Though not a state with the most acres of sunflowers, California produces a substantial amount of hybrid seeds for this crop in the US and the world as a whole. If you’re contemplating when to plant sunflowers in California, late February to April is the optimal time, though there are variations to this estimate depending on where you live.
Read below for more tips on growing sunflowers.
Table of Contents
Best Time to Plant Sunflowers in California
1. Plant indoors and outdoors from December to June
Before growing sunflowers, it is imperative that you look up your last frost date to protect your plant from cold weather. Decide whether you want to start seeds indoors or outside, and do the following:
- Count backward four weeks from the last frost for indoor sowing in pots.
- Add one day to the final frost date to determine the time for transplanting and direct seeding outside.
If we look at the average last frosts in California, they’re often in January to April, making December to March the best time of year for indoor seeding and January to April the ideal months for outdoor planting.
However, the area where you live may change this estimate. People in Bishop, California, will likely need to wait until May to start their sunflower garden outside, as the city’s last frost often occurs within this month.
It is also imperative to take into account the first fall frost while growing sunflowers, since yield and seed quality will suffer if the plants are exposed to freezing temperatures before they reach maturity.
If we use 80 days as the growing period for sunflowers and a first frost of October to February as the basis for estimates, it’s possible to plant sunflowers in California up until July or even November.
The chart below sums up the best time for cultivating sunflowers. Some months only apply to certain regions in California, which we will explore in detail in the next section.
| Jan | Feb | Mar | Apr | May | June | Jul | Aug | Sep | Oct | Nov | Dec |
| ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
2. Planting time in different areas
Since California has hardiness zones 5 to 10, here is the start of each zone’s planting season based on their average last frost.
| Zone | Last frost | Planting time |
| Zone 5 | April 30 | April 2 indoors, May 1 outside |
| Zone 6 | April 21 | March 24 indoors, April 22 outside |
| Zone 7 | April 3 | March 6 indoors, April 4 outside |
| Zone 8 | March 28 | February 29 indoors, March 29 outside |
| Zone 9 | February 28 | January 31 indoors, February 29 or March 1 outside |
| Zone 10 | December 15 – January 15 | November 17 indoors, December 16 outside OR
December 18 indoors and January 16 outside |
3, How late is too late to plant sunflowers in California
It all depends on the first frost in your location and how long do sunflowers take to grow.
If we subtract 100 days (which is the upper range of maturation time for sunflowers) from a fall frost in October or February, June or October will be the latest month for planting.
That said, in southern California and areas with little frost, such as Sacramento in northern California, you may be able to grow winter sunflower and cultivate these plants year-round.
Benefits of Planting Sunflowers
Sunflowers have more to offer than just pretty looks. See if you’ll enjoy these benefits of growing them:
- Attract birds to your garden to pollinate crops
- Help with pest control and reduce weeds
- Provide seeds and oil for cooking
- Improve the soil by removing toxins and adding organic matter
- Act as an outdoor privacy screen
Varieties of Sunflower to Plant in California
If you’re looking for sunflowers to plant in California, look no further than the following varieties.
| Cultivar | Note |
| Red Velvet Queen | Matures in 75 to 100 days. Has mahogany blooms that are excellent for vases. |
| Sunzilla | Matures in 75 to 100 days. An excellent option if you like tall plants and bird watching. |
| Autumn Beauty | Matures in 75 to 85 days. Cuttable for display and attractive to pollinators. |
| Teddy Bear | Matures in 65 to 75 days. Vibrantly yellow and up to three feet in height, Teddy Bear sunflowers are suitable for homes with little space. |
| Moonwalker | Matures in 65 to 70 days. Moderately tall (8 to 12 feet) and blooms around late summer. |
| Big Smile | Matures in 50 days. Suitable for patios and decks and containers or borders. |
Factors That Affect the Optimal Time to Plant Sunflowers in California
Aside from the frost dates, you must pay attention to the soil temperature, which should be 6o to 85℉ for successful growth.
Even when the weather’s warm, it is wise to avoid planting when there has been extended rain or the soil is overly wet and soggy, since these conditions will cause the seeds and roots to rot.
Tips for Successful Sunflower Planting in California
- Sunflowers do not respond well to sudden changes in their planting location, so avoid transplanting them and sow your seeds outdoors if possible.
If you insist on indoor planting anyway, sow the sunflowers seeds in a biodegradable or natural-material pot.
- The sowing depth must be 1 to 1.5 inches, while the spacing should be 30 inches between rows and six inches between seeds.
- Take care of a sunflower by irrigating it once a week and letting the water soak in three to four inches from the plant. Up the watering frequency if the weather is hot or your plant is experiencing drought.
- It is also essential not to wet the blossoms and to water sunflowers sparingly so that the soil is damp but not soggy. This practice helps prevent fungal growth and downy mildew.
- Care for sunflowers by shielding them from harsh winds. Grow them along fence and tie the shoots to bamboo stakes for extra support.
- Last but not least, maintain sunflowers by fertilizing them according to the recommendations of your soil test. Usually, nitrogen, phosphate, and potash are the compounds worth paying attention to, but you may find it easier to amend the soil with compost instead.
Frequently Asked Questions
Do sunflowers come back every year?
Sunflowers can be annual or perennial. If you’re growing varieties like prairie and willow-leaf sunflowers, expect them to come back every year. Meanwhile, annuals like Delta and Moonwalker will die after they bloom.
Can you grow sunflowers from sunflower seeds?
Yes. But note that perennial sunflowers are tougher to find seeds for, and you may need to buy divisions if you want to grow these instead of annual sunflowers.
Conclusion
We hope you found the care tips here helpful in growing your sunflowers. These plants make for beautiful additions to gardens anywhere and are wonderfully practical in terms of their use. If you still have questions on when to plant sunflowers in California, leave us a message.
Read more: Best time to plant sunflowers in North Carolina, Michigan, Texas and other states.
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