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Determine seed and plant quantities

Choosing the quantity and stock type is just as important as selecting

plant species. This decision will greatly affect project establishment. It

is influenced by overall project goals, budget, and time frame.

Seed quantities

When using native seed, we recommend calculating the amount

of seed needed for a particular species by estimating the amount

of native seed of that species to apply per square foot or per acre.

Native seeds vary greatly in size and shape, depending upon the

species you are using. A species with a high seed count per ounce

will require much less seed to cover a given area than another

species with a lower seed count.

For example, 1 ounce of Broad-Leaved Purple Coneflower

(Echinacea purpurea)

contains 6,600 seeds. In contrast,

1 ounce of Foxglove Beard Tongue

(Penstemon digitalis)

contains 115,000 seeds. To provide the same coverage per acre,

you need approximately 17 times as much

Echinacea purpurea


Penstemon digitalis


Determining how many total seeds per square foot are enough for

a site depends upon project goals, budget, and resources. Cardno

native seed mixes are designed with an application rate of 50 to

95 native seeds per square foot, depending on the mix. Acceptable

results can be achieved by using an approximate seeding rate of 20

to 30 seeds per square foot, including grasses and forbs.

Note that some species are early successional, or “pioneers,”

meaning they are dominant early on in project establishment. Others

are more conservative and do not establish readily from seed. These

more conservative species might be more suitable to be included as

plugs or larger container sizes. Cardno’s nursery team can discuss

these options with you.

Plant quantities

The size of the live plant to use will depend on budget and project

expectations. Plugs are less expensive than quart or gallon-sized

stock, but they will be less showy after planting. After a full year

in the ground, it is difficult to distinguish a planting installed with

plugs versus gallons. However, because gallon stock is larger at

installation, they are typically second-year plants, meaning they will

be more likely to bloom during the year following installation.

When estimating the number of plants, keep in mind plant size at

maturity. Many native species are at least 3 feet tall and 1 or more

feet wide at maturity. While a planting density of 1 foot on center

will look great during the first year, the plants will be very crowded

once they mature. Spacing larger plants 18 or 24 inches on center

will be less costly and just as showy in the end.

Prepare site for installation

Prior to installing native seed or plants, the site needs to be

prepared properly, which involves identifying existing native plants,

removing unwanted vegetation, stabilizing erodible areas, and

preparing the plant and seed beds. Before making modifications to a

site, however, be sure to obtain any required permits and put proper

erosion control measures in place. Cardno can assist with your

permitting and erosion control needs.

Creating a Native Landscape