Time to plant Winter Vegetable Gardens here in Florida

I love the winter garden.  Though Judy tells me it is hard to determine just when to plant the winter veggies - the hot and humid dog days of September can really hurt arugula and winter mix lettuces-greens - I always look forward to the stretch of year where  a good batch of tasty, organic greens is just outside the back door.

Check out Judy's latest raised bed planting - a whole new set of Winter Greens!

Winter Gardening Starts in Florida, Judy's Garden (September 2010)

You can grow an amazing amount of food in a very small, Urban Core plot.

Be sure to use non-treated wood for raised beds - we use standard 2 x 10 pine boards for one of the home improvement stores.

Lots of organic compost to keep the nematodes at bay.

Happy Urban Gardening!

Kevin

Green Roof Design and Stormwater in Florida

We are starting a series of blogs on green roofs and stormwater in Florida - especially since Florida's (FDEP's) new Applicant Handbook - the design manual for site Stormwater Permitting in Florida lists green roofs as a treatment option.

Click on the above link to download the manual.  The green roof section is located beginning on page 83 or so.

We are proud the State of Florida recognizes green roofs as providing stormwater treatment.

We are concerned with some of the material in the handbook though.

The handbook approaches green roof design from a stormwater storage function first, though.

As green roof professionals we believe the appropriate design for a green roof should be from an integrated approach - habitat, carbon sequestration, beauty, insulation and stormwater - not just primarily stormwater.

We are concerned the handbook allows primarily volume credit for green roofs.  Green roof design is approached from a 'stormwater retention pond' on top of a building approach.  The more volume you store between the roof and the associated cisterns, the less you have to treat for discharge.

This approach may be appropriate for stormwater treatment but in our opinion, stormwater treatment should be a benefit of good green roof design - not green roofs should serve stormwater treatment.

Not trival, our concerns are valid because under the stormwater handbook approach one ends up designing green roofs from a 'demand side' perspective - or peak load perspective.  Stormwater treatment systems are designed based on annual rainfall loading numbers, graphs and data as presented in the applicant's handbook.

A deep, intensive green roof may be great for helping handle stormwater on a site.  However a deep, intensive green roof may not be a sustainable system.  Lets discuss why.

Florida has an overall significant rainfall average amount of between 48" to 64" per year.  To handle that peak load, stormwater systems have to be rather large.  Green Roofs designed to attenuate or hold portions of that volume are usually substantial and, deep - 4" or deeper across the roof.  Cisterns are considered a vital part of a green roof system for additional volume storage.  The more volume stormwater your green roof can store, the less you must account for in other portions of your on-site stormwater system.


An intensive or deep extensive green roof system has more soil along with the additional storage volume.  More soil means deeper roots.  Check out the attached photo.

Green Roof Plant Root Architecture

The root system here is typical of a green roof plant with 6" of soil.  Roots grow down then out.

On deep stormwater based green roofs, the plants used will develop deeper root systems.  We've discussed this principle before - it is called acclimation - plants adapt to the site.  So with deeper soils found on stormwater roofs you will have deeper plant root systems.

Now, the dry months of the year run from mid-October to mid-March.  During this portion of the year the Florida average rainfall amount will be less than the required landscape plant evapotranspiration requirements.  In other words, during the wet summer months it rains enough in Florida to provide irrigation generally for most landscapes, including green roofs yet during the winter months irrigation is usually necessary because the rainfall amounts are significantly less.

Importantly, here in Florida though we have a large annual rainfall amount - over 50" per year, most rainfall events are less than 1" - and many less than 1/2 " in total volume.  This is representative of the typical afternoon summer quickie rain shower.

Going back to the photo above, many times after a rain event the first 1" of soil may be wet after an afternoon rain but the deeper soil can be very dry.  On deeper green roofs designed for stormwater systems this can be a problem for the plants.  Additional irrigation is usually required to reach the deeper plant roots.

So by building a deep green roof capable of handling heavy rainfall events as part of a site stormwater system we are designing in a landscape feature that actually requires irrigation.

The green roof helps reduce the overall annual rainfall discharge but requires irrigation to keep the plants alive year around.

This is what happens when you design a green roof to function primarily as a stormwater system feature.

We will talk about required fertilization in the next blog - and ask - why are we adding fertilizers to stormwater green roofs?

For now - let's agree green roofs can work wonderfully as a stormwater system - however - Florida green roof design criteria should not be based on green roofs designed for stormwater systems.

Florida green roof design criteria must also take into account the following - cost-effectiveness, habitat, water-wise design, beauty and other considerations.

A stormwater designed green roof will be very heavy when saturated with water and the cost associated with critical roof support may be way too high for many projects.

A lighter weight, thin extensive green roof system may not hold as much stormwater but will be less expensive.  A lightweight green roof may be used on many residential projects that could not afford a heavy, structural stormwater based green roof.

So the point here is - great news our state stormwater handbook specifies green roof design for credit in designing site stormwater systems.  Yet we must also realize - not all green roofs function primarily as stormwater systems and so design criteria cannot be restricted to stormwater purposes.

In future blogs we will explore habitat creation, food production, landscape beauty and other important criteria affecting green roof design.

Happy Green Roofing,  Kevin

Florida Stormwater Applicant's Handbook - Green Roof Rules pages 83 - 108

Posted here on the above link are the new rules proposed under the Florida Stormwater Rule.

We'll be discussing the rules and how they affect our Green Roof Industry.

Issues in the rule we will be exploring include:

* Irrigation is required on Florida Green Roofs,
* Fertilization is expected on Florida Green Roofs,
* Florida Green Roofs are to serve as a retention mechanism for stormwater treatment trains
* Florida Green Roofs and Cisterns are treated equally in the same section - shouldn't they be considered separate entities and systems?
* Recommended plant list includes those species that may represent a fire hazard under dought conditions.
* and other issues.

The stormwater rule is written from a stormwater perspective, calling some pioneer native plant species 'weeds'.

How do these issues potentially affect the Florida Green Roof Business?  Find out - stay tuned for a series of exploratory posts.

Email me with your questions and comments here.

Kevin

Green Roofs and Florida's new Stormwater Rule

The following is an excerpt from Florida's new Stormwater Quality Applicant Handbook.

Section 12.0 discuss how Florida will treat green roofs and cisterns with respect to stormwater.  For a discussion of concerns read subsequent posts.

12.0 Green Roof/Cistern Design Criteria
A greenroof/cistern stormwater treatment system is a vegetated roof followed by storage in a cistern for the filtrate which is reused. A greenroof/cistern system is a retention BMP and its effectiveness is directly related to the annual volume of roof runoff that is captured, retained, and reused. The filtrate from the greenroof is collected in a cistern or, if the greenroof is part of a BMP Treatment Train, the filtrate may be discharged to a downstream BMP such as a wet detention pond. A cistern is sized for a specific amount of filtrate and receives no other runoff water. Other pond storage must also provide capacity to detain a specified quantity of filtrate. The detained water is used to irrigate the roof. Irrigation must be provided to maintain the plants. A back up source of water for irrigation is necessary. Excess filtrate and excess runoff can be discharged to other stormwater treatment systems, infiltrated into the ground, or used for irrigation or other nonpotable purposes. The greenroof/cistern system functions to attenuate, evaporate, and lower the volume of discharge and pollutant load coming from the roof surface. Greenroof systems have been shown to assist in stormwater management by attenuating hydrographs, neutralizing acid rain, reducing volume of discharge, and reducing the annual mass of pollutants discharged. Concentrations of pollutants discharged from a greenroof with pollution control media have been shown to be approximately the same as would be anticipated from a conventional roof. Thus, the concentration and mass must be managed. If no pollution control media are used, greenroof concentrations are greater than those from conventional roofs. In addition, with fertilization of the plants, increased nutrients are expected and storage for the filtrate is required.

Green Roof Mat - Florida - Root Barrier and Cut Away View

Extensive Green Roof Mat System Cutaway Section

Here is an interesting photo of a Florida extensive green roof - 2-4" thick on a 5/12 slope (built in 2005) with a HDPE root barrier.  A portion of the vegetated roof has been removed for root barrier inspection and root behavioral studies.  The plants are growing in a soil filled woven mat and the roots are thick into the mat.  Once the roots reach the liner they turn and grow parallel with the liner's surface.

Urban Food Gardens - Hanging Planters - Porch Gardens for the City

Rob Overly, the renown Jacksonville sustainable and green architect - and Rotary Water Congress man is always looking for simple yet effective ways to be 'green'.

Growing food is one way.  He has a huge orange tree - special orange tree - in his front yard (must try) - and is now talking about terracing the front lawn from his door to the road and planting blueberry bushes all the way down the slope.

Back to the food growing.Not only does Rob think about growing food, he thinks about the topic in a sustainable manner.

Rob is into vertical green - you can see the green screen he planted in front of his west facing window (shades during summer and allows for sunlight penetration during winter).

So it was natural he thought about growing vegetables vertically in his front patio area.

Leave it to Rob to design a cost-effective replacement to $ 20.00 upside down topsy turvey tomato growing hanging basket

Using 2 liter plastic soda pop bottles he cut the bottom section off (bottom section becomes the top), installed a couple holes for the hanging rod, added soil, twine and plants and hung the vegetables along his porch roof.

Great job Rob! 

Check out the photos.

Rob's Hanging Planters

Urban Food Gardens - Rob's

Hanging Food Planter

Urban Permaculture the new paradigm in Urban Survival thought.

As always, comments and ideas should be shared.

Kevin

Green Roof Plants and Water - A Special Relationship

Click here for Masaru Emoto's clip of ice crystals forming while the U.S. National Anthem is being played.

To understand water is to understand the universe.

Water and green roofs have a special relationship.

Kevin

9 Best Food Plants, Foolproof and Easy to Grow in the Urban Core

Growing your own food is a path to independence and true freedom.

Urban Foodfare is the take control counterpart to Urban Warfare.

With Urban Foodfare your body is healed.

Urban Foodfare creates community.

Urban Foodfare offers freedom form bondage to those who would control what, when and how much you eat.

Today is the first blog of hopefully many.

The nine Urban Core Food plants to start with are:

1. Lemongrass
2. Rosemary
3. Garlic Chives
4. Banana Peppers
5. Greens
6. Mint
7. Broccoli
8. Eggplant
9. Okra (Quimbombo)

Look what I picked out of our backyard garden in the span of 5 minutes the other day!

Judy's Urban Permaculture

We will be talking about how to cost-effectively grow much of the food you need, teaching you about organic methods of raising your own - be it a small patio garden, an edible landscape or larger garden.

Looking forward to sharing the journey with you!

Email us with your questions.

Kevin

Green Roof Soil - Agave Root Structure, Acclimination and Plant Data for the Vegetated Roof

I ran across an interesting article in the American Journal of Botany entitled

Root deployment and shoot growth for two desert species in response to soil rockiness by Gretchen B. North, Edward G. Bobich and Park S. Nobel.

Now posted as a link on the Florida Green Roofs Blog for a while, the article confirmed interesting data we've been seeing with respect to root formation in coarse and shallow green roof soils.

Agaves and Yuccas are some of our standard green roof plants for use here in Florida.  There are two agave species native to Florida (and the Southeastern U.S.) - they are false sisal (Agave decipiens) and wild century plant (Agave neglecta).  Native Yuccas include:  Spanish bayonet (Yucca aloifolia), Adam's needle (Yucca filamentosa), and moundlily yucca (Yucca gloriosa), and curve-leaf yucca, Yucca recurvifolia.

Though the paper looks at Agave deserti and bunchgrass, Pleuraphis rigida, the concepts and conclusions are important.

Observations included:

1.  Water potential was higher in sandy soils than in rocky soils.

2. Agave deserti preferred rocky soils and was absent in pure sandy soils.

3. Root growth was greatest in sandy soils 

4. Agave deserti had twice the biomass and root surface area in sandy soils over rocky soils (example of environmentally induced acclimination)

5. Agave deserti leaf's water potential was the same at rocky and sandy sites but the transpiration rate was twice as high in rocky soils.

Conclusions and assumptions Green Roof Designers can use are:

Certain agaves (and yuccas) growing in well drained soils (rocky instead of sandy) exhibit acclimation characteristics of slowed growth rates and biomass production.  Slow growing plants on the green roof may be  more likely to survive long periods of drought.

Agave root architecture will develop slower and more shallow in rocky soils than in sandy soils.  Again, on an extensive green roof - one with relatively shallow soils - a plant with a shallow root system does better than a plant requiring a deep root system.  Agaves can acclimate to the coarse soils. Again, a shallow root system plant may be preferable over the deep rot system species.  A deep root species may have the tendency to assert agressive root barrier or roofing membrane attack.

Agaves do not want wet feet.  Where there is an over-abundance of moisture (very sandy soils) agaves may not be present.  Keep the green roof well drained.  This concept is in general disagreement with the school of thought that green roofs should serve as stormwater retention volumes or basins in conjunction with cisterns.  We've made the suggestion many times that due to Florida's water crisis, an irrigated green roof may not be considered sustainable - as one third to one half of the year it will end up irrigated with potable (during times of drought).  Within rainy season periods one will being irrigating the roof more frequently to empty the ever filling cistern - thus exposing the agaves, or any slow growing and green roof tolerant plant to 'wet feet' conditions.  Keep your green roof plants in conditions that do not generally comprise long term saturation.

Rocky soils may have a tendency to absorb and capture more dew than sandy soils.  This assumption/conclusion has many important implications for green roof plants water needs.  Because air can flow more easier through rocky soils, the dew has a tendency to penetrate to rockier soils.  Sandy soils may block moisture laden air.

I like to compare the ability of rocky or coarse soils to capture dew to the summer morning wet grass in your front yard.  There will always be more visible dew on the high surface area grass blades than say, on flat concrete.

There are many more serious considerations to be taken into account in the article.  Read and enjoy.

In the meantime, if you are interested in discussing agaves and yuccas in your green roof project, feel free to email me.

Happy green roofing!

Green Roof Design Guidance Summary

Good brief design guide for UK Green Roofs - click here.

Low Cost Green Roofs - Florida, Secrets to Building A More Beautiful, Cost Effective Extensive Green Roof

Keeping the cost down on any construction project today is critical, otherwise your system is likely to be 'value engineered' right out of the final build.

I can remember the days before green roof systems were common and prices were high (they are still expensive).

As someone who has much hand on type experience - in other words - has worked with many types of systems to optimize performance - fix design mistakes by others, I can assuredly share a true maxim:  Green Roof system designs tend to be overly complicated.  Each additional component or layer of material adds cost, sometimes significantly.

Once the green roof system is designed and specified, plants are then usually chosen to accommodate the type of trays, sacks or mats the plans call for.

Hopefully the landscape architect or green roofer in charge of the plant selection will have had some input into the type of green roofing system chosen.  This is important because different species possess varying degrees of planting requirements with an important one being root architecture.

Importantly, green roof plants should be purchased from a nursery with green roof plant species experience.

Many times this is not the case though, as the green roof plants will be grouped in with the other landscape plants and selected based on a minimum amount of specification data but primarily on price.  You get what you pay for.

Unfortunately, there are instances where root-bound plants, in 4" or gallon sized plastic pots will end up on the job site.  The plants may have insects, soils high in degradable organic content that will decrease in volume rapidly, fertilizer pellets scattered throughout the media.  They may be used to large volumes of irrigation water and sprayed with ecologically damaging pesticides (always ask about existence of pesticides on green roof plants).

Significantly, they probably cost approximately $ 3.00 - $ 4.00 U.S per plant.  On a typical 50,000 SF (15,150 meters squared) vegetated roof planted with a density of one plant per SF ( or 3.3 plants per meter squared) the cost would run approximately $ 200,000.00

If you want to have a cost-effective and beautiful alternative then consider growing your own green roof plants for your project, or contract growing the required specimens with a local nursery.

Make sure either you or your contract grower are licensed in Florida by the Department of Agriculture as a licensed nursery.

Be sure to use sterile soil,  soil that has been prepared and treated in an environmentally friendly manner.

Lay groundcloth down in a staging area - preferably a greenhouse, but if you don't have a green house then choose a portion of the site with similar climatic exposure conditions as the roof will have.

Use nursery potting flats - I like the 72 count and fill with your inorganic soil.  The flats should be new or washed if recycled. 

Purchase five pounds of Allium canadense seeds and sow according to instructions.  The Ion Exchange native wildflower site is just one of many you can find doing a quick Google search.

Soon you'll have 50,000 -70,000 plants that you can let grow and acclimate on-site.  Total cost, including labor should be less $ 5,000.00 - a savings of about $ 195,000.00.

The issue with this approach is it requires solid planning and coordination.


 Rather than specify the plants according to the green roof system, one must specify the green roof system according to the root architecture and planting requirements of the green roof species selected.

Happy Green Roofing!

Kevin

Green Roofs Clean Stormwater - Help Protect Florida's Springs

Florida has a thick layer of limestone bedrock throughout much of the state.  Over time water has eroded channels throughout the stone, creating areas where the cold, clear subsurface water flows up and out into rivers.

Exotic and pristine.  Water from hundreds and hundreds of feet below the surface roiling up out of the g round.

Blue Hole, Itchtucknee Springs, Florida

Under the pressure of nutrients and pollutants associated with growing populations, Florida's springs are directly affected by nitrogen and phosphorous found in fertilizer.  The water in many of Florida's springs are now becoming filled with algae thriving on the polluted stormwater that flows off roofs, yards and roads into the limestone aquifer.

As green roofs are one of the best first line defenses of Florida's groundwater, care should be given during design and maintenance not to introduce additional nitrogen and phosphorous from fertilizers into runoff.

In fact there are many good reasons to minimize or eliminate fertilization on green roofs, including cost of the ongoing fertilizer applications (labor and material), avoidance of potential pollution and more.  Herbaceous plants exposed to fertilizer may exhibit weaker acclimation characteristics.

Look for a blog post coming up soon discussing ways to eliminate fertilization from green roofs.  Some of the approaches we will be looking at will include; companion planting with trace element producing and /or nitrogen fixing plant species, native xeric species, designing with an understanding of NOx rainfall content (especially for the Urban Core), slow release v fast release fertilizers, organic v inorganic, etc...

Unfortunately, too often will a green roof landscaper or designer either schedule a heavy regime of fertilization or hoping to make stressed green roof plants look better, add a coating of nitrogen rich pellets.


Doing so shows a lack of green roof design and natural resource stewardship understanding.

Florida's springs are fragile and cannot process significant N and P loadings.  And green roofs are supposed to be an environmental positive - not a point source for pollution.

I'm looking forward to discussing alternative solutions to green roof fertilization and would appreciate your comments and experiences here.

Protect Florida's Springs - Install a Green Roof

For more information on Florida's unique springs and awesome state park system Google Florida's springs.

Happy Green Roofing!

Kevin

Green Roofs for Florida - Secrets of Cost Effective Green Roof Systems

Many Green Roof Systems have a reputation for being expensive but I am going to begin a series of blog posts on how you can achieve the most cost-effective green roof system possible.

That is for Florida and the Southeastern U.S.

MetroVerde is creating a new business paradigm based upon the areas of expertise we've felt most comfortable with - those of green roofing soils and green roof plants - for Florida.

We have worked with many systems in the past and want to take the opportunity to share our knowledge base of years of trial and error field work.

MetroVerde is not a roofing company - we have always worked with licensed roofers for the installs.

We are green roofing plant and soil experts.  Our educational background lies in botany and environmental law - especially natives and those plants meant for green roofs in Florida.

Rather than focus on green roof mechanical systems - there are lots and lots of good green roof systems - both mat based and tray based - and many more come on the market each month, we want to focus on those Green Roof components we understand best.

Honestly, with the right soil and right plants, most any green roof system will function successfully - if you follow some required fundamental principles.

In our opinion, the skeletal mat or tray based system is a component of the roof and an important one.  You certainly want a system that has been wind tested for tropical storm resistance.

Yet equally important are the soil material and the plants.

As we see green roofs planted, go through the blissful period of newly planted beauty, then experience acclimation issues - especially diseases, drought, wind and other issues - the variables that are the most unpredictable are plant centered.

Participating in a Green Roof charrette the other day, one of the lead mechanical members asked - 'What are we going to do if weeds pop up in the pretty plantings?'   In reality, it is when and not if.  Designing with the appropriate - preferably natives - is important - especially here in Florida.

So if you are interested in our reviews of the many types of systems we've worked with over the years and how to make these seemingly terribly expensive products much more cost-effective then you will want to stay tuned.  I'm going to share all I have - photos included.

My intended purpose is to make the Florida Green Roof Industry more successful.  Information is crucial.  Sharing experiences is all important.  I invite you to share your comments here also.  Check back tomorrow for the first of the upcoming blogs - what types of mats (and where can I buy them) make the best mat based green roof.

Happy Green Roofing!  Kevin 

Green Roofs Clean Stormwater in Florida - 3 Important Issues to Consider about Stormwater and Green Roofs.

ACF's 3 Reasons to Build a Green Roof

Sometimes we miss the forest for the trees.  I ran across this simple but true list of reasons Volumetric Green - Green Roofs and Living Walls - in the Urban Core is a correct approach for cleaning stormwater.

The purpose of a green roof is to provide the benefits of vegetation vertically.

Integrating plants into a roofing system, installed by a licensed roofer accomplishes what the above illustration suggests.

1.  Green Roofs manage stormwater at the source - how much closer to the source can you get?
2.  Green Roofs let plants do the work.  Plants and their root systems possess a combination of efficient processes that remove nitrogen and phosphorous and other nutrients or pollutants from stormwater.  Plants also sequester carbon and provide a steady supply of oxygen back into the atmosphere.  Instead of pumps and gears and filters and motors - keep it simple - use Green Roof Plants to clean stormwater.
3.  Green Roofs are simple and cost-effective.  Imagine a city full of green roofs and the degree to which that city's stormwater has been filtered and cleaned by those plants.  Now imaging the amount of revenue a city could save with reduction in stormwater utility costs and direct costs of clean water rather than polluted, algae filled runoff.

Now is the time for cities and municipalities to take the lead and follow those forward thinking governmental or regulatory entities like Port Orange, Florida - who realize adoption of volumetric green (Green Roofs and Living Walls) building incentives will lead to healthy and prosperous communities.

Atlantis Water Management Vision of a Green City

Happy Green Roofing!

Kevin

Extensive Green Roofs Florida - Best Plants for Green Roof and Finally - How to Avoid a Marilyn Monroe

Happy Labor Day!

Yesterday we talked about the genus Allium and how some allium plants had the capability of acclimating to the harsh conditions on a green roof.

Today I wanted to share a photo of an extraordinary, yet small, extensive green roof here in Jacksonville, Florida.

Florida Extensive Green Roof - Jacksonville

There are three important points here to note.

1. The engineered soil is only 1/2 inch thick on average yet the Allium sp. plants shown growing here are doing quite well.  Also note the roof is sloped and the runoff has not washed out or eroded the soil (because the plant roots have grown into soil and the system mat - holding the soil into place).

2. This is a non-irrigated, extensive green roof that has been growing with no maintenance now for three years.

3. The exposed edges of the mat and root barrier are a poor design.  Especially here in Florida where tropical storms and hurricanes bring winds of up to 120 mph or more, exposed edges are not acceptable.  Having said the above - the root barrier and mat have withstood a direct hit from the 2008 Tropical Storm Fay.  It is important from a design and building code perspective that a green roof have no exposed edges.

Look what wind can do to exposed edges!

Green roofs in Florida can be irrigated or non-irrigated!  They can be mat-based or tray based!  They can be thick and intensive or lightweight and extensive!

All you need is a good green roof team that has plenty of experience and understands solid green roof design.

Happy Green Roofing!~

Kevin - Email me with your questions, thoughts or comments here!

Best Green Roof Plant for Florida and Southeastern US - Green Roofs and Living Walls

Couple of posts back we spoke about how we are working with green roof plants to 'acclimate' each to the conditions they will experience on a green roof.

Today I am writing about a non-cactus or succulent type, but a herbaceous plant species that I will heartily recommend for any green roof in Florida or in environmental with similar ecoclimes.

Acclimation is an important word in the business of horticulture and arboriculture  Acclimation is generally defined horticulturally as the plant's ability to adapt to environmental conditions.  A plant that can adapt usually survives.  One without an acclimation ability may die under extreme conditions.

As mentioned previously, we've been working with greatly reduced irrigation schedules on some of the green roof plant species we use.   We've found some species that over time acclimate really well, while others do not.  Ultimately we took the test to the extreme to find the species that would survive the harshest of greenhouse-prep conditions.

Now realize that even the worst of greenhouse conditions only approximate what a Florida vegetated roof can experience.  Greenhouses for example are usually sheltered from hard, hot desiccating winds Florida vegetated roofs deal with.

And even though greenhouse temperatures may reach well into the 100  - 130 degrees F (50 - 55C), roofs can get hotter.

In the end we found that one species out-preformed all others, consistently.  Even reducing the watering down to no irrigation over a 90 day period - pretty amazing considering the plant is herbaceous and the soil availability for each seedling was 1" by 1" by 3" (25mm x 25mm x 77mm).

At the end of the testing period the soil was usually hard as a rock - brittle like.

After two years of acclimating the plant under minimal irrigation (less than 1/4" per month) - we planted the seedlings on one of our harshest trial roofs - and they thrived!

The species we are referring to are several within the Allium genus.  Most notably, Allium canadense, acclimated by slowing down metabolic processes - going into a state like hibernation during times of environmental stress.

Allium canadense can be found growing along many of Florida's highways - tolerating inundation and drought.


Here you will find photos of a Allium seedling over two years old taken in June 2010.  Following the seedling picture is a photo of the same plant three months later after being placed on a test green roof (non-irrigated - extensive).

Green Roof Plant - Florida Extensive - Acclimation 

Florida Green Roof Plant - MetroVerde - Allium - Extensive, Non-Irrigated

Allium's show great promise as Florida green roof plants.

There are many species to work with from within the Allium genus.

The use of A. Canadense may contribute to a successful green roof planting of native species that are evergreen, that flower, clean stormwater, create habitat and are beautiful.

You may email me with your questions here.

Happy Green Roofing!  Kevin

Florida Living Walls, Green Roofs - Urban Core Volumetric Green

Meg with Blue Leaf Landscape called me up a couple months ago and asked if we could do a living wall for the new Indochine  Thai Restaurant going in the historic brick building where Burrito Gallery is located.

She came up with an awesome design!  Click here to see the sketch on her website.

Using the 52 MM Atlantis product, RJ and I created a fully hydroponic based wall panel (actually two).

We installed them this week!

The same technology is used in green roofs and exterior walls to clean stormwater from roof drains!

Beauty.  Fresh O2.  Habitat.  Sense of Place.  Volumetric Green for the Urban Core!

(Bet the anoles set up shop!)

Green Roof Mats Florida - Choosing Your Green Roof System For Florida

There are many good green roof systems available on the market today.  Both tray systems and mat systems are widely popular.  Pre-filled soil bags for the roof and other green roof designs are also available.

With so many choices, how do you know what system will be best for your green roof project?

I am going to offer a few suggestions here.

Importantly, you should first talk with licensed knowledgeable professionals in your area.  Make sure you talk to roofers that have been doing business in your area and have a solid reputation.

Just as important, make sure you involve a local landscape architect for plant selection.

Ultimately your installation should be completed by those who have experience with green roofs.  This will involve a company or team that is knowledgable about both roofing systems and plants.

A roofer that doesn't know plants may put on a good roof system but your plants may die soon thereafter if he or she doesn't understand how to choose the appropriate plants.

A landscaper may have a solid understanding of what plants are more likely to survive the harsh roof conditions in your area, but may not be licensed to install those plants on a roof, or may damage the integrity of your roof during inappropriate installation.

A successful green roof requires a team of professionals.  A good green roofing team can help you select the type green roof system best suited for your geographic area, your cost and your project requirements.

The above photo, for instance shows a green roof mat being installed over white roofing TPO (thermoplastic olefin).  We will discuss TPO as a green roofing component in another blog entry.  Due to TPO's stability (TPO contains a significant amount of stable polypropylene - ppe) the material is used frequently in roofing (and may make for a good root barrier in some applications).

Mat-based green roof systems have different preferred applications than tray systems.  Both have their place in Green Roofing.

Here in Florida, plants tend to grow quickly due to the extended growing season (some year-round) and mild climate.  Mats tend to allow plant root systems to grow radially all they want to.  Mats also allow the plants to 'move' across the roof over time until they find just the right spot for the species' requirements.

Another advantage of the mat system is it's light weight profile and interlocking ability to allow roots to grow through the mat weave - holding plants in place during storms or on slopes.

Again, your green roof project should involve a number of team professionals - those who understand plants and those who understand roofing.

As always, email me with your green-roofing questions and I'll use your questions here on the blog to help share green roofing data and information!

Happy Green Roofing!

Kevin

Green Roofs, Tropical Storms, Green Roof Plants and Hurricanes

Its that time of year again.  There are three cyclones in the Atlantic and another wave forming.

If your roof has a parapet then you are lucky.  Most testing has shown parapets minimize wind damage to a green roof - though in a large hurricane, all bets are off.


Even if your green roof does not have a parapet it can still be designed to withstand significant tropical storm wind damage.

The video here is of a small green roof in Jacksonville, Florida on August 25th, 2008 when Tropical Storm Fay pummeled the northeast Florida area with over twenty inches of rain.  The video shows how the roof reacted to gusts up to 50 mph.  Wind speed was recorded using an ExTech anemometer.

The roof shown in the video does not have a parapet.  The video illustrates how the irregular surface of he vegetated roof interrupts wind generated uplift that can damage asphalt shingle roofs.  The plants range in height from two inches to six inches and can be seen moving back and forth in response to the wind.

Wind racing across a flat surface can create lift - or a vacuum - and literally lift the shingles or roll roofing up off the decking below.

The plant habit acts to break the shear flow of air, creating turbulence and working against damaging uplift.

Another important quality of a well designed green roof is the drainage factor.  The roof here is allowing a rapid drain of roughly 18" of rain over a 24 hour period without washing out.

Monolithic mats used as the basis of the planting system allow for quick drainage of the stormwater.

Moreover, the engineered soil, though primarily held to the mat by extensive root systems, is also considered erosion resistant due to an embedded natural, low VOC tackifier.

We will always deal with the 5 H's here in Florida - High Heat, High Humidity, Hard Frosts, Hurricanes and Hard Desiccating Winds, but with good green roof design your Florida Green Roof can withstand a severe storm, including tropical storms!

Email me with your Questions or Comments!

Port Orange, Florida Adopting Incentives for Green Roofs and Low Impact Development

Port Orange, Florida is considering adopting incentives for community gardens, green roofs and other low impact development approaches.  Be sure to read Grow Your Own Roof, Port Orange Approves Green Initiatives.

We applaud the vision this group has for their community future and support their efforts.

Happy Green Roofing,

Kevin