What Green-Thumbed Gardeners Know About Sunlight

The Common Read

Plants need light. We all know that, but some of us get confused on the needs of our garden plants because some of our non-garden plants do well with smaller amounts of direct light or even indirect light. Not so with garden plants. In gardeners’ terms, indirect light is shade. And garden plants just don’t do well in shade. Instead, they need full, direct sunlight and massive amounts of it!

The gardening literature hasn’t helped this misunderstanding.

If you were to read several gardening books, you’d find the light requirements for garden plants mentioned on one page in the beginning of the book, if at all, as the authors hurry toward their main points—of disease or pest control, a specific idea for bed or soil preparations, or an overview of each plant’s requirements—without explaining what all plants need and why. Those who mention it all say the same—at least six hours of full sun—as if they’d just looked up the definition of full sunlight, or “full sun,” and saw that most sources define it as at least six hours of sunlight a day. Experience, however, tells every good gardener something more. So let’s start correcting the record.

First, let’s be clear for everyone what constitutes “full sunlight”, or “full sun.” It means sunlight is directly hitting the plants for several hours each day. They aren’t just brightly lit up, as can be the case in brightly lit shade. The sunlight hits them first before hitting anything else. And this is not dappled sunlight and shade. It is absolutely full, complete, unobstructed, direct sunlight. There is no shade or shadows cast on them at all during this time. 

What Green-Thumbed Gardeners Know

Green-thumbed gardeners take it a step further. Since they know there’s nothing like sunlight, they know that siting their garden plants for maximum direct sun exposure is their most important and first priority. They, therefore, plant in a space that’s as open as possible to get as much full, direct sun as possible.

Gardeners with two green thumbs often go a few steps further. These gardeners take all possible shade casting features into account within that open area—houses, sheds, trees, bushes, etc.—to choose a specific spot with the absolute most available sun. They’ll also mull the tough decisions to move a garden or remove some trees or buildings to give them completely unobstructed horizons and the absolute maximum amount of full sun. Whenever I see a garden clearly situated with maximum sunlight in mind—for example, at the far backside of a yard to avoid the evening shade of even a small shed to the west—I know it’s the handiwork of an expert gardener, someone who understands there no substitute for having the maximum amount of direct sunlight. 

These two-green-thumbed gardeners can also quickly tell whether it’s worth it or not to site a garden on any prospective site—some sites just won’t have enough available sun—and, on marginal sites with significant but passable obstructions, they know how to position the garden for the maximum sunlight available, even if less than perfect or ideal.

Two-green-thumbed gardeners also have few special tricks up their sleeves. They know the one or two garden plants that benefit from slight, or slightly dappled, shade and how to easily provide it, just as they know how to start cool-season plants in heat of direct mid-summer sun when they’ll usually remain dormant or languish. Additionally, most will take steps to extend their outdoor growing seasons—and, hence, their plants’ time in the sun—with cold frames, row covers, hoop houses, greenhouses, and carefully-timed plantings. And, because these gardeners know the exact path of the sun as it changes throughout the growing season, they’re able to plan ahead for maximum sunlight in each of these future seasons that have much different sun angles and shadows.

To many new gardeners, these two-green-thumbed gardeners’ skills seem so ingrained and intuitive as to be inborn. In fact, these skills may be such second nature for many green-thumbed gardeners that they may have a hard time explicitly explaining all of their finer points. But all were learned. And, although it may seem hard to gain this knowledge, each piece can be broken down into a discrete, easily learnable skill—that’s the purpose of this website and book—and I’ve created some tools to make the difficult processes easier.

In the following posts and pages, you will learn how to do all of this! But, first, let’s start by truly understanding how much sunlight our garden plants really need.