Gardening Principles: Light | The Best Gardening

Gardening Principles: Light

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What exactly does light have to do with the growth and productivity  of our gardens? Everything.

Garden principles - how to plan and arrange a garden for maximum light and food production.png

Growing a successful garden takes some careful planning.  You need to consider water, soil fertility, climate, crop rotations, organic matter sources, etc.  But one of the most important things you want to consider from the very beginning islight and how you manage sunlight in your garden.

Light is the source of energy plants use to turn carbon dioxide from the air into carbohydrates that we can eat.  Put simply, plants must have sunlight to make food.  It’s a pretty cool thought to consider that when I bite into a juicy tomato or a crisp apple, I’m eating a bit of sunshine.

In the absence of light, plants loose the energy needed to fuel their food producing systems.  Crops that are grown in the shade will be stressed trying to feed themselves, and if they’re having difficulty feeding themselves, they certainly won’t feed you or me.  In fact, as the sun goes down, plants still need energy to maintain their biological systems, so the production train reverses for that short period, and the plant uses a bit of its stored sugars to feed itself during the night.  When sunlight returns, the plant resumes its carbohydrate producing ability.

The amount of carbohydrates that the plant uses at night are only a fraction of what it produces during the day to form structural and edible sugars (to learn more about that topic, I think you’ll find this article informative).  But imagine if the plant only got half the amount of light it really needs.  The amount produced, overall, would be hugely reduced, and the ratio between production during the day and energy consumption at night would be much smaller.

The highest levels of food production require the maximum amount of sunlight exposure possible.  Ideally this would amount to 8+ hours of direct sunlight per day, so choose your garden location carefully!  Observe shade patterns throughout the year (particularly from late spring to early fall) and avoid putting your garden in the path of shade on your property.  Where possible, prune back overhanging tree limbs and remove other obstacles that will cast a shadow on your garden.

Also, remember to arrange plants within the garden plot itself so crops don’t shade each other (unless your particular crop requires partial shade).  This means putting taller crops in the back of the garden and shorter crops in the front of the garden.  Not sure which side of your garden is the “front” or “back”? … That’s okay because, in general, it depends on where you live.

☀ For those in the northern hemisphere, the “back” of the garden is the northern end of the garden and your “front” of the garden is the southern end of the garden.

☀ For those in the southern hemisphere, the opposite is true: the “back” of the garden is the southern end of the garden and the “front” of the garden is the northern end.

☀ First exception: If you live close to the equator, then you’ve got a lot of overhead sun, so there’s not really much of a ‘front’ or a ‘back’.  Even where we are, in the southern United States, the sun seems slightly north of us for 6 to 8 weeks or so.

☀ Second exception: If you live on a hill or mountain slope, it’s going to impact the way sunlight hits your garden, whether you’re in the northern or southern hemispheres.  (Are you on the north, east, south, or west side?)  Besides changing what kind of light and shading you get, the rise of the land will also change the angle that the sunlight is hitting your crops (see image below).

growing plants on a hill changes the way the sunlight hits your plants

What about growing crops indoors?  Either put crops next to the sunniest window  in the house, or use the brightest artificial light you can find.  If you choose to use artificial light, the closer the light is to your crops (without burning them) the better.  But artificial lights, even the best ones, are significantly inferior to the power of direct sunlight.

Light color in artificial lighting is of less importance, but for those interested, plants use red and blue light the most.  In order to get a good mix of these two heavily used colors, and the other colors plants use too, white light is the best.  You don’t have to buy any ‘special’ lights for plants; a good white, bright light is best.

As an ending topic and side note, have you ever wondered what it is about plants that actually makes them green?  It turns out that of all the light colors in the rainbow green is the least used by plants.  And because green light is the least used it is mostly reflected by the plant instead of absorbed.  The reflected green light is what we see coming off of the leaves of plants.  So there you have it: plants are green because green happens to be worthless to the plant, but I’m grateful plants don’t use green because I love the color green.

About John

Gardening for life, liberty, and happiness. I enjoy being with my wife and family; mowing the lawn; working in the garden; eating (I love food... what can I say?); studying business, gardening, and other subjects; and experiencing all the amazing things life has to offer us.

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5 Responses to Gardening Principles: Light

  1. Sandra March 27, 2013 at 8:49 pm #

    I guess it should seem obvious, but it didn’t. Our garden is just too shaded. I thought, “Oh, it’s getting enough light, maybe we’re just not watering enough.” (But then maybe we started watering too much.) I really think it’s a light issue.
    I wonder if my neighbors would be cool with us having our garden in our front lawn since our backyard just doesn’t get enough light? :)

    • Anni March 27, 2013 at 10:07 pm #

      Let’s hope your neighbors are okay with that! I know there are some HOA’s that don’t allow it. Which is only one reason why I will never, ever, ever be part of an HOA!

  2. Heber April 6, 2013 at 7:37 am #

    We live on a hill, and we’ll be installing a garden this year. To get enough light, the best place for us to put the garden would be on the south side, which is entirely hilled. My first question is, is that going to be an okay place to grow a garden?
    Second, you mention that light from the sun hits plants at a different angle when they’re grown on a hill than when they’re on flat ground. What implications does that have for the plants and the productiveness of the garden?
    Thanks very much.

    • Anni April 6, 2013 at 6:55 pm #

      Heber,

      Having a garden on a hill will work just fine, as long as it’s terraced somehow, to help hold on to water instead of having it all drain away.

      Sunlight does hit the plants at a different angle when they’re grown on a slope. If it were a steep mountainside, it would make more of a difference, but on a hill, it won’t make much of a difference. The difference, though, is that instead of hitting the leaves with light from above, it comes in a bit sideways. A lot of plants naturally adjust to the angles of the light by bending their leaves and stems to get maximum light exposure. So, I guess the final answer to that question is that in your terraced garden, it won’t make much of a difference in production.

      Thanks for stopping by!

  3. Genevra April 6, 2013 at 8:46 pm #

    I wonder what chances I have of my neighbors letting me have my garden in my front yard. It’s the only sunny spot on our property.

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