The Shade Contradiction

I am in the process of planning my food forest, but there's a big question that I haven't seen anyone address yet:
When I read/listen to experienced people (Geoff Lawton, Toby Hemenway, others) talk about permaculture, they always talk about the benefits of shade. If a plant casts a lot of shade, they will praise that as a major positive.

However, when I'm looking at preferred growing conditions for individual edibles (including on permaculture websites), they always say that the plant wants full sun. They often say that it "tolerates" partial shade but will have a reduced crop yield.

There are a few exceptions (mostly leafy greens and flowers), but what I continue to find is that shade is lavishly praised until you start talking about specific plants, at which point it becomes the enemy. What am I missing?

I think it is very site-specific. Geoff Lawton, for example, is working in Australia. So maybe his vegetables need a bit of shade to even survive the summer. If you’re in a climate that’s not quite so hot, or a latitude with less direct sun, maybe instead you need full sun in summer to even get your veggies ripe.

You also may need shade for keeping houses/animals cool even if you don’t need to shade you garden bed.

What MK said.  The further you get from the tropics, the more light becomes the commodity for what we generally consider food producing crops.  As such, I went for more of a savanna than a forest.

Every garden and every individual plant would need to be taken into consideration.

What is the shade contradiction? Good question.

Like Mk and Gary suggested warmer climates need more shade than a forest garden.

Hostas like shade where corn needs more sun though corn can tolerate some shade.

As specific examples, we planted and had decent production from both cucumbers and squash under a tree this year. In Texas most plants described as full sun flourish with six hours and suffer if they receive true full day sun. And a tree can pull surrounding temperatures down a few degrees.  That's very important when even the nights are almost too hot for plants to function.   Last night it barely went below 80 degrees Fahrenheit and we are in early summer.

Hi, Josh.
When you look at a plant requirements, the information is usually misleading. When it says that the plant wants full sun, they are not considering places where summer temperatures are above 40 degrees Celsius, the skies are clear the whole day and the sun melts everything exposed to it during 12+ hours every day. Especially not without irrigation.

If you really want to know your plant, look at the range of temperatures it survives, also what temperatures are right for thriving, the range of sun hours (8 hours per day is considered full sun), the range of humidity both in the soil and in the air, the maximum winds it tolerates, Then, try to figure it out if your plant is going to have what it wants during the period it will be growing, and if you can make it without irrigation for the most part.
In a food forest, you need plants that mostly thrive in your climate, and also can survive extreme events, without irrigation.


So about "Greening the desert", they needed the shade, especially in the heat of summer, otherwise nothing would have survived. They had access to grey water, but it wouldn't have been enough without the shade. Then, in late automn, when temperatures were milder, they pruned the canopies, as to allow enough sun hours for the crops below. The canopy regrows in spring, and shade is back for next summer.
Most farmers just irrigate their crops as much as they need, as long as they have available water. The instructions you have read might be good for this type of farming, but not for a food forest.

So first you have to know what climate you are dealing with, your soil composition, then you pick a few supporting species that need no help, and they become the basis for your microclimates where you can grow other things.
Keep in mind that organic matter constantly degrades, so you have to have some plants that are replenishing all that organic matter if you want your soils alive (this is called carbon farming). Plants that grow fast without any help, whose primary function is to be chopped and dropped for your other crops to benefit. Where there are harsh summers, shade is a critical function. In a food forest it's all about functions. This tree here is for three or four different functions, that bush there is for other two or three different functions, ... and when all functions are supported by several different plants, you get your resilience.

The other approach is the easier one: plant a wild variety of species you'd love to have, let die anything that doesn't want to live on its own. Rinse and repeat.


Another bit about the instructions: in my location, when in the seed package says "plant in May", I know I have to plant in March, because March where I live is like May where the instructions were written.

Hi Josh,

Welcome to Permies.

I am definitely coming to the conclusion that at my latitude and climate, I need to be going for more of the "savannah" approach, than a "food forest" which I agree seems to be a term aimed at hotter, sunnier ecosystems. Even my Black Currant which is supposed to tolerate some shade, got shaded out by raspberry canes and a kiwi vine and produced fairly poorly this year. We got a lot of cloudy weather all spring, which really cut back on the light levels.

Josh Mc, if you want ideas for your specific plans, giving us some idea of your approximate latitude and weather patterns would help.

Don't discount seasonal sun/shade patterns....got to take advantage of the entire potential growing period.  One of the benefits of perennial herbaceous layer plants is that they can take advantage of full sun in the spring under deciduous trees.  The trees have to wait to leaf out so that a late snow/sleet/freezing rain event doesn't rip off their branches.  Not a problem for herbaceous plants that just have their leaves bent to the ground and then spring back up after it melts off.  So there are months of wonderful full sun to be taken advantage of.  The spring ephemeral crops, like ramps, take full advantage of it and store the harvested energy in bulbs.  Many of these bulbs are wonderful crops.

Thanks for the comments: A few responses:

I am in northern Utah. Semi-desert, often slightly tops 100 degrees, but not nearly the oven you would get in Arizona or somewhere like that.

There's a lot to process in some of these responses (that's a good thing. I'm still a beginner here), but one of the themes I'm pulling out of everything is that it might be better to think about heat tolerance first and ideal sunshine second: i.e. find out if a plant can handle 100 degrees. If not, make sure it has afternoon shade no matter what people say about "full sun".

I can see how a label that says "needs 6+ hours of daily sun" could be based on a place with average cloud cover, while somewhere with very few cloudy days (like my home) would likely get the same amount of photosynthesis in 4-5 hours of daily sun.

Thanks again, everyone. I am planning to start planting trees this week, and I think I need to look up a little about heat tolerance before I go with my intended layout.

Abraham Palma wrote:

If you really want to know your plant, look at the range of temperatures it survives, also what temperatures are right for thriving, the range of sun hours (8 hours per day is considered full sun), the range of humidity both in the soil and in the air, the maximum winds it tolerates, Then, try to figure it out if your plant is going to have what it wants during the period it will be growing....

Yes and in addition to temperatures, sun hours, humidity and wind, seed companies could help growers by identifying the optimal growth spectrum for plants at different stages. For example, our temperature in Albuquerque was in the mid-nineties today and our ultraviolet (UV) index in NM at midday was 11 in full sun and 11 under cloud cover. Very few plants can handle extreme UV light at the early stages of their growth and some cannot tolerate high UV at all. High UV levels can occur on sunny and cloudy days, regardless of temperature. If we really want to fulfill a plant’s “sun requirements,” understanding the spectrum of radiation that most benefits the plant variety is a key to getting the plant what it needs without frying it or starving it. High noon shade is necessary here to prevent burning from high UV for many plants, even if the temperature is acceptable. However in other parts of the world, high-noon light might give the plant its necessary infrared (IR) and/or UV spectrum requirements. Heat (temperature) from the sun and UV radiation from the sun are highly variable: full sun does not tell us what region of the electromagnetic light spectrum a plant actually requires or can tolerate. Differences in the spectrum of radiation at different altitudes, latitudes, months of the year and times of day basically means that -- in addition to temperature -- plants  infrared (IR) to UV spectrum requirements and limits. The 4 hours after sunrise and the 4 hours before sunset are the 8 hours that really help my 5,000' "full sun" plant selections.

I agree. There are so many factors, that it's just easier to look at what grows well next door, to try new seeds in moderation and variety, and let go of the ones that dislike the environment.

I totally agree with Abraham and lots of others who look beyond the immediate property lines to see what is working in the larger eco-community. Build on those successes!

I think there is so much nuance in this that it can't really be summed up in a "full sun"  "part shade"  listing on a seed pack.

I also find there is a lot of "common knowledge" passed around that isn't really accurate.

I rented an allotment plot this year.   It's way in the back of the field near the tree line.   I can't tell you how many other renters have come up and said "too bad about getting a shady spot,  next year see if you can get on in full sun"   Shaken their head sadly at my bad luck.    They just "know" that full sun is "best."   My plot actually still gets full sun for 7 hours a day.   In the morning it's cool and shady,   allows me to work without sun exposure,  retains moisture well despite the proximity to trees.   Even though I started my garden almost 2 months later than others (I discovered the allotment late and was luck to get a plot at all)  it's PUMPING out harvests and my plants are doing really well.   Which contradicts what the other gardners are just SURE that they "know" about raising food crops.

It also matters if you are asking a crop to perform at it's fringe range of environment.   If I tried to grow more "southern" crops in my northern z6a,  then I'd be trying to get it into the sunniest/ warmest conditions I could manage.   Full sun probably.   But if I'm trying to extend cool weather crops like lettuce and radishes,  than that summer part shade is going to be really welcome and help me continue growing those plants well into the summer.  

Some of the difference is a mindset of choosing your crops based on the conditions you have,   vs.  trying to choose all your traditional idea of what you should grow and then trying to make it happy in conditions it doesn't like.   Even within those traditional crops,  you can often find varieties with a big variation of what/where they can grow.    I personally prefer part shade conditions to grow in!

Josh said, "When I read/listen to experienced people (Geoff Lawton, Toby Hemenway, others) talk about permaculture, they always talk about the benefits of shade.

Being in Texas, I can also praise the benefits of shade.

I feel people in Australia, California, Arizona, and New Mexico will also agree.

Even here in southern Oregon, shade is a very welcome thing hence my best dappled shade tree for raised bed garden post. I have come to find that nothing likes full sun/heat here in the summer. Some things will tolerant it but nothing really wants it.

Good to hear so many people sharing similar experiences. All of your comments have been extremely helpful.

I agree that temperature tolerance is most important to determining shade requirements, but where can I find a chart of plant heat tolerances? Mr. Google has not been too helpful. There is mostly charts of germination temperatures.

I want to add one more point. John Kempf of Advancing Ecoagriculture in this video    says that when a plant reaches the highest levels of health it can photosynthesize infrared radiation. So, theoretically a healthy plant in healthy soil can grow and produce in the shade as long as temperatures are warm.