How Late Can You Plant Sunflowers?

Sunflowers are beautiful flowers and are simply breathtaking when in full bloom. The sunflower is synonymous with the late summer and early fall seasons. Whether you’re a farmer, gardening enthusiast, or just fascinated by sunflowers, planting them at the right time is key.

Today, people plant sunflowers for various reasons. Some primarily plant them for their rich and nutritious seeds, while others plant them for their aesthetic value. Regardless of the reason you’re planting them, getting the timing right will help them bloom. Without the bloom, they won’t give off the seeds or bright colors.

But what is the right time to plant your sunflowers, what can you do when you’re late, and how can you effectively care for them? If you’ve been wondering just how late can you plant sunflowers, read on to learn more about these amazing plants.

Table of Contents show

When is the best time to plant sunflowers?

As with many other plants, the answer to this question is rather nuanced. However, to try and give a generally accurate answer, you should aim to sow your sunflower seeds when the soil is at least 50 degrees Fahrenheit (or 10 degrees Celsius). This is around the time after the weather is gradually warming up and spring frost is passed.

Depending on your location, this could be anywhere from April to mid-July. However, if you’re in the Southern part of the United States, the soil and climate could be okay to initiate a plant from midway through March to early April.

Ideally, you should sow your sunflower seeds where you wish them to grow. Sunflower seeds don’t like being disturbed once they start germinating, so transplanting could significantly affect them.

How late can you plant your sunflowers?

If you miss this golden period, should you have to wait until the next season? Well, that depends on a number of factors. First, it’s important to realize that sunflowers are a fast-growing plant. This means they can still bloom fully even when you’re a little late to plant them.

Ideally, sunflowers take about a week to germinate, then an additional 55 to 75 days to bloom. However, it is noteworthy to mention this could slightly vary from one variety to another. The window for when you can plant sunflowers is wider the further south you live.

If you miss the golden window, you can still plant your sunflower seeds any time before July or mid-August at the very latest. However, if you surpass this period, you should just save the seeds for the next favorable window.

If you plant the sunflower seeds after mid-August, they’ll likely be destroyed by the early frost in October, long before they have had time to mature and bloom. Sunflowers perform best in sunny and warm weather. About 6 to 8 hours of sunlight each day is ideal for the perfect bloom.

How do you care for sunflowers planted late?

If you missed the golden planting season and you just sowed your sunflower seeds around mid-August, these tips will help you get the most favorable results.

1. Plant healthy seeds

You want to reduce factors that could hamper the sunflower seed’s growth by using quality seeds and eliminating all unhealthy seeds. Sow the seeds 6 inches apart and about an inch deep in the soil. Additionally, you should cover your sunflower seeds with a net to prevent birds from eating the seeds before they can sprout.

2. Plant the seeds on fertile soil

Ensure the ground you plant your sunflower seeds is rich and fertile to encourage speedy germination and growth. Late germination means the sunflowers will be caught by the October Frost before they bloom.

You can further enrich the soil with compost manure. Try and steer away from fertilizers, especially if your soil is rich. Adding fertilizer to the soil increases Nitrogen concentration in the soil, which will, in turn, weaken the sunflower stems, causing them to break.

3. Occasionally water the sunflower seeds

Sunflowers are resilient plants and can survive with little water. However, since you want to encourage them to grow fast, you can water sunflower seedlings daily around the roots. As they grow and mature, you can gradually reduce the watering interval to once a week.

Take extra caution not to overwater the soil. When the soil is too wet, the leaves turn yellow and can prevent the plant from blooming. Moreover, wet soil can lead to fungal diseases that will likely hamper the plants’ maturity and blooming.