short green cover in temperate climate

Hi everybody

I live in Cfb (oceanic temperate climate, in the SW corner of France).

I need to plant a green cover, firstly to "hold" a freshly made bed mulched with sawdust, and secondly to fertilize it.
The bed is just a few square meters.
Ideally, it would be something of short length wherein I can plan winter salads.
Ideally again, I'd like to plant several types of green cover for diversity.

Can you advise me on what green cover to choose ?

Thanks

Interesting scenario because of the sawdust mulch. I'm not an expert but I would consider a deep mulch to be a mutually exclusive option compared to a green manure (at the same).

If the sawdust is deep, I wonder if a fungal innoculation might be helpful. Like some half rotten forest floor litter, or potentially compost. I've seen first hand that sawdust dominated by fungus holds together very well. It will also help to decompose the sawdust faster, realizing the nutrients and humic acid. That could satisfy both your goals.  

Unless you have rich soil underneath, you will likely benefit from adding a nitrogen source too. The salad greens and the sawdust are going to be competing for that if the sawdust is fresh.

I've read and seen that sawdust tends to dry out and create a crust that doesn't allow the soil to breathe. Also, with a light rain, the rain will run right off of it. Heavy rain, it will wash away.

As far as a cover crop, how about clover? It grows fairly low and is a legume so it will fix nitrogen in the soil.

Thanks for your answers.

Glenn van Agten: yes maybe that deep of a mulch excludes a green manure...
It's a good idea to inoculate. I think I am gonna try a rotten piece of wood from a forest nearby.
I added a nitrogen source because I input my kitchen vegetables scraps below the sawdust.

John Pollard: thanks for the warning. For now, the sawdust is not crusting and is resisting rain and wind very well, and we have had storms over storms for a few weeks. So it's seems to work, maybe also because it's not exposed to direct dominant winds.

I've planted salad seeds... We'll see if they grow !

creeping bramble could work, and every few year you get a raspberry harvest too

Glenn Van Agten wrote:Interesting scenario because of the sawdust mulch. I'm not an expert but I would consider a deep mulch to be a mutually exclusive option compared to a green manure (at the same).
If the sawdust is deep, I wonder if a fungal innoculation might be helpful.

It just so happens I've tried this experiment.
Every winter I go spend a month with my mother in the US, and my husband is tasked with holding down the fort. His only responsibility is to water if needed. Our compost goes into a bokashi barrel, so he takes that out.

While I was away he said he had "found some sawdust" and asked which bed to dump it in. I had a bed that needed some mulching, so in it went.
Turns out it was actually not sawdust, it was an entire barrel of bokashi inoculant I had mixed up to last a good 6 months or so before I left, so sawdust that had been inoculated with lacto bacteria serum. That batch did not have any bran, it was only fine sawdust (consistency of powder). When I first got back, a few weeks after he had dumped it, it was kind of clumpy and maybe 6-9 inches deep, but within another month it was simply gone, pretty much melted into the ground. That was August, and it was pretty warm and dry (compared to our normal winter which is cold and rainy), I imagine it would have decomposed even faster had it been wet. I planted some beans on top of there a month or so ago and they are pretty happy.

(yes, I learned my lesson, next time I will request a photo when my beloved "finds" things he wants to dump in the garden. he gets credit for trying.)