Green Roof Fundamentals: Building an Epic Rooftop Garden 🏠🌱

Hey everyone, Kev from Epic Gardening here. I'm here in Barcelona, Spain with Lidia and Gina and they have a green roof company and the company, I can't pronounce it. So what is the company called? The company is called Eichberg, which means green path. So it's called Green Path, which is what we're about to walk down this nice green path. And this is their test garden. So they're testing vegetables, edibles, ornamentals, all sorts of different types of things to see what works best on a green roof. So right now I'm going to take you behind the camera and we're going to walk through and they're going to talk about all the different things that they're doing so that maybe if you have a green roof at your house, you can try some of these techniques. So let's go ahead and get into it. All right, we are here now at the first edible raised bed. And so what are you guys working on in this section? Here in this section, we have a tall raised bed with a soil that is based on coconut fibers, which supposedly absorbs a lot of water and doesn't weigh a lot because that's one of the requirements in the garden. Very lightweight. And it's not turning out to be that great, even though we were using last year a cover crop here. Here we planted fava beans and peas last year and we use it to attract the nitrogen into the bed. These beds are using ecological agriculture, as you see here we have rosemary and we have a sage over there and carnations. Those are the carnations we don't eat, but you can eat if you want, but they're here to attract flora and fauna to our little bed. We're trying to represent here a real ground garden, but here the conditions are different. We have more sun, more wind. We don't have pollination. Everything is more extreme on a rooftop. Here this year we have onions, we have cabbages and broccoli. Broccoli, some carrots and cabbage. Radishes. Oh yeah. And there are also garlics. Oh, there's garlic. Yeah. And then you've got these very large sage. Three year old sage. Look at how it's coming up in all these different spires like that. It's very cool. And so you're mixing in the herbs and the, uh, the herbs are, obviously you can eat the rosemary, but also the rosemary will put out flowers like crazy, which then the pollinators come, the bees and everything. And many times a year, no? So it's not only one fruit, one flower. It's like many times a year. Which helps if you've got something down here, maybe a cucumber or maybe a tomato that you need a pollination for. Yeah. Cool. We find it to be a challenge the pollination system because for instance with the pumpkins, not always they just get pollinated. Yeah. We have to do it ourselves. Yeah. Yeah. It makes sense. You have to hand pollinate. So then as we go here, sort of the same thing, but more, more lettuces, right? Yeah. Here, this bed is similar to that one, but it has less soil. It has like about 30 centimeters instead of 45. Oh, so this is, yeah. So this one is two planks tall and that one is three planks tall. And that's partially because you're testing how heavy. How heavy it is. I mean, in a green roof construction, you're going to just put all the soil that you want. It depends on the resistance of the building. And we wanted to see which is the loss in productivity when you have only two planks, meaning 30 centimeters of soil. In our test, we've seen that the leafy greens, like we have here lettuce and the broccoli over there and the onions, they all develop the same way. Between 30 and 45 centimeters of soil. However, when we go into tomatoes, the tomatoes in the bigger raised bed, they're like three times more productive than here. So any deep rooted plant, it does better in the 45 centimeter bed and then any of these shallow rooted lettuce or, or onions, it doesn't matter. It's the same either way because their roots only go maybe this far. If you have a building that only takes, that can only take this amount of soil, you are not jeopardizing that much your garden. You can still have a big harvest of leafy greens. Not so much of tomatoes. You can change it to cherry tomatoes perhaps. Because the tomatoes here, they're rich above me. Like they're like two meters tall. Or maybe you could grow determinate tomatoes versus indeterminate, right? So like a shorter dwarf variety. The cherry ones were really, really productive. Okay. In either type, in either height? Yeah. Yeah. Okay. And here we also have the daisies. We have daisies and rosemary and astrogems over there. And this is, this is for the pollination as well. Right. Yeah. So it's a nice mixed type of bed. And the parsley that has overgrown here. Yeah. Look at this parsley, everyone. It's, it is for sure the biggest parsley I've ever seen. Just, it's like four feet long this way. It's a challenge when we combine different species in a raised bed, as opposed as in a regular ground, because the nutrients in this bed are shared among these people over here. It's not like the parsley can go over there or enjoy the nutrients from over there. It's stuck. We need to, yeah, we need, right now the parsley is too big compared to the rest. Yeah. So those are things that we're also trying to learn, no? Perhaps. We need to cut back the parsley. Yeah. Harvest it more often. Not put the parsley next to the leafy greens. Maybe put the parsley somewhere else. So those are things that we learn. Makes sense. Cool. And so now we move to I guess the third of the edible garden beds, which is kind of, this is sort of a hybrid, right? Cause you have some grasses here. This is biodiversity. This is the biodiversity bed. And usually in spring we just put up the seeds. We just let them go. Yeah. And, and let's see what's, what's going on. At the beginning it's what, it was like, this is what piece. I don't remember. This is biodiversity one. What we're trying to get at is places. Remember that this is a green roof and here's a test site, right? But we may have green roofs and so here we're trying to see like, um, uh, this is a, this is a bed where we put seeds, but we wanted to see like how they plant and they grow on their own. Yeah. Like, like no help from you. No help, no maintenance, no nothing. So maybe this could work for a green roof company or a green roof building that maybe they don't want to take as much care. Right. Right. Right. Makes sense. We're going to see later some other decorative plants like sedum and stuff, but this would be an alternative to that. We can have kind of like a wild prairie in the green roof where you, we don't need to interact with it too much. It's not trying to be like a horticultural bed. It's more trying to be like a decorative bed. Decorative bed that still provides... That attracts biodiversity to it. And takes the temperature of the roof down, right? There still does the benefits of a green roof. Right. It accumulates water runoff and it cools down the building. It attracts, uh, pollinators, pollinators and insects. And it also, it also helps the membrane, the waterproof membrane to be, um, it lasts longer, I suppose. Oh, you mean the protection on the roof below. Yeah. The protection of the roof lasts longer when you have a green roof on top because the membrane is not subject to the... Cause the, so the bed is taking most of the water. It's not being abused by the membrane. Not only the water, but also the temperature. Oh, true. That expands and contracts. That's what breaks the membranes. Okay. Now we are at the last of the two edible beds here. So this first bed, you can see we have, uh, fava beans. And so why do we have the fava beans in this particular bed? Based on legumes. In this case, it's a fava bean. And we're doing this like before reproducing and the roots are going to stay, uh, in the soil. And that's going to bring... Makes sense. So it's similar guys to this other video I did in, um, New York. We're doing the same thing, but in milk crates. And he would, uh, plant, maybe not fava beans. I think he planted, uh, shorter legume crops and he would do the same thing. Chop them, lay them down. And then, cause he only had, each milk crate was one cubic foot. And so not a lot of space. And so he had to make sure he put organic matter back into the soil. Yeah. Okay. And so then, um, behind us we have, uh... So these two raised beds, as opposed to the other one, are not based on coconut fiber, but they're, uh, they're more, the soil is most readily available locally. Yeah. And it's cheaper too. It's not as sophisticated, but it turns out that, um, with the years, this one has more capacity to grow. Oh, the soil has to grow over the years. Yeah. You have to work it and you have to add and you have to put organic matter and such. Yeah. So this one has more capacity to build and to grow than the other one. The other one. Oh, interesting. It's kind of losing its initial bump. So the coconut core started out better. Yeah. And now it has gone down. Correct. Versus what's in this one? This one is just, it has, it's regular, um, it's regular soil. Just like a local potting, sort of raised bed mix. Yeah. And it has volcanic pumice to help with the, uh, to the drainage. Okay. The first year that we put it here, all the plants disappeared because it didn't drain enough. This is another problem that you have to consider in a green roof. The drainage of the water has to be provided. If the water stalls, the plants are going to rot. They drown. Yeah. So how do you deal in a green roof then? It's like, if this was on the ground in a raised bed, it wouldn't be so bad because the drainage could run off into the street or something like that. But how do you do it here? Does it just... Here we did a one third mix of pumice. On the bottom layer? No, in the whole. Oh, in the whole mix. Yeah. So they cannot compact. And they also have to have little spaces where the water accumulates. Like the pumice is a great place where the water accumulates. Got it. Here we have this year artichokes and oregano. These artichokes belong from the last year. We keep it, we keep the, the... Oh, do you just cut them back? And then, yeah, they come back. Yeah. Yeah. These look really healthy. Oregano and stevia. Stevia. And let's see if it's, if it's going in the wintertime. And also the strawberries that in the, in the last, we just put two years ago, two seasons ago, the strawberries and this, the last summer inside of a cucumber plant, it goes all this. Oh wow. So two years ago, they put the strawberries right here. Just two. Just two plants. And then, you know, guys, the strawberries make runners and they propagate downwards. And so boom, boom, boom. All these strawberries just propagated from the initial two plants right here over the course of maybe 18 months or two years. Yeah. Something like that. Yes. Yeah. So automatic strawberries for you. And they are producing. Yeah. In the wintertime we have many. They're producing. We're in the dead of winter in Barcelona right now and we're still getting free strawberries. Yeah. Yeah. And also we have this mint that we have to control it because of the roots that. Yeah. Cause they always say don't plant mint in the same bed as anything else. We just put a pot inside. Oh, did you? Yeah. To contain the roots. Oh, look at that. Okay. It's not, it grows everywhere and it's not worth it for us because we have less space than, you know, than in land now. Yeah. No, that's creative. Cause usually I would always say, or it's always recommended never plant mint in the same container. But if you put it in its own pot, then put it in, you, you skip the problem. Yes. All right, everyone. So now we're in, you can see behind them the ornamental section or the ornamental section of the test beds. And this is really interesting because over here we have a lot of sort of things you're used to seeing on the channel, which is organic gardening, permaculture style practices applied to a raised bed. Over here we haven't done a lot of on the channel, which is really exciting. So what are you guys testing in the ornamental section? Well, uh, here we have what's called a, uh, uh, ecological green roof. An ecological green roof. It's a green roof that requires very few, very little water and very, uh, short depths of soil. Uh, it doesn't weigh that much. Uh, but the plants have to be, um, low maintenance too. So the king, the queen of the plants that are low maintenance are sedum. Sedum. So when we have to put them in a group, um, over here we have a mix. As you can see different types of plants. Yeah. And this is part of the nine test beds, uh, that we planted about three years ago. And, uh, we had, um, in collaboration with two universities, we were doing, uh, we put, um, uh, sensors, temperature sensors in the test beds to verify the efficiency, the energy efficiency for the building. Because the green roofs, one of the biggest, um, benefits is it reduces the, the cooling and the heating cost of the building. Yep. Cause they're absorbing most of the heat here. Right. It's a heat sink for, for, for the roof. Yeah. And also, uh, all these green roofs, they have a layer under, it's called a drainage layer. That the drainage layer also has water. So the same water under the 10 centimeters of soil, it's also an insulator. So it gets less hot, but it also gets less cold. That's correct. Yeah. So the, the thermal sensor that we had here underneath is show that in the peak of the summer, there could be 40 degrees difference between sensor not under the green roof versus a sensor under the green roof. You say 40? 40. 40 degrees. Yeah. Celsius. Yes. Wow. That's a lot. That's a lot. That's a huge difference. What do we see over the year? We see over the year that the temperature sensor under a green roof, it moves between, I want to say Celsius, between 16 and 22 degrees Celsius. In the winter, it only goes down to 16 and in summer it only goes up to 22, maybe 25. So the fluctuation is not that big. Yeah. Here without the green roof, the peak goes up all the way up and all the way down. We can have the temperature outside up to 50 C in summer and below zero in the winter. But under the green roof, it stays constant. So in a perfect world, you could have the whole roof being a very thin, cause look how guys, this is a very thin, maybe six inches or less of soil here compared to all these, which is maybe 24, 18, 24 inches or maybe 30 inches over there. Way less and probably even cheaper, lower maintenance plants that provide a massive insulative effect on the roof. So in a perfect world, you could have many roofs covered with this and then electricity costs would go down. Like drastically. Yeah. And it also protects your waterproof membrane, as I was saying yesterday, in Germany where they've been doing this for 40 years. Those that were set 40 years ago, the waterproofing membrane is still intact. And normally you have to do that every 15? Every 10 to 15 years. So almost twice as long improvement on some of the upgrades to the building. Yeah. Wow. Wow. So here you see a test bed of two by two meters, but in a real building this green roof would just be from wall to wall. So it will just be an extensive... It would be the whole roof. Except for the places you want to have a pavement or like a walkway or something, it would just be the whole rooftop. Cool. And so then we'll go down this way and see some of the other tests. So this is one version. This is one version. And as you can see down here, there's many different crops they're testing. You can see the lavender right here as a potential ornamental or also an herbal test, but then also some other types of sedum over here, as well as other types of soil medium, right? We're trying different manufacturer layers. So we're not providers of any specific brand. We just test here, everything that is available in the market. And we recommend to our customers what's the best. So there are different test beds with different depths of soil. Here is just the three or four inches, three or four inches. And then we also have a little bigger over there, which is twice as much. Again, it depends on the building. If you have a building with low capacity for load, you're going to put this one with a lower soil. If you have a building that can take the double, you're going to put over there that bench. Because with more height equals more possibility of plants. The low growing plants can still grow in the tall, but the tall sometimes cannot grow in the low. You can add aromatics and you can add more flowers and you can add bushy plants. Over here, in addition to the sedum, we're trying... Lipia. This is Lipia nodiflora. And this is two kinds of thyme. And this is thyme serpillium. And this is thyme ciliatus. And so you're trying to see which variety of thyme is going to perform the best here? Yeah. And also we are trying to realize which kind of plants they grow with less soil, no? Okay. Sure. And so then if we move down here, there's still sedum here, but a different type of a medium. Sedum that it came in a carpet, kind of like the... Like a sod. Yeah. It came already made. Versus the first one that we just planted different species. Okay. So this is more densely compact because it came this way. It's been like this for three years. Yeah. Cause this is almost like a green carpet. The sedum, what they have is that you can walk on them. I mean you can set a table on or you can just play soccer because you can walk eventually, but not a high traffic area. That's what we also try in different plants. Oh, so maybe you could have an entire green roof and the pathway would be more hardy plants that you could just walk on instead of having to carve out a separate pathway. That's correct. Okay. Over here we have the same sedum, but again, we said in between, under, we have layers of different manufacturers and different substrates, soils. Over there and over here you can see four different types of plants repeated in the both test beds by one test bed is based on more sand and coarse sand. And in the other one, it's a, it doesn't have that much sand. It has a little bit of volcanic pumice too. We're trying to find providers that are more locally available because when we have to do a rooftop, many tons of substrate soil are involved. So if they come from closer, that's better. Yeah. Reduces environmental costs. Yeah. Costs to the client, costs to you and also costs to the earth. Yeah, that's correct. So I don't know if you want to see this substrate. Yeah, this, this would be cool to see. Yeah. So this is a very sandy mixture. Yeah. The green roof soils have to keep its structure and they have to enable drainage and they have to have little spaces where the water can accumulate. With the pumice. Yeah. It holds in its pores, a lot of water, right? That's correct. Yeah. And then this final one here, this is I think so interesting is this is a sort of like a lumpy grass. Yes. It's called poesia. It's not a lawn per se. Yeah. There are many people that still ask for grass type of green roofs, even though they are not the most sustainable because they require a lot of water. Yeah. And depths of soil that are big. But this one is kind of a compromise. It's a kind of a Gramenia that doesn't need to be mown or anything and it's like a standalone. So it still has a look of grass, uh, but way less maintenance and way less environmental input required to have it grow. And it also feels really nice. It's a cool, very cool grass. And then you can mix in, you can see some of the other additions that they've added here to spice up the look of it a little bit. But it's a very cool look. Even if you have, let's say maybe four of these in a row, like one, two, three, four, with some pathways, very like cool, broken up look of the pathways. Yeah. Yeah. Um, as you see here, the sand is complete. When we're in a rooftop that is above a building, a lot of insulation. So plants need to have a lot of ability for the sand and we also choose plants that require less water. But there are also roofs that are in between buildings that don't get that much sun. So that's why we're investigating some species over there that are not sunny. Shade loving plants. Right. Okay. So we're at the final section here and as you can see, that's where we just came from the ornamental side. There's a big wall right here and this is shaded out, would you say half of the day maybe? Yeah, it's partial sun. And so if you've ever been to Barcelona or anywhere with very thin alleyways, many of the roofs are shaded by other roofs. And so there's, there's no real ability for a full sun plant to thrive. And so you guys are testing some different types of varieties here. Yeah. We have the serum that we are really surprised about this serum because it's working really good. And this would be the same stuff we just saw. And it's actually, if you look guys, it is doing extremely well. And the other side there are more red because with the, with the fresh air and with the cold, the serum usually turns red. That's why we, we see it here more greeny. Yeah. And then the other side has more red. So it's responding to that, that sun environment. Yeah. Also we have like vinca minor. The vinca has this purple flowers. Yeah. Yeah. And it works in shadow. And we are, we are like testing that it grows with less soil. Yeah. And also we are trying lipia, nodiflora, as in the total sun. Yeah. Yeah. I know it's interesting because vinca, at least in my area, can sometimes be invasive. But if you grow it on a green roof, sometimes the invasive plants are invasive because they're resilient. Right. And so on a green roof, it would make sense to grow something like that because it's not going to spread because it's isolated from the, the, the nature. Yeah. Yeah. And also we are trying, uh, plants that they, that they keep going or they are more, yeah, they have more resistant to the drought. To the drought. So as we can see, the ficus repens is not working in that. So this one, because in the summer we had some problems with some water problems. Uh-huh. So we already see that ficus repens is not working for us. And then you said, okay, well, what plants will last if it doesn't get watered for maybe a week? Yeah. And the ficus did not survive the test. All right guys, that is it. The wind is crazy here. Sorry if it's been hard to hear, but I wanted to say thanks to Lydia and Gina for showing me the space. And then we wanted to talk a little bit about some of the benefits of a green roof in general, because I know we, we jumped right into the tour. We talked about maybe some of the temperature and the insulation, but there's other reasons why green roofs are important. Maybe as a home gardener, if you want to grow vegetables, something like that would be fantastic. But also environmentally speaking in the city, there's a lot of reasons why a green roof would be good. So what are, what are some of those things? Well, we already talked about the thermal insulation. We talked about improving the biodiversity and we also talked about the water runoff from the rain. Instead of going down to the sewage, it stays here. But also there are things like pollution, like the plants absorb the pollution of the city. Like imagine this whole city of Barcelona, if all the roofs had, pollution sinks, you can call it. Yeah. Yeah. Pollution sinks. I mean, the pollution will be obviously reduced. Yeah. Yeah. Another benefit is that there are also studies that say that the people that work the land, the soil and the garden, it has like a therapeutic benefit for them. And the World Health Organization also calls for nine square meters per person for the green area next to them. So because Barcelona doesn't have nine square meters per person, I mean green roofs also add to that. Yeah. And what's crazy to me guys is Barcelona compared to where I'm at in San Diego has many more open spaces and squares and even parks. And even still not nine square meters of green space per person in the city. And so like just imagine if you're working at a company job, you go into the roof to have lunch and instead of, you know, going maybe to a McDonald's or wherever you go down on the floor, you come upstairs, you maybe grab some herbs to put on the salad that you brought from your house. And it's just a different way of living, which is more in tune with nature. Cities are always going to exist, of course. And we're always going to live in big cities. We love big cities. This is an amazing city, but it would be even more personally, and I think you agree, if you could come and maybe live more blended instead of just so separate from nature. It's a city, but let's bring the nature back into the city as much as we can. And so it's cool to see the different ways that they're doing it with the edibles here, which you know, you guys are probably all about, you know I'm all about, but also the ornamental benefits of maybe some of the sedum or those lower lying plants that are very low energy. But then reduce the energy that a building needs to use by very drastic amounts. I didn't know the temperature swings were cut down by that much. So anyways, the company is called Green Path. I got it right this time. In Spanish you say it? Es verde. It's in Catalan. Oh, I was going to say because it would be verde something, right? I was like, there's no way that's better. Something verde. Yeah. Okay. So all their links and stuff will be in the description below if you want to contact them. Or if you're in Barcelona, I'm sure that they would love to give you a tour. So thanks guys. I appreciate it. Really thank you. It's been really nice to meet you. Yeah. So until next time guys, good luck in the garden. Keep growing. I'll see you in the next one. Bye. Adios.