If you are starting sunflowers from seed, you can use a seed-starting tray or other small container. Sow about 2-3 seeds per cell to ensure at least one germinates. Once the seedlings sprout true leaves, you can transplant them to a larger pot.
Tips on soil, sunlight, and moisture levels.
To sow sunflower seeds, choose a commercial seed-starter mix or mix your own using 2 parts compost, 2 parts coco coir, and 1 part perlite. If you are starting the seeds indoors, you will need to use supplemental grow lights because sunlight from the window is not intense enough to sustain the seedlings and will cause them to stretch for more light. To start your sunflowers outdoors, wait until the soil warms up to at least 60 degrees Fahrenheit in the spring.
What types of pots work best for growing sunflowers?
Select a pot that is a few inches larger than the rootball, so the sunflower has room to grow. You don't want to use a pot that's too big, because the extra soil around the roots will hold onto moisture and may cause rot issues. For growing sunflowers outdoors, make sure the pot is weather-proof and will not crack during a hard freeze. You also don't want the pot tipping over in windy conditions, so a heavy pot or one with a wide base is best.