How to heat a forest garden?

I know something about common ways to heat a garden, creating sun traps, hugelkultur, ponds, rocks etc. Is there any other idea, maybe still not tested, or tested and working?

My first thought would be to place additional thermal mass. Maybe you have rocks, maybe you don't. But you could always get some old water heater for free? They are commonly used as solar collectors, painted in black and placed on flat roofs. So they could be also filled with water, sealed and left in the garden? Since they are pained in black, they would absorb sun and heat water, and release heat during the night, wouldn't they?

Second thought is to dig a well. Left it empty, in the middle of the garden. Earth is warm down there, so will the air be. Since warm air raises, it will come out this well all night? I can not estimate how significant this could be, has anyone tried? I know it is not so easy to dig a well, but if it could heat the garden, this would be permanent solution, would work when there is no sun, and it does not take any space, can be placed in least productive shade.

Of course I don't think that only one technique is enough, I would use this only as addition to proven techniques. Frosts bothers me a lot, there are a lot of plants that I can not grow because of them or they will bring fruits only after warm springs, so garden heating system would be a miracle to me

I think the painted water heaters is a good idea and should help as thermal mass. 

One type of sun trap is a south facing parabola of light colored wall (rock, brick, etc) that reflects and focuses light on a central pillar (dark rock, water filled barrels painted black, etc).  That can raise the temperature significantly in the center.  If tall deciduous vegetation is used inside the parabola, it's growth will "turn off" the suntrap once the growing season gets going and it is warm. In cold summer climates, one might want to grow shorter plants to keep the temperature higher and reflect more light on the plants.  Tall evergreen vegetation behind the parabola wall (north side) provides a wind break so that more heat is retained. This can create a nice warm pocket during leaf-off season and might add a zone or two of protection against the winter minimum temperatures, and an earlier spring.

For visualization and calculating the curve:
http://www.jc-solarhomes.com/fair/parabola20.htm

In that diagram, sunshine would be coming from the top; ie, south is up, and it is reversed compared to normal expectations.  The curve can be made steeper or shallower, depending on the design objectives.

there are a lot of ways but one way to help your fruit trees is to put them up on a mound, some of mine are up on hugel mounds and they do quite well. Also if you have some large rocks available you can place them near a more tender plant..

windbreaks are a wonderful way to increase yields from a warmer garden..as well as fences if windbreaks aren't feasible..or walls.

I have planted windbreaks in lots of areas on our property and our neighbors, bless their hearts ..have planted a windbreak for us on their property as they are west of us and winds come from the northwest here most of the time.

our main food forest garden is 20' east of their property line so the evergreens the planted inside of their property line will provide for our garden when they grow..I'm so blessed.

most of our plants right now are still in their younger stages..as we had a fire and had to relocate our food forest gardens

This just popped up in the daily. Thanks Jay.

Coincidentally I was just reading about the eastern skunk cabbage, Symplocarpus foetidus. It apparently creates it's own heat and melts snow in the spring along with the smell to attract pollinators. Then I learned there are many plants that create their own heat. Plants that attract pollinators with infrared light and therefore create heat at the same time are believed to possibly be an oldest form of attracting pollinators.

I have no idea if one could heat a food forest with these plants but any added heat is added heat. If you happened to have a wet spot in your forest with a bunch of skunk cabbage it certainly couldn't hurt.

Milan Broz wrote:I know something about common ways to heat a garden, creating sun traps, hugelkultur, ponds, rocks etc. Is there any other idea, maybe still not tested, or tested and working?

We use doublecoated wool from our sheep. Esp the less useable bits. We thickly wrap the lower trunk, crown, and ground around the crown of our lemon trees which are susceptible to frost. We put wood mulch on top of that.
So while top and outer branches might get frost burned, the roots and trunk are protected. (We also have Xmas lights for the upper and outer branches, but the superficial crown and roots are super important).

It’s important remember to take off that crown and trunk wrapping after frost is done though. It doesn’t do to suffocate the tree in its growing season. We leave the wool and mulch down on the root and under-canopy  ground. It’s slow release fertilizer. And nest material for birds if the pick through the mulch.

For the last 2 years the pear trees lost most their blossoms so had reduced fruit and the walnut trees produced no nuts. I am guessing it was due to very late, hours long freezing periods. Have other PNW experienced this? I was thinking to use the rock/heat sink idea tho it looks like it might be a warmer winter (tho that would not mean we won't have the mid to late April freezing, I guess).  The walnut trees are about 20' tall and the pears about 12 so not too sure if thermal mass on the ground can help. Thoughts??  Thank you

Les Frijo wrote:...Coincidentally I was just reading about the eastern skunk cabbage, Symplocarpus foetidus. It apparently creates it's own heat and melts snow in the spring along with the smell to attract pollinators...

Hi Les,

That is very interesting!
However I do wonder: What time of year will it generate heat and what time of year does it smell?

To be used for protecting plants against cold, like Milan needs, the heat is needed at the beginning of winter, otherwise the plants to protect, might suffer from the frost before the skunk cabage starts to generate its heat. Does anyone here on permies.com knows?

My second concern is the smell. I am worried about the neighbours surrounding my urban garden. I expect some trouble when my garden starts to produce a foul odor just when everybody starts to come out to enjoy the sun. Are the smell and the heat produced simultaneously, or is the heat first and followed by the smell later? How long does the smell last? Are we talking days, weeks or months? How far does it carry? Can I mask the smell with a better smelling plant? Is there anyone with experience on these matters?

I would love to use the thermal heat of this plant to protect some fruit trees, or add it to the protection, but before I start the hunt for this plant, I would like to know what I am getting myself into, because it seems hard to remove later.

Kind regards, Nynke

Your idea about the heat well is interesting! Made me smile - gave me a nice flowing visual of the warm/cool energy flow in constant motion.

I am skeptical of its affectiveness tho, as you would need some way to essentially trap that warm rising air before it shoots to the sky, and the hole would likely just fill with water, and/or be a potential hazard as a death pit for non-plant life.

Doesn't mean you shouldn't try, as there could be some work-arounds of your idea that may actually lead you to creating some sort of small microclimate area :)

Nynke Muller wrote:

Les Frijo wrote:...Coincidentally I was just reading about the eastern skunk cabbage, Symplocarpus foetidus. It apparently creates it's own heat and melts snow in the spring along with the smell to attract pollinators...

Hi Les,

That is very interesting!
However I do wonder: What time of year will it generate heat and what time of year does it smell?

To be used for protecting plants against cold, like Milan needs, the heat is needed at the beginning of winter, otherwise the plants to protect, might suffer from the frost before the skunk cabage starts to generate its heat. Does anyone here on permies.com knows?

My second concern is the smell. I am worried about the neighbours surrounding my urban garden. I expect some trouble when my garden starts to produce a foul odor just when everybody starts to come out to enjoy the sun. Are the smell and the heat produced simultaneously, or is the heat first and followed by the smell later? How long does the smell last? Are we talking days, weeks or months? How far does it carry? Can I mask the smell with a better smelling plant? Is there anyone with experience on these matters?

I would love to use the thermal heat of this plant to protect some fruit trees, or add it to the protection, but before I start the hunt for this plant, I would like to know what I am getting myself into, because it seems hard to remove later.

Kind regards, Nynke

Hi Nnyke,

I don't know the answers but it sounds like the heat and smell are generated in the spring flowering stage. Being first to flower in spring, it melts the snow and helps to carry the scent to attract pollinators. Maybe it could be helpful in early spring frosts in some areas. I will have to pay attention this spring and see if I can notice the odor around a large patch of eastern skunk cabbage. The related western skunk cabbage is apparently not thermogenic but maybe there are other plants in your area that might help.

https://en.wikipedia.org/wiki/Thermogenic_plant