food forest: sheet mulch or not?

I am helping with a very young food forest at a local a primary school.
It's been planted without a 'masterplan' and there's quite a bit of retrospective design happening...
It's important that it looks 'tidy-ish' and at the moment it looks really messy: there's still grass etc in there, which is kind of mowed by the maintenance guy and kind of not, so long, short, scraggly and so on.
The current thought is to sheet mulch the entire, large, food forest.
Thing is, I'll be wanting to broadcast a ton of seed, and that would require tons of compost on top of the card.
Seeding on top of card going into our summer sounds like a recipe for dried-out plants.

Has anyone tried a side-by-side experiment of sheet mulching and...what'd you call it: 'managed groundcover succession'?
There's a couple of very difficult plants in there: kikiyu, which is a really aggressive running grass, and buttercup (Ranunculus repens), which loves the wet, acidic soil.
I'm pretty sure sheet mulching won't kill the kikiyu, probably not buttercup either.
I'm wondering whether scalping the whole thing, digging the buttercup, forking up the soil a bit, overseeding with a beneficial poyculture, and just trying to keep the kikiyu back from the trees etc.
I'd love to hear your experiences; I've never worked on this scale and I'm very keen for any ideas, even vaguely related!

On my very small suburban lot, I sheet mulched my front garden last winter, around existing ornamental shrubs. I also planted a few plants by punching through the cardboard in the spring. Now, nearly a year later, the bed looks just as weedy and untidy as it did before sheet mulching, and the few annuals I put in haven't thrived. In fact, most of them died, though the existing shrubs are fine.

There was a spot out front I left without sheet mulch, and essentially scattered seeds and then chopped and dropped the existing weeds onto them. This spot also has a few weeds but the groundcover seeds I sowed have outcompeted them for the most part. Now, I did not sow any seeds on the sheet mulched part, so I can't say if the groundcover would have done equally well there. However, the sheet mulching was a lot of work, and chopping and dropping gave perfectly acceptable results with a lot less effort!

Thanks Galadriel, that's great info

Sounds like this could make a good experiment for the students; comparing chop and drop to the sheet mulch patch.

Would their be enthusiasm for this with the students, teachers and parents?

...Then after that the science of composting...

Hi Leila:

As to your query:
"Has anyone tried a side-by-side experiment of sheet mulching and...what'd you call it: 'managed groundcover succession'?
There's a couple of very difficult plants in there: kikiyu, which is a really aggressive running grass, and buttercup (Ranunculus repens), which loves the wet, acidic soil."

Yes, I've successfully sheet composted with cardboard to eliminate kikuyu, Pennisetum clandestinum, in my former garden in Onehunga Auckland. You do need to be vigilant it is tenacious, but I mowed it low first and also did a shallow 5 cm trench/ditch thing around the outside perimeter. It will send out runners too, but you can lift the edge (cardboard and chip layer)--a great job for the kids and simply pull the runners which then need to be dried prior to composting. I used to think kikuyu was an ecological disaster in New Zealand, but someone explained to me it would be hard to have a year round dairy industry in Northland without it.

As to buttercup, I was taught that it is often a sign of pugging, compaction or poor drainage.

Good luck, enjoy your summer!

Edith

The newspaper and mulch method of growing potatoes and sweet potatoes could smother weeds and possibly out compete them. It does a total job on many lawn grasses. I'm sure most of us have seen this, but it is always worth another look. link--- http://www.youtube.com/watch?v=q1OShZZUt0k

Edith Stacey wrote:I've successfully sheet composted with cardboard to eliminate kikuyu

That gives me hope!

Thanks people, I think this calls for some experiments involving the kids