I've had spotty results with seed balls. Generally they are best suited to soil that has been recently disturbed and without existing groundcover. It's not to say it can't work but you may want some additional grow medium to ensure establishment. That may come in the form of a couple handfuls of compost accompanying the seed balls (I've taken to planting trees and shrub tree seed balls rather than throwing them on the surface.
6 to 12 inches of biomass is fantastic for the system as a whole but the short term will pose its own challenges. Firstly, if the material is fresh-ish (one year) then the quantity is going to suck a ton of nitrogen from the soil before it starts giving back. this is a natural part of the decomposition. what you may want to do is select species that are hardy to poor soils first. These plants (pioneers!) will support the soil food web you will depend on, encourage fungal growth and consumption of the chips, and blend the soil below and the mulch you've added. I would go for nitrogen fixers (and their accompanying inoculants) and anything with tap roots to start as they'll likely have the structure to support themselves on this medium. Shallow rooted plants may find the 12 inches of mulch hard to spread in with adequate support. It'd be a shame to lose a bunch of 4 or 5 year woodies to a serious wind storm.
The wood chips are going to tilt the soil food web toward a fungal dominated system so woodland and edge perennials will love it but finicky prairie perennials and annuals may find it inhospitable. If you need some help selecting species let me know and I'll do what I can to help.
We're all experimenting and we all benefit from communities like this. The best answer I can give is in the form of a request. Please document, test, scrutinize, and share your experience with us. We all have a hand to play in furthering our collective knowledge-base!
Yes, the material is fresh. Just a couple of months old. Things break down fast in my climate, though, so a year should do it. I started planting sweet potato slips deep into the mulch... we'll see how that goes. Having plant cover on top of it should be a big help in keeping it moist and fostering more biological activity.
And also - yes on the fungal domination. That's what I'm hoping for. The trees in my front yard have done poorly since I planted them a few years ago. My guess is that this is because it was a chemically treated and regularly mowed lawn... close to a dead ecosystem. All the chips are part of my attempt to fix it. On the other side of my yard I have nicer soil and the trees grow well so the potential is there. It will just take time.
I was also told by my friend Sean Law (the one in trouble with Longwood for going Fukuoka on his front yard) that seed balls do better when carefully sown, not thrown. I think drying out is a big problem.
Good idea on pioneer species. I've been sticking to tough stuff: nitrogen fixers, cosmos, etc., just to get some things going.
If you have plant lists I'm always game to read them.
As for documentation, my daily blog is an ongoing journal of my experiments. I don't get everything on there, but a lot of it is posted.
Richard Gorny wrote:The best results I had were with covering sandy soil with wood chips and planting in pockets filled with a bit of a good soil / compost.
Ah, good to know. This is exactly what I was planning on doing to kickstart growies on my new place (high, dry, and cold) with thin sandy loam. It's sad to leave an establised system and start over again, [sigh], though the possibilities are much bigger and better.
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