Sheet mulch planting time frame, and sandy soil improvement

Hey folks,

I had two questions regarding sheet mulch, one of which I'm sure has been asked a million times.

The first is regarding the time frame in which it will be able to be planted into. I've heard varying reports. Some people say you can plant into it immediately, others I've heard say you should let it decay for a bit. If I were to lay a sheet out in January or February (assuming there's not snow on the ground, and also assuming I can get the materials together), that should be enough time, correct? If it's not possible to do that early, if I were to wait till march or april, would that be too short of a time for it to be ready for planting? I would think that the material laid down is not decayed enough, and would result in poor plant growth, and possibly even plant death. I'm not sure though, so your thoughts/experiences on this would be helpful.

The second question requires a bit of a backstory. I will be doing this sheet mulching on my parent's yard, which is almost 100% sand, since they live close to the beach. I was able to do liquid sedimentation to confirm this percentage, but have not been able to get nutrient/pH tests done yet, although that is high on my list of things to do, and will definitely be done before I do the sheet mulching so I know what amendments to add into the mix. What I'm wondering is if I should do some double digging of aged manure/compost/leaf mold before sheet mulching, since the soil is so poor, or will sheet mulching be enough to improve the soil? I don't want the nutrients that I add to immediately leach away, so I'm thinking the incorporation of high CEC humic material dug into the first foot of existing sandiness would be beneficial. Your thoughts on this? Also, any tips for further improving this sort of poor soil, or is what I have outlined above sufficient?

Thanks in advance for your input!

Sheet mulch planting's for someone else, but...
My area used to be under the sea 150 years ago (think massive earthquake) so I know about sand!
Since there's millions and millions of cubic meters of sand all around my garden, I think I'm stuck with pretty extreme leaching and I just attempt to mitigate it.
My soil dries out really fast, so anything that makes the garden beds above ground-level is a real irrigation problem.
When I first started gardening, I read all this stuff that said "raised beds good, blah, blah, blah". Unfortunately 'they' didn't add "for very specific soil and climates. No, not yours Leila!"
My gardens are now at, or below, ground-level and the 'raised-bed' edges keep the mulch in.
In order to maintain fertility and moisture I need to add a LOT of organic matter. While unfinished compost isn't ideal from a humus etc perspective, I find a thick layer of half-finished, cold compost under thick mulch is great. Seaweed's fantastic. I get lawn guys to drop off fresh grass clippings (we don't use lawn poisons over here much though)
Be aware though, that adding lots of some things can throw out the nutrient balance. I added tons of horse manure before I got my soil test, then found phosphorus was really high. I'll never add high P things again, but I wish I'd known.
Entire areas often have a similar nutrient profile, so you may be able to get a general idea from your local extension agent. I'm glad you're getting a good soil test!
You're in the US? Where? Over here, it's considered a waste of time testing in the winter since the microbes pretty much stop work and nutrient readings can be pretty innacurate. Might be different round your way though...

Hi Rob,

We planted immediately in our first attempt at sheet mulching and had great success. We didn't have enough compost/topsoil to cover the whole area so we created little pockets of compost for each individual seed/seedling within our top layer of straw. Everything grew amazingly well and we've been expanding ever since! Good luck and have fun!

Leila, thanks for that. We are located in zone 7a, in the "jersey shore" region of NJ. Actually a few town north of where that show was filmed, hah. I have actually added manure to the current garden area several years in a row, so I think that are should be good on phosporous, but when my dad made that the garden area, he didn't pay attention to light to well, and we're realizing that there's a much sunnier area of the yard we could be using for the main veg garden. That area has never been touched by plants, except for the small sand dwelling weeds that are there. But yea, we do have cold winters, so you're saying I should wait to take soil tests? I mean, are there really any soil microbes in that sandy environment to be active? I can imagine there being life in the area where I've been adding amendments already, but in the barren sandy areas, I would imagine that soil life would be minimal.

Rob, that's good to know about your success with direct planting. You're not the first case that I've heard in which that's worked, so it seems like that's the general consensus. Thanks for your input!

Rob, in my climate we'd ideally test in early spring when the soil warms. That's not always possible, but we only get a few frosts a year round here, so unless your soil-testing is very different to ours, I'd recommend holding off.
While there probably won't be all that much microbe action in poor soil, there'll definitely be some. I'm not a scientist, but I'm pretty sure that organic nutrients only become available to plants through microbial action and adding goodies and testing before they 'wake up' in spring, could give you misleading results.
Check it out further though, I'd hate you to follow misleading information. Hopefully someone with more knowledge will chime in
If the old garden areas had a lot of soil-improvent work done, it might even be worth doing a 'swap': dig out X amount of sand from the new area, replace with the better soil from the old garden and fill ex-garden with new-garden sand. If you know what I mean That would be a lot of labour, but it would be one way of improving the soil while maintaing the bed height arond the level of the native soil.
Aside from my thing with avoiding too much height in sand, making beds narrow enough not to stomp on or fall into and paths wide enough to actually use is really important to me.

Hmmm, a thought just dawned on me. Is there any reason hugelkultur wouldn't work in my soil? Ya know, bury some logs in the shape of the beds, maybe used most of the sand I dug up for the paths, and sheet mulch on top of the logs to the level of the sand I dug up. How do you think that would work?

I don't see any reasons why it wouldn't work, Rob. Adding organic material of any sort is going to be beneficial somewhere along the line. The rotting wood will hold more water than sand, certainly.

Now, if it were me ... I would gather food scraps from local restaurants for a few days and add that to the mix under the sheet mulch. But my son is a cook so I could obtain the non-composted compostables quick and easy. According to my reading of Lasagna Gardening it doesn't take long for them to break down under conditions like this.

Rob Viglas wrote:Hi Rob,

We planted immediately in our first attempt at sheet mulching and had great success. We didn't have enough compost/topsoil to cover the whole area so we created little pockets of compost for each individual seed/seedling within our top layer of straw. Everything grew amazingly well and we've been expanding ever since! Good luck and have fun!

I did the same. I didn't have any compost, so I pulled the layers apart, stuck a couple of handfuls of black dirt in to plant the seeds in and let it go. My garden was awesome, much better than other people's in the area this year. My garden was no work at all after the initial build and I had no weeds. I literally did nothing but harvest. I'm completely sold on that type of gardening after my first try.

Thanks for everyone's responses so far, very useful info all around.

So it seems the best thing to do at this point in time would be to get working on site a&a/design, and worry about site prep/soil testing once it starts to warm up, with the plan of doing the sheet mulching on top of hugelkultur beds. Awesome, now I know where to focus my efforts. Thanks again guys!! Although my question's been answered, any further input is certainly obliged if you happen to have any.