Thanks to Grace at DBG and PlantSelect.
If you know anyone new to this, which is basically essential in rock gardening and dry/native plantings, please pass this on to them.
If you aren't a believe, try it. I dare you.
New Plant Exploration with Kenton J. Seth, Colorado, USA
Thanks to Grace at DBG and PlantSelect.
If you know anyone new to this, which is basically essential in rock gardening and dry/native plantings, please pass this on to them.
If you aren't a believe, try it. I dare you.
Back in 2013 I started working for myself, and started hiring employees, with a nearly religious mission to make landscapes that use natives and need no water. ...And that get better with age and do ecologically good things, et cetera. Over the years, my landscaper era waxed and waned as I felt drawn to address crevice gardens and work away from my semi desert valley. But the mission remained.
After years of this, I of course find myself answering many of the same questions for people dealing with the same issues. I'd like to think I've gotten better with a decade now of practice in helping folks decide what they're going to do with a patch of earth. With a full ten-year scope, I've also reflected on the vast difference of then and now.
When I started I had little experience and native landscapes were a hard sell, a very hard sell, and I underbid in desperation for work. I ate a lot of beans and rice. Luckily I had a few great mentors like Bob, and his integral book back then. Now, I have to turn down work and I can barely keep up with the demand for it and am ever re-balancing what sector needs help the most to spread myself out most effectively.
Another thing that has changed is that I'm not alone.
Early on, and I think still to this day, the finest book on no-water gardening is French. FRENCH! Olivier Filippi's books still have not been surpassed, and isn't that embarrassing in some way to us proud Americans? But in recent years I've found friends like Jo Wakelin in New Zealand (her garden above) and John Murgel of CSU's Douglas County Extension Office. He gave a mic-dropping talk to WildOnes a while ago that isn't available, but this parallel one is still up. Treat yourself to it- a real foundation of ground-breaking principles- over lunch.
It feels like things are coming to a head.
Emboldened with the experience of writing The Crevice Garden, I'm writing one on Irrigation-free landscaping and gardening. With the momentum of an even longer experience than my crevice work, and aiming to address the biggest issues dry gardeners face, with the working title of:
"No Water, More Flowers: Gardening and Landscaping with little to no irrigation."
I think there are isn't an elephant in the room about dry gardening, but a whole herd of them: What can you really expect without irrigation? When is it just inappropriate not to water? Isn't that religiously dogmatic? How the heck can you possibly get what you need when you deprive yourself of such a tool? Where does this fit into ecologcal gardening? Aren't we just gonna desalinate the oceans and solve water shortages? What about fire? What plants can actually go without? Why do all these alleged xeric plants suck so bad at staying alive in drought when they were sold as "drought tolerant?" (I'm looking at you, Redbirds in a tree, Agastache, and Kniphofia!)
Well, I don't think I will be the last word on it but I want to start a conversation. Now I'm going to put my slippers on and turn into my writing den; see you next year...
A whole family of California Quail totter over the garden: daddy stands watch on top, upper right.
There is no better way to ensure you finish designing a new basket than to put all of your eggs in one.
This winter I have been building a 1000 square-foot (100m2) greenhouse to produce hardy native and rock plants and replace my backyard hoop nursery. I was unable to find anyone who has already tried to make a passive solar (self-heating and cooling) greenhouse but using traditional materials that nursery people are familiar with. (Most passive solar greenhouses are serious things, framed in wood like a house or shed whereas most production greenhouses are metal frames wrapped in plastic film.
I aimed to create a hybrid: something economical enough for a business- like my own- to reasonably use. This means lighter materials. (versus concrete floors, glass roofs, et al, of a long-term and serious greenhouse). There are also no utilities on site, so being off-grid is not solely to prove a point.
The dark truth and problem with greenhouses is twofold: They consume prodigious amounts of energy to heat and cool (usually propane of natural gas). In America, the average greenhouse costs four times that of a house to heat/cool. Secondly, a traditional greenhouse is a needy, fussy, fragile bastard teetering on disaster all the time. A brief over/under-heating, usually from a power outage or vent catching or door left open, can result in damage or loss to everything in there. This shit kept me awake at night when I worked in commercial greenhouses.
So the drive to create something better is both environmental and mental.
So we built it from scratch in the old-school way that the last generation of Colorado nursery-people did: bending fence rail into hoop ribs and building the ends by hand. A hoop-house on steroids kind of deal. It is inside of such things that my mentors have produced all of the cacti, native plants, and trees… where I worked for years and where for years later I have purchased the plants for my gardens. These humble greenhouses are the workhorses behind all the things we love.
Anyhow, I found myself inventing a wheel- a prototype and F.O.K: First of a kind. I have not finished and I don’t have the answers. Yet. But I want to share some main lessons so far.
Heating:
For economy and sanity, it’s not dug in. It’s powered only by water. IBC totes. I hadn’t seen anyone use those before so I’d like to take credit for that idea if nothing else and the rest of this folly ends in tears. 20 of them gives me 5500 gallons (21,000L) of water as a north wall, well above (50%) the average used in passives. (per square foot of growing space).
Insulation:
I was going to make a straw-bale wall as the north side’s insulation but that grew more painfully more complex than useful. Instead, there are 2”-thick rigid styrofoam boards (salvaged) which would have cost $600 new, half that of using straw. Next winter I want to try hanging infrared reflective foil behind the water totes and measure the efficacy.
One of the most heartening surprises has been how well the size, proportion, and two layers of film are working, getting me off the hook for further insulation. Usually, insulating the ground around the perimeter of a passive greenhouse is important, but the proportions of this one seem to be mitigating that. This is a huge win towards my goal of creating something that is not a complex pain for other growers to do.
The floor is simply black (heat absorbing) groundcloth on top of compacted gravel fines. Wherever possible, I’ve used salvaged, used, or free materials. While it’s an experiment, it needs to pay itself off some day.
Glazing:
For sanity the outside skin is one whole piece, as it will have to be replaced every 4-8 (or 10) years. The proportions are about 50x25, (15x7m) so the ends are theoretically big enough to vent it without side or peak vents. There is no electricity, so no extractor fan per se, but I will try solar-powered circulation fans which can be directed toward aiding the convection cooling.
The Biggest pain in the Ass and one tentative regret
Two film layers. Traditionally these are laid together and a fan inflates them apart, operating perpetually for the whole life of the greenhouse, creating that critical insulating and structural airspace. Without electricity on site and a learned shyness to risk so much on electronics, I avoided that and had to build an interior wooden intra-structure to hang my second layer. It’s been a pretty flexible, easily adaptable system but a hell of a job to do: lots of hours and lots of exercise climbing ladders with a drill. I think if I were to do it over, it may have actually been easier to engineer a solar-charged battery-powered blower fan, rather than engineer the whole greenhouse.
The Regret?
At the moment, I feel that if I were to do it over, I’d use a kit greenhouse (without the heaters and motors) and retrofit one for ease of framing. But I’d shop around hard to see what brand or design would be sanest to retrofit. After all, more and more growers are not building their own from scratch but using modal kits. So far, materials have cost exactly what a kit greenhouse would cost of that size. ($6700) I’m taking that as a win. Hell, it’s bigger than our house.
Snowload:
Most of the greenhouse sheds it fine, but there is one hoop whose curve isn’t right, and it accumulated a heavy snow in part also to an interior purlin acting as a dam. I’ve moved that purlin to solve my problem, but to any future builder I’d recommend going gothic shaped for any film structure wider than say 10’ (3m).
-Ventilation is yet to be seen. I’m building these now, and their proving time is spring and summer. Stay tuned.
-Cooling will be a multi-part thing. Wax-opener powered and convective Passive vents, shadecloth (on the outside of the greenhouse- this is critical) over the growing area, a shadow over the water wall, and we’ll see what evaporative cooling happens from plants and floors.
Good news so far:
All the water and two layers of plastic are doing the trick. Outside temps around 5F (-15) made it freeze inside the unfinished greenhouse, sending a tomato plant, a “canary crop”, to its maker. Even when unfinished and before I sealed air leaks, the greenhouse’s coldest was 22F (-6C), which to its credit is 20F (10C) warmer than a 2F(-16C) outdoor temperature, and no sun for days. It’s sealed up snugly now.
I wonder if it would have frozen had it been fully glazed. The water tanks have never frozen, lingering in the 40-50 (4-10C) range so far. A tray of cilantro is growing like a chia pet even through the solstice. Hardy woodies and semi hardy agaves are all sleeping like beauties so far. The greenhouse refuses to go below 35F(1C) which is pretty ideal for sleeping hardy plants. Without ventilation it peaks at 75/80F (24/27C) on a very sunny 45F (7C) winter day.
Cherries on top:
The greenhouse project became a village affair to finish in time for snow and deep cold; I had some back trouble that required friends to help out a day or two now and again, which led to having a thank-you solstice party with the aid of my friend Marla, which in turn led to a sort of a decorative Altar/shrine (after all, it is a plant-church!).
The greenhouse’s landlord insisted we re-use an old woodstove which had been sitting around gathering snow. While, for reasons of physics, a woodstove cannot actually heat a greenhouse in earnest, it will be useful to warm a corner of the greenhouse next to the potting bench on winter mornings (which might otherwise be 40F(4C) in there) to something comfortable for me to work sowing seeds and potting plants. It’s also just really nice.
{Well, I say it’s no way to heat a greenhouse, but what organically came up in conversation and now sits in my mind like an inevitable, potent, explosive seed, is the concept of running a passive water radiator coil from the stove and through the water tanks, which could hold the BTUs of heat from a single stove firing for weeks... Yet another passive system with high payoff that may be too fun not to try, even though the greenhouse will probably not need additional heat… stay tuned for that madness next winter}
I want to end with thanks: To my endlessly supportive greenhouse landlord. My ex-coworker did lots of tedious prep work on materials throughout her year working for me. I’ve also received generous advice on many occasions from folks including Kelly Grummons, Mikl Brawner, Jeff O, Dare Bohlander, Shane Smith, my neighbor orchid-Steve, John Stireman, the three musketeers of Minneapolis (you know who you are) and especially Tony Urschitz. My bible has been a gift from my other neighbor Steve: the cookbook for making passive greenhouses, Lindsey Schiller’s “The year-round Solar Greenhouse” Thanks to that second Steve, as well as Iain, Trina, JC, Hannah, Eric, and my endlessly patient partner Tori for lending a hand when I really needed it. I owe you all plants now.
2023 so far:
Manhattan Chapter NARGS (Zoom) Jan 16: Crevice gardens but mostly plants for them.
Utah Green Industry Conference (Salt Lake City) Jan23: Back to back crevice and no-water talks.
Christchurch Botanic, New Zealand, Jan 27, afternoon crevice workshop in the Rock Garden with Grant.
Landscaping with Colorado Native Plants Conference (zoom) Feb 25 Real Unwatered Landscapes
High Plains Landscape Workshop (Fort Collins, CO) March 4 Home Meadow Gardens
Durango Botanic's Gardening with Climate Change Seminar: Mar 9, 11 or 16 tbd, How to make a Future-proof Crevice garden
Spring Fever Symposium, Iowa Arboretum, Des Moines, IA April 15 2 talks: Crevice gardening for the midwest and favorite plants
Tucson Cactus and Succulent Society, Tucson, AZ Nov 2: Desert+Cactus Crevice Gardening
Buddies: Isaiah, Jacob, and John during conferences last year.