It's not really summer until you bite into a warm, juicy ear of corn on the cob, fresh from the farmer's market or a roadside stand. But while everyone's used to seeing yellow and white kernels when you peel back the husk and the silk, rainbow corn is so beautiful it'll make your jaw drop. Known as Glass Gem corn, it's an absolute stunner with shiny purple, pink, blue, red, and yellow kernels that look like polished beads. You're not likely to find farmers selling rainbow corn on the side of the road in the summer like sweet corn, but you can grow these gorgeous ears and even make popcorn with the one-of-a-kind kernels.
Rainbow corn can have dozens of different colors and combinations, and you won't know what they'll look like until you peel back the husk. You could end up with genuinely multicolored ears or kernels, primarily shades of blue, red, or even pale, shiny pastel kernels. Every cob is a surprise.
Rainbow Corn Overview
Where to Plant Rainbow Corn
Plant rainbow corn in a location that gets lots of sun all day, with rich, well-draining, acidic to neutral soil.
Make sure not to plant it in the same location where you grew corn for the two previous years. Also, keep in mind that it reaches a towering height and casts shade on shorter crops. Plant it next to crops that benefit from being shielded from the hot summer sun, such as lettuce.
How and When to Plant Rainbow Corn
Like sweet corn, plant rainbow corn in the late spring when there is no more danger of frost and the soil has warmed up to at least 60 degrees F. Corn doesn't transplant well, so it needs to be planted directly in the garden.
Plant the seeds at a depth of 1 to 2 inches. The lighter the soil, the deeper you should plant seeds. Space seeds 6 to 12 inches apart. For better pollination, rather than planting it in long rows, plant it in a block of short rows spaced 30 inches apart.
Buy It: Glass Gem Corn Seeds $4, Native Seed
Rainbow Corn Care Tips
Rainbow corn is easy to grow but it has a long growing season of 110 to 120 days to maturity.
Light
Corn needs a sunny spot with at least six hours of direct sun daily.
Soil and Water
Corn does best in loose and loamy soil with a pH between 6 and 7. It does poorly in heavy soil. Give it at least 1 inch of water per week in the absence of rain.
Temperature and Humidity
Corn needs warm weather. It only germinates at temperatures between 60 and 80 degrees F. It has no issues with high or low humidity as long as it's given sufficient water.
Fertilizer
Corn is a heavy feeder. Even if you plant corn in rich garden soil with plenty of organic matter and compost, you must fertilize corn with a high-nitrogen fertilizer, following label instructions. The first fertilization should be when the plant is about 8 inches tall and has a sound root system, and the second should be when the plant starts producing tassels.
Pruning
Corn does not need any pruning.
Pollination
Corn is wind-pollinated and planting it in blocks aids pollination.
Different types of corn can cross-pollinate, which is an issue if you plan to save the seeds of your rainbow corn. To prevent cross-pollination, plant different varieties at least 25 feet apart.
Pests and Problems
Rainbow corn, like all corn, is sought out by wildlife, including rodents, raccoons, and birds. Corn borers are a common pest. Smut fungus, which turns the corn kernels into bulbous grey-bluish-grey galls, is a serious disease; if you detect it on your plants, remove and dispose of them in the trash immediately to prevent it from spreading.
How to Propagate Rainbow Corn
Rainbow corn is an heirloom variety, and you can save the seeds if there's no cross-pollination. Leave the cobs in the plant to dry as long as possible, but remove them in wet weather so they don't mold. Peel off the outer leaves and remove the silk. Let the ears air dry in a cool, dry location. Then, remove the kernels from the cobs and store them in a paper bag in a cool, dry place to plant the following year, as described above.
Harvesting
Unlike sweet corn, rainbow corn is harvested when the husks are papery-dry and brown, about 110 to 120 days after planting. To remove the husk from the stalk, twist it downward in a pulling motion. For drying and storing the kernels, follow the directions under How to Propagate Rainbow Corn, above.
Guides to Growing Vegetables
- The 12 Best Types of Root Vegetables to Grow in Your Garden
- The 7 Watering Mistakes That Could Sabotage Your Vegetable Garden
- How to Start an Organic Vegetable Garden
- What Vegetables to Plant in Your Edible Garden Each Season
- The Benefits of Raised Vegetable Gardens
Frequently Asked Questions
- Where did rainbow corn originate?Carl Barnes, an Oklahoma farmer, started planting ancient varieties of corn as a way of connecting to his Cherokee heritage. A mix of a few different varieties of corn eventually produced a couple of multicolored cobs, which he showcased at a native plant gathering in the mid-1990s. Greg Schoen, a grower, was particularly enthralled by the colors, and Barnes entrusted a few of his seeds to him. Schoen planted the seeds, crossing them with another variety of popcorn, which resulted in rainbow colors with a glossy, polished sheen. Schoen eventually shared seeds of this rainbow-colored corn with Bill McDorman, who was able to save the seeds and help make them more widely available for gardeners through the nonprofit Native Seeds.
Carl Barnes, an Oklahoma farmer, started planting ancient varieties of corn as a way of connecting to his Cherokee heritage. A mix of a few different varieties of corn eventually produced a couple of multicolored cobs, which he showcased at a native plant gathering in the mid-1990s. Greg Schoen, a grower, was particularly enthralled by the colors, and Barnes entrusted a few of his seeds to him. Schoen planted the seeds, crossing them with another variety of popcorn, which resulted in rainbow colors with a glossy, polished sheen. Schoen eventually shared seeds of this rainbow-colored corn with Bill McDorman, who was able to save the seeds and help make them more widely available for gardeners through the nonprofit Native Seeds.
- Is rainbow corn edible?Rainbow corn is grown primarily for its colorful kernels. Pretty as this corn is, don't expect to cook and eat it like regular sweet corn, right off the cob. It's a type of flint corn with a high starch content and a hard outer layer, so you can only eat it by grinding it into cornmeal or popping it into popcorn (which, sadly, isn't rainbow-colored). But, whether you choose to eat it or not, it's gorgeous enough to grow in your garden just for its beauty, and it also makes a great fall decoration.
Rainbow corn is grown primarily for its colorful kernels. Pretty as this corn is, don't expect to cook and eat it like regular sweet corn, right off the cob. It's a type of flint corn with a high starch content and a hard outer layer, so you can only eat it by grinding it into cornmeal or popping it into popcorn (which, sadly, isn't rainbow-colored). But, whether you choose to eat it or not, it's gorgeous enough to grow in your garden just for its beauty, and it also makes a great fall decoration.