If you have been perusing the website or catalog, you may have noticed that we carry both open pollinated and hybrid sweet corn. The hybrid sweet corn is actually the only hybrid that we carry. So why do we carry both? What are the differences and how do you choose the right one for your garden? In today’s blog, we’ll discuss the fundamental differences and pros and cons of hybrid and open pollinated corn.

What is Open Pollinated Sweet Corn?

The basic fundamental between hybrid and open-pollinated is how they’re bred. Open pollinated means that the plant is fertilized naturally, like by wind, insects, or birds.

Seed growers save seed from open-pollinated varieties over generations to create varieties that are relatively stable, but still genetically diverse. If you save seed from open pollinated corn, you will get the same corn next season, so long as you don’t have another variety nearby that cross-pollinated it. 

To isolate different varieties, growers usually use distance or time. Crops that flower at different times won’t cross-pollinate.

Heirlooms are open-pollinated varieties dating to before 1940.

Corn is wind pollinated. Home gardeners should separate varieties by 600 ft. for home use, or 1/2 to 1 mile for absolute purity. Save at least 500 seeds from at least 10% of the plants to maintain vigor and genetic diversity of the variety.

What is Hybrid Sweet Corn?

Hybrid crops are the first generation crosses of two varieties. In breeding hybrid sweet corn, seed growers select two genetically pure lines of corn to cross.

Breeding hybrid corn is tricky! Typically, growers will alternate rows of the two types of corn. Though corn has both male and female parts, growers think about them as male and female parents. 

Growers leave the male parent stalks intact. These will provide the pollen for the pollination. Growers remove the tassels from the female parent rows as they form, ensuring that they don’t produce pollen. The pollen from the male parent rows will fertilize the silks of the female parent rows. The growers then harvest the seeds from the female parent rows.

This technique ensures growers get the desired mix of genetics. 

During the season, growers also go through and remove and volunteer or “off-type” corn in a technique called rogueing.

Pros and Cons Open Pollinated Sweet Corn

While we love open pollinated crops, we know they come with a unique set of benefits and challenges. 

The Pros

• Farmers and gardeners can easily save seed from open-pollinated sweet corn.
• Foodies often find that open-pollinated varieties have more “real corn flavor” rather than just sweetness.
• Growers can save open-pollinated varieties can over years to adapt to a specific local climate.
• Home gardeners may enjoy that they tend to have an extended harvest period. 
• Open-pollinated varieties typically have higher protein content than hybrid varieties. 
• When pigs, chickens, horses, and cows have a choice between open-pollinated and hybrid corn, the animals invariably prefer the old open-pollinated varieties (possibly because of the protein content).

The Cons

• They typically aren’t as sugary sweet as hybrid sweet corn varieties.
• They don’t store well and are best used or preserved quickly after harvest.
• Open pollinated corn isn’t uniform in size, which can be an issue for commercial growers.
• It also doesn’t mature all at the same time, another feature which can be a struggle for commercial growers.

Pros and Cons of Hybrid Sweet Corn

While hybrid may be a typical choice for market growers, it too has its pros and cons.

The Pros

• Hybrid corn tends to mature all at once, which is ideal for market growers. 
• The ears are uniform in size.
• They are sugary sweet and hold their sweetness well in storage. 
• Hybrids often have better disease resistance. 

The uniformity of hybrid sweet size and maturity are the two main reasons we offer hybrid for our commercial growers.

The Cons

• Hybrid seeds tend to rot in cool soil. 
• They may have weak seedling vigor. 
• The ears are more susceptible to insect damage than open pollinated corn. 
• You cannot reliably save seed from hybrid corn.

Which Should You Grow?

What you should grow depends on your needs and personal preferences. As mentioned above, hybrid sweet corn’s uniformity is a key feature for many of our market gardeners, but if you’re looking to enjoy sweet corn over an extended period, open pollinated may be the right choice.

Open pollinated is also a good choice if you’re hoping to save seed. Saving seed from your corn can help preserve genetic diversity, connect you with your land, and adapt a variety to your garden’s specific conditions as you work to save seed from the best plants over the years. 

If open-pollinated corn is new to you, we suggest planting less than 1/4 lb. until you are familiar with its characteristics. It grows a bit differently and has a distinct flavor. Don’t forget, you’ll need to use it more quickly, too. Open pollinated corn doesn’t store quite as well as hybrid corn. 

For good pollination and ear development, plant open-pollinated corn in blocks at least 5-6 rows wide, and hybrid corn in blocks at least 4 rows wide.

Want to save seed from your open pollinated sweet corn? Check out the 8 Steps to Saving Corn Seed.

Each winter gardeners dream of spring, tucking seeds into the soil indoors where they’re safe from winter’s chill. Most of garden seeds like tomatoes, zinnias, cabbage, and basil all benefit from relatively warm soil conditions. But, there are some seeds that actually require cold temperatures to germinate. This is when gardeners must use a method called cold stratification.

What is Cold Stratification?

Cold stratification is a seed starting technique where the gardener exposes the seeds to cold, moist conditions to mimic natural conditions. For some species, these conditions are necessary for the seed to break dormancy. 

Seeds that require cold stratification typically have a hard seed coating. In a natural setting, the frosts, snow, low temperatures, and rain of winter break down the coating.

What Seeds Require Cold Stratification

While you can simply plunk many annual vegetable, flower, and herb seeds straight into warm soil in the spring, some varieties, especially native perennials, need or benefit from cold stratification.

Some species like Butterfly Weed will germinate without cold stratification. However, they may have a lower germination rate and germinate more slowly. Others, like the Yellow Coneflower, require cold stratification. I have marked those species that require cold stratification to break dormancy with a “*.”

• Butterfly Weed
• Milkweed*
• Narrow-Leaved Coneflower (Echinacea Angustifolia)*
• Pale Purple Coneflower (Echinacea Pallida)*
• Yellow Coneflower (Echinacea Paradoxa)*
• Purple Coneflower (Echinacea Purpurea)
• Lupine
• St. John’s Wort
• Asparagus
• Rudbeckia
• Catnip
• Soapwort
• Perennial Sunflowers
• Larkspur
• Violas
• Coreopsis
• Anise-Hyssop

This list includes many of the common plants that benefit from cold stratification but isn’t comprehensive. Always check on your specific variety’s needs. 

How to Cold Stratify Seeds

There are several techniques for cold stratifying seeds, but we like to keep it as simple as possible at SESE. However, these seeds will still need to be started far in advance of your typical crops. While a few species will germinate after just 3 weeks of cold stratification, most need 2 to 4 months before they break dormancy.

To stratify seeds indoors, sow them as directed in pots or flats, and then place them in the refrigerator for 2 to 4 months. Keep the soil moist during this period. If you have access to a cold frame or hoop house, you can also set your pots or flats into it for the winter.

Some native perennials may still have relatively low germination rates, even after cold stratification. 

That’s what makes them sow tricky to grow. Thankfully, once established, they will often self sow or you can divide them after a couple of years. 

Cold Stratification Alternative: Direct Sow Fall Planting

If cold stratification doesn’t sound like a fun project for you, there is an easy alternative, direct sowing in fall. As long as you live in a region where the winters naturally provide moist, cold conditions, the stratification process will happen over the winter.

In a previous post, Spring Flowers: Fall Sowing, we discuss how to use this technique and what flowers grow well using this method. Some flowers, like Dara, will grow well when fall sown even if they don’t require cold stratification.

Generally, we recommend fall sowing any of your seeds about 4 to 6 weeks before your first expected frost date.