Wood chip gardens and rhizomatic grasses

Not sure whether this is a mulch topic or a gardening topic, so feel free to move it to a better home if needed.

I've had a few years of gardening under mulches on this property. Year 1 was a load of old straw and hay. Year two and this past year were woodchips.

The original straw and hay can no longer be found, having broken down it's entirety. Despite depositing 12" of woodchips between fall of Year 1 and Year two, the woodchips were very thin by this past spring, and I had to add another ~4-6" to the garden. In other words, they've been breaking down fast. However, I am not getting tremendous production from my garden - my root vegetabls (beets, turnips, carrots, potatoes) didn't do great - the plants just didn't seem to want to grow until later in the season, despite me being very careful to ensure everything was planted in soil. The broccolli didn't really form heads, yet the cabbage I grew was show-worthy, and the brussels sprouts grew huge plants / leaves, though didn't actually develop useful heads on the stalk like I would hope. I feel like something must be missing from my soil profile - I *should* have strong organic matter and microbiology now. I see huge amounts of worms, the soil (a clay loam) under the chips has great tilth. The moisture levels were consistent - the mulch did a great job of keeping the soil moist despite 6 weeks with no rain. Everything about the soil suggests great fertility except the results...

Anyways, I'm making plans for next year, and one of my goals is to be more relaxed with weed contol - just focusing on preventing flowering / seed production, and only cutting them down if they start impacting plants. My thoughts after reading some threads is that additional root mass in the soil is only beneficial from a microbiology perspecitve, and roots that decompose in place aren't a bad thing. My main weeks are thistles, plantains, and grasses with small amounts of other plants in small quanitites..

While the thistles and plantains are manageable, I see trouble with is the grasses I've been fighting. I have a fairly aggressive rhizomatic grass in my garden. Every spring at planting time, I spend hours and root out as many rhizomes / plants as I can. However, I rarely have time to put in several hours per week into the grass battle over the summer, and by the end of the season, the grass has reestablished itself across the garden.

Has anyone succesfully conquered a grass like this? The rhizomes spread as deep as 6-8" below the surface - even in the soil under the woodchips. They *do* seem to be responding to increased soil fertility. The rhizomes will grow 4-5' in length in a few months. Rooting them out is a large job, and almost impossible once a bed is planted, which is part of the reason why the garden is half overrun by harvest. I do think I need to put in a hard edging around the outside of the garden, going down 6" at least... but that will be a big job.

I've tried smothering the plants, but that hasn't been effective. They still seem to survive and find a place to emerge even with cardboard and 6" of additional woodships on top. I eventually have to clear places to plant and put my veggies, and they come up there, and work their way through gaps and seams in the cardboard layer and colonize the chips above it...

Nature is putting up a great fight to reclaim this garden space. I'd love to work with nature... but if I let it go to sod, I won't be growing a garden anymore. The best option I can think of is to grow plants that close canopy and shade out the grass, but this gets back to my initial issue - my plants stay fairly thin, and don't grow anywhere near full potential.

Oh, and we don't have many allelopathic trees here, so I don't think the poor plant performance can be traced back to that.

I'd appreaciate any thoughts and suggestions. I'm already itching to go for next season!

Sounds like you have two problems and some really awesome cabbage.

Your first problem about the veggies, I don't have an answer for. Could it be a timing issue? Either starting too late or growing veg that aren't suited to your climate? I hope you get good advice on this site, but the best advice might come from growers in your neighborhood.

Your second problem about the grass, I think Ruth Stout would tell you to trench a border then dig up every morsel of rhizome all at ounce. Operation eradicate.

This video should be pretty relevant for you.

https://youtu.be/FwUw_Bq2p1Y

Brian Vraken wrote:Not sure whether this is a mulch topic or a gardening topic, so feel free to move it to a better home if needed.

I've had a few years of gardening under mulches on this property. Year 1 was a load of old straw and hay. Year two and this past year were woodchips.

The original straw and hay can no longer be found, having broken down it's entirety. Despite depositing 12" of woodchips between fall of Year 1 and Year two, the woodchips were very thin by this past spring, and I had to add another ~4-6" to the garden. In other words, they've been breaking down fast. However, I am not getting tremendous production from my garden - my root vegetabls (beets, turnips, carrots, potatoes) didn't do great - the plants just didn't seem to want to grow until later in the season, despite me being very careful to ensure everything was planted in soil. The broccolli didn't really form heads, yet the cabbage I grew was show-worthy, and the brussels sprouts grew huge plants / leaves, though didn't actually develop useful heads on the stalk like I would hope. I feel like something must be missing from my soil profile - I *should* have strong organic matter and microbiology now. I see huge amounts of worms, the soil (a clay loam) under the chips has great tilth. The moisture levels were consistent - the mulch did a great job of keeping the soil moist despite 6 weeks with no rain. Everything about the soil suggests great fertility except the results...

Anyways, I'm making plans for next year, and one of my goals is to be more relaxed with weed contol - just focusing on preventing flowering / seed production, and only cutting them down if they start impacting plants. My thoughts after reading some threads is that additional root mass in the soil is only beneficial from a microbiology perspecitve, and roots that decompose in place aren't a bad thing. My main weeks are thistles, plantains, and grasses with small amounts of other plants in small quanitites..

While the thistles and plantains are manageable, I see trouble with is the grasses I've been fighting. I have a fairly aggressive rhizomatic grass in my garden. Every spring at planting time, I spend hours and root out as many rhizomes / plants as I can. However, I rarely have time to put in several hours per week into the grass battle over the summer, and by the end of the season, the grass has reestablished itself across the garden.

Has anyone succesfully conquered a grass like this? The rhizomes spread as deep as 6-8" below the surface - even in the soil under the woodchips. They *do* seem to be responding to increased soil fertility. The rhizomes will grow 4-5' in length in a few months. Rooting them out is a large job, and almost impossible once a bed is planted, which is part of the reason why the garden is half overrun by harvest. I do think I need to put in a hard edging around the outside of the garden, going down 6" at least... but that will be a big job.

I've tried smothering the plants, but that hasn't been effective. They still seem to survive and find a place to emerge even with cardboard and 6" of additional woodships on top. I eventually have to clear places to plant and put my veggies, and they come up there, and work their way through gaps and seams in the cardboard layer and colonize the chips above it...

Nature is putting up a great fight to reclaim this garden space. I'd love to work with nature... but if I let it go to sod, I won't be growing a garden anymore. The best option I can think of is to grow plants that close canopy and shade out the grass, but this gets back to my initial issue - my plants stay fairly thin, and don't grow anywhere near full potential.

Oh, and we don't have many allelopathic trees here, so I don't think the poor plant performance can be traced back to that.

I'd appreaciate any thoughts and suggestions. I'm already itching to go for next season!

Good morning, Brian.

I have been gardening with arborist's wood chips for 3 years now.
Although they are a great source for garden amendment, wood chips alone are not always enough.

When I made my beds in the late summer/ early fall, I first used several types of compost and several types of manures. I then put down about a foot of chips.

That winter, I planted my brassicas in trenches of good soil. They grew spectacularly, however they needed more water than I was used to using. I use Korean organic farming inputs, and I had to water with fertilizer once per week.

By that next spring, I was able to grow anything that was not a root vegetable with ease!

Now, starting year 3, root crops are growing great because the texture of the soil is perfect.

I constantly mulch with leaves, grass clippings, and more chips; as needed and constantly, being sure to keep at least  4 inches of mulch across the garden at all times.

I hope you can glean from this experience to help with your vegetable problems.




Onto the subject of the evil grasses; I have bermuda grass, Devil grass. I was able to conquer this nuisance by first laying down layers of cardboard and newspaper, but I have been plenty successful with just plain wood chips.

The key is to really load down the mulch, over 16 inches, after being packed down with rain and foot traffic.

You will still get a few survivors that you need to pull up.

You then need a fairly wide and deep trench around the perimeter of the garden.

Finally you have to maintain the trench and the mulch in your garden, constantly add mulch.

My garden is approximately 2000 square feet, and I can maintain the weeds and trenches alone with less than 15 minutes of work per week, as long as I stay on top of it.

Nick Neufeld wrote:Sounds like you have two problems and some really awesome cabbage.

Your first problem about the veggies, I don't have an answer for. Could it be a timing issue? Either starting too late or growing veg that aren't suited to your climate? I hope you get good advice on this site, but the best advice might come from growers in your neighborhood.

Your second problem about the grass, I think Ruth Stout would tell you to trench a border then dig up every morsel of rhizome all at ounce. Operation eradicate.

This video should be pretty relevant for you.

https://youtu.be/FwUw_Bq2p1Y

I'm not growing anything too out of the ordinary for this area of Ontario.

Thanks for the video, it more or less summed up the issues I'm encountering and offered a few solutions. Unfortunately, sounds like there's no way around it being quite labour intensive all summer, but repeated smothering seems much more practical than constant rooting out and pulling.I *may* need to trench around my garden however... in the video they create a 2' mulched barrier, but I suspect that will be crossed by invading rhizomes within a few weeks.

Hamilton Betchman wrote:

Good morning, Brian.

I have been gardening with arborist's wood chips for 3 years now.
Although they are a great source for garden amendment, wood chips alone are not always enough.

When I made my beds in the late summer/ early fall, I first used several types of compost and several types of manures. I then put down about a foot of chips.

That winter, I planted my brassicas in trenches of good soil. They grew spectacularly, however they needed more water than I was used to using. I use Korean organic farming inputs, and I had to water with fertilizer once per week.

By that next spring, I was able to grow anything that was not a root vegetable with ease!

Now, starting year 3, root crops are growing great because the texture of the soil is perfect.

I constantly mulch with leaves, grass clippings, and more chips; as needed and constantly, being sure to keep at least  4 inches of mulch across the garden at all times.

I hope you can glean from this experience to help with your vegetable problems.




Onto the subject of the evil grasses; I have bermuda grass, Devil grass. I was able to conquer this nuisance by first laying down layers of cardboard and newspaper, but I have been plenty successful with just plain wood chips.

The key is to really load down the mulch, over 16 inches, after being packed down with rain and foot traffic.

You will still get a few survivors that you need to pull up.

You then need a fairly wide and deep trench around the perimeter of the garden.

Finally you have to maintain the trench and the mulch in your garden, constantly add mulch.

My garden is approximately 2000 square feet, and I can maintain the weeds and trenches alone with less than 15 minutes of work per week, as long as I stay on top of it.

Thank you for the thoughts. I suspect you are on the right track in that I need to supplement the fertility. My hope was that the woodchips alone would provide that fertility, but so far no dice. My intention for next year is to strongly supplement the garden with (imported) compost, as well as bringing in some mushroom spawn and red wrigglers to increase the activity and decomposition rate.

I have a good relationship with the local electric utility's forestry crew, so I have a near-unlimited supply of ramial woodchips cur from power lines along the rural roads here, so as fast as the woodchips decompose, I can replace them.

If the tilth of the soil is good, and you’ve eliminated the competition in the form of weeds, and (I presume) you have a good handle on meeting the light and temperature requirements of annuals in your climate … then it’s time to think about nutrients. Nice succulent, fleshy, fast growing annuals are nitrogen hogs. You’ve added a ton of carbon to the soil, but both straw and wood have notoriously poor nitrogen content. So I agree with Hamilton Beltchman — compost may help. Manure compost, or vegetable/comfrey compost, or worm bin castings made with kitchen scraps, or aerated compost tea sprayed on specific plants that need a boost. Pee in the pile. Scrape any little weeds that pop up in garden with a hoe and let them die on the surface next to your plantings. Mulch with fresh cut green grass/pasture (before the seed heads!)

From the standpoint of the microbiome of the soil, I think of it this way: The majority of plants prefer to live in soil made up of other plants that occupy the same ecological niche as themselves. That’s what they’re adapted to, and that’s the microbial community they will respond to best. Hardwood fruit trees, for instance, “like” ramial wood chips and leaves. It’s the soil of a hardwood forest, sped along. Conifers and acidic bog plants such as vacciniums are fond of conifer chips. And fleshy annuals, the denizens of early succession and disturbed ground, like soils where a lot of other herbacious plants have lived and died. They are a bit grudgy against wood and all the fungal associations with wood, because the forest is not kale’s natural habitat. Unfortunately, grass pretty much loves exactly the same environment as herbacious annuals. Perennial grasses are the next ecological stage after the annuals, and they absolutely know it, as much as plants know anything. So battling grass tends to be ongoing.

What I do is this: I’ve established beds that I think of as enriched annual islands among the various perennial plants. Compost, leaves, grass clippings and wood ash go into the islands, but not too much wood or needles/forest duff. Even in a hugel pile, it has worked best to have the wood fairly buried under a lot of herbacious materials. Wood chips I use on the paths around the islands and around various trees ands shrubs. Chips do help establish a grass-free perimeter, so there is less grass invasion into the tempting beds. But the annuals are happier to have the wood degrading off to the side instead of right in their immediate root growing zone.