This variety of Helianthus annuus, the common sunflower, is the most popular type for commercial growers involved in vegetable oil production. We link to vendors to help you find relevant products. If you buy from one of our links, we may earn a commission. To begin with, they’re iconic, an emblem of summer, whether you plant a whole patch in rows or a couple in a container. They’re also easy to grow, reliable about blooming, and a wonderful source of food for songbirds and other wildlife. Their high oil content is appreciated by birds like cardinals, yellow finches, and wrens. The seeds are also smaller than the “confection” seeds grown for humans to eat, such as ‘Mammoth Russian.’ That and their thin shells make black oil seeds easier for smaller birds to consume. I’d like to introduce you to this multi-purpose sunflower, and sing its praises. Here’s what I’ll cover:
What Are Black Oil Sunflowers?
Black oil or oilseed sunflowers are annuals that reach five to seven feet tall and produce bright yellow flowers that are four to eight inches in diameter. Like others of their species, the plants actually form two types of flowers. What we know as the petals around the “face” are technically ray flowers, while the center is made up of literally hundreds of separate disk flowers. Those lovely seeds form from the disk flowers, and are known as achenes. Oilseed sunflower seeds are black, and as mentioned, have a higher oil content than the striped ones we enjoy as a snack. They are grown commercially for sunflower oil production and for bird feed. There are a number patented cultivars and hybrids, though most of these are not available to the home gardener. These particular H. annuus plants have a stature and color that make them a good choice among ornamentals for privacy screens, borders, and flower gardens. Their height also makes them a natural part of a Three Sisters vegetable garden planted with beans and squash as an alternative – or in addition to – corn. Pollinators flock to these flowers, which makes them an asset as part of a vegetable garden, and they’re also a bright focal point for wildlife plantings. And let’s not overlook their beauty as a cut flower, either singly or massed in short-stem bunches for a centerpiece or even a bridal bouquet. This variety is also the primo type for microgreen sprouts, which are rich with plant-based protein and contain trace minerals. While sunflowers are one of the larger seeds that can be a bit tricky for beginner microgreen growers, they produce three- to four-inch, flavorful green shoots seven to 10 days after sowing. For more directions on growing microgreens, see our guide. They can also be eaten as a nutritious snack or used to press your own oil. There is one minimal downside to selecting oilseed sunflowers to grow in your garden: They are generally hybrids, which means any seeds you save are not going to be good to plant the following season, if you’re looking for identical results. They ordinarily will not grow true to the parent plant. But that’s okay! Not saving the seeds means more for the wildlife to eat…
How to Sow
Sow your seeds directly in the garden after all risk of frost has passed. Provide a full sun location – at least six, preferably eight hours of sunlight – and organically rich, well draining soil. All sunflower seeds should be sown at a depth between one and two inches. But since this variety produces smaller seeds, you should only plant them about an inch deep, or more like three-quarters of an inch deep if the soil is cool. The minimum soil temperature for sowing is 50°F. If the soil has already warmed to 60 or 70°F, you can plant the seeds one inch deep. Space them eight to 12 inches apart. Usually, it takes four or five days for the seedling, formed from two cotyledons, to emerge. This smaller-seed variety is especially susceptible to soil crusting over and preventing germination. While you can plant black oil sunflowers without tilling, if the soil tends to dry into a hard crust, it’s a good idea to cover the seeds with an inch of lighter soil or growing medium, instead of expecting them to break through compacted dirt.
How to Grow
Sunflowers are tall and have a deep taproot, which helps them to compete against weeds. But that’s only a factor when the plants are a month or more old. Before that, the young seedlings don’t fare well when nearby weeds block the sun or steal their water. Make sure to plant only after diligently removing any weeds from the area where you plan to sow. And once the seedlings sprout, make sure to put down a two-inch layer of untreated mulch – like straw or dead leaves – to suppress weeds and help retain water. When you’re growing a sunflower strictly for ornamental purposes, it’s okay if it gets a little dehydrated – as long as it blooms. But with a variety like this, when you want the plants to stay healthy throughout the blooming period and on into seed production, it’s important to keep them watered. When they’re newly germinated, they’ll need a good soak every day that it doesn’t rain for at least a week or two. After that, you can scale back the supplemental water to once a week in the hottest weather, watering only if the rain isn’t doing the job for you. Use a rain gauge to get an accurate idea of how much water your black oil sunflowers receive in a given period. Once the plants are established, they can withstand high temperatures and near-drought conditions. But they’ll grow more easily if they receive that water. With your birdseed supply at stake, it’s a good idea to irrigate your plants in those thirsty times. For full cultivation instructions, consult our guide to growing sunflowers.
Growing Tips
Plant in well-draining, organically rich soil.Provide a full sun location.Apply a layer of mulch to suppress weeds.
Where to Buy
While there is a vast array of pollenless sunflowers to swoon over in seed catalogs, and heirloom after colorful heirloom, black oil sunflower seeds are a bit more difficult to find. Most cultivars are produced for the commercial market and home growers don’t have a large selection to choose from. You can use ordinary black oil birdseed for the purpose, but know that they may not be organic, and might not grow true. But if you’re planning to harvest the seeds, protect the blooms throughout the growing season. The best idea is to establish any scare tactics ahead of the birds discovering this tasty crop. But as you may already know from any volunteers that have grown beneath your feeder, most of the time, the birdseed does okay. ‘Peredovik’ is a hybrid Russian cultivar highly recommended for anyone who is planting for wildlife. ‘Peredovik’ There are also a handful of vendors that sell seeds primarily for those interested in growing microgreens. Of course, any of these can be grown for full-size plants and flowers that mature anywhere from 60 to 100 days from sowing, and are ready to harvest a couple of weeks after that. Black Oil Sunflower Seeds Small-seeded black oil sunflower seeds are available from True Leaf Market in various package sizes, from 700-seed packets and on up to 25-pound sack. Larger seeds are also available via True Leaf Market in packets and in one-pound sacks. Neither of these are listed as a specific cultivar.
Pests and Disease
You can opt to plant black oil sunflowers with the express purpose of allowing the birds to eat the seeds while the flowers are still in the garden. Put scarecrows or owl decoys in place once the seedlings are a few inches tall, for example. Once the birds have figured out where this food source is located, they won’t be scared off nearly as easily as they are when the scary implements have been in play for months. Also, consider netting and supply alternative food sources. Look for more information on deterring birds in our guide. There are a number of insect pests that may plague your plants, including:
AphidsCutwormsWeevilsWireworms
You can find more information on dealing with common sunflower pests in our guide. In terms of disease, the common ones to watch out for are:
Alternaria blightPhoma black stemPhomopsis stem cankerRustWhite mold
You can learn more about these in our guide to growing sunflowers.
Harvesting
When you’re trying to beat the birds to the harvest, you’ll want to be well aware of when that harvest is set to occur. Most oilseed varieties will grow to maturity and bloom in about 60 days, and then form seed heads that are ready for harvest in the following month. Be sure to note those potential dates in your gardening journal or on your calendar, and also set a cell phone reminder. As bloom time nears, do a visual check to make sure all is on schedule. And when the individual flowers start to form seed heads and the petals begin to shrivel, get ready to pick! The indicator will be a brown or yellow color on the back of the flower head, and obvious seeds that form beneath the disc flowers. When you’re ready to harvest, cut off the seed head leaving about five or six inches of stem attached. You can hang them upside down in a cool, dry, well-ventilated location until they are fully dry, then remove the seeds by hand. Learn more about how to harvest sunflower seeds in our guide. Store the seeds in an airtight container in a cool, dry location until you are ready to fill up your bird feeders. If you need to store them for more than four weeks, it’s best to place them in your freezer to prevent the oil from turning rancid. When you fill your bird feeders, make sure you discard any moldy or damaged seeds, as these may be toxic to birds. But the main reason to grow this type over other, equally beautiful varieties is because of its appeal to wildlife and pollinators, and for the prospect of saving the seeds for winter birdseed. That makes a nice change from all the human-centric gardening projects. Are you one of the bird lovers already sowing black oil sunflowers, or have a few perhaps sprouted near your feeders? Let us know in the comments section below! And if you found this article helpful, and would like more information about growing sunflowers, read these guides next:
A Pot of Gold: How to Grow Sunflowers in ContainersHow to Grow Sunflowers as a Cover CropHere Comes the Sun: 15 Popular Sunflower VarietiesHow to Help Sunflowers That Won’t Bloom
