Proper Plant Spacing and Why it Matters
Give new plants the best possible start through careful placement in the garden.
When spring fever strikes it’s easy to come home from the garden center with a carload of new plants. Whether you are planting a flower garden, shrub bed, or vegetables, proper plant spacing is your first step to a healthier garden. It is easy to overcrowd plants when they are young, but plants need a bit of elbow room to gather sunlight, spread their roots, and simply look their best. These tips will help you achieve proper plant spacing in the garden and understand why it matters.
Why Plant Spacing Matters
One reason to consider plant spacing is curb appeal. We’ve all seen misshapen trees or shrubs swallowing the corner of a house after having been planted too close. Proper plant spacing helps us to avoid a tangled mess of branches in the garden. By giving plants enough room to grow into maturity, we ensure they remain visually pleasing long into the future.
Aesthetics aside, plant spacing is critical to ensuring long-term plant health. When plants are crowded together, they compete for water, nutrients, and sunlight. Crowded plants often bloom poorly due to poor nutrition, or because not enough light reaches the shaded branches. In a vegetable garden, this results in lower yields. By spacing plants to accommodate the expected mature size of a plant, you ensure plants have enough room to develop a healthy root system and limit competition for access to water and nutrients. As a result, plants are less stressed and more resistant to pest problems.
Proper plant spacing also allows for adequate air circulation around plants, which helps fight plant diseases. Many disease agents require a moist or humid environment to develop. In crowded plantings, reduced airflow prevents moisture from evaporating from leaf surfaces, increasing the likelihood of foliar diseases. Good air circulation through proper plant spacing helps reduce fungal diseases in the garden.
The Basics of Plant Spacing
Before you begin planting, consider the amount of space the plant will require when it is full grown. This information is found on plant tags and in catalogues. When starting with small, young plants, it is easy to set them too close together. Resist the urge to fill every gap in the garden. Remember, plants grow!
Using the information from plant labels, think of the mature size as the circle of space the plant needs to grow. A hydrangea that matures to 5 feet wide needs a circle with a 5-foot diameter. When setting out three of these hydrangeas together in a grouping, you will want to set them 5 feet apart, measuring from the center of each plant. While we commonly plant vegetables in rows, you can use the same circle-based method to save space in the vegetable garden.
When planting two plants together that mature to different sizes, consider the needs of both plants. The easy way to determine spacing between different plants is to use the average of their mature sizes. As an example, when planting a 5-foot-wide hydrangea planted next to a boxwood that grows up to 3 feet wide, space the plants 4 feet apart. Remember to measure from the center of one plant to the next.
It is a good idea to set out all the plants before digging holes. A yard stick or small tape measure are handy tools to ensure proper plant spacing. And don’t worry if the garden looks sparse at first. Young shrubs will fill out the garden in two to three years, and perennials much quicker. You can always plant annuals in open spaces until shrubs put on some size.