Why Is Sunlight Necessary for Vegetable Garden Success?

Sunlight. It's the first thing that should be on your mind when you're thinking about setting up or creating an edible garden. Sunlight is critical for most plants in a vegetable garden, and for many plants in the garden, the more hours of sunlight, the better.

Plants are living things that need food to grow... just like animals. But much cooler than animals, plants actually know how to make their own food. In fact, they're basically a food factory. And just like a factory, plants need a few things to run.

First, a machine. Good news for us gardeners: the plant itself is the machine. It's got all the mechanisms it needs inside to convert raw materials into food so it can keep growing.

Second, just like a factory, plants need some raw materials. For plants, these materials include carbon dioxide, minerals and vitamins from the soil, and water. These three things provide what plants need to crank out the food.

Finally, plants need POWER. Pull the plug on a factory, and even if the machines are top of the line and the raw materials were just delivered, nothing's happening until the machine gets plugged back in. Where do plants get the power for their in-house food factory?

Sunshine!

Sun rays are the power source for the amazing plant power of self-sustainability. The sun is the fuel that runs the plant's engines to crank out its food supply so that the plant can keep growing.

Now that we know why a vegetable garden needs sun, let's discover how much sun plants actually need.

How Many Hours of Sun Does a Garden Need?

The answer to this question really depends on the type of vegetables you're planting and growing in your kitchen garden.

Going back to the factory analogy, the amount of power your machine needs to make a certain product really depends on how complicated the product is, right? If it's just making a toy slinky, chances are that a little bit of power is needed to crank out a slinky or two or three every few minutes. But if that factory is making a motorized toy car or an iPhone, well, I'm guessing that factory is going to need a lot more fuel and energy to crank out the product.

The same is true in the vegetable garden.

If the plant you're hoping to grow is a simple, quick-growing one, like arugula or chives, then the sun necessary to get that plant to grow all the way into a beautiful harvest won't be that much. But if the plant you're growing is an eggplant or a huge gourd, these plants involve more complex steps to reach maturity. It's going to take much longer for them to grow to the point that you're ready to harvest their fruit. That long growing period and complexity means one thing: they'll need more sun.

You Can Still Have a Vegetable Garden Even if You Don't Have Lots of Sun

The more sun you have on your vegetable garden, the more success you'll have overall. If plants are planted at the right time and season in your garden, they'll thrive if they get loads of sunshine.

But that doesn't mean that you still can't have loads of success with less than 8 hours of sun. There are many edible plants that will grow even if their leaves aren't covered with light from sunrise to sunset. I know this is true because I've seen it work in my own kitchen garden and in dozens of my clients' gardens, as well.

My first company worked exclusively inside the city of Houston, TX, where the chance of finding a large prospective kitchen garden space that got at least 8 hours of sun a day was slim to none. I was happy if I could manage 6 hours a day. And yet, my clients have beautiful and productive kitchen gardens all over the city, just like the one you see pictured here.

Plant Your Vegetable Garden According to How Much Sun You Have

Once you find the spot for your vegetable garden with the most sun possible, you'll then select appropriate plants for the garden based on that amount of sunlight. Most plants will survive with less light than they'd prefer, but they won't thrive. If you're okay with plants taking forever to grow to maturity or never quite maturing, then you can stretch the boundaries a bit with the plants you decide to grow.

Let's start at the very bottom of the sunlight requirements.

2 to 4 hours of sunlight

This is the bare minimum of sunlight that an edible plant can survive on. If you only get 2 to 4 hours of sun, then you'll have to stick with growing herbs. Many herbs are from the Mediterranean area and love sun. They will nevertheless continue to grow with less-than-optimal light—they just won't thrive. That means you'll still get delicious leaves to harvest, just not as many as you would if the plant were growing with more than 4 hours of sunshine.

You'll know your herbs are not getting enough light if they start getting leggy (tall and spindly) and/or the new leaves seem stunted compared to older ones.

Herbs that tolerate partial sun or shade include mint, chives, lemon balm, dill, cilantro, and parsley.

4 to 6 hours of sunlight

With just 4 hours of sunlight a day, you can still have a garden filled with leafy greens like lettuce, arugula, and spinach. These plants will produce leaves with just 4 hours, but they'll grow to their full potential with something closer to 5 or 6. Basically, the more hours of sunlight, the more leaves you'll get and the bigger the plants will grow, but you'll still get plenty of salad green harvests from a bed that receives just a few hours of light. 

On warmer days, many of these plants actually prefer a bit of afternoon shade, which you can work in your garden's favor.

You could try to grow carrots, radishes, and beets with 5 to 6 hours of sunlight, but they'll take perhaps twice as long to grow. You're also likely to get most of the growth happening above the ground, when it's the root below the soil that you really want to enjoy.

Only attempt to grow tomatoes, peppers, and eggplants if you don't mind disappointment.

6 to 8 hours of sunlight

With this amount of light, you can easily grow your own root crops like carrots, radishes, and beets. Don't forget that you can also grow leafy greens and herbs, so it's very easy with this amount of sunshine to have a flourishing kitchen garden filled with delicious things to eat.

You can also grow bulbs like onions and garlic if your garden receives closer to 8 hours of sunlight.

8 or more hours of sunlight

If you've got a space with eight plus hours of sunshine, you can plant just about any vegetable as long as you get the timing right with your growing seasons.

Lettuces, herbs, and greens? Yes.

Carrots, beets, and radishes? Yep.

Tomatoes, peppers, and eggplant? For sure.

You could even grow your own potatoes and sweet potatoes, which will soak up every minute of sun you give them.

If you've got loads of sunlight and you grow your edible plants while they're in season, then they're going to thrive.

Vegetable Gardens Without Full Sun Can Be Lush & Beautiful

The great thing to know is that unless you're trying to set up your vegetable garden in a dungeon, cave, or basement, something green will likely grow in that space. Remember the factory? The machine still works, it just produces simpler things when it has less power.

Your plants are amazing food machines that are dying to grow. And they'll stretch and reach and make the most of every bit of sunlight that you can give them. At the very least, you'll get lots of leaves.

And if you've never tasted homegrown salads, herbs, and greens, then you're in for a treat, even if you were wishing you could grow tomatoes.

So whatever you do, don't quit on your garden dreams just because you don't think you have enough sun to make it happen. Grow the simpler plants, harvest all the leafy greens you can, and if you've got more sun, grow beautiful fruiting vines, too.