Picture yourself at the garden center salivating in front of that hot new perennial or the hard-to-find shrub you’ve coveted for the last few years. You know you’re going to give in and buy it, so the real question is, Exactly how many do you need? When deciding the number of plants to use in a composition, you can sauntera garden path between rigid theory and emotional abandon. Though most design courses drill into students the dictum of planting in threes and fives, there are ways to successfully incorporate other numbers of plants as well. Learning how to use each number gives you the tools to forge a well-designed garden. It will also give you the confidence to sometimes fudge the rules to suit your project or budget, or to simply satisfy a craving.
Learn more theory: How to Use a Color Wheel to Design a Garden
Success lies in identifying your design goals and using the correct number of plants to meet those goals. Think of each plant as part of an overall composition, considering its form, its weight, and its relationship to the surrounding plants and architecture. Evaluating your site’s conditions will also help you to choose appropriate plants and to decide how many of each to include.
The following guidelines for selecting the ideal number of plants for various situations reflect the conventional wisdom I learned by studying landscape design as well as insights I’ve gained designing gardens over the last six years. Once you become familiar with the concepts underlying these guidelines, you’ll likely find that the decision-making process about how many plants to buy becomes second nature. As you play with the numbers, just remember that if the design of your garden is not adding up the way you imagined, you can always get a shovel and shift a few plants until the whole picture is greater than the sum of its parts.
One-of-a-kind plant is OK when used correctly
Contrary to its popular musical identity, one is not the loneliest number but rather the ultimate prime number. Unless you have a specimen garden composed of one of everything (a recipe for disaster except under the most skilled eyes and hands), one plant will read as either a specimen or a unifier. If you’re going to use a single plant as a specimen or focal point, be sure its qualities are strong enough that it can stand on its own.
Two plants signal formality
Like the guards at Buckingham Palace, the number two conveys formality. Two plants tend to divide your eye, so this number works best when used like sentries to mark both sides of an entrance or passageway. Trees and shrubs are easy to use in pairs, but perennials are more challenging. Some of the larger perennials and ornamental grasses work well in pairs, as do some annuals and tender perennials.
Three plants creates balance
Though three can be tricky in human relationships, this number fits expertly in a landscape. The trick is in the arrangement. Three plants in a row is dull because you know what to expect. If you have enough space, group them in an equilateral triangle. This looks particularly good with mounding or vertical plants. Be sure to leave some space between the plants, especially if they are three different kinds. You can even use a garden ornament, like a birdbath, to count as the third item in a set of three.
Four plants work best when divided
Four can be divided in various ways. Avoid planting two and two, even on the sides of an entry, because it rarely works. It feels off-kilter, always calling for more to make it three and three. A good way to use four plants is by putting one in each quadrant of a circle or square, either planting four distinct specimens or repeating the same plant. Another device that works well is dividing 4 into 3 + 1, positioning three on one side of a path and one on the other. Because of their strong weight, this is especially effective with evergreens.
Five plants is pleasing to the eye
Five is a number that is used often in designs. A classic example of five is to set up two parallel rows with three in one row and two in the other. This works best in rectangular beds but can work in irregularly shaped beds too. That is not the only way to use five plants. I have found that positioning two plants on one side of a path and three on the other does not work (especially with mounding plants), but having four balanced by a fifth feels right.
Six plants should be divided into two sets of three
Six works best when it is broken into two groups of three. You can either duplicate the arrangement of threes (in a staggered row or in a triangle) or position them to fill a corner. Dividing plants into groups of two and four doesn’t work because it is unbalanced, nor does a line of six specimens, because they will compete for attention.
Seven plants and more becomes a mass
With seven plants, you achieve enough mass to start making a strong visual statement. Once you get as high as seven, you have some leeway to either plant in masses or plant the same plant in groups of 3 + 3 + 1. Avoid 3 + 4 because it feels unbalanced. Even numbers higher than seven can be divided into two sets of odd numbers, such as 12 divided into sets of 5 and 7. Odd numbers higher than seven can be separated into groups of odd numbers. For example, 3 + 3 + 3 = 9 works, but avoid breaking up an odd number of plants into an odd-numbered group and an even-numbered group, such as 5 + 4 = 9. At a certain threshold, roughly around a dozen depending on the type of plant, the eye can’t tell whether you have a mass of 12 or 13 plants. Once you reach a critical mass, you don’t need to worry about counting anymore.
FAQs
How Many Plants Do I Need?
- For a square bed, multiply the length of the bed by its width to determine how many plants per square foot.
- For a circular planting bed, you can calculate how many plants per square foot is ideal by multiplying 3.14 by the distance from the center to the edge of the bed.
In general, multiply the number of plants per person by 3 or 4 for a family-sized planting. We've done the work for you in adjusting the numbers of these plants in the chart so at harvest you aren't overwhelmed with too many delicious veggies.
What is the gardening rule of 3? ›
Three plants creates balance
If you have enough space, group them in an equilateral triangle. This looks particularly good with mounding or vertical plants. Be sure to leave some space between the plants, especially if they are three different kinds.
What is the ratio for garden design? ›
Proportion. Many people overlook the golden rule of proportion when planning out their garden. The golden rule of proportion is a ratio of 1:1.64 and it's the same proportion as the human body. To create a feeling of 'rightness' and comfort in your garden, apply this rule to all hard landscaping.
How do you calculate the number of plants? ›
Explanation: The plant population of any given area is calculated by multiplying the plant life spacing by the row spacing. A hectare is ten thousand rectangle metres in size in general. Divide ten thousand by the result of multiplying the plant spacing and row spacing among each other.
How do you estimate plants? ›
To calculate plant population per acre:
- Determine the area of the field in acres.
- Multiply the area of the field by the number of plants grown per stand.
- Divide the result by the product of space between plants in acres and space between rows in acres.
You can typically grow 6 to 12 small plants like lettuce and carrots per square foot. You can grow 4 to 6 medium plants like basil or zinnias per square foot. Each large fruiting plant like a cherry tomato will cost you 1.5 square feet.
How many plants are needed for one person? ›
Moreover, the absorption rate for carbon dioxide also changes at different temperatures. According to scientists, one leaf produces around five millilitres of oxygen per hour. So, it will need around 300-500 plants to provide oxygen to one person.
What is the best layout for a vegetable garden? ›
As a general rule, put tall veggies toward the back of the bed, mid-sized ones in the middle, and smaller plants in the front or as a border. Consider adding pollinator plants to attract beneficial insects that can not only help you get a better harvest, but will also prey on garden pests.
How to arrange garden plants? ›
There are two basic rules when arranging plants in the beds: 1) space the individual plants so that they touch each other when they reach their mature size, and 2) overlap the masses of plants and connect them so that they flow without space between them. Avoid gaps or large open areas between masses.
The ideal number for groupings is always an odd number – 3, 5, 7, or even more. This allows you to space them more naturally. Remember too that a group should look like a unit, so space the plants a distance about 65% of their final width, so they grow together a little and make a solid mass.
What are the three elements of gardening? ›
But before that day comes, there are three essential elements you should consider when planning your garden space: soil, water and light.
What is the golden ratio in gardening? ›
The golden ratio is 1.618, and it can be used in a myriad of ways. The “Golden Rectangle” takes it a step further: the ratio of the short side to the long side should equal to the ratio of the long side to the sum of the long and short sides.
What is the golden ratio in design? ›
Consider the Golden Ratio a useful guideline for determining dimensions of the layout. One very simple way to apply the Golden Ratio is to set your dimensions to 1:1.618.> For example, take your typical 960-pixel width layout and divide it by 1.618. You'll get 594, which will be the height of the layout.
How do I plan my garden layout? ›
Map Out Your Plants
Sketch out your plan on paper. Use graph paper and draw to scale, keeping in mind the mature size and habit of each kind of plant. Site larger plants, like corn and tomatoes, where they won't cast shade over shorter plants. Choose compact varieties if you have limited space.
How do I know how many plants to buy? ›
Calculate the square feet each plant will cover by multiplying 0.67 feet by 0.67 feet, which equals 0.45 square feet per plant. Divide the 42 square feet of the bed by the 0.45 square feet each plant will fill to calculate the number of plants to purchase, for a total of 93 pachysandra plants.
How many plants can you have in a 10x10? ›
Most cultivators utilize roughly 70% of a room's floor space as the canopy. In this scenario, a 10 x 10 room can hold up to 70 plants. Efficient facilities take advantage of tiered growing systems. Each tier increases production capabilities and can triple a room's canopy.
How many plants are needed for one human? ›
A person would need to be in a room with about ten thousand leaves. About 300 to 500 plants would produce the right amount of oxygen, but it's much harder to estimate the amount of carbon dioxide the plants absorb, especially if every time a person breathes out, they inhibit oxygen production.
How many plants needed for one person? ›
Moreover, the absorption rate for carbon dioxide also changes at different temperatures. According to scientists, one leaf produces around five millilitres of oxygen per hour. So, it will need around 300-500 plants to provide oxygen to one person.
Three plants creates balance
