The best seeds to sow in August

Summer might be slowly winding down, but the garden is far from slowing up. Flower beds are still bursting with colour, with new blooms joining the show every day.

With plenty of sunshine and warm late-summer days, August is the perfect time to sow seeds and plant for a bountiful harvest this winter and into spring.

Need some ideas? Here are our top tips on what to grow and how to get the best results.

And don’t forget—keep those beds well watered to help young plants and seedlings thrive during the dry, sunny spells.

Seeds to sow

Plants blooming in August

1. Seeds to sow

Spinach

How to Grow Spinach: A Hardy, Easy Crop for Your Garden

Spinach is a brilliant choice for any garden—easy to grow, hardy against frost and rain, and perfect for a steady supply of fresh leaves. Sow your seeds in August, and you’ll be harvesting your first crop by October. After that, spinach goes dormant over winter, ready to bounce back with tender ‘cut-and-come-again’ baby leaves in early spring.

Growing Tips for Spinach:

Sow seeds thinly in shallow drills about 1.5cm deep and 40cm apart, in fertile, well-prepared soil placed in a sunny spot.
Cover the seeds with soil and give them a good water. If the weather is still chilly, protect your young plants with cloches to keep them cosy.
For a continuous harvest, sow a new batch every three to four weeks throughout the season.

With these simple steps, you’ll enjoy fresh, homegrown spinach almost year-round—straight from your garden to your plate.

Rocket

How to Grow Rocket: Add a Peppery Kick to Your Garden

Nothing beats the fresh, peppery zing of rocket to spice up your salads. Sow wild rocket seeds in early August for a steady supply right through to winter, with fresh new growth returning in March and April.

Growing Tips for Rocket:

Mark out a row about 1 to 2 metres long in well-prepared soil.
Sow a small number of seeds, spacing them roughly 3cm apart, every two weeks to keep the crop coming.
Cover the seeds lightly with soil, removing any weeds or large stones as you go.
Water gently with a watering can fitted with a rose head, to avoid disturbing the seeds.

Top Tip: To protect your rocket leaves from pesky flea beetles, cover your rows with a mini tunnel or horticultural fleece. This simple step keeps your crop healthy and thriving.

With these easy steps, you’ll enjoy a fresh, peppery harvest for months—perfect for salads, sandwiches, and more.

Cabbage

How to Grow Cabbage: Fresh, Crunchy, and Ready to Harvest Almost Year-Round

Cabbage is a versatile garden favourite—perfect for coleslaw, stir-fries, soups, and more. With plenty of varieties to choose from, you can enjoy fresh cabbage harvests in around 20 weeks, nearly all year round. Sow spring cabbage seeds in late summer, and now’s the time to plant out winter cabbages started from seed earlier in the year.

Growing Tips for Cabbage:

For best results, start seeds indoors in pots or trays, about 2cm deep.
Around five weeks later, transplant your young cabbages outdoors into a sunny spot. Make sure to prepare the soil well—firm, moist, alkaline soil enriched with plenty of garden compost works best.
Space your plants according to the variety: about 25cm apart for spring cabbages and 45cm for the larger winter types.
Protect your crop by suspending fine netting about 1 metre above the ground to keep pigeons and cabbage white caterpillars at bay.
Feed your cabbages with a nitrogen-rich liquid fertiliser every two weeks to encourage strong, healthy growth.

With these simple steps, you’ll be enjoying crisp, homegrown cabbage from your garden all year long.

Forget-me-nots

Bring a Touch of Spring with Delicate Forget-Me-Nots

Add a soft splash of pale blue to your garden with forget-me-not flowers. They’re perfect for brightening shady spots under trees and shrubs, filling the front of borders, and edging paths. Their natural charm also complements spring favourites like tulips, wallflowers, and hostas beautifully.

Growing Tips for Forget-Me-Nots:

Sow seeds thinly in trays filled with compost. A heated propagator or a warm windowsill helps speed up germination.
Once seedlings appear, prick them out and pot on. You can expect flowers to bloom the following year.
Forget-me-nots are great self-seeders—either let them spread naturally or lift and replant them where you want a burst of blue.

With a little care, forget-me-nots will bring a timeless, cottage-garden charm to your outdoor space year after year.

2. Plants blooming in August

Flowers

August Blooms: A Mix of Mature Beauties and New Arrivals

Plants that began flowering in June and July continue to brighten the garden with their full blooms throughout August. Think carnations, zinnias, and coneflowers, alongside stunning bulbous perennials like dahlias, gladiolas, and lilies. But August isn’t just about wrapping up the season—there are plenty of plants just starting to flower now, adding fresh colour as summer fades.

Here are some August highlights:

Blue Leadwood (Ceratostigma plumbaginoides): This eye-catching plant shows off intense blue flowers in late summer, with leaves turning a rich reddish-brown in autumn—perfect for adding seasonal contrast.
Garden Chrysanthemum (Dendranthema × hortorum): A showy perennial that blooms in August, ideal for brightening your garden or balcony with vibrant yellows, reds, pinks, and whites.
Asters: Varieties like dwarf aster (Aster dumosus) and narrow-leaved aster (A. sedifolius) display charming flowers with yellow centres and delicate pink or white petals.
Sneezeweeds (Helenium): These frost-hardy plants offer fascinating flowers in warm shades of yellow, orange, and red, adding late-season drama to your borders.
Colchicum: A lesser-known bulbous perennial, Colchicum blooms in August with striking purple flowers, with some beautiful yellow and white varieties to choose from.

August truly offers a wonderful blend of mature flowering favourites and fresh newcomers, keeping your garden vibrant as summer turns to autumn.

Shrubs and trees

When it comes to autumn blooms, few plants are as iconic as heather. Some varieties, like the common heather (Calluna vulgaris), start flowering as early as August. This charming small shrub, with its needle-like leaves and distinctive purple flowers, continues to brighten gardens well into early autumn.

Another standout is Caryopteris (Caryopteris × clandonensis), a blue-flowering shrub known for its long stamens and vibrant colour. Its pleasant fragrance makes it a favourite among bees and butterflies, adding life and movement to your garden. Alongside these, hydrangeas, roses, summer lilac, and lavender keep the flowering season alive with colour and scent.

For something truly special, look out for the double-flowering magnolias, such as Magnolia soulangeana and Magnolia grandiflora. These stunning varieties bloom not only in spring but again in August, offering the joy of their beauty twice a year. While they may require a bit more care, the breathtaking flowers are well worth the effort.