Garden Chat

[ginja_ninja]

Thank you for being my personal garden planner! This is so helpful!!

@Panda

is this like literally mulch made from rubber tires? If it is, not to be too hippy/dogmatic, but I would strongly recommend you get rid of it entirely - that kind of mulch leeches nasty stuff into the soil below, and it does nothing to improve soil quality as it breaks down (it only does the opposite, lol)

Yes it is straight up ground rubber tires, sometimes you even get a pokey metal bit into your foot. I’m not sure I’m ready to take on full removal of it this year (probably like 3000+sqft of it over the yard) but I will for sure remove it from anywhere I put plants!

@Panda

I wouldn’t do any border that requires digging into the dirt (like for a metal edging border, or even maybe brick), as you don’t want to block the flow of water

This is a good point! I can totally make the border out of the logs, especially when I was hoping to use them anyways. Maybe not the big stumps but some of the smaller ones for sure.

@Panda

Then plant, then mulch, then water, then prosper.

I can for sure do this! I like the idea of prepping the bed for the spring, I’m not sure what I would plant this fall that would get me a harvest. I’m already doing greens and radish in my raised beds and I definitely don’t need this full space worth of greens and radish

@Panda

Note on the goat poop - I would still recommend using regular compost and dirt in addition to the goat poop bc I’m guessing the goat poop is still pretty hot and not fully aged

That’s kind of why I was thinking it’s a good addition this fall for spring planting. It is technically a cold manure and doesn’t need the same aging as cow/chicken/horse. They have a big pile that’s decently aged and mixed with bedding that is what I’m pulling from so it’s not fresh fresh and looks half composted. I’ll still get some dirt and compost too though!! Do you have any thoughts on how thick to do the layers? This can help me decide how much to buy!

Would you mulch with just arborist chips? There is a municipal mulch pile close to my house I can use. My husband might kill me if we did another chip drop

One other question - there was a Bradford pear tree on part of the space I want to plant in that still throws offshoots sometimes. I was thinking for that section I could put a ton of cardboard to try and smother it for good. Do you have any other suggestions? The stump has already been ground.

[LadyDuck]

@ginja_ninja

Do you have any other suggestions?

Poison. (Re: bradford pear)

[LadyDuck]

@ginja_ninja

straight up ground rubber tires

Definitely be very thorough about removing this and any adjacent soil from areas you are planning on plants such as lettuce and root vegetables, because tyres are exactly the kind of leaching contamination of heavy metals and plastic you dont want in your food. I’d classify that soil contaminated unless you’re getting it tested! But yeah, thorough removal plus soil (dont try to save the dirt, remove it WITH the tyre bits).

[ginja_ninja]

I will look at getting a soil test first then! If it is contaminated then maybe we are back to raised beds. There is a layer of intact landscape fabric between the tires and the soil so it might not be as bad as I fear.

[Ferngully]

I’m so jealous of your wood scraps and log offcuts! I’m trying to get some for a nature playground. If you set them so they’re unlikely to roll, the kids will go wild.

[ginja_ninja]

I will look into some nature playground inspo! That would be a great use for them.

[ginja_ninja]

Okay yall, can you tell me if this is a reasonable plan with the tire mulch?

I just measured and we have about 4000sqft of it throughout the yard.

I am thinking about removing it from the 620 sqft of where I want this bed to go and all of the uphill areas where it could runoff into the bed. Then doing a soil test ($210 through my state extension for heavy metal testing) to determine how much remediation I need to do (dig out the dirt or look for other options, if it is really really bad we will do raised beds).

I will leave the rest of the yard for now and look at removing it one section at a time. We do like the tires under the play structure because it is bouncy and doesn’t have splinters.

I did ask my concrete contractor for a quote if we wanted to fully remove and replace the entire project. I suspect that will be too much effort and expense for this year.

What would you do if this was your yard? I didn’t realize how bad the tire mulch was but I also don’t think it is ‘OMG I NEED IT ALL GONE RIGHT NOW’ level of remediation.

Does anyone have sources they trust for further research? I am looking at my state extension website as a good first step.

[turtlegirl]

Is the entire yard tire mulched? No grass? I assume it was the previous owners?

[ginja_ninja]

We have 3000 sqft of grass in the middle, it is tire mulched around the edges. Yeah this was previous owners, we have not done any landscaping.

[Ferngully]

Ok I might have some existential questions for you, garden style: What do you like about the garden you have? What do you want this space to add?

What’s important to you? Do you want the family to have space to be active? Curious? Creative? Patient? Grow food? Engage the kids? Support native habitat? Do you want to have space to host others like in backyard yoga? Climbing wall? Pumptrack? Garden party?

Are you concerned about soil quality for playing & digging (this can be somewhat mitigated by washing hands, designated areas, etc.), or mostly food growing (raised beds)?

So much possibility!

[turtlegirl]

I guess I’ve only seen tire mulch around playsets, never so much of it. I wonder why someone would do that. Like others have said I’d remove it whenever you can where it’s not needed. All of my flower beds are in the ground with rocks as the borders, the wood you have will look nice.

[Panda]

@ginja_ninja

Do you have any thoughts on how thick to do the layers?

That’s awesome the goat poop is technically cold manure and it’s already partially aged with bedding! I think I aimed for a couple of inches for each layer of compost/dirt, then like 4-6 inches at least of mulch - honestly I just went on vibes, lol

@ginja_ninja

Would you mulch with just arborist chips? There is a municipal mulch pile close to my house I can use. My husband might kill me if we did another chip drop

…go back to your old house and steal some of your previous chip drop? Only partially kidding…

Does your city say what’s in the municipal mulch pile? I’ll admit I always buy my mulch (from Harlequin’s, natch) because I’m terrified of getting bindweed or tree of heaven remnants in free stuff So I’m not much help there…

@ginja_ninja

One other question - there was a Bradford pear tree on part of the space I want to plant in that still throws offshoots sometimes. I was thinking for that section I could put a ton of cardboard to try and smother it for good. Do you have any other suggestions? The stump has already been ground.

I’d try to dig up any offshoots if you can, then smothering seems like a decent thing to try (although I’d just do straight cardboard and weigh it down with rocks or something - don’t water this cardboard, and ideally this area wouldn’t get any irrigation). If they are persistent, you would probably need to use poison, but I’m hopeful digging and smothering would get them. I had cottonwood sprouts that kept coming up last year, but digging and the drought got 'em this year

@ginja_ninja

Then doing a soil test ($210 through my state extension for heavy metal testing) to determine how much remediation I need to do (dig out the dirt or look for other options, if it is really really bad we will do raised beds).

Sounds like an excellent plan! Fingers crossed the landscape fabric has kept it from contaminating the dirt . Normally I hate landscape fabric, but in this case I’m glad they used it, lol

@ginja_ninja

What would you do if this was your yard?

Do you have a junk hauling service near you? For example, I’ve hired Junk Monkeys before to remove yard debris, and I thought they were pretty reasonable price-wise for the amount of work they did.

I saw your considerations about removing the mulch from uphill areas, which is a very good plan! But I’m also wondering - does the mulch blow around in the wind? I would be a little worried that, once you start converting areas into gardens, mulch from other parts of the yard would blow into the newly converted food gardens and contaminate the soil anyway. Not to be alarmist, but…if it was my yard, I’d try to remove as much as possible ASAP.

@ginja_ninja

Does anyone have sources they trust for further research? I am looking at my state extension website as a good first step.

What other types of resources are you looking for? Just for soil & safety stuff, or other topics? You know if you need native plant/gardening resources, I gotchu hahaha

[ginja_ninja]

@Ferngully

What’s important to you? Do you want the family to have space to be active? Curious? Creative? Patient? Grow food? Engage the kids? Support native habitat? Do you want to have space to host others like in backyard yoga? Climbing wall? Pumptrack? Garden party?

Are you concerned about soil quality for playing & digging (this can be somewhat mitigated by washing hands, designated areas, etc.), or mostly food growing (raised beds)?

Such great questions!!

We want space to be active and creative, also space for growing food and supporting the native habitat. I dont know if we want a climbing wall or pump track but that would be epic!!

TBH our current yard has absolutely everything we want. A massive patio for backyard yoga, enough grass to play in and host parties, space for the kids to explore outside of adult eyes but we still know they are safe (big pine trees in the back). We have 4 pollinator gardens between the front and back yard.

Some of the mulch areas would stay playing and digging and the one section I am thinking here would be for growing food. Maybe as the kids get older we can dedicate more of the space to growing food but we don’t need the whole backyard to grow food. I don’t think self sufficiency is the goal, just fun.

@turtlegirl

I wonder why someone would do that.

My guess is that it was a lower cost option and maybe sold as a “green” option by using recycled materials.

@Panda

I saw your considerations about removing the mulch from uphill areas, which is a very good plan! But I’m also wondering - does the mulch blow around in the wind? I would be a little worried that, once you start converting areas into gardens, mulch from other parts of the yard would blow into the newly converted food gardens and contaminate the soil anyway. Not to be alarmist, but…if it was my yard, I’d try to remove as much as possible ASAP.

The mulch doesn’t blow in the wind at all! The area we are looking at turning into the garden is probably the worst case for the whole yard because it is in a low spot.

Our plan for now is to dig down 3-4" and get the soil tested to see what we are working with. I will have the results in 7-10 days and we can make our plan of attack then. Maybe it is not as bad as we fear and maybe it is way worse. I feel like making a plan before I have the data is only going to make me crazy.

[ginja_ninja]

I lied, I have done a little bit of research and these two resources have been really interesting!

Soil_Contaminants.pdf

Metals-in-Urban-Garden-Soils_May-2025.pdf

The metals in urban garden soils is extremely comprehensive on where the different metals can come from Form and behavior in garden soil, human health, plant health, and what gardeners can do.

It also seems the acidity of your soil matters if there are heavy metals present (more acidic soil can increase the presence in the plants).

Soil Contamination - Cornell Small Farms

This resouce has a table as well for concentrations and differentiates levels for root vegetables and leafy greens compared to other plants. Heavy metals mostly concentrate in the roots of the plants, not the fruit. Leafy greens could be a risk because of soil splashing on to them and a source said up to 80% of the lead can be removed from through washing.

I am dropping off the samples tomorrow and am curious on the results but this has been an interesting deep dive.

[LadyDuck]

That matches what I know, definitely a great resource!

[Sunflower]

This matches the little bit I know from living in a recent urban fire zone. Check out resources from UCLA and Caltech (from the Eaton and Palisades fire) and UC Boulder from the fire a couple years ago. All three had massive amounts of houses burned that have nasty things in them compared to a forest fire and various studies have looked at gardening and soil impacts after these events.

Avoid leafy greens and root vegetables is also what I’ve heard.

[ginja_ninja]

I just looked up the Marshall fire and it showed that there were only 2 out of 26 test results with higher than normal heavy metals after the fire! I’ll look at the other two tomorrow. That is a really good data point after fires.

Marshall Fire: Air, Soil and Water Quality

Soil toxic levels mostly minor after Marshall Fire

[LadyDuck]

The 2 plum trees I bought to be pollination partners do not flower at the same time. Should I buy more plum trees?

[turtlegirl]

Is it too late to start perennial flower seeds and plant them this fall? Maybe I should wait until late January or so? I’m in zone 6A and my first frost is mid October.

[ginja_ninja]

Heavy Metal	My soil	Typical Levels for Non-Contaminated Soils	Unsafe for Leafy or Root Vegetables	Unsafe for Gardens and Contact
Arsenic	2.8	3 to 12 ppm*	>50 ppm	>200 ppm
Cadmium	<0.001	0.1 to 1.0 ppm	>10 ppm	>50 ppm
Lead	9.1	10 to 70 ppm	>500 ppm	>1,000 ppm
Selenium	<0.001	0.1 to 3.9 ppm	>50 ppm	>200 ppm
Chromium	16.9	36 ppm
Molybdenum	<0.001

The soil results came back! We are way lower than all of the limits I could find so I am going to remove the mulch from the growing space and we will systematically remove the rubber and replace it in the rest of the yard over the next few years.

Thank you for bringing this to my attention so I could test it and make a good decision for my family.

Now the actual heavy work begins of getting the space ready!

I think we are going to add a bit of expanded shale, compost, goat poop, and cover with leaf mulch or woodchips using the fun broadfork mentioned by @Panda. I got a few fertilizer recommendations (sulfur and manganese) from the test that I will implement as well.