Sheet Mulching Over Gravel Driveway

Hi All. I live in the beautiful PNW and am converting my land over to small food forests and zone one raised beds. Since our house is on a small lot (0.09 acres!), every square foot is precious. One recent area we have decided to turn into food production and duck foraging grounds is part of a gravel parking area on the east side of our house. It is the width of a car (makes sense) and about 30 feet long. I decided to extend our backyard gardening space into this gravel parking area, leaving just enough gravel towards the front of the house for one car to park. This has given my about 16 linear feet of the gravel driveway for gardening (a total of about 160 sq ft). Big Win!

And now for my question: This 10ft x 16ft new garden area is gravel. In the spirit of laziness, I am curious what would be the best way to get the ground producing biomass again with the least effort possible. My hunch is to scrape off as much gravel as possible, get down to mostly dirt (which is compacted from parked cars), top dress this with an inch or two of compost, put a thick layer of newspaper on, then another layer of compost, and then 4 inches of wood chips. Then, plant pockets of deep rooted soil breakers, nitrogen fixers, and soil building green manure crops to get this soil back into fertility and good soil structure. What are your thoughts?

I actually have the opposite problem....trying to keep green stuff FROM growing in my gravel driveway! There is concern here about it becoming a fire hazard when it dries out in the summer. So I can't see why your idea shouldn't work. The only thing is that the subsoil may be so compacted that it will take a long time to get it in condition, and any water will seep sideways along the surface layers rather than penetrating. Punching, digging, or even augering into it, especially near or under long-term plantings, might be worthwhile.

#Alder Burns: I know what you mean about stuff growing in gravel. Seems like grass and dandelions are always able to find enough nutrients to establish themselves. I would say there is dirt a couple inches down and the gravel itself is not that clean anyway (thus, the weeds). Do you think it is important to try and remove much of the gravel before sheet mulching?

Following you suggestion, I might punch some deep holes in the gravel under some of the shrubs I'm planting to break through the compaction.

I'd rake the gravel to the kept parking space, don't worry about getting all of it, or even most of it. do the sheet mulching and plant those deep rooters and nitrogen fixers. If you wanted to really get aggressive with the soil reconditioning, use a ripper over the area (you should be able to find a tractor and ripper at a rental store). Overall it sounds like you have a good plan and just need to get-er-done!

On your scale, I would recommend getting a broadfork. Very efficient man powered decomposition device, well suited to garden scale.

Peter Ellis wrote:On your scale, I would recommend getting a broadfork. Very efficient man powered decomposition device, well suited to garden scale.

Josh, it looks like you are in Portland. If you live within the area of Southeast Portland served by the "Southeast Uplift" neighborhood coalition, you can borrow a broadfork from the Southeast Portland tool library. The Northeast and North Portland tool libraries may also have one if you are in their service areas instead.
I've been trying to renovate my Portland gravel driveway/parking lot/front yard too, and tried the broad fork but the soil under the gravel was so compacted that I couldn't get it half an inch in. I've gone through a few iterations of plans to break up the concrete-like driveway -- first seeding some radishes (supposed to be daikon, but the store sold me standard red ones), then changed plans and dumped several loads of wood chips, then seeded some actual daikon on top of the wood chips with some other soil and stuff thrown in on top too. Portland nursery has daikon and other cover crop seeds in bulk at what seem like good prices for driveway-busting quantities.

Hi Tim,

I just mulched my driveway in one instance and built a hugel in another. The hugel was more work, but better results. It's still kind of wintry here, so only the Nanking Cherry is blooming.

Timothy Holdaway wrote:

Peter Ellis wrote:On your scale, I would recommend getting a broadfork. Very efficient man powered decomposition device, well suited to garden scale.

Josh, it looks like you are in Portland. If you live within the area of Southeast Portland served by the "Southeast Uplift" neighborhood coalition, you can borrow a broadfork from the Southeast Portland tool library. The Northeast and North Portland tool libraries may also have one if you are in their service areas instead.
I've been trying to renovate my Portland gravel driveway/parking lot/front yard too, and tried the broad fork but the soil under the gravel was so compacted that I couldn't get it half an inch in. I've gone through a few iterations of plans to break up the concrete-like driveway -- first seeding some radishes (supposed to be daikon, but the store sold me standard red ones), then changed plans and dumped several loads of wood chips, then seeded some actual daikon on top of the wood chips with some other soil and stuff thrown in on top too. Portland nursery has daikon and other cover crop seeds in bulk at what seem like good prices for driveway-busting quantities.

Great ideas. I wasn't aware of tool libraries in the Portland area. I actually live in Clackamas County, so I'll have to research if there is anything like that in the area. Since it was such a great weekend, I went ahead and got to work on the driveway with a shovel. Didn't spend much time removing gravel, but took my pick and punched through the gravel in most of the driveway. The gravel is about 3 inches thick, but wasn't too hard to break up. Underneath is clay.

Once I broke it up, I added about an inch of compost. Next steps will be to plant some of the large nitrogen fixers, newspaper around everything, put a bit more compost and then mulch with wood chips. I was going to do a thick sheet mulch, but there isn't any existing grass or vegetation to kill and I want to try covering the whole area with pioneer annuals/perennials and cut and drop biomass, so am planning on doing a thinner layer of wood chip mulch and planting in the compost all over the area. Should also make a nice foraging area for our ducks.

I'll try posting some pictures sometime. It is looking pretty good already.

Here is an update about converting the gravel driveway into a garden:

A long due update on the gravel driveway conversion...

Sorry for the double post. My phone said the upload of the images failed, so I did it twice.

I'm not sure how much good all of the augmentation in the world will do without some work to relieve the compaction.  My "farm" lot is on an old dirt parking lot.  I gardened on it last year with a shallow tiller (<3") and lots of composted yard waste our county dump makes.  Stuff grew in the beds, but didn't perform very well.  

I think your/my options are limited.  Either you have to mechanically break up the compaction to allow root/water penetration and aeration, or you're going to need to plant some stuff that will do that for you, such as oilseed or daikon style radish, okra, etc.

My landlord has all three south-facing houses on our block.  The far one was where his grandmother lived until her death.  I sincerely doubt that the garage on it has been used to park a car since the late 1980s or earlier.  The driveway has completely grown over, but anyone with half an eye can tell where it was because the grass is less vigorous due to the compaction.  I can tell it's the compaction because after 30 years or so, you can still see the tire marks when it starts to dry out.  

The only significant difference between that space and yours is that the gravel prevents mudholes, so it might not be "quite" so bad.