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PermaGRIN! (And microclimate questions)

 
April Boughton
Posts: 6
Location: Southeast Missouri
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I've been digging around in this forum for many days straight, as well as watching videos and listening to podcasts. I feel like I've wasted the last five years trying to get a conventional farm going. Now, I can't get the silly grin off my face! My existing (useless) landscaping and conventional gardens are quivering in fear every time I walk around outside thinking about what I can do here or there.

I'm very intrigued by the creation of individual microclimates to suit different areas, but I have a couple of questions.

We have tons (literally) of granite rock here on our little mountain in the Ozarks. I understand the idea of using them as heat stores and am making many plans to that regard. As I was driving up the road yesterday, I noticed that many of the sofa sized granite boulders still had snow on them when the rest of the snow had melted away. The ones I saw were in the woods and not getting as much sun as they could be. But it got me to thinking. Do they also "store" cold in the same way they store heat? Can cold even be stored? Ice cubes store cold, I reckon. I don't think I'm thinking about this the right way.

My second question concerns the extremes of weather that we have here in Southeast Missouri. If I'm creating a microclimate for some protection against the harsh winters we have here, will I be creating an oven in the blistering heat of summer time? If that's the case, are there steps I can take to ameliorate that situation?

Lastly, is it horribly un-permie of me to consider using plastic (or other artificial means) in winter time in order to extend seasons or grow veggies that I really shouldn't considering my climatic conditions?

You all have really struck a chord with me. I know it's going to be a lot of work to get from where we are to where we want to be, but it's going to be SO worth it!

Thanks,
April Boughton
Southeast Missouri
 
Julie Helms
Posts: 110
Location: SC Pennsylvania, Zone 6b
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Hi April,

I am a total newbie to the whole permaculture idea and like you have been scouring this site for ideas! But one thing I can speak to is rocks and cold. We used to live in a stone farmhouse. When it got cold, it got very cold inside. It would take awhile to warm up those stone walls. Once we did it was fine, but the transition in the season to winter could be brutal for a few days. SO yes, rocks hold cold.

Julie
 
Fred Morgan
steward
Posts: 979
Location: Northern Zone, Costa Rica - 200 to 300 meters Tropical Humid Rainforest
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One wonderful thing about having stones is that they will prevent you from starting something too early, and hopefully stop premature flowering of fruit trees. Sometimes it just takes a little to protect from frost, and having a large heat sink will help. Both in the spring, so that your fruit trees don't flower too early, and in the fall winter, so that weather fluctuations don't cause so much damage.

 
Jami McBride
gardener
Posts: 1948
Location: PNW Oregon
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books chicken duck food preservation forest garden hugelkultur trees
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Welcome April,

Rocks are good store houses and conductors of heat and cold, as is water.

My second question concerns the extremes of weather that we have here in Southeast Missouri. If I'm creating a microclimate for some protection against the harsh winters we have here, will I be creating an oven in the blistering heat of summer time? If that's the case, are there steps I can take to ameliorate that situation?


Making sure you have air movement and plenty of companion plantings to keep the ground shaded and transpire moisture helps things not to over heat in your microclimate during the summer day.
Does Missouri cool off at night in the summer? Then what is released when the temp drops won't be a problem. Remember microclimates won't make all your plants happy, they may jump start a planting but then be to much later on. So only plant sun loven plants up against rocks.

Lastly, is it horribly un-permie of me to consider using plastic (or other artificial means) in winter time in order to extend seasons or grow veggies that I really shouldn't considering my climatic conditions?


I say - if it's helping you to learn and move forward in your quest for sustainability until you can move forward without it, fine. One day you might want to try something else, because buying plastic and hauling it to the dump later just won't fit your lifestyle any more. And there are mushrooms that will compost plastic (I'll try to find the thread here and post it) so...... if your not dumping your plastic, but composting it, fine again.

Cut out the areas that are not leading toward toxic free sustainability - like modern cleaners, cosmetics, fertilizers, insecticides, non-stick coatings in your pans, etc.... using these isn't going to be offset by a prolonged harvest of organic veggies

 
              
Posts: 31
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April,

you are thinking in the right direction and your intuition is good.

for practical purposes, it's good enough to think that rocks hold "cold" just as well as they hold heat. you can think of rocks as heat buffers, they help lower the amount of temperature fluctuations (both up *and* down), which makes sense, since physics makes sure we don't get any free lunches. FYI, the heat capacity of water is about 5x that of granite, that is, it has 5x more "buffer" per kg of mass.

trapping in heat will cause it to over-heat in the summer, that is correct, so make sure you can open a few large vents at the bottom sides and top. cool air will enter bottom and convection currents will carry all the heat away in minutes.

toan
 
Ian Erickson
Posts: 11
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Yes, most rocks retain cold also, but might be useful to think of cold a little differently to understand this better. Cold is not something different from heat in the same way dark is not something different from light. Absolute darkness is the absence of light and absolute zero (cold as anything can get) is the absence of heat. When something gets cold, it is a little more accurate to the process to say it is loosing heat rather than 'gaining cold'. Rocks usually have thermal mass which means they are good at storing large amounts of heat energy. The energy that they retain has to come from somewhere. When rocks loose their heat energy (get cold), it takes a lot of heat energy to 'recharge' something with a lot of thermal mass. In the spring, the rocks you see are slower to 'recharge' with heat energy than the surrounding environment, so they are colder. Color also comes into play with the speed with which they gain heat energy. Lighter rocks in the sunlight will generally be slower to heat than dark rocks. Color (reflecting properties) aside, rocks with thermal mass you could say 'mellow' the surrounding temperature because they absorb (steal) heat energy when they are colder than the ambient air temperature and give off heat energy when they are warmer. I hope this helps.
 
April Boughton
Posts: 6
Location: Southeast Missouri
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Thanks for the responses! I've got some more thinking to do. Good thing it's winter or I'd already be out there mucking around with stuff before I have a good understanding of the big picture.

The idea of water being a better heat buffer than granite is extremely thought provoking. I had also though about burying the heat retainers to slow down heat loss through radiation. My husband is already starting to raise an eyebrow at me at the thought of digging up rocks just to bury them again, but he'll get over it!

I think I need to rein it in a bit and work on some simpler things before I try to grow lemons. I have a bad habit of rushing into things too quickly. We've gotten to the point where we've got dairy, eggs, chicken, beef, goat meat and pork provided for ourselves from the sweat of our own brow using very sustainable and mostly organic methods (except for "milk stand grains" - still working on that). I struggle with veggies, but I think hugulkultur/permaculture is the answer there. That will happen this spring. So exciting!

Thanks to everyone for your passion and thoughtfulness!

-April

 
Paul Cereghino
gardener
Posts: 855
Location: South Puget Sound, Salish Sea, Cascadia, North America
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The classic solution to the 'warm up quick, but keep cool in summer' is deciduous canopy. Use a late leafing tree, or vines to cover your rocks during the hot season. Before they leaf out, you capture early season radiant energy.

To add to the 'heat theory' discussion... there are two ways that energy enters your 'thermal mass': radiation and conduction. Conduction is when energy moves from high to low (hot to cold) from object to object.. This can be from stone to soil, or from air to stone... Radiant energy in our context is usually sunlight or fire... the degree to which an object reflects or absorbs becomes important. So dark rocks are better radiant energy sinks than light rocks (called albedo). The angle of the absorbent surface relative to the source (sun) affects efficiency (also called aspect)... which is why a south facing slope heats of faster than a north facing slope.

Sorry if too didactic.. but useful concepts.
 
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