Top 7 Flower Seeds to Sow in April - Best Garden Seed

Find out which beautiful flower seeds you can sow this April for stunning summer displays.

April is an excellent time to sow flower seeds, as the days become longer and temperatures begin to rise reliably. Many annual flowers can be started now, either under glass for planting out later or directly into the garden soil where they will flower. Sowing in April gives plants enough time to establish before the main flowering season, ensuring a spectacular display from early summer through to autumn. Whether you’re looking to attract pollinators, add color to borders, or create cut flower arrangements, these seven flower seeds are perfect for April sowing.

You will need: While many seeds can be sown directly outside this month, the weather can still be unpredictable in April. Consider investing in some equipment to give your seeds the best start:

Seed trays or modules: ideal for starting seeds under cover
Peat-free seed compost: provides the perfect growing medium for young seedlings
Propagator or clear plastic covers: helps maintain warmth and humidity for germination
Cold frame: offers protection from late frosts while hardening off young plants
Fine spray watering can: ensures gentle watering that won’t disturb delicate seedlings

Flower Seeds to Sow in April

Cosmos

Flowers: June to October.

How to grow: Cosmos is easy to grow and offers a long season of blooms. By sowing now, you’ll enjoy early flowers by midsummer. It thrives even in poor soil, making it ideal for low-maintenance gardeners. Sow seeds indoors in seed trays or modules. When seedlings reach 5–8cm tall, harden off and transplant into full sun. Avoid overfeeding – lean soil encourages more flowers.

Top tip: Stake tall varieties early. Deadhead regularly for blooms well into October.

Sunflowers

Flowers: July to September.

How to grow: Sunflowers bring instant cheer to any garden with their bright, bold blooms. Sow seeds individually in small pots or directly into the ground once the soil has warmed. If sowing in pots, keep in a warm, bright position and plant out after hardening off when frosts have passed. Choose from dwarf varieties for containers or giant types that can reach over 2m tall. Sunflowers need plenty of sunshine and regular watering, especially when forming flower heads.

Top tip: Sow every couple of weeks for a longer flowering season.

Sweet Peas

Flowers: June to September.

How to grow: Sweet peas produce beautifully scented flowers that are perfect for cutting. April is an ideal time to sow directly outside. Prepare a well-drained soil with plenty of organic matter and sow seeds 2cm deep in a sunny spot. Provide sturdy supports such as bamboo canes or trellis for these climbing plants. Pinch out the growing tips when plants reach about 20cm to encourage bushy growth. Regular cutting of flowers promotes continuous blooming.

Top tip: Pick blooms regularly to encourage more flowers.

Nasturtiums

Flowers: June to October.

How to grow: Nasturtiums are incredibly versatile, with varieties suitable for hanging baskets, and containers or spreading through borders. Their vibrant orange, yellow and red flowers also have the added benefit of being edible. Sow seeds directly where they are to flower, as they dislike root disturbance. Plant seeds 1cm deep in average to poor soil – too rich a soil will promote leafy growth at the expense of flowers. Nasturtiums are drought-tolerant once established and will self-seed readily.

Nigella (Love-in-a-mist)

Flowers: June to August.

How to grow: Nigella produces delicate, star-shaped flowers in shades of blue, pink, and white, followed by attractive seedpods that are useful in dried arrangements. Sow seeds directly into well-prepared soil in a sunny position. Scatter seeds thinly and rake in lightly – there’s no need to cover them as they germinate best with some light. Thin seedlings to about 20cm apart when large enough to handle. Nigella is perfect for cottage garden styles and will often self-seed gently for displays in future years.

Top tip: Sow in patches every few weeks for staggered flowering.

Zinnia

Flowers: July to October.

How to grow: Zinnias produce vibrant, long-lasting flowers in a range of colors including orange, pink, purple, and red. They’re excellent for attracting butterflies and making superb-cut flowers. Sow seeds in pots or trays under cover, keeping at around 18-21°C. Zinnias dislike root disturbance, so use biodegradable pots or sow in modules. Plant out after all risk of frost has passed, spacing plants 30-45cm apart. Zinnias prefer full sun and moderately fertile, well-drained soil.

Top tip: Water at the base to avoid mildew on foliage.

California Poppies

Flowers: June to September.

How to grow: California poppies (Eschscholzia californica) are drought-tolerant annuals with silky, cup-shaped flowers in shades of orange, yellow, pink, and cream. Sow seeds directly where they are to flower, as they dislike transplanting. Choose a sunny spot with well-drained soil – they’ll even thrive in poor, sandy soils. Scatter seeds thinly and rake in lightly. Once established, California poppies need very little attention and will often self-seed. Their finely cut, blue-green foliage is attractive even before the flowers appear.

Top tip: Avoid over-watering – they prefer tough conditions.

When to Expect Flowers from April Sowing

With these seven flower seeds sown in April, you can look forward to a garden filled with color and scent throughout summer and into autumn. Most will begin flowering in June or July, providing months of continuous blooms. Many will attract beneficial insects, and most make excellent-cut flowers to bring the garden’s beauty indoors. Whether you have a large garden or just a few containers, these easy-to-grow flowers will bring joy for months to come.

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