If you have ever driven through Lancaster, Pa or another heavily farmed area, you have probably seen the giant sunflowers that grow in people’s gardens. They don’t seem to be your average sunflower crop and that is because they are not.
The giant sunflowers you see come from different seeds and require special care. When grown and maintained properly, these plants will provide you with beauty and a tasty treat. Take a look at our tips before starting your giant sunflower seed crop.
Choose the correct variety
Sunflowers grow to all heights, at different times of the summer and shed different amounts of seeds. If you are looking to grow the tall ones with the huge faces and leaves, stick to seeds such as Mammoth, Russian Mammoth or California Greystripe. The Sunzilla variety are a very reliable hybrid that grows strong stalks to hold up their giant seedheads. Sunzillas have been known to reach over 16 feet and produce huge seedheads.
Pick a sunny spot and prep the soil
Sunflowers need a full 6-8 hours of sun a day. Knowing how difficult that can be in Northeastern PA, you should choose the sunniest spot in your yard. Also make sure the area will drain easily.
Next, prepare your soil by digging an area of about 2-3 feet in circumference to a depth of about 2 feet. Sunflowers are heavy feeders and deplete the soil more than many other crops – especially if you are growing them to reach a massive height so the nutrient supply must be replenished each season. You can use Osmocote to fertilize your soil.
Sow your seeds for success
If you want to grow the tallest sunflowers, you should sow your seeds right into the ground where you want them to grow. Sunflowers have long taproots that grow quickly and become stunted if confined. Peat pots in particular often dry out and block off root growth.
Since sunflowers need a long time to dig their roots deep, you should plant your seeds as soon as the night temperatures no longer drop below 50 degrees Fahrenheit. For NEPA, this usually means late May to mid June.
The ideal spacing in rows for giant sunflowers with large seed heads is 20 in. apart. If you plant closer, you might get taller stalks but smaller heads. If you plant farther apart, the seedhead may be larger, but possibly too heavy for the stalk to bear.
To sow seeds, water your soil, and press seeds 1 inch deep in clumps of 5-6 seeds about 6-8 in. apart. Put snail bait in a circle around the clump. Cover loosely with netting to protect emerging seedlings from birds. Keep the soil moist so that seedlings will appear in 5-10 days. As the plants grow, thin them to the best and most vigorous growers. Leaving even several seedlings growing too close together will keep you from growing a giant in your garden.
Caring for your growing giant
Feed often and water regularly. While the plant is small, water around the root zone, about 3-4 in. from the plant with about 2 gallons of properly diluted liquid fertilizer solution per week. When the plants get bigger, scrape out a small doughnut-shaped moat about 18 inches around the plant and about four inches deep. Pour several gallons of properly diluted fertilizer into the moat every week. Sunflower roots can grow to 4 feet below the soil surface. Avoid pouring fertilizer directly on the stems, since this can cause them to rot. Another feeding method for larger plants is to make several holes by driving a steel stake into the ground about 3-4 feet deep and about 1½ feet from the plant. Fill the holes with properly diluted liquid fertilizer.
Be very attentive to your sunflower seedling. Keep an eye on weather reports of high wind. In the case of a wind storm, delay watering to reduce their chances of blowing over.
Enjoying the seeds of your labor
As the petals fall off, the center florets dry up and the seed kernels begin to swell in the disks, carefully climb a stepladder and cover your flower head with a mesh onion bag or loose burlap or paper bag. This will keep the seeds from being eaten by a passing bird. If you plan to use the seeds for your bird feeder, wait until the seeds are completely dry. Remove them by hand or by rubbing them over wire mesh into a basket.
Information for this story came from Renee’s Garden.