Understanding Sun Exposure:
There are three basic sunlight conditions that are used to describe the amount of sun during the prime-growing season:
Full Sun: Full sun areas receive direct sunshine for 6 or more hours per day between the hours of 10 am and 6 pm. In northern climates where the sun strength is weaker, plants requiring full sun do better with 8 or more hours per day.
Partial Shade: Partial shade or partial sun both refer to areas that obtain 3-6 hours of sun each day. Partial sun areas receive 3-6 hours of direct sunlight but are shaded the rest of the day. Partial shaded spaces are moderately shaded during part of the day or receive filtered or dappled sunlight all day. Dappled sunlight is where the light is filtered through the leaves of trees.
Full Shade: Full shade areas receive no direct sun or reflected light during the day. An area with deep shade is not a good place for growing vegetables. All plants need some light to grow.
Partial Sun and Partial Shade Vegetables
On the seed packages in the garden stores and catalogs, you will often see the words “partial sun” or “partial shade.” But what does this mean, exactly?
“Partial Sun” are vegetables that require at least four hours of sunlight per day, but often thrive with less than six hours of direct sunlight.
“Partial sun” usually means that the plant could still do well with more sun, and “partial shade” often means that the plant would do better with four to six hours as a maximum.
Partially shaded garden areas provide an opportunity to extend your cool-season crops from spring into early summer. A little shade in late spring will help prevent your leafy greens from turning bitter and bolting as the temperatures rise.
While the heat loving tomatoes, melons, and peppers prefer drinking in as much sunshine as they can get, some crops wither and die in hot, bright sun conditions. There are plenty of vegetables that grow in shade, dappled sunlight, or with as little as 3-6 hours of sunlight per day:
Vegetables that fruit from a blossom, such as cucumbers, tomatoes, peppers, and squash are the least tolerant of shady areas. Plant these in full sun areas that receive the most direct sunlight per day.
Root vegetables, such as beets, carrots, and potatoes will grow in partially shaded areas that have less direct sunlight, but will appreciate at least a half-day of full sun and some partial shade.
Leafy vegetables, such as chard, spinach and salad greens, are the most tolerant vegetables that grow in shade. In fact, keeping these plants shaded as the season heats up will help them last longer. Plant these crops in areas on that are moderately shaded during part of the day or receive filtered or dappled sunlight all day.
Vegetables That Grow in Partial Shade or Partial Sun
Salad Greens – Salad greens like loose leaf lettuce, sorrel, endive, cress and arugula will actually scorch and bolt to seed if they get too much sun all day. If you plant them in partial shade, you might be able to harvest these veggies for a few weeks longer than those with full-sun gardens.
Herbs – Herbs like as mint, chervil, coriander/cilantro and parsley prefer partial shade. In fact, mint is a such a strong plant, even your best attempts to kill it will probably fail. Be sure to grow it in a container so it doesn’t smother everything around it.
Peas and Beans – If your garden area gets at least five hours of sun each day, you might be able to grow some peas and beans. Just be sure to choose bush and dwarf varieties rather than pole varieties.
Broccoli and Cauliflower – Full sun on broccoli can cause rapid flowering (which ruins the taste), while partial sun encourages tighter heads and slower flowering. Remember that after you cut off the large central head, leave the plant in the ground so smaller heads can form along the stem in the leaf axils. With cauliflower, limiting sunlight to under 6 hours daily means tighter heads of cauliflower.
Cabbage and Brussels sprouts — Brussels sprouts are a cold-tolerant plant, and like most cool-weather plants, they do well with limited sunlight. Although cabbage is broad-leafed, too much sun will dry it out and encourage smaller heads and bigger open leaves.
Radishes – Radishes are fast-growing, easy veggies that fit nicely between your larger plants. They prefer a bit of shade during the heat of summer, when too much heat can cause them to turn woody and bolt to seed.
Leafy Greens – Super nutritious greens like spinach, Swiss chard, collards, mustard greens and kale only need about three or four hours of sun each day to thrive.
Root Vegetables – Beets, carrots, potatoes, rutabaga and turnips will do OK in partial shade, but you’ll have to wait longer for a full crop. But the good news is that less light encourages more root growth than leaf growth. And, don’t forget that with beets and turnips, you can harvest the delicious greens, even if the root stays small.
Leeks and Onions — Leeks and onions thrive in cooler, more moist environments, and need less sun in order to encourage below-ground growth.
Most vegetables and herbs require at least six hours of sunlight a day to grow, but some plants will tolerate partial shade. Great shade-tolerant vegetables include: