up to a bit of morning frost and still keep growing.  

Check this out:

http://www.johnnyseeds.com/t-library-farm-seed-winter-cover-crops.aspx

Best of luck.

I agree with getting a better fix on your location to help with advice.

Another way to mulch is to limb up a bunch of your trees and use that for mulch. Just put the whole branch down and cover your bare soil. This works much better if they are evergreens like pine, spruce or the like. Prep for that would be to put a bunch of cool season seed down as suggested, prior to the branches going on. This allows the branches to stabilize the soil and even give protection to whatever seedlings will sprout up.

Other items to use to protect your swales/berms is to grass cuttings from your property, if you have any at this point. That gives you cover without having to import straw or chips of any kind.

Thanks for the replies, Bill and Marco.

A few comments.

Marco said: "I don't see the risk of a collapsing berm, as you put it, any less severe in spring than it would be in the fall.  Most places, you get heavy rains in spring just as you do in the fall --- perhaps even heavier."

Thanks for chiming in Marco. The issue that I'm concerned about is not more or less rain in fall versus spring. The issue is that I don't think roots will grow during the fall/winter to help stabilize the berm, no matter whether it's spring or fall. Sorry if my post wasn't clear on that.

Re: Mulch. Fortunately, I have lots of that. My yard is pretty much a leaf wasteland and I have 4 acres of mostly wooded property. Between dead branches and leaves, I have lots. I also have a wood chipper that I use frequently to make additional mulch.

I actually dug two trenches on contour. The one on the downside of the slope, I buried tree limbs in a pseudo-Hugelswale configuration then backfilled with dirt (kind of like Bill suggested). This morning I did as both of you said and heaped a bunch of mulch (cardboard, leaves, and wood chips). Given this, do you think it will now withstand any erosion issues?

Re: Erosion control fabric. Thanks for pointing me in that direction. Based on your suggestion, I was actually thinking about using my furniture blankets from moving. Any potential issues you see with that? Or would that be overkill (given that I've already heavily mulched the berm)?

Re: Where I live. Yeah, big oversight on my part not telling you that. I live in South Jersey, which is 7a. My property has a lot of Sweetgums, maples, and oaks, with the occasional cedar.

Thanks again for all the help!

I'm guessing that furniture blankets wouldn't be organic --- some sort of polyester/non-biodegradable fabric.  If you could get a big box of cotton sweaters and stake them down, covered with a nice layer of mulch, that would all break down.  :>)  

If you just want to use such blankets to cover the swale and then pull them up in the spring, I suppose you could do that  . . . but yuck.  I wouldn't want to do that.  Muddy, stinky from sitting out there all winter.

Lets think about hard rains:  you've got a couple of issues.  First is the actual erosive effects of the falling rain itself.  Mulch would armor your soil so that it would not get pounded directly.  The mulch would deflect the impact.  So mulch = a smart move.

Then you have to think of infiltration.  Mulch will keep the soil warmer longer, and thus allow more moisture to wick down into the soil profile.  Not as much water would sit on the surface or run down your hillside.  This is why you built the swale in the first place, yes?  So that's a net +.

Finally, thinking about the cumulative weight of the moisture in the soil—this is where things might get hairy.  Saturated soil becomes tremendously heavy.  Once it starts to move, look out.  With no roots to keep it stable, a heavy rain storm will create a great deal of pressure as the soil becomes very saturated.  It's one thing for the slope to erode as water rushes down over the surface creating gullies.  It's quite another thing when you have a slope fail and tons of earth starts to move.  Get out of the way.

What is the angle of the slope --- have you measured it?  Perhaps there is a civil engineer reading this thread who could speak to the forces generated by heavy soil in relation to the degree of slope.  Obviously, the steeper the slope, the greater the danger.

Plastic sheeting (sold in big rolls) is cheap enough.  If you felt like your soil were getting over-saturated, you could cover it and deflect that water down before it ever hits your swale -- but that's a pain in the ass.

Get out your protractor and measure the slope of the hill --- that is important information.

Marco Banks wrote:I'm guessing that furniture blankets wouldn't be organic --- some sort of polyester/non-biodegradable fabric.  If you could get a big box of cotton sweaters and stake them down, covered with a nice layer of mulch, that would all break down.  :>)  

They're actually recycled denim.

Marco Banks wrote:Finally, thinking about the cumulative weight of the moisture in the soil—this is where things might get hairy.  Saturated soil becomes tremendously heavy.  Once it starts to move, look out.  With no roots to keep it stable, a heavy rain storm will create a great deal of pressure as the soil becomes very saturated.  It's one thing for the slope to erode as water rushes down over the surface creating gullies.  It's quite another thing when you have a slope fail and tons of earth starts to move.  Get out of the way.

Yes, this is what I'm worried about. I started thinking that maybe I could plant some strawberries, rhubarb, asparagus, and daffodils now. I know these can be planted in my zone this late in the fall. I just don't know if the roots grow at all. Do you happen to know?

Marco Banks wrote:What is the angle of the slope --- have you measured it?  Perhaps there is a civil engineer reading this thread who could speak to the forces generated by heavy soil in relation to the degree of slope.  Obviously, the steeper the slope, the greater the danger.

Good question. I'm at work so I can't immediately answer. But these are fairly small berms; not more than two feet high and 2 feet wide.

Rye grass seed not an option? Where im at (texas), just scatter the seeds  and it's up a week later. Needs water Of course.

wayne fajkus wrote:Rye grass seed not an option? Where im at (texas), just scatter the seeds  and it's up a week later. Needs water Of course.

I like that idea. It's still in the 60s and 70s here (and will be for the next week), so that may work.

Throw the seed on and put a light layer of straw on it to keep it in place and keep the birds from stealing all of it.

Excellent suggestion on the seeding, Wayne.

South Jersey? Buckwheat, winter rye, Austrian winter peas, hairy vetch.  Those will get started now, some will hold on through the winter and give you another round in the spring.  And the peas and vetch are both nitrogen fixers.