Mary and Tess collected moss for me, and Mary and Natalia dug up some lovely ferns, to add to our rockery. (I should call it a rock yard, there is so much of it!)

These generous gifts coincided with the arrival of the West Coast Seeds catalogue.

Among all the enticing seeds (and crazy cotton socks made from t-shirt manufacturing leftovers!) there are a couple of items in the catalogue (Moss Milkshake and 1 kg of three different mosses) that I have finally attempted myself.

Regular readers will remember the recipe I passed on (throw a handful of moss into a blender with 1 cup of yogurt or  buttermilk,

and paint it onto your shady rocks to generate lush moss growth.)

Yesterday, I made this recipe. Will update its success in a while, if the dog doesn’t lick it all off before the spores get busy and reproduce!

Meanwhile, in the garden, we’re still harvesting some herbs,  lettuce, carrots, beets, adorable Little Tokyo turnips (the latest seeds I planted), Swiss Chard and spinach (albeit very tiny quantities of the latter two.)

In my studio, I have resurrected my interest in natural dyeing, which began (and ended, actually) during university. Late in the fall, I harvested marigold flowers, artichoke leaves, and onion skins before the frost put most of the garden to sleep. I planted a sumac bush in the layer of the garden that will soon be devoted to dye plants.

The first plant, a Sumac, in the dye garden

I have begun the search for seeds, but many common flowers and leaves lend their dyes to cotton. This is what gardeners do on the shortest day of the year – plan their gardens.

And, the last outdoor note for now: the songbirds (if there are any hanging around still) have been offered a treat: little wreaths, stockings and stars made of birdseed mix especially-formulated for songbirds. I read about this kind of bird treat/decoration on a website/blog called Everyday Eden.

Christina and John are the creative team behind this blog and their excellent book of the same name, published earlier this year. Christina Symons has major talent in the area of styling, writing and photography, and does freelance work.  John Gillespie is a landscape designer, horticulturalist, arborist and green roof technician. They live and work here on the Sunshine Coast.

So, it may be the “dead” of winter here, but there’s lots of growing going on at “This Green House.” (And, it’s not just around the waistline.)

Our first summer in the garden, and it proved its worth: each broccoli and carrot is worth about $100, if the cost to install the structure and soil is taken into account! But, hey, that’s not what it’s about. It’s about a connection to the earth, about feeling good about self-sufficiency, about knowing what you’re putting into your body, right?

The rooftop site is windy, but gets 12 daily hours of sunlight all summer. The hot-weather crops like peppers, beans, cucumber and tomatoes were partly successful, but I will protect them from the wind better next year, and move them to a different location. Powdery mildew attacked the brassicas and cucumber, even though we water with drip irrigation.

Pests were few. The worst one was our dog, Kitty, who liked to dig in the fresh compost early in the season, and has lately taken to feasting on our peas, trampling over the beets in the process. We have to remember to close the gates. The cabbage moth found the brassicas, but they were mature by that time, so not much damage. The root barrier mat did its job for several plants. A small infestation of black aphids found the beans. There are plenty of ladybugs and bees around this year. Not a single slug or deer was observed in the garden.

I was able to grow oddball crops like artichoke and kohlrabi. I am a huge fan of Sea Soil, a new variety of which is now available nearby. I will top-dress with it next year.

As an idealistic new-ish gardener (haven’t had much of a garden at any of our homes yet, although we keep trying), I have kept a good journal.

As I headed out to pick blueberries in Delta yesterday, I fortuitously passed the West Coast Seeds (organic) retail outlet. Screeched to a halt, and stocked up on fall seeds (little Tokyo Cross turnips, spinach and lettuce) and cover plants (fall rye and hairy vetch), Serenade for the powdery mildew,  and edamame (soy) seeds, for next year’s garden (couldn’t find them this year.)

We have been feasting on fresh harvest every day, and keeping the house filled with fresh cut flowers.

I declare the garden a success.

The roof garden needs pathways between the beds. Spilled dirt has been host to weeds, right through the heavy-duty weed barrier! And, although the roof was designed to take the weight of a 14″ deep soil bed, I  choose to keep the weight down, making 2″concrete pavers unreasonable.

I had seen recycled tire pavers in the Rona store, but they were expensive (How can that be? Old tires are free) and then they disappeared from the stores.  I searched online, to find that the US manufacturers of the product were even more expensive – $23 per 24″ paver, not including shipping!

Then, lo and behold, our local building store, Gibsons Building Supply, brought in a small supply of them at a more reasonable price. I bought 52 of them, in two colours, and fit them around the garden boxes. Unfortunately, they are manufactured in China!! There goes the green benefit.

Some months ago, we picked up 94 lineal feet of wrought iron fencing (Craigslist – Langley). It was heavy, but the Toyota was up to it. With helpful strong men (and one woman) we moved it to the house, then to the sand-blaster, then to the studio roof, then to the grassy knoll by the garden. You’re getting a picture that this stuff is being shoved around, with some effort and expense. Finally, this week, the rusty-again wrought iron has been extricated from the weeds, and pressed into its second life as our garden fence. Here’s the “Before” photo:

A careful plan was drafted to use the fence to its maximum. I designed, ordered, and painted, and D installed 14 post brackets and posts alongside the garden’s perimeter box.

Kim, the welder, adjusted the posts for plumb with plastic shims and set screws in the brackets. Then, he cut and welded the sections according to my plan. That took him about 12 hours. This is all the railing that was left over:

I treated the rust with Rustmort (above), let it do its chemical thing for 24 hours, then rinsed the fence panels. (1.5 litres of Rustmort.)

Next, a rather painstaking primer application.

By trial-and-error, I learned a few techniques. Regular nap rollers do not bend around the twists and curlicues. I found that the cheap foam roller got around the curves much better, but lasted about 2 minutes:

I have read that a tube sock over a rubber glove is a good way to paint wrought iron. But…messy.

Then, because the stores were closed by this time, I found a piece of (free) foam in my art supplies. I scrunched it up, dipped it into the primer and it worked great. It held lots of paint and got into those small spaces.

Then, a thick coat of paint with a water-based rust paint. Because the paint was thinner than the primer the foam roller and an ordinary brush worked better.

It took me a whole week of 12-hour days to paint the wrought iron, and I am soooo tired of painting. (Quantities used: 2.5 litres primer and 3 litres paint.)

Kim and Dave lifted the sections into place, and hung them on a clamped-on bracket to tack then weld the sections to the posts, taking great care not to step on the plants.

This photo shows the majority of the railing installed.

The pole beans and sunflowers will be very happy to have a fence to finally climb/grow against:

I know we should have installed the fence BEFORE planting the garden, but time happened to be marching on.

And, by the way, would you like to see one of our cauliflowers?

We have already harvested 2 broccoli, all our spinach and most of the lettuce, swiss chard, and given away those plus cilantro and parsley. I’m loving the organic pest-free garden (the pests haven’t discovered it yet.)

Update July 22: The cabbageworm found the brassicas after all! I deleafed them and crushed the larvae, as well as harvesting most of the broccoli, cauliflower and cabbage. The threat seems abated.

Also today, Kim the welder finished installing the railing.

According to D, this is a banner day at This Green House. It’s coloured blue. Let me explain:

Many years ago, the wooden seats at the beautiful Nat Bailey stadium near Queen Elizabeth Park in Vancouver were being replaced. D got his hands on a pair.

In our family, we make one Christmas gift for the person we drew the name of last Christmas. One year, I drew D’s name, and decided to sand down and re-finish his stadium seats for his gift.

Today, we unveiled these seats, after a few years’ worth of storage, and planted them on the rooftop garden, under the arbor. Don’t they look inviting?

Hoping for another hot summer for the garden and valuing my time, I planned and ordered a drip irrigation system from Northern Garden Supply in Smithers, British Columbia. Their web site has instructional videos and case studies that are very helpful.

Drip irrigation can save at least 50% of your water, because it waters where it’s needed, and because it’s shaded by the plants so evaporation is minimal.

You’re supposed to install the system before planting, but I just finished installing it yesterday. It was reasonably easy to do. Required strength and very hot water to get the pipe into the compression fittings, and required patience to straighten the pipe, which just wanted to curl, even in the hot sun.

Our goal is to use the collected rainwater for the garden. The plumbers and I are having some difficulties getting that working. I have finally cleaned up the collected water in the cistern (It was collecting dark-coloured water draining from the roof garden, with its rich black compost soil, creating an unattractive water flow in the waterfall and a rich medium for unattractive algae bloom. We’ve diverted the rooftop drain so it doesn’t flow into the cistern.)

How to create the required 25 lbs pressure for the drip irrigation faucet to work? The plumber cut into the big 2″ pipe that recycles the pumped water to the waterfall, but it wouldn’t pump up to the garden faucet.

So a stop-cock was installed, which would require turning off the waterfall while watering the garden (not an ideal solution.) Surprisingly, even that was not enough pressure to create a low-pressure flow through the garden hose.

Now, I’m thinking that we’ll have to pump the water out of the biofalls filter bottom, setting its own pump up on our timer.

The Biofalls filter is quite deep. A pump could be installed below the filter pads.

I will talk to the plumber again, and update this post when we finally have a solution.

My family and my other two blog followers are always badgering me (yes, badgering me, I tell you) to keep the posts coming. We’re well-occupied working on the house still, but this blog is called “This Green House”. To stay true to the theme of the blog, I feel it’s best to only post when I have something green to report.

Algae is green. There’s too much of it in our pond, especially the notorious string algae.

When Endless Rain installed our rainwater collection system, we got a water feature built to take advantage of the many benefits of flowing water, not least of which is for flushing toilets and watering the garden.

We ran the pump for our lovely waterfall June to December, until the plumbers came to do some toilet-flushing work and the electrician to install an outdoor plug for it. They left the pump off during the freezing weather, and the pipe to the pump burst. The water feature was turned off for 5 months, during which the 6″ deep top pond stayed full of water.

The plumbers came a couple of weeks ago, and hooked up the pump. After only a week of running waterfall, it became obvious we had an algae problem. Green slimy algae covered the rocks and obscured the pond bottom. Why did the algae bloom so fervently in one week, when there didn’t seem to be a problem for the first 6 months of the pond’s existence?

When Allan installed the system, he told me that pond plants would help keep the pond clean. In addition, because the water would be continuously flowing, there shouldn’t be an algae problem. After a bit of research, this is what I think has happened:

As it turns out, the water is only flowing on the surface of the pond. Below the surface, the water can be quite still. (Had I known then what I know now, I would not have had them build a pond at all, just a series of plateaux for the water to run over.) Shortly after the system was completed, I did buy a few water plants, and they flourished, particularly the water hyacinth, which was planted in the filter basin (to control its growth – It can take over like a bad weed.)

Biofalls Filter with dormant water plants

Over the winter all the plants died back, but water and organic material still collected in the pond. And, horror-of-horrors, the new garden, with its rich composted soil, was draining its dark, nutrient-rich water into the storage tank. So when the system was turned on again, the plants couldn’t do their job of using /filtering the nutrients that collected.  The goop fed the algae very nicely. It was happy. I was not.

I spent several hours today cleaning it out. We diverted the garden drainage so that it didn’t enter the system. I drained the pond into the “wild” with my neat new Lee Valley siphon pump. Then I took out as many rocks/gravel as I could, setting them out in the sun to bake away the algae.

Sun baking the algae-covered gravel

I scrubbed all the boulders, rocks and gravel with a brush (and cloth in the tight spots), spraying them down with a water hose. There was still lots of sludge, so I pain-stakingly used my masonry sponge to sop up the dirt and wring it into a bucket.

Cleaned (top), sludge (bottom)

Basin cleaned: just clean sand and a bit of gravel left to dry

The pond is drying out thoroughly before I put the gravel back and plant more water plants. I will also use a product called EcoBlast, which purports to add beneficial nutrients and enzymes and remove pond debris. I hope this does the trick, or it will be a running battle for the life of the water feature.

We’ll see if it returns to its former beauty. Will report.

Update, July 14: I was so optimistic when I wrote this post, but in fact, the algae came back and I had to do the whole cleaning routine again.This time, I used the shop vac (wet and dry vac) to vacuum up the gungy water.

I purchase more pond plants, mostly iris and water hyacinth.

And, I don’t know if this has helped, but I read that algae, like most plants, don’t like copper. I could throw a bunch of pennies into the pond, but I decided to try wrapping copper wire around a flat stone at the top of the waterfall, right after the biofalls filter.

The danger is I could kill all the beneficial plants with it, too.

Whatever the reason, the water feature is behaving itself. It’s been running for about 5 weeks, through sunny and cloudy weather, and the water looks clear.

What a relief!

Progress is being made. Here’s the April 9 view:

It doesn’t look like much work has gone into it, but it took me several hours.We haven’t had a veggie garden for about 4 years, so are quite excited about the potential.

The twigs you see are pea brush – used instead of sticks and strings to support the peas.

We are not growing organic, although many of our seeds are organic, and the Sea Soil is certified organic. We’ve mixed in non-certified garden mix, with composted steer manure and sand.

The Sea Soil is also a fertilizer, mostly from the fish, but also the forest fines. And I plan to use only organic/natural pesticide/herbicides. In the photo, you can see the planting mats around the brassicas and root crops, to protect against root maggots and cutworms.

I have been saving eggshells should any slugs find their way up to the roof.

We’re companion-planting as much as possible, while keeping in mind the climate needs of the early crops.

Lettuce, spinach, brassicas and peas are cold tolerant, so they have been planted first (brassicas and onions are purchased seedlings.) The spinach and lettuce will be shaded when the sweet-pea vines grow up against the posts.

Old tires are used for potatoes, which have few garden “friends”.  When the green growth shows, I will add another tire and some more soil, so the tubers grow all the way up to the surface of the fourth tire. Tomatoes, pole beans and strawberries seem to have few garden friends, so will be carefully-located when it’s warm enough to plant them.

Rain is forecast for the next week or so, and I think it’s good to keep the seeds moist enough to germinate. The irrigation system is not set up yet. The soil drains well, so I’m not worried about the seeds rotting.

I threw  some wildflower seeds along the bank outside the main window. They gave me such joy last summer when I did the same.

April 29 view:

It’s been a cold spring (3 weeks late), but the plants have survived the windy, rainy weather. We’ve built an arbor and the 2-foot-wide perimeter beds.

A successive sowing of  lettuce, spinach, carrot and beet seeds  should spread out the harvest somewhat.

All the seedlings have emerged, except for the leeks. Sturdy peas here.

Our biggest pest so far has been the dog, Kitty. She loves digging in the soil (steer manure?) and licking up compost tea.

The herb box has been started.

In order to control bully plants such as chives and mint, they have been planted in chimney pots set on the bottom of the bed.

The drip irrigation parts have arrived, and we’re just waiting for the plumber to hook us up to the rainwater storage cistern, so we can install the pipe (requires 25 gpm pressure.)

I am trying to grow marigolds indoors, so put some commercial garden mix into a tray, and covered it with a plastic bag.

Only one seedling has emerged, but a couple dozen of these sweet lacy one-centimeter-in-diameter mushrooms (?) popped up one night. I should have used a sterile potting mix or coir substrate.

This is a new post about our veg/flower/herb garden, even though there is some repetition from the last post about the structure required to support the garden. We are building the garden on top of the studio roof for two main reasons: It is designed to be accessible by walker or wheelchair from the main living floor of our house (just thinking ahead.) And, the deer need to be discouraged from chomping on every new tender plant in sight. With the railing built all around the perimeter, I don’t think deer will venture onto the roof. If they do, we can install an electrical fence or use this disgusting stuff called PlantSkydd, which definitely discourages them (and me!)

Our garden boxes are made from rough cedar 2×8, 2 boards high. Although the soil depth is only 12″, we decided on a 16″ height, because it would allow the gardener to perch on the side while tending the garden. It may also protect the young seedlings from the heavy winds we get in our coastal location and help prevent spillage.

The cedar is milled about 500 meters away, as the crow flies. (And the crow DOES  fly!) (Most gardening books discourage the use of treated wood or preservatives for vegetable gardens.) The boards are screwed together at the corners, and a galvanized corner bracket screwed into each lower corner. Then, a length of 2×2 cedar screwed into each corner keeps the two layers of boards together.

Because the garden centre professionals did this, we lined the boxes with another layer of root barrier cloth, in the hopes that keeping the soil out of direct contact with the cedar will discourage pests and the attendant decay. The ubiquitous sowbug, for example, doesn’t seem to be put off by the ‘toxic’ cedar. We hope it will also preserve the first layer of root barrier cloth, helping to prevent holes from gardening implements.

Then, with our freshly-arrived garden crew (D, Tess and Kaan), we unloaded the bulk soil from the poor old Toyota truck. We are using approximately 1/2 Sea Soil mixed with 1/2 garden and lawn mix from our local garden centre. It’s made of compost, sand, and topsoil and is purported to be weed-free because of how hot it is inside the pile (steam rises off the pile as it’s loaded into the pick-up.)

Perlite, a lightweight white inert lava product, and coir, a peat substitute made from coconut husks are added in smaller amounts. (Wikipedia: “Large-scale peat harvesting is not sustainable as it takes thousands of years to form the peat “bricks” that are harvested in just a week.”) (We used 4 cubic feet of Perlite and six cubic feet of coir for 63 total cubic feet of soil.) Sea soil has the reputation of clumping in dry hard clods, so the perlite and the coil will break up the clumps while retaining moisture in dry conditions.

The coir starts out as a dense cube 12″x12″x5″, and quintuples in size with the addition of water. It breaks up the soil clumps and holds water.

Here, Tess mixes in the wheelbarrow. The next iteration of mixing occurred on top of the piece of plywood laid over the cedar boxes. Spills from our enthusiastic activity then fell into the boxes or on the plastic spread beneath.

We were able to fill most of the garden in a rainy afternoon. Now to decide on what to plant where.

Stay tuned!

(Warning: This is a long, detailed report of the requirements for a rooftop garden and the report of our process. I am well aware that blog posts should be short/concise, but this is not an “E-How” version. I am posting this for people who may wish to design such a garden themselves and need all the detail I wish we had had when we began.)

When our engineer and I were doing research about building a rooftop vegetable/flower garden on the studio building, we found little information. Wikipedia makes an applicable  distinction between a green roof and a rooftop garden:

“Roof garden vs. green roof

A roof garden is actually very different from a green roof, although the two terms are often and incorrectly used interchangeably. A roof garden is an area that is generally used for recreation, entertaining, and as an additional outdoor living space for the building’s residents. It may include planters, plants, dining and lounging furniture, outdoor structures such as pergolas and sheds, and automated irrigation and lighting systems. A roof garden reestablishes the relationship between humans and nature that can be lost in urban environments.

It is different from a green roof in that the considerations are primarily of an aesthetic or recreational nature, whereas a green roof is usually constructed to cover a large area in the most economical and efficient means possible with an emphasis towards improving the insulation or improving the overall energy efficiency of cooling and heating costs within a building.

The panels that comprise a green roof are generally no more than a few inches up to a foot in depth, since weight is an important factor when covering an entire roof surface. The plants that go into a green roof are usually sedum or other shallow-rooted plants that will tolerate the hot, dry, windy conditions that prevail on most rooftop gardens. With a green roof, “the plants layer can shield off as much as 87% of solar radiation while a bare roof receives 100% direct exposure”.

The planters on a roof garden, on the other hand, can generally range anywhere from 6 in up to 3 ft (0.15 to 0.9 m) in depth, depending on the weight-bearing capacity of the roof, and would be placed more for aesthetic purposes. These planters can hold a range of ornamental plants, anything from trees, shrubs, vines, or an assortment of flowers. Since the planters on a roof garden are placed in random fashion, it would be much less likely to provide the environmental and energy benefits of a green roof.”

I went to the Light House Sustainable Building Centre, but there was little help there. They did have some models of green roofs from BCIT’s Centre for Architectural Ecology, but the models didn’t include a full garden on top of a building nor was there an indication of supporting substructure. Communication with the BC Landscape and Nursery Association (BCLNA) revealed a list of landscapers who have qualified to design green roofs. I ordered their publication, “BC Standards for Green Roofs.” The information therein did not address the design of the building to support a rooftop garden. From a qualified BCLNA rooftop landscaper, I learned:

“The best way to proceed with designing your studio is to first determine the live weight of your roof. This is determined by your requirements for soil or growing medium on the roof. If you plan on growing vegetables and shrub then you will need at least 12 inches of soil but 18 would be better. The weight depends on the type of soil used, the rule of thumb is for a light weight growing medium (not soil) is 60 pounds per cubic foot.”

Torsten, an engineering friend of our son, helpfully replied to our enquiry:

“Green roofs consisting of membrane, protection layer, gravel drainage layer, filter fabric, and soil, have been in use over parking garages and underground structures for decades.  Green roofs are not new, despite the fact that they have only become mainstream in the last few years…  they have been around for centuries, and consisted in a multitude of different configurations, including simple wood and dirt.  The real issue these days is with durability and insurance requirements.  The design criteria being implemented are intended to make the systems more durable and rugged, to avoid short term failures and costly insurance claims. The main concerns from insurance firms are leakage and fire.   Leakage can be attributed to premature failure of the membrane due to low quality materials, poor workmanship, insufficient protection from foot traffic (during installation) sharp components and root penetration, or tears due to excessive deck movement.  Fire can result when plants or grasses become dry and brittle during a drought.  You should confirm what requirements need to be met with your insurance provider, or you may run into problems down the road.

A typical torch on membrane is acceptable, but considered low quality and may only provide 15-20 years of expected service life in a properly designed system.  Obviously you would have to use a self-adhered or mechanically fastened base sheet to encapsulate all flammable/wood elements prior to torching on a cap sheet.  Thicker more durable torch on membranes are available from many of the manufacturers.  A high quality green roof membrane may be worth the material cost increase (eg. Siplast Teranap).  The concern with a wood deck would be load capacity and movement.  Wood decks will move significantly more than concrete decks, and put more stress on membranes at plywood joints and perimeter interfaces. Consideration should be given to using a high density moisture resistant cover board over the plywood deck.

Gravel is an excellent drainage layer, but is quite heavy and therefore not often used on green roofs, especially on wood structures.  Same goes for soil…  average topsoil is quite heavy…   modern assemblies use drainage mats and specially formulated growing media to reduce loads on the structure.  If you are planning to use gravel and soil, make sure your structural engineer is on board.  The membrane should be protected from damage by the gravel above, and from root penetration.  Some root barriers could likely do both.  The gravel would have to be wrapped in filter fabric, to prevent contamination from the soil.  Consideration should be given to irrigation systems or similar, as gravel will have poor water retention capability.”

Our engineer could figure out the weight loads, and so, together with what I had learned, he designed the roof with these layers (in order of construction):

1. Into the concrete walls is bolted an 8×12 laminated beam to support the weight in the centre (see photo in point 3.) then a double 2×12 joist, 16″-on-centre construction. 22′ x 24′ is the size of the roof.

2. 3/4″ tongue-and-groove plywood for the roof deck

3. Inside, 15″ batts of R20 insulation covered with vapour barrier. That doesn’t sound like much, but the soil above has some insulating quality as well. Besides, as the building inspector has noted, it’s not a residence, only a studio, so it doesn’t matter so much.

4. Back outside, there are two layers of torch-on roofing. One drain hole at the lower corner of the roof deck collects water to send it to our rainwater collection cistern. (Later edit: we discovered that such nutrient-rich drainwater created a huge algae problem in our waterfall and shallow pond, plus it was too muddy for flushing toilets. We have diverted the rooftop drain to a rain barrel for watering the plants only.)

5. A layer of heavy-duty landscape pond liner, skillfully finished with flashing by the roofer so that there are no perforations in the waterproof layer.

The roofer used an S-finish method of joining the flashing so that he didn’t  have to screw through the fascia boards. Additional insurance by way of silicon caulking.

The flashing corners are custom-made to shed water.

6. 3″ of round 3/4″ grade gravel for a drainage layer. (Round so that sharp edges don’t perforate the waterproof layer.)

7. Heavy-duty landscape root barrier cloth over the gravel.

8. Our garden boxes and pathways.

Around the perimeter of the garden are placed lengths of cedar 2×12. This box will be bolted to the outside of the fascia board with custom-welded steel brackets at the corners. We have found used wrought iron fencing to make the railing on top of the 2×12, which will bring the rooftop railing up to BC Building Code height of 42″.