As you probably already know, sunlight is a vital element in the process of photosynthesis and is thus incredibly important to plants. Different amounts and types of sunlight are required by specific plants in order to grow or produce fruit. As important as it is, unfortunately sunlight is one of the plant requirements that we are able to change or manipulate the least. You can amend your soil, add organic matter, create a water schedule, but for the most part, creating more sunlight is beyond most people’s means. When designing your garden, it is quite important to understand how the sunlight moves across the property in order to place plants in their best locations.
Most fruiting vegetables, trees, and shrubs require full sun in order to produce substantial yields, though beans and peas can tolerate higher levels of shade than other fruiting plants. Root vegetables are typically able to thrive and produce with less sun than fruiting plants. Leafy greens are usually able to tolerate the least amount of sun, as far as the most commonly cultivated plants are concerned. They still require some sun, though.
The categories most typically used when discussing amount of sunlight are full sun, partial sun, partial shade, and full shade. Each one is defined by the daily amount of uninterrupted sunlight a location receives. Full sun is typically defined as at least 6 hours of unfiltered sun while partial sun and partial shade are between 6 to 3 hours of sunlight. Shade is typically defined as less than 3 hours of direct sun, with filtered light during the rest of the day. Important to note that full shade does not mean no sun, as that is inhospitable to most plants.
While these categories are useful, the full picture is a bit more complicated as sunlight can not only vary in length, but also in intensity. Afternoon sun is more intense than morning sun and a denser canopy will allow less light to pass through. A plant which needs partial shade may be alright with a few hours of sun, as long as it is in the morning. Sun loving plants can tolerate less direct sun as long as the rest of the day the shade is not too dense. Some shadier plants are able to stand more sun if they are watered more frequently while some shade plants will only burn in direct sun.
So, now let’s say you’ve a property with a lot of shade but you still want to garden. There are a few techniques and design strategies you can use. First, there is the possibility, depending on circumstances, of thinning out a canopy, either by taking down limbs or entire trees, in order to allow more sun in. Though clearing trees will not normally create a drastic shift in sunlight, due to forest and gap dynamics. A clearing has to be a certain ratio of width to height in order to create a sunny spot. Trees will also grow in order to fill in gaps that were once occupied. This means in order to create a lot of sun in a fully wooded area, many trees would have to be cut down as the clearing needs to be wide enough to let sun in as well as big enough to keep the trees from closing the canopy.
Second, you can take advantage of what little sun may be present and simply design around that. Typically, the northernmost edge of a clearing will receive the most sun. Eastern edges will get afternoon sun while western get morning sun. Sunnier plants would be on the northern and eastern edges while the shadier plants would do well on the western side. Selecting plants to the site is a very useful design process. While you may have really wanted to grow tomatoes and watermelons, you may have to grow shadier plants, like strawberries or blueberries, which can thrive in sun but are also able to tolerate more shade. Shading greens can keep them from bolting too quickly in hot summers. Herbs are also able to tolerate greater amounts of shade. In such an instance, I’d suggest making friends who also garden. You can exchange resources, like herbs or other medicinal plants, for veggies that they were able to grow.
The third technique may seem counterproductive but can actually be quite useful and interesting and that is to possibly create even more shade so as to grow specific plants, many of which can be medicinal. You could also grow mushrooms in a denser shade.