Growing plants meant for COLDER Zones

A question from one of my teen Permculture students.  I was stumped because I don't think I've ever encountered folks wanting to create a COLDER microclimate.  I was sure that there MUST be someone - likely several someones - who have desired to grow crops meant for cooler zones.

And so... If YOU are one of those people, would you share, please, how you went about it?

I'm looking forward to passing the info along to her and adding what we learn to future PDC courses!

Thanks heaps,

Does it need to be colder year round or just during one season?

I am planning to do it, so just theory at this point.

I want some fruit trees that need more chill hours than I normally get. I plan to observe for a few years after I move to the land (I own it, but still working on moving to it) and mark all the frost pockets as locations for those trees.

Generally, folks who want to grow a plant that is recommended for a USDA zone lower than theirs will plant in the shade or use shade cloth.

Another way is to use a mister to create humidity.

I would use methods to conserve moisture which would help plants in extreme heat.

While these threads talk about drought conditions I feel these methods would also work for pushing the zones or making a colder microclimate:

https://permies.com/t/138768/Water-Plants-Trees-Drought-Conditions

https://permies.com/t/113313/Ways-Homestead-Resilient-Drought

Okay, theory.  I love theory.

I also love pushing the zone.   David The Good has a great book called Push the Zone  which is an awesome read for just this kind of thing.

I find that a plant wants a colder zone, often means it needs a cooler summer or it needs a cooler winter.  (there is also day length but that get complex).  

If it's one or two zones, I just try it and things tend to do well.  It's gotten to the point where I don't even know what our zone is anymore and I don't look at zones.  

That said, some plants don't like how hot our summers are.   For these, I find a place where they get shade in the afternoon (a large leafy tree to the west of the garden).  Or if they want a shorter summer, like the turnips from Finland, I wait until after the summer solstice to plant them.

Where we get the most issue is plants that want a cold winter.  Like how we might dig up trees in the winter to put them somewhere to protect them from the cold (fig trees around here often get dug up, buried completely in mulch for the winter, then replanted as a tree in the spring), it used to be common to dig up perennials that want a colder winter.  Rhubarb is the one we think of most, as it's often dug up in the fall, left on top of the soil until spring. That way it can get a good freeze and abuse.  Keeping trees in pots so they have their roots freeze is another trick.  We tend to put these on the north side of the building so they don't thaw during the day.  Or simply shading the roots (a small rock wall to the south of the tree roots) in the winter can keep them cooler.

r ranson wrote:Does it need to be colder year round or just during one season?

I would think she meant during the winter.  But practically speaking, it's generally colder LONGER in northern places.  Also, longer days during the growing season compared to more southern areas (in the northern hemisphere).

So... yeah.

I don't know.   Most would consider me pretty far north at about 49 degrees.   It doesn't get anywhere near as cold here as it does in much of the usa in the winter.   We just had our first solid frost of the year on our farm, possibly one of the last until neigh Christmas.

Places further north of here get way hotter in the summer.

Day length seems to be independent from temperature needs.

I find with plants,  it's usually one season they need cooler which makes it easier to create a microclimate.

Can you better define colder, does it mean:
1a) more chill hours
1b) does it have anything to do with late frost killing blossom
1c) humidity
2a) less summer heat
2b) does it have anything to do with water/drought
2c) growing degree day
2d) direct sun vs patial sun.
3) day lenght and bolting of vegetables/etc

I have found that for zone 8 or 7 or 6 or 5 or 4, there is usually a cultivar that will grow in a hotter/colder USDA Zone, its just looking around until it is found and there.
There is also the option of finding a cousin species that can be used for rootstock.

I think that it would be hard to grow Hazelnut in say zone 9, but there are cultivars of apples that will give a good harvent in zone 10.