YES, you’ve prepared the soil by testing the pH and amending it for good drainage; you’ve started tomato seeds and transplanted sturdy-looking plants. But your young plants is pale and leggy. And why? It is not getting enough direct sun. More often than not, it has nothing to do with soil fertility. It’s about contrast of actual direct light on the leaves versus ambient brightness around them.
Most gardeners misunderstand the term “full sun.” They assume plant only need a bright place without anything in the way, as if they could grow in open sky. What they mean is full sun: six hours or more of actualy direct rays on the plant canopy. Three to six hours of direct sun are part shade; anything less is shade.
How to Check Sunlight for Your Garden
The difference between those conditions can be crucial, for instance, a tomato plant in four hours of direct sun look fine but doesn’t set fruit. Longer exposure should of been required to get the intensity and heat it want.
Each type of crop have different light needs. For example, crops that will bear fruit (tomatoes, cucurbits such as squash and melons, peppers) require at least seven or even up to eight hours of direct sunlight to fuel their fruiting process. If they don’t get that much, they expend energy on growing rather than bearing fruit. Leafy vegetables are less picky about sun exposure: They’ll accept four hours of sun (lettuce, spinach), or three (kale, swiss chard). That’s also why your lettuce is cooked by the heat while your tomatoes is powered by it. You have best chance of increasing your harvest by matching crop to hours of sun you can provide.
Keep in mind: Your yard has multiple micro-climates. Some get less than five hours of direct sun; others up to 10 (depending on the time of day). One side gets more sun then another; for instance, a south-facing wall gets more sun than a hedge. A place next to a tree is not like a raised bed in the middle of yard. And your tree canopy will shift over the course of the year. In spring, bare branches let light filter through, making it look sunny under them. In July, leaves form a tight roof overhead and cast shade. Count your sunlight hours when the trees are out, not when they’re dormant.
How do you measure sunlight hours? It’s easy. You do not need any special equipment. Drive a post into your chosen garden bed and mark down the time of day when it recieve the first direct ray. Mark it again mid-day, and again at late-afternoon. Add up those chunks of time to equal the total. Do so on a clear day in the season you intend to plant. Want some kale come fall? Measure in September. Need a summer squash crop? Do it in June.
Sunlight hours vary by season. In mid-latitudes, June daylight totals almost fifteen hours; December daylight dwindle to less than ten. What’s full sun in summer might be part shade in winter.
Where a spot is located is just as crucial as how many hours of sun it gets. Delicate things aren’t always safe on west-facing walls; those get lots of hot afternoon sun that can burns the wits out of them. Even if they’re getting enough overall hours. Plants with delicate leaves, such as leafy greens that love heat, enjoy the gentle morning sun of an east-facing spot, but heavy feeders like corn might not.
Before sowing seed, plan the light dance and put your hungry sun-things in the brightest parts of the garden. Let the rest fill in the shady bits. Otherwise half your crop might not cooperate because you treated all garden space equally. Respect the hour count, and what the land can naturaly sustain.