Having a shaded garden does not mean you can't grow and enjoy vegetables. Many vegetables tolerate some degree of shade with leafy vegetables most suitable and those that require flowers to produce edibles least suitable. Root vegetables, such as potatoes, that require a half a day of full sun can do well in partial shade if that requirement is met.
Types of Shade
Not all shades are the same. Full shade has minimal levels of direct sunlight on the ground at any time and is often found on the north side of buildings. Partial or medium shade exists where the sun is blocked for the majority of the day, but some direct sunlight will reach the ground at times. Areas with dense tree cover, recessed south-facing areas, or ground under decks is usually medium shade. Light shade occurs where the ground is shaded but bright, or experiences only a few hours of complete shade in a day. Ground that receives only morning sun and areas under small or open trees experience light shade. Filtered sunlight occurs when lightly-branched tree canopies block some of the sun's rays.
It is important to assess the water and nutrition needs of the shady area. If the shade is caused by tree canopies, bear in mind that there may be root competition for moisture. Nearby trees and structures may also cause the area to be deprived of nutrients. Adding soil amendments such as leaf mould, compost and sphagnum peat moss can help dry soil hold moisture. As shade plants tend to do best with rich, fertile soil, adding fertiliser may be necessary before planting.
Effects of Shade on Growth
Although some herbs, especially in the mint family can do well in shade, lack of moisture and nutrients due to root competition has a negative effect on their growth. Light or partial shade will give better results with all vegetables than full or medium shade. Leafy vegetables will not be as robust and leaves will be thinner. Two to six hours of sunlight is generally required, even for leafy vegetables. Leafy vegetables can be used to fill in shady gaps created by other plants and harvested as needed.
Vegetables That can Tolerate Shade
Herbs that can be grown in shade include garlic, mint, tarragon, lemonbalm, coriander, thyme, lovage and parsley. Root vegetables such as potatoes, carrots, beets and turnips can grow in partial shade. Leafy vegetables are the most shade tolerant and include lettuce, Swiss chard, spinach, arugula, endive, radiccio and broccoli and its relatives such as kale and mustard.
- Colorado State University Extension; Perennial Shade Gardening; Dick Christenson; August 11 2007
- University of Minnesota Extension: Gardening in the Shade; Deborah L. Brown; Reviewed 2009
- Old House Web: Vegetables - Shade
- Colorado State University Extension; Vegetables for the Shady Garden; John Durham;