How to Get the Lead Out Of Your Soil... Maybe

Urban Farming Nerd Alert!

Today's topic is phytoremediation!  

Since we live in Brooklyn, and Brooklyn has an industrial past, I read that our soil was likely contaminated with lead.  As I understand it, the lead gets into the soil by settling out of the air (in the form of pollution) and flaking off of buildings (in the form of paint).  

I had our soil tested by Brooklyn College in Autumn 2014.  The middle area of the yard tested at 332 parts per million (ppm).  The flower beds around the edge of the yard tested at 413 ppm.  The front yard tested at 453 ppm.  The green roof soil and the potting soil in all the containers on the roof were lead-free.

Once I got our soil test results, I had to figure out what to do about it.  

Brooklyn College's recommendation is: 

• for lead levels below 100 ppm, no precautions are necessary (the green roof and all the potted plants are safe).
• for lead levels between 100 and 400 ppm, follow best‐management practices for garden soils, i.e. don’t grow green leafy vegetables or root crops, children should not play in areas of bare soil. Other suggestions would be to further investigate actual lead distribution in the area and to test the blood lead levels of children. (this applies to the middle section of our back yard)
• for lead levels above 400 ppm, the soil should not be used for growing food plants, and remedial actions should be taken for residential use. (this applies to our front yard and the garden beds around the edges of the back yard)

So, for the middle area of the back yard - where the lawn has been - the recommendation is "best-management"...  The lead levels are below 400, so it's okay that we've got an apple tree planted in that section, but the soil is still pretty contaminated, and I'd rather it wasn't.

For the surrounding garden beds, the lead level is over 400, which means we're not supposed to be growing any food plants in that area, and the soil should be cleaned up.  Unfortunately, that's where I've got black raspberry vines, may apples (a native species of plant that produces small fruits in July, not May), and ramps.  I have two theories as to why the edge beds tested higher than the central section of the yard.  First, I've been putting a lot of compost in the central section to try to raise its level up to match the brick walkway.  If I understand my research properly, compost can make heavy metals less accessible to plants.  Maybe the compost also makes heavy metals less detectable to soil tests?  Second theory: the back bed runs along the rear side of our neighbor's garage, and the paint has been peeling off that thing for a long time.  I took soil samples from all around the edge beds, including the back, so maybe the soil from the back skewed the results.

Regardless, I don't want to live with lead in our backyard soil.  I want to clean it up.

Back when I lived in Boston (in the 1990's), I worked with a community action group to get an area along the Chelsea Creek cleaned up.  The soil there was throughly contaminated, and we were told that the only way the land could be made safe enough to become a park was to actually scrape the top 12" of the soil off the land, send it to a land fill, cap the remaining earth with plastic, add new topsoil over the plastic, and, voila: Safe park!  By the looks of it, that's exactly what was done to create "The Condor Street Urban Wild":

It's a wonderful triumph that the site was cleaned and made into a public park.  However, before the soil was scraped off, capped and/or replaced, the land had varied contours.  It had trees.  It was interesting.  I like interesting.

Digging our own backyard down 12", throwing all the soil away, buying 12" of clean replacement soil, and carting everything through the house both ways (we don't have an alley or any other way of accessing the backyard) didn't sound like a viable option.  It sounded wasteful in every way, and it would likely remove any character that's there.

But then I remembered I had once heard that sunflower plants pull toxins out of soil.  I did a lot of internet research and found that sunflowers aren't the only plants with the ability to "clean" soil.  In fact, other species of plants draw lead up into their roots, stems, and leaves even better than sunflowers!

According to my research, indian mustard (Brassica juncea) was one of the best plants for bio-accumulating lead and phytoremediating soil of all those I read about.  Here's how it is supposed to work:  

You seed the contaminated soil with indian mustard, grow the plants to maturity, pull them out (roots and all), and dispose of them.  While I could find no record of any land that had been 100% cleaned by this process (perhaps because no one has tried for long enough), The Boston Health Department conducted a study for 2 years in Dorchester, MA in 1997-98.  During those two growing seasons, they managed to reduce the lead in the soil by 63%.

So I thought this year I'd give it a shot!  I tilled the middle part of the back yard with a pitch fork and sowed the whole thing with indian mustard seeds.  I left the side beds un-touched for a control to my experiment.  In the Fall, I'll pull up all the indian mustard plants and retest both the central area and the side beds to see if there has been any change in the lead content.  Of course, I'm hoping we see a noticeable improvement in our lead levels.

Half-way through tilling the back yard with our new tiny pitchfork.

Mustard Greens (about 3 weeks old)

Below is a wide shot of the back yard today.  You might notice that I've taken down the back fence, scraped and painted the back wall of the neighbor's garage, and thereby hopefully stopped the flow of lead into the soil from that source.  

In my next garden post, I'll explain the cube-shaped contraption in the back.  In the meanwhile, baby mustard greens look nice as a lawn!

If you'd like more information on phytoremediation and creating a lead-safe garden, have a look at the Lead-Safe Yard Manual and this paper called Phytoremediation for Lead-Safe Yards.

Wine Bottle Planters, Compost Tea, and a Garden Update - June 2014

I've been working on a post about the Lanikai Stage project, and I've got that ready to roll just as soon as one last video comes in from Hawaii.  In the meanwhile, I've been doing some puttering around the house (as usual).  Here's an update on the gardening stuff.

First, I have been doing some seed starting experiments with my wine bottle planters.  Over the past couple of years since I started making them, I experimented with using a variety of "soil."  I tried potting soil, but that stayed far too wet.  So I tried a mixture of green roof "soil" and smashed-up terra-cotta pots for drainage, but they were still retaining too much moisture in the top for most plants that I tried.  I remembered seeing some Grow Bottles at The Green Depot (one of my favorite stores) and reading on the package that they used expanded clay pebbles as the growing medium.  I've kept that in the back of my mind as I was doing these experiments, and since none of them was particularly successful, I finally bought some expanded clay pebbles (they're mainly used in hydroponics; I bought Hydroton, but if I ever need more, I'll be getting Growstones).

I sewed a bunch of seeds in my wine bottle planters and put them in the window - forgetting the basic rules about seed starting (keeping them in a dimly lit place being the main one).  After two weeks, only my friend Rosie's dill seeds had sprouted.  I moved those out onto the window ledge where they could get more sun, and a warm day dried them up and killed them.  Clearly, I now had a problem of not enough moisture!

So, I took a peek at the instructions online for Grow Bottles, and discovered they mix vermiculite in with the clay pebbles for moisture retention!  Well, I don't have any vermiculite on hand, but I do have some left over peat moss from when I made the hypertufa planters for the roof (click the link and scroll down to see pictures and read about the process), so I sprinkled that among the pebbles, sewed some more seeds, and have been spritzing them with a water bottle every morning and evening.  And I'm having some success!  So far, the eggplant, cucumbers, tomatoes, and (once again) Rosie's dill have sprouted and are looking strong.  Now I just need to give them some fertilizer.

Speaking of fertilizer, I'm making my first batch of "compost tea" as I type this.  Soil health is foundational to plant health, and plant health is related to Cindy's and my health.

Let me explain: healthy soil is not unlike our own bodies.  The human body is comprised of more bacterial cells than actual human cells (skeptical?  read this article from Scientific American).  Healthy soil is, we are learning, is also comprised largely of bacterial cells.  These tiny bacteria break down the minerals and nutrients in the soil so that they can be absorbed by plants' roots.  The bacteria create sort of a transitionary zone around plants' roots that is not exactly plant and not exactly non-plant (such a Buddhist concept!).  When we kill off the bacteria in and around our bodies, or we kill off the bacteria in and around our plants, we are interrupting ecosystems on the micro scale.  These ecosystems, actually known as "micro-biomes" are responsible for all sorts of mechanisms related to processing food (or sunlight and fertilizer, if you're a plant) as well as protecting us from disease (and pests, also in the case of plants).  This is a pretty great article to read if you want to know more.

Cindy and I compost our kitchen scraps, but our compost operation isn't big enough to make enough compost to create healthy micro-biomes in all the new potting soil and potted plants that went up on the green roof this year.  And the wine bottle planters don't have any nutrients in them yet either.  So, I'm making my own liquid fertilizer that is rich with aerobic bacteria by putting a net bag of compost (actually, I believe we originally received this bag as a wrapper for a bottle of champagne we were given), a couple of tablespoons of unsulphered molasses, and some water in a bucket.  I'm then forcing air through the water with some aquarium air stones and a used aquarium pump.  The molasses is a bit of extra food for the bacteria (like flower and sugar are for yeast when making bread), and the bubbles going through the water allow for the mixture to support aerobic bacteria (which are highly beneficial to plants) as opposed to anaerobic bacteria (which could be trouble).  A small amount of compost itself acts as the starter (think sourdough bread starter) - introducing the good bacteria to the water, which then multiply with the abundant food (molasses) and air.  Tomorrow, I'll put the compost tea in our new sprayer and spray it on all our plants and surrounding soil.

Here's the "brewing" operation with the net bag hanging off the handle and two air lines running into the bucket with the air stones bubbling away:

I learned about this stuff by doing youtube searches for "compost tea."  Although he doesn't tell you what type of yeast he's putting in his compost tea in addition to compost, this Alaskan guy is sort of an adorable coot, and I like his video: Compost Tea for BIG Vegetables.

In other Project Happy Life gardening news, I'm trying a new technique with the chicken wire squirrel protection up on the roof.  I started putting chicken wire directly over the soil around plants rather than upside down baskets over the plants, because now a lot of the plants are getting too big for the baskets.  It seems to be working, but there's more to do.  Here are some pictures from this morning's trip up to the roof to get my bucket.

The squashes are getting huge.  The watermelon on the left is lagging behind.

 The lavender is blooming!

 The row of seedlings on the West side are getting taller, and I have to sort out the chicken wire/squirrel problem this weekend.

 The artichoke is getting bigger.

 And the blue potatoes are off and running - again, another chicken wire problem to solve this weekend.  There's a zinnia on the right.  I kept it in the kitchen window for too long, and it got leggy.  Then I transplanted it to the roof and it didn't get enough water... inadvertent zinnia torture.

The hairy hens and chicks are getting VERY prolific.

The red sunflower is also getting ready to outgrow its chicken wire.

Tomato seedlings doing well.

Rosemary, fairy squash, and two eggplant seedlings. 

 And the green roof sedum are getting ready for their second round of flowers.

And on the left, you can see the beginnings of a chicken wire cage I'm making to protect the strawberries from the g. d. squirrels.

Anyway, hang on, all you plants!  Compost tea is a-comin'!!

Green Roof Two Step

Hello, pals!  Here's a mid-May update on the green roof.

The last couple of weeks have been what I like to call, a "green roof two-step."  In other words, we've been going two steps forward, one step back.  Is there such a thing as a project without successes and disappointments?  I doubt it.

The first and most stress-inducing problem is that the roof hatch is letting in a slow leak when we have hard rain.  I'm pretty sure it doesn't have anything to do with the green roof system and is more related to the way the hatch was built and installed.  But I'm trying to get a hold of the contractor we used to re-roof the house so he can come and take care of it.  We're within the 10-year warrantee on the work.  I left him a phone message a couple of days ago (without answer), and I sent him an email last night after going up and taping some plastic around the outside of the hatch to see if I can prevent the leak in today's rain storm.  We'll see.  Here's a picture of that bummer from the last rain storm:

There are two other leaking issues that need to be addressed.  One has to do with moisture somehow coming in between our side wall and our neighbor's side wall (our two houses abut each other - I'll take a picture of that some other time).  The third issue has to do with water finding its way into the upstairs apartment's kitchen ceiling through a vent pipe boot when the silt from the drainage rock on the green roof gets washed down to the roof drain and slows the flow of the water off the roof.  For more depression, here's a picture of what that kitchen ceiling looked like in the last storm as well:

Luckily, I can prevent this leak by keeping the drainage rock cleared from the roof drain.  If you ignore the loops of cable (which is for our home-made digital TV antenna), that's the vent pipe on the left, and the water flows down to the roof drain on the right hand side of this photo.  I want to have the contractor look at this issue, because we need a more permanent fix than this.

Come to think of it. I'd say those roof leaks are more than one step back.  Let's say that's two steps back.

But, a few days later, we got some un-related good news!

News 12 Brooklyn sent a reporter, Kena Vernon, out to do a little story on the green roof!  They found us through this blog, which was really pretty neat.  If you'd like to see the story Kena did, you should be able to watch it by following this link to the News 12 Brooklyn site.  Or, here's a copy of the video right here:

Let's hear it for Cindy Keiter wearing her pink pants, ladies and gentlemen!  Also, in case you're wondering what's up with my shirt, I was wearing my roof garden shirt.  See?  There are vegetables flying off the rooftops...

But before we get too happy, and since this is a good news/bad news post, we've got more to talk about.

Now, I've been working on the wooden hand rail that goes along the top of the metal railing on the roof, and after some amount of visiting hardware stores in the area (does no one carry anything better than drywall screws these days?!), I found some self-tapping screws that I decided to use to screw the wood to the steel railing.  After a certain amount of trial and error, I finally got a little system working, and I managed to get all the pieces cut and installed for the back railing.  I'll do a full blog post about the hand rail install process later, but here's the bummer:

Went I went  up to the roof to check it out before the reporter came, I found a piece of the railing section laying on the roof - totally broken off from where I had attached it!  

Well!  At first, I thought, "Who came up here and broke this off?  Were there vandals on the roof?  Did a neighbor come up and stand on this section to look at the chimney?  What the hell happened?!"

But then I noticed that another smaller piece of wood which had been firmly screwed down was completely un-attached, but it was still resting in place.  Did someone break that too and put it back?  I ran around the roof, checking all the pots, looking in my tool bin to see if anything was stolen.  Everything was just as I had left it.  No vandals.

So I went back and looked at all the sections of wood.  A couple of the other small pieces had one of their two screws broken off - all of them broken off right at the top of the steel where the screws enter the wood.  The only answer is wood movement caused by the rain had sheared the screws off.  

I realized all the broken screw ends would have to be drilled out, and I'd have to replace the screws with something stronger, and drill wider holes in the steel to allow for more wood movement.  I calmed down, but was a little wary the whole time that the reporter was going to go to the back of the roof and see my mistake.  While I'm happy to share it with you, I was too embarrassed to have it broadcast on TV.

Luckily, she never wanted to see the back of the roof - probably because the poor dear had to lug her own camera around (I brought it up and down the ladder for her), and she didn't want to navigate the stepping stone path with it.

Then there was another Unfortunate Situation on the roof.  

A couple of days after the news story, while chatting on the phone with my mom (hi, Mom!), I was putting in some drip irrigation fittings to keep these big pots watered.  The main drip line runs behind the pots, and I was trying to keep the little individual lines to the pots semi-concealed, so it was tight quarters.

I was squatting down to do the work, and I was right in front of the first of the four pots - the one on the right.  See that?  The one right next to the skylight...?

Yup.  I cracked a pane of glass in the skylight with my butt!  Such a bummer.  I made a crack - a butt crack - in the skylight.  I put some duct-tape on my butt crack to keep it from leaking...  There's a new glass shop in the neighborhood, and they made us a replacement piece, but it took them a week.  It was a real pane!

A few days after that incident, I came up on the roof to check how the potted plants were doing.  I had moved last year's sage and lavender to two of the fabric pots, and I sewed seeds in the self-irrigating planters and the rest of the fabric pots.  I had gotten drip irrigation fittings installed on all the pots near the sitting area, and I was eager to see if any seedlings were sprouting.

The sage was busy making blossoms (wonderful news!), but the squirrels had dug holes in the soil of all the pots (boo!).  I filled all the depressing squirrel holes (squirrel depression?) before I took a picture, but at least here are the nice sage blossoms.

Ignoring the squirrels for a moment, there were a couple of other nice things.  These hairy hens-and-chicks in the back are making little satellite babies.

And here's Cindy, hand-modeling a little green strawberry:

But, the ding-dang squirrels are a problem.  So I made some chicken-wire basket things to go over the tops of the pots.  I also got some organically raised seedlings from the excellent Silver Heights Farm Nursery at the farmer's market in Union Square last weekend, and our friend Robin (hi, Robin!) came over to help me do some gardening.  I don't have enough dirt to fill all my pots yet, so we stuck some of the seedlings in with seeds I had sewed previously - I wasn't sure if the squirrels had eaten all the squash seeds I planted anyway...

As I said, I was up on the roof last night putting some plastic around the roof hatch to see if that prevents leaking when it rains today, and I took the opportunity to check all the plants with my little flashlight.  The watermelon and squash seeds I thought the squirrels had gotten are now starting to sprout.  They weren't eaten after all!  And the rest of the plants look great.  In fact, the green roof sedum are starting to bloom, and for me, that makes all our little set-backs completely wash away.

Well, not completely, but you know what I mean.

P.S. Special thanks to my dear friend Dave for the pane of glass pun.  The butt crack was entirely my own.

Green Roof and Garden Update early May 2014

Yesterday was a big day for us up on Ye Ole Green Roofe.  A reporter named Kena Vernon from News 12 Brooklyn came and did a story on the project.  She was a very nice lady, and as long as you don't get your internet through Verizon (due to some weird corporate war), you can see the story they aired at this link.

Since my last update (in early April), I bought and hauled a bunch of potting soil up to the roof and filled some of the fabric pots (from a company called Root Pouch) we're going to use this year.  It feels very weird to be paying for dirt, but in the Big City, dirt isn't actually dirt cheap.  Besides, you can't use just regular dirt for container gardening - it's moisture retention is all wrong, and it gets too compact for the plants to develop good roots.

Anyway, here's a wide shot so you can see both how green the sedum are getting as well as where I put some of the pots.  I put big ones (15 gallon) for pumpkins and squashes next to the sitting area.

And there are two different sizes of smaller pots (7 and 10 gallon) on the parapet wall.

The potting soil came from a big pallet of bags of soil at Kings County Nursery.  Big chunks of the bags were still frozen from the Winter when I brought them home.

 Every time I bring a bunch of heavy stuff up the ladder to the roof, I remember the 55 pounds per square foot of green roof load for which we're approved, and I think, "This is the last heavy stuff I'm going to bring up there."  I wonder when that's going to be true?

A picture of dirt in pots isn't all that exciting, but when you contrast my neighbor's black asphalt roof on the left with our green roof on the right, you can sort of imagine a better world, which is very exciting indeed.

I've had a revelation about the stump stools: They're uncomfortable.  I'm going to repurpose them into firewood and make some chairs that are lighter-weight and actually pleasant to sit upon.  Until then, the stump stools also make uncomfortable sawhorses.  What on earth would I be sawing up there, you might ask?  Well, I've finally started putting the wooden handrails on the tops of the metal railings.  I'll write about that in a separate post.

As for the back yard, we've got daffodils.

And these little purple flowers have started blooming all over our "lawn".  They're a native violet. Some people will tell you they're a type of pansy.  I'll tell YOU who is a type of pansy...

Speaking of natives, this type of plant is called "May Apple".  They're rhyozomatic, and they produce a little edible fruit, from which I'm told one can make a nice custard.  

Although they're called May Apples, apparently their fruit won't be ready until July.  You can see the green bud for the flower that will turn into the fruit between these two leaves:

Also in the native, rhyozomatic, and edible category, we've got a couple of ramps coming up!  I got some more from Good Eggs this week, so we'll chop the rooty ends off and plant them as well.  Maybe in a few years, we'll have enough of our own ramps growing to make a whole meal's worth!  Such goals!

Is it weird to be so excited about ramps that I'm including two pictures?

For pure native decoration, we've got two colors of "Bleeding Hearts" blooming.

We've also got Peaches McNugget - our feral cat, sitting on the chair.  Ignore the dead body under the tarp in the background.  That's actually our christmas tree waiting to be burned in the fire pit, and I wanted to keep it dry...  You'll also notice a ton of dandelion flowers in the yard.  I don't bother weeding anymore.

And the blossoms on the honeycrisp apple tree turned white and opened up.  Here's my cue to practice non-attachment to things.  If I'm not careful, the squirrels will eat our apples, and I'll have murderous thoughts about the squirrels.

Speaking of pansies, here's a couple of beauties:

Quick Project - Sprucing up the Tree Pit

Here's a quicky, "Look What I Did" sort of post.

Last year, when I cut the sedum mat out to place bluestone slabs on the roof to make a sitting area, I didn't throw the sedum mat pieces away.  Here's the only photo I have of that process.

I tossed all the sedum mat chunks overboard (aka - into the backyard) and laid them out on the cement in the back yard for the winter.  I wasn't sure what I was going to do with them, but I didn't want them to be wasted.

Well, a few months ago, the city put these new railing things around the tree pits on our block, and they removed the old cobblestones that were in there since long before I moved in to this house.  They also made the tree pits wider, presumably so more water could get to the trees.  But the barren dirt sort of gave the impression of a wasteland, and it was a magnet for trash.  Here's a shot of what it looked like after I picked the trash out.

For context, here's my little front yard full of ephemerals that are almost done blooming.  I hope to replace our chain link fence with something that mimics the green roof railing one day.

Anyway, back to the tree pit.  I decided to make that my target for the left over sedum mats.  But I didn't want the plants to get squashed by people getting in and out of their cars.  So, first I carved out a strip of dirt along the curb to make a landing spot for people's feet.  The tree roots were too close to the curb in the middle, though, so I didn't carry my strip of bricks all the way across.

I found a MONSTER earth worm under the sedum mats in the back yard.  I'm sure you want to see a video of it, so I'll oblige:

Out front, I watered the dirt, tried to push as much of the fine stuff in between the bricks as I could, stomped it all down, and laid the sedum mat pieces in place.  It turns out, I had the exact right amount to do the whole tree pit.  Once I had them all in place, I watered them some more.  

So, there you have it.  A nice, spruced-up tree pit (even though it's a maple tree that's growing there) for our neighborhood to enjoy.  The sedum are native to this area, and they shouldn't need me to water them once they're established.  They'll also send up really pretty flowers within a month or two.

Ta da!