Any ideas on how to thaw out the ground in my hoop house?

[molly]

At Christmas time I could still work the ground but after the cold
start to January, the ground started to freeze. How can I thaw it out
enough to start preparing beds within the next month? Next winter
I'll need to have a better set up for capturing heat - I welcome any
ideas!

[Christopher Patton]

Dear Molly,

I understand your dilemma. Last fall I planted some mixed lettuce and harvest before the cold October and at the end of November. I left row cover only over my improvised supports (tomato cages lain on their sides) and wait to see if the lettuce grows this spring.

I have 3 raised beds to hoop and cover on the south side of my house in early March. I have decided to wait until most of the lasting new snow falls are past, I hope. Then, I plan to scrape what snow there is off the ground and set up my hoops and row cover to let the sun do its work. Without having put hoops and heavy plastic covers in place last fall, that is the best I think I can do. 

I think you may be a bit too aggressive on your March tomato planting timing, but it is worth a try. You might think about a back-up effort by starting another set of seeds in a month or so for an April planting. For March I plan to start cold hardy greens, brassica and onions. 

Good Gardening!

Chris

[Robert Frost]

Without supplemental heat an option would be to build an inner low
tunnel or cold frame over your beds to trap in extra heat. Even
laying greenhouse plastic down directly on the soil will help. Next
season, if you are not using the hoops for winter production, a 4-6"
straw/leaf mulch layer inside will prevent the onset of frost to allow
for earlier spring production and may be the easiest option.

If you feel that the frost is creeping in from the edges, then a thick
mulch layer outside may help give you some buffer. We have access to
municipal leaves and pile them up 3-4' tall and 6' wide around the
sides of our Hoop House for extra insulation and as a frost buffer
zone - ensure you are bracing the structure enough to support this!
We run a 4' wide compost pile along each inner side to support the
walls and add significant heat and thermal mass during the winter.
These piles then give us plenty of compost for spring production and a
warm spot to start lettuce transplants. We are in Zone 5b and have had
120-150 degree compost temps all season, providing enough heat to keep
our starting flats at 80 degrees under a tent of plastic.

-Rob
www.onestraw.wordpress.com

[Stefan Meyer]

Thank you Robert! and that's right, the farmers up north using high
tunnels will also use the secondary crop cover (think a cloche, within
a greenhouse) to add a thermal layer. Just be aware if you are
leaving this on 24/7, there is significant light loss due to the dual
layering. Most farmers remove the inner cloche during the day.. can
be a hassle/work, so it depends upon how much it means to you to get
the edge on the local growing season.

--
"Those who make peaceful evolution impossible make violent revolution
inevitable..." JFK

[Carol Ford]

Molly, the folks at Food Farm in Wrenshall, MN laid down that blue board insulation horizontally around the perimeter of their hoophouse used for hot lovin' veggies. I can't remember how deep it was, less than a foot deep, I think, but the effort was designed to stave off the frost coming in around the edges of the structure. They seemed very pleased with the results for late season tomatoes but I don't know if it lets them get in there early or not.

As long as you feel like experimenting, might I suggest an interesting alternative to explore next year? You might even be able to get a SARE research grant to see how this works for you. A few years back, I got a farmer/rancher research grant from SARE to experiment with soil temp in my passive solar greenhouse. Our design keeps our soil temps around 55 or better mostly (this year's been a challenge). I wanted to see if warmer soil temps would boost production, but I"m only dealing with cool weather crops and they actually preferred cooler soil as it turned out.  But the materials I used to test this might help you get into your hoop earlier with your tomatoes.

Farmtek is an equipment supplier you may be familiar with. They put out a product for moveable raised beds. The sides are made out of their heavy duty pond liner and have pockets built in for setting in posts that hold it up. We filled ours half full of soil, then laid on top of that metal hardware "cloth" that had heat coil attached and added another eight inches of soil on top of that. We also used a temp control for getting the soil to 70 degrees. It certainly worked, just didn't give us the results that would warrant the cost.  Now for you, a bed like that, covered with hoops and row cover at night or cloudy days might let you get some early tomatoes established. The heated soil would help heat the enclosed plants from the ground up. The crops you're talking about need happy feet, hot, happy feet.

Just figured I'd throw that out there as a possibility. The nice thing about that raised bed system is it's easy to dismantle and move elsewhere if needed. Ours has held up incredibly well after 4 years, even in a greenhouse that gets solarized every summer. We took the metal cloth and heat cable out but left the raised bed in. Nowhere else to put it and it's nice for crops that have deeper root structures.

Carol Ford

On Feb 7, 2010, at 10:23 AM, molly wrote:

Carol Ford

Office Goddess

Division of Sci & Math

Univ. of MN, Morris

for...@morris.umn.edu

"Unless someone like you cares a whole awful lot,

nothing is going to get better, it's not."

       -The Lorax, by Dr. Suess

[Carol Ford]

Yes! Robert's post reminds me of another useful idea you can consider, Molly. At Growing Power, in Milwaukee, WI, they create hot compost trenches in their hoop houses that they make raised beds on top of for winter growing. I think their compost is a mix of sawdust and either vermicompost or manure.  I don't know how much they've been monitoring, but the assumption is, the decomposing compost heats the soil above it and again, if covered, would give plants in that raised bed some added warmth in cold nights.  If you want to know more, contact them at growingpower.org

Don't give up on your goal to start early. This kind of curiosity and determination is what helps us push the envelope on what we think we can do. Go for it! Share what you learn! I can't wait to see what you discover!

Carol Ford

[Robert Frost]

Carol,

I live and farm about 30 miles from Growing Power and have visited their operations many times which influences our work here significantly.  From what I have seen, much of their compost is catch all - grocery store and restaurant waste, brewery mash, manure, etc.  I have seen at least three methods used at GP to heat their passive hoop houses:

>The "hot bed" technique you mention

>The side windrows I mentioned in my earlier post

>"Corner Beds"  Where they make massive 8x8x7' tall piles in each corner (again bracing the structure) which start small, but are added to all season to stay hot.  Due to their size they go anaerobic mid winter in the lower levels, but are turned come Spring.

A combo of "hot beds" and either the corner or windrow method would work well in concert - Corner/windrow beds could add significant thermal mass and heat during the dead of winter to keep greens harvestable when there isn't enough light for growing.  In late January as daylight nears the 10 hour mark needed for growth, the windrow/corners could be broken down and "hot beds" built in the now played out greens beds to raise soil temps for early season crops.    Fertility levels would be insane with a few seasons of this, but labor intensive as all get out.  GP has a virtual army of dozens of volunteers per weekend to accomplish this.  Still, working up a sweat turning compost in warm humid air is not a bad way to spend a January Saturday!

-Rob Frost

www.onestraw.wordpress.com

[Carol Ford]

Robert, 

Oh man, no kidding! After spending just one workshop afternoon helping to haul compost materials to their long row of bins at Growing Power, I can back your observation that any and all waste materials go into the GP compost (and, inevitably, their worms)!  And it is true that their methods are very labor intensive. It's a low cost innovation that requires not only the physical army, but the logistics know-how to manage the relationships that provide access to the waste, the maintenance of the raw materials being broken down and moving it where it's needed. A bobcat could become your best friend in a situation like that but I still like GP's approach for the way it builds community. 

In my case, with just two of us managing a small business (and maintaining other jobs), we chose to invest in a beefier structure. I'm in zone 3 (feels like 2 this year) and want to harvest cold tolerant crops all winter. Not going to happen in a hoop. So, the passive solar greenhouse did the trick. And despite the short daylight in the solstice weeks, I do get continual growth in that structure. In particular, pac choi, chinese cabbage, broccoli raab and several varieties of greens do grow well in less than 10 hours of daylight per day. And our thermal mass below the structure keeps the soil temp above 50 at the least and usually more like 60. So in our case, the investment was in structure rather than relationships but it addressed our situation amazingly well. 

I'm kind of pondering the possibilities of hybrid structures that incorporate some of our passive solar design features with lower cost hoophouse construction materials. But then we get another arctic gut punch and I'm just so grateful for the structure we have. After five years, the greenhouse has handled everything from 2+ ft of heavy wet snowstorm to -40 windchills to 100 mph front line winds without a problem. It's a peach. No structural or heating solution is going to solve everybody's problems to be sure and I do hope to get a hoop for season extension some time soon but for all-winter production, a passive solar greenhouse is a beautiful thing.

Carol

[Stefan Meyer]

Carol and Robert,

This is a fascinating conversation and I think it really keys into a
key component as we seek to bring agriculture back to a smaller scale,
and that is of economics. While I whole-heartedly applaud GP, their
model is based upon extensive free labor. If we want to be examining
ways to make small-scale agriculture economically viable, we need to
find a balance between the work-load and the upfront capital
investment for the structure. The passive solar greenhouse you have
created Carol, is a true marvel to behold! Unfortunately, here in the
city the permitting barriers around such constructions are costly. So
we have a lot of work to do around this issue. Also, as more and more
urban ag projects are starting up, we are finding that the urban
organic waste stream is needing to be shared between many interests
(granted, there is still a whole heck of a lot out there, but if even
a couple of of major compost heating greenhouse operations started up
in the city, this could take up a lot of organic waste). As well,
getting manure within the mpls city limits often requires quite the
haul from the outlaying agricultural communities.

Basically, moral of the story is you two keep up your great work, and
keep the ideas flowing.. we definitely need to seek out creative
approaches to these challenges.. but that is the exciting part!

Upward and Onward ;)

stefan

--

[Carol Ford]

Stefan,

Permitting is an barrier. There are a lot of things we can do about obstacles. I have been astounded more than once at how political we must become to reclaim our right to take back such a basic right as local food production. Here I am in a town of 300 and I can't have chickens--but a person in south Minneapolis can! Permitting laws and building codes are rules made by people and people can change the rules when we have the political will. Sometimes we have to raise awareness before we can raise structures.

When a greenhouse like mine is built as part of a community project or a school, it gives more people the opportunity to rethink things like building codes and permits. It gives those involved practical, valuable experience they can take with them wherever they go to pursue their own dreams. That's one of the services Growing Power provides and is doing it on a national level, bless their hard working hearts. 

Here's how I look at barriers. I was told when I began my journey that what I wanted to do couldn't be done. It wouldn't work, it would cost too much, blah blah blah. Rather than being dissuaded by these expert opinions, I used them as identifiers of the challenges I would need to overcome. Why won't it work? Why would it cost too much? Are there solutions to those answers and are they deal killers for me or not? Every innovator faces this test. Will the reasons why it can't be done be a self-fulfilling prophecy for defeat or a chance to stretch those creative problem-solving skills we clever, adaptive humans possess? The only marvel about the Garden Goddess greenhouse is that we didn't let the nay sayers stop us from actualizing a dream. The rest was just practical application of sound research.

I'm not saying a passive solar greenhouse is everybody's solution because each person on this list has unique values, goals and skill sets they bring to the growing-under-cover scene. For some, low hoops and cold frames get them where they want to go. We start at that end of the continuum and go all the way to the passive solar greenhouse. No single solution has any higher merit than another because they all address different pieces of the season extension puzzle and come with their own challenges. 

I just don't want to see any part of that puzzle removed because "it can't be done." It might take longer than we like and involve working for change to get to the point where we can implement these solutions but that does not invalidate their place in the conversation or the research efforts. While some have to struggle with their local officials, others can experiment with the best hoop design and construction to maximize production in winter. We all gain from both efforts. I'm not giving up on having chickens someday and what a wealth of information I'll have available from the back yard coop group of the twin cities!

You are right about the need to look at the economy of scale any grower currently has. I'm keenly aware of that because I dance upon the fence of still needing a full time job (and its benefits) and wanting to expand my own produce business. I'm not alone in this dilemma. There's always the option to consider that a group can pool resources and talents to move forward together. That model contains its own challenges and rewards that do not suit everyone, but it does provide the collective ability to take on challenges that seem daunting to an individual. 

There are organizations in our state that are committed to supporting small and beginning farmers whether in rural or urban locations. They can put their energy into helping us. And the media loves a good struggle story. Public awareness is important for our pursuits. Putting the face on the farmer is what it's all about and we've had good evidence of the positive effects of the news coverage that follows the fight against outdated local permit policies in our region. That battle can be won by people unwilling to accept status quo. 

There's lots of clever and meaningful quotes out there which speak to the power of grass roots change, but it's not a fight everyone is able and willing to take on. I get that. Notice that I haven't butted heads with my own city council about chickens yet because they oddly seem far more opposed to small scale livestock in town (a town that's about 5 blocks square and surrounded by agriculture, by the way) as opposed to lax building codes. Sense?!? Who said this stuff had to make sense?!?

As to your comments about managing compost materials, Stefan, I am excited about that challenge for urban farmers, the true modern pioneers in uncharted territory. We are going to come up with wonderful, creative solutions to these questions of how to access and manage soil fertility components. This is the undramatic but profound revolution. Talk about your grass roots movements, people! Wow! Will we be jailed for harboring animal waste? Will we march to have the right to construct hoophouses on empty lots? It's a fundamentally worthwhile political action when people recreate their basic right to feed themselves and their neighbors without unneccessary (key work there, debatable, I realize) government intervention. 

I hope I get to stick around for the next 20 years and see how far we take this. It's the legacy we can be proud of, as opposed to the fallout of wars and national debt and health care bondoogles.  Let us lift our hoes and dig! Unfurl the floating row covers of the revolution! I am proud to feed 18 families with my part time labor and ingenuity and I am proud to be a very small part of a very good thing. And I am grateful to every person who brings her/his talent to this marvelous campaign to reclaim the goodness of local food production. Grow on!

Oh my goodness how did I get on such a roll today? What was in that Fair Share coffee this morning? Something spicy. It's working for me. 

Carol