Category Archives: Green roof systems

Green Roof article

Kim Grové of House and Leisure did a piece on green roofs for their online magazine, a Q & A with me that simplifies what a green roof system is, and how simple it is to do for yourself.  Well simple if you’re dedicated and have the will.  But still, very doable.

Here’s the article, very cool!  Thank you Kim.


Green Roofs H+L



Some of the photographs in the article were by Tom Gray of some of his designs and installations.  Tom’s company, Good Hope Gardens Landscaping (affiliated with Good Hope Gardens Nursery) installs green roofs and landscapes with indigenous plants specific to each area and thus supports the creation and maintenance of ecosystems.  Tom knows what he’s doing, and he does it well.  Good Hope’s blog here  .



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Oh my, harvest!

I harvested finally, finally, I think the whole neighbourhood exhaled when that happened.  130 days it took!  One-hundred-and-thirty, normally it takes about 68 to 110 days depending on the conditions (this is for Beta vulgaris ‘Crimson Globe’, a quicker variety) but due to various factors mine took longer.  Oh, much longer.  I could speculate that this is due to it being the height of winter and even though winter was mild we did have very cold nights.  Also the soil depth and the type of substrate must have impacted on the growth rate, and very possibly wind exposure could have stunted them too.  They turned out alright though, considering?  Deeper soil, summertime, no pressures of a research deadline… next time it’ll be in and out!

First Beet

I could have harvested a lot sooner but I needed to line up all the necessary statistical methodology for the research, as well as methodology for sampling and analysing the samples for the lab.

An interesting point about them is that they didn’t really develop a taproot but rather the roots developed adventitiously, I speculate it could be from the loose, humid, nutrient-rich substrate and the fact that the soil was at an average of 75mm depth.

Adventitious Root System

What did happen though was that the roots developed along an axis and not centrally, and one has to think about the whole process of vegetable production:  post-production, cleaning, storage etc.  It would be interesting to see how the root waste of beets such as these compare to conventionally grown beets.  The total waste off this harvest was 572g out of a total yield of 11kg.

Root Development

The point is that it works, growing vegetables in an extensive green roof system has its advantages.  Most definitely Round 2 will see deeper substrate (I was governed by student budget) and not monoculture.

The bulk of the stock went to Lola’s Restaurant on Long Street to be turned into deliciousness such as borscht, juices, salad with award-winning gorgonzola, and the leaves will be utilised too, most likely for crisps (either in the oven or in shallow oil in the pan).

I have the rest of the leaves which I will dice and freeze and will go into caramelised onion, feta and beetroot leaf quiche and quiche and quiche (easy to freeze)!

Et voila!


Filed under Green roof systems, Horticulture, Recipe, Urban agriculture

Beta beets to beat

Beat beets

The beets, the beets!

So, we are in week 13 of Beets-on-a-Green-Roof and they are mostly quite sizeable.  Remember I am working with soil depths of about 5cm to 20cm, this beet sits at about 8cm soil depth but is breaching, most likely as it hits the surface of the roof.

Beta vulgaris in 8cm depth

Still, going to watch and wait, see what happens.  This is not the biggest, just the only one that’s bolted up.  Keep in mind it is winter in the Cape, averaging at around 7°C min temp since they were sown so it’s very slow growing.  If this was solely about leaf production I would be cooking in results!

Beet leaves and mushrooms and mustardseed and garlic

Speaking of leaf production, like I said, beet leaves are much like chard and spinach (since 2003 they have all been classified in the same family Amaranthaceae, although it is still disputed and the subfamily Chenopodioideae is also accepted), high in vitamins and nutrients and they last a long time post-harvest as long as you keep them cool and dry.  Tossed with a little bit of olive oil and garlic they are delicious, and this way they keep their colour.


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Not too late to thin!

Not too late at all, the beets were divided 7 days ago and they are strong and healthy and growing.  Granted the sun has been out in full force and I removed the limp outer leaves and at the moment there is 100% success!

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Too late to thin???

I don’t think so.  Although I didn’t give myself a chance to take NO for an answer.  I thinned the beets out when they were perhaps a bit too old.  Ok, definitely, they were definitely too old.

Beetroot seed is known as cluster seed, meaning they contain around 3 seeds per cluster.  This means that all three generally germinate, hence the need for thinning to get that beetroot shape we’ve all become accustomed to.  This is an example of a germinate cluster seed, you can see three roots pushing out.

Germinated Cluster Seed

Leaving them too late means they’ve established themselves and the roots are nicely developed.  So I literally had to cut them out, leave the strongest and space them accordingly.

I have unfortunately not had uniform success before thinning.  There was much die-back but now I have successfully filled the space.  LOTS of beetroot left over:

The Leftovers

That’s literally half a sink-full (2 shopping bags full).  What’s great about beetroot leaves is that they can be used much the same as spinach or as salad greens.  High in Vit A and Vit C, fibre, protein, iron and calcium.  They go down great with a bit of olive oil, salt and pepper, in the pan or out.

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Where are all the green roofs in Cape Town?

Well, there’s one on the Civic Centre, also on the New Life Sciences Building at the University of the Western Cape, an oldie but goodie on the Cape Peninsula University of Technology (beautiful masses of Gazania’s) and various domestic homes around Cape Town.  There are many roof gardens, which aren’t quite the same (think more along the lines of contained gardening, which defeats the purpose really, no?).  So there is a NEED.  And believe me when I tell you it is SO easy, so so so easy.  One MUST ensure the roof is structurally sound to support the weight of saturated substrate and the various plants to be introduced.  This is done by a structural engineer, unless you know for a fact that it will hold.  My roof is tin and not at all built with purpose of green roofing but I figure that it will only be up until October and so far, in the wet of winter, it’s holding up.  The concern is more about oxidation, about pitting in the metal as no matter how waterproofed it is, condensation is a surety.  I have since learnt that this is not the case and there are many succesful tin green roof systems.  I am in the process of getting more information about that and will report back.

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Green Roof!

September 2011.  Deadline.  Deadline.  Handing in of research project entitled “Urban Agriculture in a green roof system”.  By Zayaan Khan.  No word from supervisor or lecturer, no support, no yay, no nay, no maybe.  No guidance, no word, no response to e-mails, to phone calls, to going-via-other-lecturers.  Pressure.  So what to do?  Can’t wait around, plants don’t listen to deadlines, nope.  So.  Just.  GO!

so much measuring, and re-measuring and working out quantities, calling suppliers, explaining the situation, expressing quantities and ideas.  surprisingly a lot of suppliers didn’t think it would work, this plan, this study.  Especially the Roofing Expert.  I can’t wait though, I can’t really change my plans and now I’m finding I really want this to work.

The more research I do the more people I am put into contact around the world who have made this work.  It’s doable!

Constant fretting though, the anxiety and stress… and all on a student budget!

And then the weekend I decide to install is the same weekend that my friend Serisha Letchmiah decides she needs to submit an entry for the DFA’s My Town 2011 Competition.  So we filmed the Saturday: setting up, laying soil and compost and on the Sunday, the planting.  Sunday night was editing and Monday morning submitting.

The documentary was shortlisted and was screened at the Awards Ceremony this past Saturday at the Encounters Film Festival.  Serisha, seriously, WELL DONE, you DID it, I am proud to have been a part of it!

I decided to run rows of beetroot because it is a crop that may still be grown in winter and because of their quick sow-to-harvest time ( roughly 12 to 12 weeks in the winter) as opposed to something obvious and leafy, like chicory or lettuce.  If beetroot work in soil space of approximately 20cm depth then surely I have proved the hypothesis?

Much nail-biting with regard to waiting for the beets to push through, which they DID, about 15 days after sowing.  Keep in mind we’re entering Winter here in the fair Cape, chilly nights, lots of wet, wet days.  So I suppose it was fine that I didn’t soak them before sowing.

Breaching Beets

As it stands, tomorrow I will thin them out, I’ve lost about half of them due to various factors (sneaky neighbours cat getting in and using the roof as a private litterbox), some damping-off, some just deciding not to make it.  There are more than enough for me to use to thin out.

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