Wednesday, May 6, 2009

Welcome Chicago Magazine Readers

In the May edition of Chicago Magazine, there's a nice article on urban gardening, "Salad Days". I want to publicly thank author Karin Sullivan for including my rooftop garden in her story. When we met last year and she told me she was thinking of writing a short piece on growing food in city gardens--and wanted to showcase one of our rooftop gardens--I was pretty excited about the prospect of other people learning about what we're doing.

I have to say that I’ve learned a lot from Bruce and Heidi (my fellow Green Roof Growers) over the past year. Their roof gardens are much more involved – and larger – than mine but I think Karin wanted to show that someone with very little knowledge (like me!) could have success in a very limited time. I hope that came through in the article.

Whenever they see the garden, people seem to ask me the same questions. Here are answers to the most common ones:

I grow in Earthboxes; a basic one costs about $30 on the EB website.

I used Miracle Grow organic potting mix with Foxfarm’s organic fertilizer last year and am re-using the same potting mix in this year’s garden.

Last year, I used starter plants purchased at both Gethsemane and Home Depot. This year, all of the starts are grown from seed (thanks much Bruce).

The Earthboxes (as well as all sub-irrigated planters – aka SIPs) will use less water than conventional gardening since nothing is wasted.
"Our maintenance-free, award-winning, high-tech growing system controls soil conditions, eliminates guesswork and more than doubles the yield of a conventional garden- with less fertilizer, less water and virtually no effort."
One of the major upgrades I’m adding this year is an automatic watering system so I can go out of town without worrying that my plants will suffer.

My rooftop was built for decking and can carry the weight of the boxes (about 50 lb each). Before you put anything on any roof, please consult with a structural engineer or other building professional to confirm that your structure can handle it.
Our site has a lot of information that can get you started. I’ll also be posting some updates to this year’s garden as time goes on. If you need anything else or have any ideas, please feel free to post a reply to one of the posts here. Thanks for stopping by.

[I changed the posting date from April 14th to May 6th so it stays "stuck" at the top of the site for a while. - B.]


Grammy said...

Congratulations that is awesome you made it in the paper. You have a great blog and thanks to you I am succeeding with my seeds this year. And will be adding aka SIPs to my out side garden.

H2 said...

It's very exciting to hear about your success with seeds and SIPs. Thanks for the lovely note. Please keep us updated on how your SIP garden grows.

Bruce said...

Nice post Russ.

In order to make it "sticky", that is, staying at the top of the blog for a while, I changed the post date to May 13th.

It looks kind of strange, but Blogger Help says that's the easiest way to keep it up top.

It can always be changed again if it needs to make room for something else.

Engineeredgarden said...

I've been reading your blog for a while now, and really like the sip's, and how you use the siphon principle for them. Just wanted to say "keep up the good work", and i'll be checking out your progress.

Bruce said...

Hi EG,

I saw on your blog that you're using the siphon tubes to automatically water your containers.

Nice going. How's that working out?

Engineeredgarden said...

Bruce, first of all....thanks for the idea. (I kinda borrowed that from ya, I hope you don't mind). Although in place, the siphon hasn't been created yet. I still have to get some materials for it. I'll likely get those today, and set it up this weekend. I'll probably use plastic tubing, and coat the connections with something to seal each joint. What would you recommend?

Anonymous said...

I'm really glad you made it in the magazine. I recently moved into a top floor unit, with a lot of wasted roof space around the deck - I happened to stumble on your article earlier this week, and it's exactly what I was looking for. I'm a novice with this, so I am just looking for something fairly easy to get started - Earthboxes sound perfect. A few questions:
The local dealers only sell the full kit (fertilizer, Dolomite, casters, etc) for $60/ea. It sounds like you just used the boxes and purchased the fertelizer and mix on your own. Do I need dolomite? Where would i find it? I talked to one garden center and they said they dont' carry it and haven't really seen it. any ideas?

Thanks again for finally getting me on my way to roof top gardening!

Bruce said...


I used landscape/drip irrigation supplies from Lowes. With a sharp knife and a pair of kitchen shears you can put the whole thing together. Even without sealant, the connections are, so far, airtight.

Hi twallen,

Home Depot sells 5 lb bags of Espoma garden lime for about $4.

Russ might have some more ideas about sourcing materials for earthboxes.

Bruce said...

Forgot to add: The Espoma package says it's "Derived from Dolomite lime".

There's some confusion on the Earthbox boards about this.

Here are the side by side percentages from the labels of both.

EarthBox supplied dolomite/Espoma lime
Total Calcium: 21.0% / 21.0%
Total Magnesium: 12.0% / 10.0%
Calcium Carbonate: 54.5% / 52.0%
Magnesium Carbonate: 45.0% / 35.0%
Calcium Carbonate Equivalent: 109.0% / 100.0%

I'm not exactly sure what the numbers mean. I've been using Espoma garden lime in my boxes for the past two years without a problem.

Russ C said...


I just bought the boxes and sourced the potting MIX, fertilizer, and garden lime separately. The Espoma stuff worked for me as well and I ended up using hydrated lime later in the year (added to the water chamber) when my tomatoes had some blossom end rot (BER). Dolomite is typically used for fruiting plants (I believe), especially tomatoes. I don't use it for lettuce and other greens.

Unfortunately, the city garden centers don't carry many of the items that would be used in container gardening (sounds strange but true). I bought my mix and garden lime at home depot, the fertilizer from Gethsemane and the hydrated lime at Ace.

Good luck on your garden. When you have more questions, please do not hesitate to ask - we've been there and would be glad to help.


Anonymous said...

Russ & Bruce - thanks for the tips. For the sake of saving some money, i'm definitely just going to buy the boxes and source the rest of the materials on my own. I'll let you know how things go!

Engineeredgarden said...

russ and bruce - do you use any epsom salt in your soil mix? I've heard that it keeps the bottom foilage from turning yellow/brown...

Russ C said...

Eng.Garden - I don't use epsom salt in the boxes but I've heard many people do use it for tomatoes and peppers grown in containers. I've also heard that they will use it to counter the Blossom End Rot common on both of those plants. Instead, I've used garden lime and hydrated lime (mixed with water). I guess that epsom salt would be more soluble in water than hydrated lime but I've never tried it.

Engineeredgarden said...

Thanks for replying, russ.

Jay Buster said...

When using the 5 gal buckets, it appears that you put the fertilizer in a ring around the plant that is planted in the middle of the bucket.

Do you build a mound and then bury the fertilizer in the mound as recommended on EB's website?

Boulder, Colorado

H2 said...

Hi Jay:
I've been planting the 5-gal buckets for a few years now and never heard of burying fertilizer in the mound.

Unless you're thinking of the lime that gets mixed into the top few inches of a bucket to be planted with a tomato (to prevent blossom end rot).

With the organic fertilizer, we do what you said: put the fertilizer in a ring around the plant. And indeed, I always mound up the soil slightly, so rain will drain away on the plastic.

Scroll down at this link for how we handle large starts like young tomatoes--planting the young plant and THEN topping off the soil before adding the fertilizer ring and covering. This requires weaving the green top of the plant through a hole in the plastic, but I prefer it to trying to plant via a keyhole (fine for seeds).

Please come back if you've got more questions...

Jay Buster said...


Thanks for your excellent information. I went back to EB's website and in about 10 places they said to place the fertilizer ON TOP of the potting mix just like you said. Then I found the source of my confusion. In Step 5 of a pdf "EarthBox Instructions" they said to dig a trough in the mound and to bury the fertilizer strip. Must be an outdated pdf. I'll go with your advice and what they're now advocating.

You guys are performing a most excellent public service. Thanks again and please forgive me because I have about 50 more questions that I'll be posting.

Boulder, Colorado

H2 said...

Keep 'em coming, Jay. We're very pleased you find our info helpful. Let us know what you're planting...H2

heyyyyyyyrenee said...

First let me say how much I love your site! My imagination is overloaded right now.

I don't have the same roof issues that you do, I want to make sip raised beds. Here's my question - if I wanted to use a 5 gallon bucket for the water and a tote for the planter could the wick be the entire height of the bucket? In theory I would expect it to work but does it? I've seen some people use nylons for wicks, but never the length of an entire bucket.

What do you think? Any advice would be appreciated.

But Man --- awesome blog!!!

Bruce said...


Good question. If I understand you correctly, you want to put a 5 gallon bucket inside an 18 gallon tote (?). I think the area taken up by the bucket would drastically reduce the volume available for plant roots to grow.

Let's say you want to put a bucket inside a much bigger planter:

I think you want to keep the ratio of the area that wicks water to that of the larger container about the same as the original Earthbox. Roughly 5-10%. For example the cross sectional area of the wicking soil in an EB is about 18 sq. inches. The total area of the EB is 392 sq. inches. Divide one into the other gives you about 5%. Our homemade planters have roughly 10% of the floor of the soil chamber exposed to our wicking chamber.

It's only a guess, but I think anything bigger wouldn't work. But honestly, I don't know. I do know that a larger diameter wicking chamber that's full of potting mix will reduce the size of your water reservoir. You'd have to fill it more often.

Hope that helps.

heyyyyyyyrenee said...

thanks for your quick response and actually it does answer my question -- but what I meant was use the entire bucket for the reservoir, put a hole in the bucket lid for the wick, and then put a rectangular container on top -- just imagine two containers stacked(as opposed to nested) with the wick passing between the two. Because then I would put a wood skin on the outside and hide the inner workings. so it would look like a regular raised bed, but it would be a sip raised bed.

But the numbers you gave me should help while I'm trying to figure it out. -- the other down side I realized to this design -- some of the ventilation holes would be completely exposed to the air and would then increase the amount of evaporation.

But amazing site -- just amazing!! you have a great day!

Jackie said...

Hi: Apologies for attaching these comments to this post - I didn't find a post that dealt with these questions.

I've been reading your blog with great interest as I used to live in Chicago, and I have had a rooftop container garden in Los Angeles for almost three years, in EBs and SIPs (buckets and smaller containers). Living in an apartment makes things rather different -
1) potential vandalism and theft. I have to place the garden on roof so it is not visible from the street
2) can’t build permanent structures, which means trellising is mostly limited to portable trellises attached to containers, i.e., Earth Boxes
c) can’t set up self-watering system, which means size of garden is limited by how much the gardener is willing to hand-water (in worst cases, carry water to roof - luckily there's a tap on the roof but hose can't connect)

I was wondering if you could help me answer these questions:

1. How do you tie down the black plastic covering at the bottom of the SIP and allow water to drain freely?
2. Are you concerned about the paint on the yogurt cups entering the water?
3. Are two yogurt cups really able to support the weight of the plant and soil?
4. I assume that you fill the top bucket of the bucket SIP all the way to the top with soil, or close to. Do you find that this depth (much greater than an Earth Box) still allows roots to breathe? Are there any plants (I assume squash and tomatoes, dwarf fruit trees) that are suited to such a deep level of soil? What about during the winter?
5. Have you flushed your soils successfully so that you can use them longer? How? Or do you recommend any place to dump the unusable soil other than the trash? I find soil becomes unusable after about 24 months.

Thanks, looking forward to hearing from you.

Bruce said...

Hi Jackie,

As you pointed out there are all sorts of limitations placed on urban gardeners, renters in particular. We've found that using these planters increases our odds in a challenging environment.

Some answers to your--very good--questions:

#1 - I grow in 18 gallon rubbermaid sip totes, which I cover with a Hefty 39 gallon yard trash bag. The bag fits almost perfectly over the tote, so I don't need to tie it down. Even if it didn't and I needed to use a string, it seems to me that the water would still flow freely--from the overflow holes--past the string encircling the bottom of the planter.

#2 - I'm concerned about using plastic, period. I've tried to understand the risks associated with different types of plastic and how they are present in the conditions we've created. That said I haven't seen any information on the paint from Polypropylene (#5) yogurt containers leaching off. If you have a link, could you pass it on?

#3 - A cylinder stood on end is incredibly strong. More importantly it's not just the yogurt cups that are holding up the soil screen. The entire perimeter is directly supported by the cut edge of the rubbermaid container. This is my third year using this design--to date, none have collapsed.

#4 - The potting mix is 12" deep in each of my 18 gallon totes. Yes, it's more than the Earthbox, but I haven't noticed any plant failures that I could connect to this difference. The roots fill up the extra depth, and are easily able to 'breathe' at the bottom of the soil chamber. I've grown giant sunflowers, 2 per box, where the root mass takes up the entire planter. Other large plants would do the same.

Each fall I take out the old plant(s) and as many of it's roots as I can. I also break up the soil with a hand trowel, remove the old fertilizer strip, and drain the water reservoir. I then cover the entire box with a new 39 gallon trash bag. This stays in place until the following spring. I then plant following the EB instructions, taking care to rotate plant varieties every year.

#5 - I'm not sure what you mean by flushing soils. The growing media (peat moss/coir) can accumulate salts, my understanding is that most of them concentrate around the old fertilizer strip, which is thrown out every fall. I check the ph in the spring, so far nothing unusual. I also add a cup of Espoma 5-3-3 plant tone every year to the entire planter. If the growing media isn't wicking water properly, it'll need to be replaced. That hasn't been the case to date, but we'll keep an eye on it. When it does need to be changed, I'll put it in my compost pile; the finished compost is worked into my raised beds.

The Earthbox Forum has a thread on the life of potting mix. A commenter notes that potting mix lasts anywhere from 3 to 15 years. Quite a range. I believe the 'official' answer from the EB people is 5 years.

Bruce said...

Forgot to add this to my recent comment.

How to tell if your potting mix is wicking properly :

"Quote from: maryal36 on April 16, 2009, 11:48:41 AM
Thanks for the help. I didn't want to dump, either. But hos can you be sure that the old mix has enough water in it to wick properly? Squeeze it, perhaps?

A box that has been wicking properly should have a dark brown color - somewhere between dry coffee grounds on the dark side to damp/wet earth/ground on the light side. And when you grab a handful, it definitely feels damp like a wrung wash cloth uniformly across the whole surface. Drier or a lighter color and not a uniform color (aside from the surface fungus/salts/etc.) are signs of faulty wicking.


Jackie said...

Hi Bruce:

Thanks for answering so promptly.

#1: Doesn't the wind blow the tote bag up and over the top of the planter if you don't tie the bag down tightly around the bottom? How do you deal with that? A bag with a tiny hole in the top that isn't entirely secured will puff up and possibly damage any small plants peeking out. My roof is extremely windy and entirely exposed on the south and west, where the winds come off the ocean, so securing the bag is an issue for me. If I just tuck the bag under the bottom of the planter, water could accumulate inside the bag on the floor. What I do is try to push the totes against another surface to hold down the sides of the bag, but that's not ideal.

#2: I haven't really looked for this info, but if I find any I'll post it. The same question goes for glues on paper labels of other plastic wicking containers.

#3: You mentioned you can get three screens out of one container. I see one - that's the bottom third of the tote. The second might be out of the lid. What part of the container do you use to make the third one? Or am I missing something?

I haven't tried this design, but I will - I haven't been satisfied with converting other plastic objects into screens. Some even shatter when drilled. I notice that the new Earth Box (I have one from 2006) has more holes and I think that's one of the secrets to its effectiveness. It's great that your system works very well with considerably less direct root access to the water. Now I have to go out and get a new 1/4" drill bit - the old one got tired from so much plastic.

#4: Regarding possible excess depth, I meant the two-bucket SIPs, not the totes. You answered the question though - you don't have plants during the winter. Even kale? I'd think some of the Seed Savers Exchange Russian varieties would be tempting.

#5: I have used some of my totes without a covering and fertilizer strip. Maybe that's why the salts have been accumulating in the soil of those totes - they actually receive more water over a year than yours does because the climate's hotter, I plant all year round, I don't always use a cover (I grow roots and greens from November-April, without a cover), and more water evaporates. Or maybe the water here is harder.

I'll try the wicking test.

So you have raised beds too? And a compost pile? Lucky guy. Those hot Chicago summers must really make your garden productive.

Another issue with an apartment is that a roof is shared, meaning a renter can't use as much as s/he wants without permission, and so one doesn't have the economies of scale for mixing own fertilizer, soil mix, etc. Ideally the first gardener will inspire other tenants to request part of the roof from the management, and eventually a good part of the roof will be in use. I'm looking forward to the day when that use of urban roofs is taken for granted.

Thanks again.

Bruce said...

#1 - The trash bag is tight, really tight. It's hard to peel off by hand, if you pull it all the way down snug on top of the container, the wind won't even budge it.

#3 - I can build 3 finished planters using 4 totes.

I'll cut one into thirds, horizontally. The height of the cut is determined by the height of the yogurt cup, or center support cup. (Which is conveniently 1/3 of the height of the tote.)

After you cut the bottom third off, you're left with a rectangular ring. Cut that in half horizontally again leaves you two rings, both slightly larger in diameter than you want. You are going to use these rings to form the outside perimeter of the screen support. Since they're too large to fit into the bottom of a tote, you'll need to make one vertical cut in each of the four sides. Then you can overlap the pieces, where you cut them, to create a ring that will fit in the bottom of the tote. Stitch them together with a nylon snap tie. To create the shelf, cut out the center of a tote lid and attach it to the ring you've just created. You can then proceed to cut 2 large holes (and a lot of 1/4" holes) in the lid and attach the yogurt containers.

Having a jigsaw makes things a lot easier.

It's very possible to do this, though words aren't the best way to learn. If you like puzzles, I'm telling you to go for it. It's not that hard.

Jackie said...


Got it. I've made my own screens out of tote lids, so I know exactly what you mean.

Your site is great; inspirational and educational. Your group is a great resource. I'll be visiting regularly.

tom_skinner said...

How is the potato box going? Can we get an update. I'd like to do this next year

Bruce said...

Hi Tom,

So far, they're doing well.

The plants inside the box are about a foot taller than the final board of the box. That is to say they're about 36 inches tall at this point.

Since I don't know if I have any actual potatoes yet, I haven't put up my results. I should know by the end of August and I'll write a post then showing what happened.