What to Plant in Summer: Flowers, Herbs and Vegetables That Thrive Above 75°F (24°C)
Not sure what to plant in summer? From heat-loving flowers like zinnias and marigolds to fast-cropping vegetables, here is exactly what to sow and plant in early and midsummer.
What to Plant in Summer: Best Flowers, Herbs & Veg for Hot Weather
Summer planting is a narrower window than most gardeners realise. By the time June arrives, the seed packet instructions that say “sow outdoors May–July” are already in their final third. Miss the window for a tender crop and you either rush a late harvest against autumn frosts or miss the season entirely. Understanding the difference between early summer planting and midsummer planting — and which crops suit each — is what separates a productive summer garden from a patchy one.
The good news is that summer is genuinely excellent planting weather for the right plants. Warm soil speeds germination dramatically. Long days push growth faster than any other season. And many of the most rewarding garden plants — sunflowers, zinnias, basil, courgettes — are at their best when started in summer warmth rather than nursed along in cold spring conditions. This guide covers what to plant, when to plant it, and how to give new plantings the best chance of thriving in the heat.
For more on this topic, see our guide: What to Plant in Spring: 20 Best Flowers, Vegetables & Shrubs.
Early Summer vs Midsummer Planting Windows
The planting calendar in summer splits roughly into two phases:
Seasonal Garden Calendar
Know exactly what to plant, prune and sow — every month of the year.
Early summer (June to early July) is the window for tender crops that need a full season to produce. Outdoor tomatoes and courgettes transplanted now will crop well through August and September. Direct-sown beans, squash, and cucumbers have time to mature before the first autumn frosts. Annuals sown now will flower by August. This is the last realistic window for most tender vegetables.
See also our guide to what to plant in autumn.
Midsummer (mid-July to August) is better suited to fast-maturing crops, succession planting, and autumn-winter crops started now for transplanting later. Salad leaves, radishes, and quick herbs are ideal midsummer sowings. Brassicas for autumn (kale, chard, spinach) can be sown now for growing on. New plug plants of dahlias, pelargoniums, and tender perennials can still be established if planted promptly. The window for courgettes and tomatoes from seed effectively closes by mid-July in most UK climates.
Flowers to Plant in Summer
Several of the most spectacular annual flowers are actually better suited to summer planting than spring. They germinate and establish faster in warm soil and bloom strongly through late summer and autumn. The key is choosing true heat-lovers rather than cool-season species that will bolt or fail in summer conditions.
See also our guide to what to plant in spring.
Marigolds
Marigolds are perhaps the most reliable summer-planting annual. They germinate within 5–7 days in warm soil, grow quickly, and produce dense clusters of flowers in orange, yellow, and red from midsummer through to first frosts. Both French marigolds (Tagetes patula) and African marigolds (T. erecta) thrive in heat — in fact, they often perform better when sown in June than in March under glass, as warm-sown plants develop a more robust root system without the leggy, etiolated growth that cool, low-light conditions can cause. See our marigold care guide for full growing and deadheading advice. Marigolds planted near tomatoes and courgettes also act as companion plants, deterring whitefly and nematodes.
Cosmos
Cosmos is a tall, feathery annual that produces abundant daisy-like flowers in pink, white, and crimson. Like marigolds, it germinates readily in warm soil and grows remarkably fast — from seed to flower in as little as 50 days in a good summer. Sown in early June, cosmos will be flowering by late July and will continue until frost. Deadhead regularly for continuous blooms. Avoid rich soil: cosmos flowers most prolifically on lean ground. A sunny, free-draining spot and minimal feeding is the recipe for success.
Related: deadheading flowers: when, & properly.
Zinnias
Zinnias are the quintessential summer annual. They require warm soil to germinate (above 18°C / 65°F), sulk in cold conditions, and hate root disturbance — which makes midsummer direct sowing ideal. They grow rapidly, produce large, bold flowers in an extraordinary colour range, and are exceptional as cut flowers. Sow directly into their final position in June or early July, thin to 30 cm spacing, and expect flowers within 8 weeks. They need full sun and good drainage. Pinch out the growing tip when plants reach 15 cm to encourage bushy, multi-branched growth.
We cover this in more depth in best plants for shade.
Sunflowers
Sunflowers sown in early June will flower reliably in August and September, giving a later display than spring-sown plants. They grow fast — often reaching their full height within 10 weeks of sowing — and are highly tolerant of heat and drought once established. Direct sow 2.5 cm deep into well-prepared soil in a sunny spot. Tall varieties need staking in exposed positions. For a succession of flowers, sow at three-week intervals from early June through to mid-July. The later sowings will produce smaller plants but still flower well before autumn.
You might also find vegetables grow summer: heat tolerant helpful here.
Herbs to Plant in Summer
Most culinary herbs are either Mediterranean natives or warm-climate annuals — both groups are fundamentally suited to summer conditions. Planting or sowing herbs in summer rather than spring often produces better results, particularly for those that require genuine warmth to establish well.
Basil
Basil is notoriously cold-sensitive. Plants sown in cold spring compost often sit sulking for weeks before making any growth. Sown into warm summer soil or compost in June, however, basil germinates in days and establishes rapidly. In the UK, basil grows best on a warm, sheltered windowsill or in a polytunnel — outdoors it can struggle with cooler nights, but in a warm summer it will thrive in a sunny, sheltered bed. Pinch out flower buds as soon as they appear to keep plants producing leaves rather than going to seed. Pot up a few plants in late summer to bring indoors before the first cold nights.
Related: drought tolerant flowers.
Rosemary
Rosemary is technically an evergreen shrub rather than an annual herb, but it establishes most readily from young plants set out in summer when the soil is warm. Pot-grown rosemary planted in June or July will root into its new position quickly and be well-established before winter. Choose a very well-drained, sunny position — rosemary’s native Mediterranean habitat means it tolerates drought and full sun well, but suffers in cold, wet, poorly drained soil. Avoid planting in heavy clay without amending with grit.
Lavender
Lavender planted in summer establishes quickly and may even produce a few late flowers in the first season if planted as a young potted plant in June or early July. Like rosemary, it needs very well-drained soil and full sun. Summer planting takes advantage of warm soil temperatures to promote rapid root establishment before winter. Our comprehensive lavender care guide covers variety selection, pruning, and companion planting in detail. English lavender (Lavandula angustifolia) is hardiest; French and Spanish lavenders are more fragrant but less reliably winter-hardy in colder climates.
Other Summer Herb Sowings
Several annual herbs can be successionally sown right through summer for continuous harvests: dill, coriander, chervil, and fennel all respond well to summer sowing. Coriander is particularly prone to bolting in heat — choose a bolt-resistant variety and sow in a partially shaded spot in midsummer to extend the leaf harvest. Dill sown in July will produce leaves in late summer and seed heads in early autumn.
Vegetables to Plant in Summer
Summer vegetable planting is dominated by warm-season crops that need exactly the conditions summer provides: warm soil, long days, and reliable warmth. The key rule is to understand what each crop needs to reach maturity and work backwards from your expected first autumn frost date.
Courgettes and Zucchini
Courgettes and zucchini are among the most rewarding summer crops. A single plant can produce dozens of courgettes through summer and into autumn if harvested regularly. Direct sow seeds on their edge (to prevent rotting) in rich, well-prepared soil in a sunny position in early June. Alternatively, transplant well-established plug plants right through to mid-July. Courgettes are hungry and thirsty — they need regular deep watering and a monthly feed with a high-potash fertiliser once flowers appear. Space plants at least 90 cm apart to allow for their substantial sprawling habit.
Tomatoes
Outdoor tomatoes should be in the ground by mid-June at the latest for a reliable harvest in UK conditions. Later planting is possible but reduces cropping time. Choose a sheltered, south-facing position and stake cordon varieties as they grow. Pinch out side shoots on cordon types weekly — each side shoot left to grow becomes a whole new plant with its own fruit, which the season is too short to ripen. Bush varieties (which include most cherry tomatoes) need no pinching. Feed weekly with high-potash tomato feed from the moment the first flowers open.
We cover this in more depth in top 20 containers.
French and Runner Beans
French beans (dwarf and climbing) can be direct-sown right through to mid-July in most climates. They germinate in 7–10 days in warm soil and grow fast — dwarf varieties start producing pods within 60 days of sowing. This makes early-July sowings viable even for shorter seasons. Runner beans, with their longer season requirement, should ideally be sown by the end of June. Both benefit from a bamboo cane support structure and consistent watering, particularly during flowering.
We cover this in more depth in fast vegetables summer.
Summer Squash and Winter Squash
Summer squash (including patty pan and yellow crookneck varieties) can be direct-sown in early June and will produce prolifically through summer. Winter squash (butternut, acorn, Crown Prince) has a longer season requirement — 100–120 days from sowing to harvest — which means an early June sowing is the last realistic window for reliable harvest before autumn frosts in the UK. Squash need a very warm, sheltered position and rich soil with plenty of moisture-retaining organic matter incorporated at planting.
What NOT to Plant in Summer Heat
Understanding which crops are unsuited to summer conditions is just as important as knowing what to plant. Cool-season crops that have been designed to grow in spring or autumn will struggle or fail in summer heat.
See also our guide to vegetables grow summer: heat tolerant.
Avoid sowing the following in summer heat:
- Spinach — bolts rapidly in long days and heat; if you want summer spinach, use perpetual beet or heat-resistant varieties and sow in partial shade
- Lettuce — most varieties bolt in high temperatures; use bolt-resistant varieties and provide afternoon shade; better sown every 2 weeks from late July as temperatures drop slightly
- Peas — midsummer sowings usually fail; peas prefer cool, long days; stick to early spring and late summer sowings for autumn harvests
- Broad beans — autumn or early spring crops; summer-sown plants will not perform well
- Cabbages and Brussels sprouts — can be transplanted in summer if started earlier, but sowing seed into summer heat produces poor results; these are cool-season crops at heart
Heat and Drought Tips for New Plantings
Newly planted specimens are far more vulnerable to heat and drought than established plants. Their root systems have not yet explored the surrounding soil, making them dependent on the immediate planting zone for moisture. The first two to four weeks after planting are the critical establishment period.
For more on this, see best plants in zone 6.
- Water at planting, then again the next day to ensure good root-to-soil contact. After that, allow the surface to dry slightly between waterings to encourage roots to go deeper in search of moisture.
- Apply mulch immediately after planting to retain moisture in the planting hole. Even a temporary covering of damp newspaper weighed down with soil works in the short term.
- Plant in the evening or on an overcast day to minimise transplant stress. Avoid planting in direct midday sun if possible.
- Shade newly planted seedlings with a sheet of fleece, an upturned seed tray, or purpose-made shade netting for the first few days, particularly in a heatwave.
- Avoid feeding with nitrogen immediately after planting — it pushes leafy growth before the root system is established enough to support it. Wait two to three weeks before beginning a regular feeding programme.
Succession Planting for Continuous Harvest
Succession planting — sowing small amounts at regular intervals rather than the whole packet at once — is the technique that turns a feast-or-famine vegetable garden into one that produces consistently throughout the season.
The principle is straightforward: instead of sowing an entire row of radishes in June and having fifty radishes ready simultaneously in July, sow a short row every two to three weeks from June through August. Each sowing matures in turn, providing a steady supply rather than a glut.
Not sure which one to pick? direct sow vs transplant compares the key differences.
The crops best suited to succession planting in summer are:
- Salad leaves and lettuce — sow every 2–3 weeks; cut-and-come-again varieties provide multiple harvests from a single sowing
- Radishes — ready in as little as 3–4 weeks from sowing; ideal for filling gaps between slower crops
- Beetroot — sow every 3 weeks from June through July for roots from August through autumn
- French beans (dwarf) — sow every 3 weeks in June and July; the fastest beans for a summer-long harvest
- Spring onions — ready in 8 weeks; sow every 2–3 weeks for a continuous supply
- Coriander and dill — both bolt quickly in heat; small successive sowings every 3 weeks manage this
Frequently Asked Questions
What flowers can I plant in summer that will bloom quickly?
Zinnias, marigolds, and cosmos are the fastest summer annuals — all can go from seed to flower in 7–10 weeks when sown in warm summer soil. Marigolds are particularly reliable, germinating within a week and flowering strongly through to first frost. If you want flowers even faster, buy plug plants or small potted annuals from a garden centre and plant them out in June or July — they will establish and flower within 2–3 weeks.
Is it too late to plant tomatoes in July?
In the UK, July transplanting of tomatoes from established plug plants is technically possible but risky for outdoor growing — the season becomes very short and a cold September can prevent fruit from ripening. If you are growing under cover (polytunnel or greenhouse), a mid-July planting is more viable. For outdoor growing, stick to cherry varieties which ripen faster than larger types. Early June is the ideal window for outdoor tomatoes in most of the UK.
What herbs grow fastest in summer?
Basil, dill, and coriander are the fastest-growing culinary herbs from summer sowings. Basil can provide leaves within 3–4 weeks of germination in warm conditions. Dill produces harvestable fronds within 4–6 weeks. Coriander is equally quick but prone to bolting in heat — sow in a partially shaded spot and choose bolt-resistant varieties for midsummer sowings. Chives, once established, can be harvested within 3 weeks of dividing a clump and replanting.
Can I plant marigolds in July?
Yes — marigolds planted in July from plug plants or small pots will still establish and flower well through August, September, and October. From seed, a July sowing in warm soil will produce flowers in approximately 8–10 weeks, meaning first flowers in September. For a full summer display, early June is better. But July planting is absolutely worthwhile — marigolds’ long frost-free flowering season means late-planted specimens still earn their place in the border.
What should I plant in July for autumn harvests?
July is the ideal time to start autumn and winter crops. Kale, perpetual spinach, Swiss chard, and leeks can all be sown in July for autumn harvesting. Autumn-fruiting raspberries planted as canes in July will produce a small crop this autumn and a full crop next year. Spring-flowering bulbs should be ordered now for September delivery. Wallflowers and sweet Williams can be sown in July to overwinter as young plants for next spring’s display.
Sources
- RHS. Sowing seeds outdoors. Royal Horticultural Society. https://www.rhs.org.uk/propagation/sowing-seeds-outdoors
- University of Minnesota Extension. Vegetable planting guide. University of Minnesota Extension. https://extension.umn.edu/planting-and-growing-guides/vegetables
