Why Garden Plants Need So Much

There are three reasons your garden plants need so much direct sunlight: 1) garden plants’ natures as annuals, 2) our expectations for their production, and 3) how they’ve been treated and have adapted since being domesticated.

The Reasons

First, except asparagus and rhubarb, common garden plants are either annuals, only growing for one year, or grown as annuals. Most annuals, by their nature, need lots of sunlight, as much as possible, with few exceptions. As annuals, their adaptive strategy is to take in massive amounts of energy to produce enough seeds to sprout the next year. It’s how annuals work: Dying after one year of growth means that creating seeds for the next year is essential to long-term survival. There are no second chances for a year of inadequate sunlight. Plus, needing to start over each year often means competing with established vegetation to get established. Many annuals adapted to this by making super energy-dense seeds to give their seedlings as much of a boost as possible in this competition, making massive amounts of direct sunlight even more critical to their survival.

Second, ever since the beginning of their domestication, we humans have been expecting, and selecting for, the most productive plants. We don’t want our garden plants to merely survive, just barely making enough seed to reproduce themselves the next year. We want them to thrive! We want large broccoli heads, full ears of corn on tall stalks, and full-bodied pumpkins, rich in flavor. Although our horticultural ancestors carefully selected for these desired traits year after year, the trade-off is that it takes massive amounts of sunlight for plants to meet these desires.

Third, our horticultural ancestors realized over time they could reach these desires, not just through selection but also, through limiting or eliminating competition for light, water, and soil space by clearing areas and spacing plants ideal distances apart. As such, our garden plants have been domesticated for hundreds and, in most cases, thousands of years to grow in cleared areas of bare soil with tons of sunlight. When your garden plot is surrounded by hundreds of similar garden plots, that’s the nature of it; there is sun from unobstructed horizon to unobstructed horizon. And that is the environment in which most, if not all, of our garden plants were domesticated and have adapted to over those many, many years.

Imagine Growing Garden Plants in Your Lawn

To get a better idea of what it takes for a plant to grow from seed each year, imagine trying to establish your vegetable patch amongst your existing lawn—just planting your seed right in your grass—or, even better, in an existing field where the dead, dried grasses and forbs from the previous year are already two-to-five feet tall and will quickly add new growth to those heights again. Your vegetables would languish tremendously, right? If they’d even sprout, they wouldn’t make it past being paltry seedlings. The already-established plants would shade them out, never giving them a chance to grow. Even if somehow they got started, they’d be outcompeted for sun, water, and soil space by the existing plants and end up being stunted miniatures of their otherwise proud selves. 

The Upshot

Garden plants need clear space to grow. That’s their genetic, cultural, and adapted nature. Not only do they need clear space, but they also need bare ground. This is why you spend so much time weeding. Most of them can’t take any competition from surrounding plants without really languishing. As you’ll learn later, even others of their kind being too close on otherwise completely bare ground, makes many of them stunted.

As such, give them what they’re adapted to or they won’t do well. They’re literally made for open areas, so much so that they’d all disappear without us clearing the ground for them and making sure they get plenty of sun. So let’s give it to them!