Pure Air Natives

Native Grass and Wildflower Seeds

Frequently Asked Questions

Throughout the year we’re often asked the same questions over again. So we’ve tried to take some of the guess work out of it & post those frequently asked questions right here. If you still don’t find what you’re looking for, you can contact us.

*May 5th, 2020 – Still adding more questions to this page as time permits.

What makes a plant ‘native’?

USDA defines a native plant as one naturally occurring at the time of Columbus. That plant is a part of a healthy, balanced ecosystem and has developed over hundreds or thousands of years in a particular region.


How can I tell if a plant is native or not?

The USDA sets the standards for native, non-native, invasive, naturalized, exotic, and other categories of plants. A quick Google search with the ‘plant’s scientific name + USDA’ will bring up results with the USDA Plant Profile where you can find out all sorts of information about the species, including if it is native and to what areas.


What is an annual, biennial, perennial?

Annual plants are plants that grow, put on seed, and die in 1 year. Biannual plants do this over the course of 2 years. And perennial plants continue to do this year after year, some are short lived and others are long lived perennials existing for several years.

It’s a misnomer that annual plants won’t come back the following year. While technically that is true, the viable seed from the annual plant can germinate and grow a new plant the following year. This happens often in nature.


Do I need a mix of annual, biannual, & perennial plants in my prairie/garden?


The short answer is no. However, in some ecology restoration projects, the goal is to mimic Mother Nature. In doing so, a healthy ecosystem has a certain level of annual and biannual plants among the prairie. So often times, you’ll see these species included in mixes.

One of the benefits of having annual wildflower species in the mixes would be to provide ground cover and shade for your soil. These beneficial annual species will typically grow faster than perennials and therefore can complete against annual undesired or weedy species. Additionally, these annuals begin providing much needed nectar and pollen for pollinator species of all kinds.


What is PLS?


PLS stands for ‘pure live seed’ and is usually expressed in a percentage (%) based on the overall amount of seed in a seed mix. The PLS is a combination of the end results of lab tested germination rates along with purity.

Purity of seed is equal to the percentage of seed in the bulk amount to actually be seed. Because native forbs and grasses vary in sizes and shapes, it can be very difficult to have 100% pure seed in a bin/lot of seed. Often times there is a % of stems, inert matter, leaves, other organic matter, etc.

The germination rate is also tested by a lab. This determines how much of the actual seed is viable, ie how much of it is live and will germinate.

With these 2 factors we can determine the Pure Live Seed or PLS for a particular bin/lot of seed. No two bins/lots are created equal, even when it’s the same species. It’s vital that our inventory is kept separated, even from itself. For example, Ironweed harvested in one area likely has a different PLS than the same species of Ironweed harvested in a different area or by different techniques.