Cold Conditioning Native Seeds (I)

Fresh garden vegetable seed will generally germinate promptly and evenly after planting. For example, if you plant 100 green bean seeds in the correct soil temperature range and water them adequately, they will begin to sprout after about 7–10 days. And, on average, 98 or more of them will emerge over the course of the next few days. The same goes for most commercially cultivated annual flower seeds. If you try that with many native plant seeds, the result will be much different. 

In the best case scenario, most of your native seeds will start to sprout relatively soon. But in some cases, early germination may be sparse and the rest will appear slowly and unevenly. Some seeds may even lay dormant until the next year. By staggering germination times, native plants avoid putting all their eggs in one basket. Their seeds will sprout at different times and hopefully at one point the conditions will be just right for them to flourish. 

In the worst case scenario, none of your seeds — or very few of them — will germinate. Many native plants additionally require some sort of trigger to get them to germinate. One of the most common of these requirements is a period of low temperatures. (Other seeds require alternating periods of hot and cold or other treatments. In general, a treatment meant to increase the germination rate of seeds is called stratification.)  Milkweeds are one example of seeds that benefit from being exposed to cold temperatures before planting, but this very common for native perennial seeds. 

Milkweed seeds (left) and monkshood seeds (right) are two of the many native perennials that benefit from cold conditioning.

In the wild, of course, the cold temperatures are supplied by winter. Seeds that form during the spring, summer, and fall are spread by the wind or by animals. Some of them end up in a location that is suitable for germination. During their time in (or on) the ground, precipation wets their seed coats and germination inhibitors are washed away. Then, in the winter, a period of cold temperatures primes the seeds for germination. When warmer spring temperatures arrive, the seeds sprout and the plants start growing. 

As a gardener, you can cold condition your native seeds in a couple of ways. Obviously, you can plant them outdoors before your first frost and simply wait for spring. To do this, you should clear the planting location of any existing plants. Unless you experience a drought, however, you don’t need to tend to the seeds over the winter. However, it may help to add some mulch over the area and label it with a stake so you remember what sprouts you are expecting in the spring.

The ground on the left needs to be cleared before seeds are planted. If not, it will be hard to tell the sprouts of desired plants from the existing plants growing there. Bare ground (right) can be mulched to keep the soil from drying out.

You can also cold condition seeds in your house to prepare for early spring planting. There are several ways to do this, and I will cover that in a later post.

Why Grow Native Plants?

One of the major focuses of this website will be growing native plants. A good question to begin with is why should we divide plants into natives and non-natives and favor growing one over the other? Plants are just plants, right? Long story short, yes but there’s more.

Purple coneflowers and blanket flowers are native perennials.

The native plants growing in your region are adapted to living there. There are adapted to the seasonal weather changes. They are adapted to the local soil types. And they are adapted to local wildlife and vice versa. As a gardener, you will find most native plants easy to establish and require less maintenance than non-natives. This is especially true of perennial plants — plants that live for more than one year. After their first year, during which they made need a little attention, perennials will often flourish without any intervention. 

A spider on a black eyed susan and a moonflower, which opens at dusk.

Native plants generally require less water than non-native plants. This is especially true for native plants adapted to living in prairies, open fields, or drought-prone regions. Of course, some natives live next to streams or ponds, and their water requirements reflect that. Knowing the microenvironment a plant lives in can help you decide what to plant where on your property. However, on average, you will need to water native plants less than non-native plants — especially those bred to be showy landscaping plants.  

Texas red salvia (a mint) and partridge pea (a legume) are native plants.

Native plants generally require less fertilizer than non-natives. They are adapted to living in soil that has not been amended by humans, unlike many landscaping plants. They also generally do not require pesticides. Native plants have insect pests, of course. They and the insects that feed on them have coevolved for long periods of times, up to hundreds of millions of year. But those pests also have native predators, including insect predators — such as ladybugs, preying mantises, and robber flies. They also have other predators. Many birds are insectivourous. So are many bats. So are many small reptiles. (I have a thriving population of Texas spiny lizards living in and around my garden.) And of course, spiders eat insects. 

Larkspur flowers and berries on a black nightshade plant. Catbirds love these berries.

If you have a typical suburban lawn (of non-native grass) and non-native landscaping plants, you can start small and simply subsitute some natives in your flower beds in the spring. Plant a ring of natives around your vegetable garden or between rows. Surround tree trunks with a ring of native plants or expand your flower beds to take up more room in your yard. Even making small changes can help your local environment and make your life as a gardener easier. 

A butterfly on a lance leaf coreopsis flower and a skipper on a Verbena hastata flower.

Native plants are connected to other species in your region in a way non-natives are not. A native plant may be a host plant for a butterfly. It may provide nectar to a bee, butterfly, or hummingbird — and in turn these animals will pollinate other plants. It may provide seeds for a seed-eating bird. It may draw in insects that insectivorous birds, bats, lizards, spiders, or other insects can feed on. Taller native plants provide perches for insect predators to survey your garden. 

A green-eyed robber fly and another robber fly (in the genus Efferia).

Having insects — and hence insect predators — in your yard and garden can also help you enjoy being outdoors more. If you have a typical suburban lawn and non-native landscaping plants, your yard and garden can easily get overun by mosquitoes or flies. Mosquitoes feed on blood, of course. And flies lay their eggs in dead animals, feces, or rotting food. As such, what you plant in your yard or garden isn’t going to attract or deter them. However, if you have a healthy population of insect predators around your house, they can knock the numbers of these insects down substantially — making spending time outdoors in the evenings more enjoyable. 

A monarch caterpillar on a milkweed plant and a black swallowtail caterpillar on fennel.

Planting natives plants does a lot to help your local environment. And they also require less care, water, and fertilizer — allowing you, the gardener, more time for other things (such as planting a larger garden).