I've been sick with a bad cold all week, but I pried myself off the sofa this afternoon and took a walk down our wee woodland path. Our house is on a 2-acre lot, and most of our trees are north of the house, but there's a quarter-acre patch to the south that I plan to turn into a tiny woodsy circuit. It's all visible from our big south windows, so it will be enjoyable from both outdoors and in.

The entry point from our front yard:

That post is our personal weather station, provided by Efficiency Vermont to collect data for their study of our house's performance. The white bags to the left contain topsoil that was cleared from our site for construction and will soon be turned into raised garden beds (more on that below).

Heading deeper into the woods:

Our whole neighborhood is overrun with wild raspberries (red and black), but it's hard to pick most of them because of the prickly brambles. I've cleared this pathway hoping to access them better, and I'll also plant more spring bulbs to enjoy before the brambles start to grow. So far I've planted a smattering of daffodils, hyacinth, and squill, but I hope to load the woods with all sorts of shade-friendly bulbs.

Turn to the left and you can see the road:

Walk down the slope and turn left again to face the house:

I still haven't decided where to carve out the rest of the path, so the only way out is back the way I came:

The lot next door is not likely to be developed—our uphill neighbor bought it for extra privacy—so we don't foresee any invasive construction in that direction:

And now the front yard. The dirt is rock-hard after two years of being driven on by construction vehicles. But later this month our excavation contractor will come and terrace it into a large fenced garden. He'll build three retaining walls made from boulders, put down a layer of sand for drainage, and then cover it all with topsoil.

This year I'll concentrate on growing vegetables, but I'm sure I'll sneak some ornamentals onto the property as well. There's a spot near our driveway, north of the garage, that would look delightful with some flowering trees if I can find any that don't require full sun:

You can see the edge of the deck outside the front door—it's a lovely spot in the afternoon once the sun goes past the top of the house.

So that's the "Before" series, which I hope will be replaced over the years with heaps of charming "After" pictures. It's probably a good thing I don't realize how much work all of this will be!

One of the few things I miss about living in Arizona is my wee postage stamp of a garden. I had two raised beds, several fruit trees, and some lovely rose bushes. Like most Tucsonans we didn't try to maintain a lawn, instead covering most of the ground with gravel, and we watered the plants as little as possible using a drip irrigation system.

I miss my roses most of all. I was initially surprised to learn you could grow roses in the desert since I always associated them with northern climes, but then I recalled that roses have thorns, and any plant that can hurt you will probably grow brilliantly in the desert. And they did, year-round! In fact, I'm not sure I'll ever grow roses again, since I'll never grow anything nicer than this fragrant beauty from 2009 (note scale):

My tomatoes were not as uniformly successful as my roses. Arizona's growing season is enviably long (the last frost is mid-March), but tomatoes won't set fruit once the temperatures get too high, starting in June. They'll start fruiting again in September or so, assuming they didn't die from some other cause over the brutal summer. My best crop came from growing very small native tomatoes, but they grew so relentlessly that I was praying for frost by Christmastime, since my plants had sprung their banks and overtaken the entire back yard.

May 2008 (note the blooming ocotillo trellis):

December 2008 (yikes!):

(Frost came a few weeks later, and overnight the entire jungle withered and my garden's balance was restored.)

You can probably understand why gardening for only six months a year in Vermont seemed a little weak after my year-round Tucson shenanigans. My initial plan was to build a greenhouse, but I quickly realized I didn't want to heat a greenhouse. So we created a nice little garden space right inside the house, with huge south- and east-facing windows.

I was curious to try hydroponic gardening, and after some exploratory Googling I built a simple deep-water culture system.

Speaking of Googling, I suspect I'm now on a DEA watchlist, because nearly all the online information about hydroponic gardening is about growing your own pot. My browser history is riddled with sites like rollitup.org, 420magazine.com, and growherbsindoor.info, which really have a lot of helpful information (even for chard-growing squares like me). There's a lot of winking in the hydro world ("Here's what you'll need for your... tomatoes"), and mail-order sites cater to their customers' need for discretion:

Here's what I bought, mostly from our local hydro dealer (cash only) and pet store. I divided the list into one-time setup items and repeat-purchase maintenance items:

Setup items (one-time purchase)

• 2 x 10-gallon plastic totes (opaque, roughly 7.5" high)
• 2 x Fusion Quiet Power 500 air pumps
• 25' of silicone aquarium air tubing
• 4 x 12-inch air stones
• 10-liter bag of hydroton pebbles
• 22 x plastic net pots. I used 3" pots but 2" pots would have worked just as well.

Consumable items (repeat purchases)

• Rapid Rooter starter plugs
• pH testing and adjustment kit
• Botanicare Pure Blend Pro vegetative nutrients. We bought a gallon but could have got away with a quart—it'll take me a few years to get through the gallon.
• Seeds!

When you set up your system, you'll need a power drill with a hole saw the same size as your net pots (3" in our case) to drill the circles through the tote lid. Don't try to cut the circles with a utility knife; many have tried and lived to regret it, or so I hear.

Our system has a total of 22 plant bays, and underestimating the efficacy of store-bought seeds I started 50 seeds in the rapid-rooter plugs. This was unnecessary, since all of the seeds sprouted and I ended up discarding half of them.

The seedlings in their hydroponic bays:

I hadn't added the hydroton pebbles yet—our neighborhood hydro vendor said we could omit them, but our plants were rather wobbly inside the too-large 3" net pots, and I was concerned about sunlight streaming into the tub and causing algae to grow. This is why it's important to get opaque tubs rather than clear.

We planted:

• Two varieties of baby bok choi
• Arugula
• Tom Thumb lettuce
• Garden Babies butterhead lettuce
• Rouge d'Hiver lettuce
• Red chard

And within 4-6 weeks we had this:

The arugula and Rouge d'Hiver lettuce turned out to be a poor choice, since you need a lot of plants to get a salad's worth of lettuce. The head lettuce varieties were better suited to our system, and after harvest I planted some more, along with some oak leaf lettuce.

We've now eaten everything from the first round except for the chard, which I am slowly harvesting for banana-chard smoothies, which taste a lot better than they sound:

Energy use

As a passivhaus dweller who has not given up on achieving net-zero energy use, I was concerned about how much electricity my indoor garden would require. The answer: very little. The two aquarium pumps draw a combined 5 watts, and my abundance of natural light means I don't need supplemental lighting at all. If I were trying to grow fruiting plants like tomatoes, I'd need a 96-watt T5 fluorescent fixture as a bare minumum, and possibly quite a bit more, even with my huge south-facing window.

I may try growing tomatoes indoors this fall, but I'll likely abandon the effort if it needs more than 100W several hours a day. I tried starting tomato seeds in dirt but managed to kill them by overwatering. Next time I'll stick to hydro!

Maintenance

Unlike tomatoes (and "tomatoes"), hydroponic greens require very little work and maintenance. Every few days I check and adjust the pH levels (a slightly acidic reservoir of pH 5.5-6.5 is ideal for nutrient uptake). I might add some water as well, but we haven't had a major problem with evaporation, and my hydroponic system hasn't affected the indoor humidity level. The biggest chore is to change the water every couple of weeks. I opted not to plumb the garden area for water, since it's not near the bathrooms or kitchen and I didn't want to introduce a risk of leakage anywhere else in the house. So I made a little cart out of a furniture dolly and an extra shelf and push the tubs to the hall bathroom:

Then I remove the lid and rest it on some 2x4 scraps:

This is a good opportunity to check out the size and density of your roots (such photos are known in the hydro world as "root porn"):

(BTW, this is pretty tame as root porn goes, because most of those plants are new—only the two chard plants are mature.)

First I remove the airstones and dump the water out of the reservoir, and then I give it a hearty rinse with the shower sprayer to clear away any algae or slime. I haven't had any reservoir issues yet, so I haven't bothered with soap or hydrogen peroxide. Then I rinse off the roots as well.

Here's a look at the airstones. The idea is to introduce lots of oxygen bubbles into the reservoir, which the roots need. One of the best things for me about hydroponics (versus soil container gardening) is that you can't overwater the plants, and you can leave town for a few days or even a week without having to maintain the system. A long absence isn't ideal for pH management, but it probably wouldn't kill the plants in a system like mine.

I could probably get away with a single airstone for each tub, but the gang at rollitup.org and every other hydro site says the more bubbles the better. Speaking of bubbles, the pumps are audible but not annoying. We started with a really cheap pump, but it was decidedly louder than the Fusion Quiet Power and maybe only $10 cheaper. I meditate in the next room, and the pump noise is not an issue.

Summer hiatus

Sadly I will have to suspend my hydroponic adventures in the next month or so—the solar angle will be too high and I probably won't get enough sunlight. I'll have to content myself with outdoor gardening, which frankly scares me. Growing 22 little plants in a weed-free environment (in more ways than one!) is so much simpler than going outside and turning our ~1,800 square feet of tire-compacted front yard into the garden of my dreams, which you can count on me to post about in, say, 20 years.

We got about 10 inches of snow today — the view from our windows is enchanting!

Ted posted last year about the challenge of choosing a dryer for a passive house. Here is the solution we came up with:

It works fine, adds some welcome humidity, and of course saves electricity. If heat pump dryers ever reach these shores we may consider getting one, but this works great for now.

In case you're wondering, the space with the checkered floor is the garden area, which I plan to populate very soon!

We've been living in the house for a little more than four months now, but it seems like much longer than that (in a good way). The long ordeal of planning and construction has faded from our memories, and we're simply enjoying living here.

In most respects the house is performing extremely well. The 12,000 BTU heat pump is having no trouble keeping the entire house comfortable. Outdoor temperatures haven't fallen much below 20°F yet (-7°C), so it hasn't really been challenged, but we're not too worried. We left town for a few days last week and turned the heat pump down to 60° (it's normally set to 68), and it never even ran while we were away. The indoor temps ranged from 62-66°, even though outdoor temps stayed below freezing.

Our one complaint this winter is that the house has been extremely dry (relative humidity ranging between 20-25%), with our heat recovery ventilator running on low, at 62 CFM. This isn't too surprising, since Ted and I are only two people living in a fairly voluminous house without pets. We don't have any houseplants yet either, but I plan to remedy this soon by setting up our indoor vegetable garden upstairs (that will be a whole other post, hopefully in the near future).

For now our solution is to run a humidifier. (I know, so pedestrian!) The main problem is that the humidifier is quite loud, drowning out our whisper-quiet heat pump and HRV. Our long-term fix will be to add plants and see how that affects things, and then maybe get an ERV core for the ventilation system. It's pretty easy to swap cores, apparently, and the ERV will transfer moisture from the outgoing stale air to the incoming fresh air. Naturally, our many geeky onlookers (including Peter Schneider of Efficiency Vermont, who installed all the monitoring equipment) will be curious to see what difference the ERV makes for comfort and energy use.

You may have noticed that this post is called "Winter in a Passive House," and not "Winter in an Almost Passive House." This is because we built a full-fledged, certifiable passive house (pending the actual certification, which we haven't gotten around to yet). We made the decision ages ago, but I never changed the name of the site because I didn't want to jinx things. I'm not so worried now, since we did insanely well on our blower door test (91CFM, which translates to 0.29ACH50). I therefore feel pretty confident about our final PHPP numbers, even if we messed up a thermal bridge calculation or two.

I haven't decided what we should rename the site, so for now I'll just strike out the "Almost" and see where the spirit moves me.

Speaking of winter, here are some lovely new snowy pix!

Peter has been asking us about doing the final installation of the monitoring system for our house, so that he can get some data out of it (finally!). In order to make that happen, we needed to finish the electrical work, and that's been a bit of an obstacle because of various lighting needs and also because our electrical subcontractor, Andy Harkness, has been in high demand recently. But we managed to lure him and one of his electricians, Karl, up to the house over the past two days to finish up the electrical work.

Imagine my excitement when Andy called me down to say "Ted, can we combine any of these circuits? The panel's full!" It turns out that we are able to keep all the circuits separate, at the cost of having _zero_ free space in the panel. If we need to add even one more circuit, we'll have to add a secondary panel.

Why so many circuits? Peter wants to be able to measure the power consumption patterns of individual devices and rooms. Along with the per-room temperature sensing and an outside weather station, this will give him (and us!) a really good idea of how the house is actually performing.

The snarl of wires coming out of the wall here are the wires to individual temperature sensors in each room, all of which terminate in the utility closet. There's also network wiring, of course—that's the other, smaller snarl of wires.

This is the control/status monitoring panel for the solar hot water. We may collect some data off of this as well.

This is a flow meter that will detect the flow rate of the hot water. We also want a flow meter for the glycol, but had some trouble sourcing one that would be reliable—Peter originally sent us a flow meter that's mostly made of plastic, and Gary, our solar subcontractor, took one look at it and refused to install it. When I called Peter about it, he told me that there had actually been some problems with the device in the field (nothing serious—one leaked a tiny bit, and another failed after a year). So we aren't installing this particular device—Peter's researching other options.

Oh, the reason for the weird bend in the pipe that comes into and out of the hot water flow meter is that we need a certain length of pipe after a bend or a valve before the flow meter, or the turbulence caused by the water flowing around the bend or through the valve will affect the measurements.

This is the flow meter for the well. We're not actually measuring this—it's just used by the sewer department for billing. But it's a meter, so I included it... :)

A gratuitous picture of fall foliage..

The spiral stairs, from above...