What to do in the garden in May?

Complete calendar of seasonal tasks for a productive and flowering garden

Introduction

May marks a decisive turning point in the gardener's calendar. The last frosts are generally past (except in high altitudes or cold regions), the days are getting longer and temperatures are becoming mild. It's the ideal time to step up sowing, plant cold-sensitive crops, and prepare for upcoming harvests.

In May, the gardener must juggle two imperatives: take advantage of the season to boost plant growth and anticipate risks linked to diseases, pests and climatic hazards (late frosts, early drought, violent storms). Good organization is the key to a successful garden.

The dates given are valid for metropolitan France and temperate climates. For Mediterranean regions, coastal areas or high altitudes, adjust this advice with a shift of 2 to 4 weeks.

🌱 Direct sowing: the complete list

May is the ideal month to sow the majority of summer and autumn vegetables directly in the ground. Here is the exhaustive list of species to sow by region:

Leaf vegetables and salads

Arugula (undemanding, grows quickly)
Spinach (summer varieties resistant to bolting)
Lettuces (cutting, headed, batavias)
Lamb's lettuce (for autumn sowing)
Swiss chard (heat resistant)
Chard (for summer harvests)
Garden cress (grows in 3-4 weeks)
Nettle (green manure and edible)

Fruiting vegetables and pods

Green beans (bush and pole, sow after May 15)
Dried beans (flageolets, coco)
Zucchini and squash (after May 15, when soil is at 12°C)
Cucumbers (under cover or after May 15)
Gherkins
Melons (under cold frame or after May 15)
Peppers and chili peppers (under heated cover)
Eggplants (under cover or after May 15)
Tomatoes (under cover or after May 15)

Roots and bulbs

Carrots (short varieties for early sowing)
Radishes (every 15 days to spread out harvests)
Turnips (for summer harvest)
Parsnips
Beets (for summer harvest)
Celeriac
Salsify
Onions (bulbs and seeds)
Garlic (autumn planting for following summer harvest)

Annual and biennial flowers

Nasturtiums (edible and aphid-repellent)
Cosmos (light, resistant flowers)
Zinnias (bright colors, easy to grow)
Sunflowers (dwarf or giant varieties)
Marigolds (anti-nematode, yellow and orange flowers)
Love-in-a-mist (delicate flowers, self-seeding)
California poppies
Poppies
Snapdragons (antirrhinum)

Green manures to sow in May

Green manures are essential for protecting and enriching the soil during summer. In May, you can sow:

Phacelia (honey-producing flowers, attracts pollinators)
White mustard (firebreak, anti-nematode)
Crimson clover (nitrogen fixer)
Alfalfa (for deep soils)
Buckwheat (flowers attractive to insects)
Flax (deep roots, improves soil structure)

For effective sowing: prepare the soil by weeding and loosening it. Broadcast sow, lightly cover with potting soil and firm down. Water with a fine spray.

🌿 Planting: which species to plant in May?

May is a pivotal period for planting. Some cold-sensitive plants can finally be put in the ground, while others take advantage of mild temperatures to root well before summer.

Vegetables to plant in May

Tomatoes (after May 15, when nights are mild)
Eggplants (under cover or after May 15)
Peppers and chili peppers (under cover or after May 15)
Zucchini and squash (after May 15)
Cucumbers (under cover or after May 15)
Melons (under cold frame or after May 15)
Pattypan squash
Basil (cold-sensitive aromatic plant)
Parsley (hardy)
Chives
Tarragon
Thyme
Rosemary (if soil is well-drained)

Flowers to plant in May

Dahlia (tubers after frosts)
Tuberous begonias (after May 15)
Gladioli (corms)
Cannas (rhizomes)
Daylilies (clump divisions)
Peonies (container plants)
Roses (container plants)
Lavender (if soil is well-drained)
Garden sage
Lemon verbena
Agapanthus
Yuccas (for dry gardens)

Trees, shrubs and perennials

May is an excellent time to plant most trees, shrubs and perennials, provided you water well after planting.

Flowering shrubs: buddleia, hydrangea, buddleia, weigela, deutzia
Rose bushes (avoid periods of intense heat)
Fruit bushes: raspberries, currants, blackcurrants, actinidia (kiwi)
Vines (after May 15)
Lavender, rosemary, thyme (Mediterranean plants)
Perennials: hostas, heucheras, hardy geraniums, nepeta
Ornamental grasses: miscanthus, pennisetum
Climbing plants: clematis, trumpet vines, honeysuckle

For container planting, soak the root ball in water before planting. For bare-root specimens, dip the roots in a slurry before planting.

🌞 Garden maintenance: essential tasks

Watering: when and how?

With the arrival of higher temperatures, watering becomes a major concern. Here are the best practices:

Water early in the morning or late in the day to limit evaporation
Prefer watering at the base of plants, not on foliage (except for tomatoes in case of downy mildew)
Use mulch (straw, dried grass clippings, ramial chipped wood) to retain moisture
Install a drip irrigation system for demanding crops (tomatoes, squash, melons)
Avoid standing water which promotes root diseases

Frequency: 2 to 3 waterings per week in May, depending on rainfall. Soil should stay cool but not waterlogged.

Pruning and pinching

Some pruning can still be done in May:

Pinch tomatoes: remove suckers (side shoots) to promote fruiting
Trim hedges (avoid flowering periods for flowering hedges)
Remove faded flowers from perennials to stimulate a second bloom
Cut back aromatic plants (thyme, rosemary) after their first flowering
Thin overly dense sowings (carrots, radishes, beets)

Protection against cold and bad weather

Although frosts are rare in May, some regions may still experience them. Protect sensitive plants:

Bring potted sensitive plants indoors (geraniums, fuchsias, tropical plants) if frost is forecast
Cover young plants with a frost fleece or cloches
For tomatoes and eggplants under cover, ventilate tunnels and greenhouses during the day
Monitor weather forecasts and be ready to cover fragile crops

Weed control

In May, weeds grow fast. Here's how to control them:

Hoe regularly to break the surface crust and aerate the soil
Use thick mulch (5-10 cm) to smother weeds
Pull young shoots manually before they go to seed
Avoid chemical herbicides, prefer mechanical or thermal methods (flame weeding)
For paths, use mineral mulch (pebbles, pozzolan) or cardboard covered with ramial chipped wood

🍅 Harvests to anticipate in May

In May, the first spring harvests can begin, depending on the region and crops sown earlier.

Leaf vegetables

Spinach (harvest before bolting)
Swiss chard
Arugula
Lamb's lettuce (if sown in autumn)
Garden cress
Nettle (young shoots for soup)

Roots and bulbs

Radishes (harvest 3-4 weeks after sowing)
Early carrots (short varieties)
Early turnips
Early beets
Spring onions
Garlic (harvest in June-July depending on varieties)

Flowers and aromatic herbs

Dandelions (leaves for salad)
Ribwort plantain (young leaves)
Borage (edible flowers)
Nasturtiums (flowers and leaves)
Chives
Parsley
Chervil
Tarragon

🐛 Diseases and pests: how to protect your crops?

In May, with rising temperatures and humidity, diseases and pests become more active. Here are the main problems to watch for and preventive or curative solutions.

Fungal diseases

Downy mildew (tomatoes, potatoes, vines): symptoms = brown spots on leaves, white fuzz underneath
Powdery mildew (squash, roses, vines): white powder on leaves
Rust (beans, leeks): orange-brown pustules
Scab (apple, pear): black spots on fruit
Gray mold (strawberries, tomatoes): gray mold on fruit

Prevention: crop rotation, mulching, watering at the base, choosing resistant varieties

Treatment: Bordeaux mixture (downy mildew), sulfur (powdery mildew), horsetail tea (strengthens plants)

Pests

Aphids (roses, broad beans, nasturtiums): leaf deformation, honeydew
Whiteflies (greenhouses, tomatoes): small white midges
Slugs and snails (all crops): holes in leaves
Caterpillars (cabbage, artichoke): defoliation
Colorado potato beetles (potatoes): eaten leaves
Flea beetles (radishes, cabbages): small holes in leaves
Ants (can protect aphids)

Prevention: companion planting, repellent plant teas, traps, physical barriers

Treatment: black soap, nettle tea, Bacillus thuringiensis (against caterpillars), beer traps (slugs)

Crop-specific problems

Each crop has its own enemies. Here are the most common ones in May:

Tomatoes: downy mildew, whiteflies, red spider mites (drought)
Squash: powdery mildew, slugs, whiteflies
Salads: slugs, aphids, downy mildew
Strawberries: gray mold, slugs, powdery mildew
Roses: aphids, powdery mildew, black spot
Potatoes: downy mildew, Colorado potato beetles
Beans: slugs, aphids

For integrated protection, combine preventive methods (rotation, choosing resistant varieties, companion planting) and curative methods (natural treatments, traps).

🌱 Propagation: cuttings and divisions in May

May is an ideal month to multiply your favorite plants by cuttings or division. Here are the techniques to master:

Herbaceous cuttings

Ideal for fast-growing, flexible plants.

Take semi-hardwood stems (neither too young nor too woody)
Cut into 10-15 cm sections with 2-3 nodes
Remove lower leaves
Plant in a mix of potting soil and sand
Keep moist but not waterlogged
Examples: geraniums, fuchsias, begonias, coleus, impatiens

High success rate if done in May-June

Hardwood stem cuttings

For shrubs and woody plants.

Take stems from the previous year
Cut into 15-20 cm sections
Dip the base in rooting hormone (optional)
Plant in a well-draining mix (sand + potting soil)
Examples: rose, buddleia, weigela, lavender, rosemary

Place under cover (tunnel, greenhouse) for sensitive cuttings

Clump division

Simple technique to multiply perennials.

Dig up the mother plant
Gently separate the divisions with a clean knife
Replant immediately
Water generously
Examples: hostas, heucheras, hardy geraniums, ferns, asters

Ideal for rejuvenating old clumps

Other propagation techniques

Layering (for plants with flexible stems): bury a stem without separating it from the mother plant
Grafting (for fruit trees): to be done in May for cleft or crown grafts
Sowing perennial seeds: some species germinate better after a cold period (stratification)

For perennial seeds, sow in trays under cover and keep cool until germination.

🌿 Ornamental garden: flowering and maintenance

In May, ornamental gardens are in full swing. Here's how to maintain your flower beds, rose bushes and other plantings for optimal flowering.

Rose bushes

Remove faded flowers to stimulate new blooming
Pinch young shoots to encourage branching
Treat preventively against powdery mildew and aphids
Add a potassium-rich fertilizer to strengthen flowering
Watch for black spot attacks

For climbing roses, guide the branches and tie them to the support.

Beds and borders

Weed regularly to avoid competition
Mulch with organic mulch (wood chips, straw)
Water deeply 2-3 times per week
Remove faded flowers to prolong blooming
Add ground cover plants to limit weeds

In May, it's time to plant annuals for summer beds (nasturtiums, cosmos, zinnias, dahlias).

Perennials and bulbs

Divide overly dense perennial clumps (daylilies, hostas, phlox)
Plant summer-flowering bulbs (dahlias, tuberous begonias, gladioli)
Cut back faded perennials to stimulate a second bloom
Add ground cover plants (periwinkle, yellow archangel, bugle)
Install climbing plants to cover walls and fences

Ornamental trees and shrubs

Prune spring-flowering shrubs (forsythia, weigela, deutzia) right after flowering
Pinch new shoots of foliage shrubs to thicken the branching
Treat preventively against scale insects and aphids
Add organic fertilizer at the base of trees and shrubs
Watch for attacks by defoliating caterpillars (pine processionary)

🍓 Vegetable garden in May: detailed calendar by crop

Each crop has its specificities in May. Here is a detailed guide to organizing your vegetable garden.

Tomatoes

Sowing: under heated cover from February-March, or directly in the ground after May 15
Planting: after May 15, when nights are mild (soil at 12°C minimum)
Pruning: remove suckers (side shoots) to promote fruiting
Staking: stake and tie the stems
Watering: regular but without excess, at the base of plants
Protection: mulching to retain moisture, frost fleece in case of frost
Diseases: watch for downy mildew (brown spots on leaves), treat preventively with Bordeaux mixture
Varieties to plant: 'Beefsteak', 'Marmande', 'Black Krim', 'Cherry'

Zucchini and squash

Sowing: under cover from April, or directly in the ground after May 15
Planting: after May 15, when the soil has warmed
Spacing: 1 m between each plant, 1.5 m between rows
Watering: generous but avoid wetting the foliage
Mulching: essential to retain moisture and limit weeds
Harvest: 2-3 months after sowing, when zucchinis measure 15-20 cm
Varieties: 'Ronde de Nice', 'Gold Rush', 'Butternut', 'Red Kuri squash'

Beans

Sowing: directly in the ground after May 15, when soil is at 12-15°C
Varieties: green beans (bush or pole), dried beans (flageolets, coco)
Spacing: 40 cm between rows, 10 cm between seeds
Watering: regular but moderate before flowering
Harvest: 2-3 months after sowing, when pods are well formed
Rotation: do not replant in the same spot for 3 years

Salads

Sowing: directly in the ground all year round, but May is ideal for summer varieties
Varieties: cutting lettuces (oak leaf), batavias, iceberg, romaine
Spacing: 25-30 cm between plants
Watering: regular to prevent bolting (premature flowering)
Mulching: to retain moisture and limit slugs
Harvest: 6-8 weeks after sowing
Diseases: watch for downy mildew and crown rot

🌳 Fruit garden: pruning, planting and maintenance

In May, the orchard enters an active growth phase. Here are the tasks to carry out for healthy and productive fruit trees.

Pruning fruit trees

Prune pome fruit trees (apple, pear) after flowering
Remove dead, diseased or poorly placed wood
Open up the center of the tree to promote fruiting
Avoid pruning cherry trees in May (disease risk)
For small fruits (currants, blackcurrants), remove branches older than 3 years

Planting fruit trees

Plant container fruit trees all year round, but May is ideal for bare-root specimens
Choose a sunny location sheltered from wind
Prepare a wide, deep hole enriched with compost
Dip roots in slurry before planting
Water abundantly after planting
Mulching: spread organic mulch at the base

Fruit crop maintenance

Here are the specific tasks for each type of fruit in May:

Strawberries: remove runners to promote fruiting, mulch with straw or ramial chipped wood
Raspberries: remove canes that fruited the previous year, stake new shoots
Currants and blackcurrants: remove old branches, treat against powdery mildew
Actinidia (kiwi): train new shoots, remove weak branches
Grapevine: remove suckers, train shoots, treat against downy mildew
Apple and pear: thin fruits if necessary to avoid overloading
Plum: watch for aphid attacks and brown rot (mummified fruits)

Orchard diseases and pests in May

Aphids (roses, apple, plum): spray with black soap or nettle tea
Codling moths (apple worms): place trap bands or pheromone traps
Brown rot (mummified fruits): remove and burn affected fruits
Scab (apple, pear): treat preventively with Bordeaux mixture
Powdery mildew (currants, blackcurrants): treat with sulfur
Scale insects (stone fruit trees): scrape bark or treat with white oil

🌱 Aromatic garden: growing and harvesting in May

Aromatic herbs are essential in the vegetable garden. In May, it's time to plant, multiply them and start the first harvests.

Planting aromatic herbs

Basil: plant after May 15, in full sun, rich and well-drained soil
Parsley: sow directly in the ground or plant in containers
Chives: divide clumps or plant in the ground
Tarragon: plant in light, well-drained soil
Thyme: plant in dry, sunny soil
Rosemary: plant in very well-drained soil, sunny exposure
Sage: plant in dry, sunny soil
Mint: plant in containers (it is invasive)
Lemon verbena: plant in pots or in the ground
Chervil: sow directly in the ground in partial shade

Propagating aromatic herbs

Take basil cuttings: take 10 cm stems, root them in water
Divide chives and tarragon in spring
Layer thyme and rosemary by burying a stem
Sowing: coriander, dill, chervil, parsley

Harvest and use

In May, you can start harvesting some aromatic herbs:

Chives: once leaves reach 15 cm
Parsley: young leaves for salads
Chervil: tender leaves for soups
Nettle: young shoots for soups or tea
Dandelion: leaves for salads (avoid treated areas)
Plantain: young leaves for salads
Borage: flowers to decorate dishes
Nasturtium: edible flowers and leaves

To preserve aromatic herbs, dry them in the shade, freeze them in ice cube trays with water or oil, or make flavored oils and vinegars.

🌿 Indoor garden and balconies: May in pots

Even in the city, May is favorable for planting in pots and containers. Here's how to maintain your indoor plants and beautify your balconies.

Indoor plants to bring out in May

Geraniums (pelargoniums): bring them in at night if temperatures drop below 10°C
Fuchsias: bring them in if there is frost
Tuberous begonias: plant in pots after May 15
Impatiens (balsams): plant in pots or window boxes
Coleus: plant in pots for its colorful leaves
Hibiscus: bring it in if there is frost
Lemon trees and other citrus: bring in if there is frost
Bougainvillea: bring in if there is frost

Potted plant care

Water regularly but without excess (let the surface dry between waterings)
Add liquid fertilizer every 2 weeks for flowering plants
Remove faded flowers to stimulate new blooming
Repot plants that have outgrown their pot (roots coming out of drainage holes)
Watch for attacks by aphids, whiteflies and red spider mites
Clean foliage with a damp cloth to remove dust

Arranging balconies and terraces

In May, it's time to beautify your outdoor spaces in the city:

Plant hardy annuals: petunias, surfinias, lobelias, bidens, lantanas
Install climbing plants: morning glories, thunbergias, cobaeas
Create compositions with aromatic herbs: basil, thyme, rosemary in pots
Add aromatic and medicinal plants: lavender, sage, verbena
Install hanging baskets with trailing plants: ivy, fuchsias, bacopas
Create shaded corners with plants like hostas or ferns
Add decorative elements: trellises, fountains, lanterns

For balconies exposed to wind, choose hardy plants and install windbreaks.

Common problems in pots

Yellowing leaves: excess water or lack of fertilizer
Falling leaves: sudden temperature change or lack of light
Mold on potting soil: excess moisture or lack of aeration
Aphids and whiteflies: treat with black soap or nettle tea
Red spider mites: spray water on foliage or use a natural acaricide
Slugs: place barriers of ashes or crushed eggshells

🌱 Lunar calendar: sowing and planting in May 2025

According to the lunar calendar, some days are more favorable than others for sowing and planting. Here are the key dates for May 2025 (UTC times):

Waxing Moon phase (root and leaf days)

May 1: leaf day (lettuces, spinach, chard)
May 2: root day (carrots, radishes, beets)
May 3: fruit day (beans, peas, strawberries)
May 4: flower day (ornamental plants)
May 5: leaf day (cabbages, salads)
May 6: root day (turnips, parsnips, celeriac)
May 7: fruit day (tomatoes, zucchini, eggplants)
May 8: flower day (rose bushes, flowering plants)
May 9: leaf day (spinach, chard)
May 10: root day (potatoes, Jerusalem artichokes)
May 11: fruit day (beans, peas, cucumbers)
May 12: flower day (ornamental plants)
May 13: leaf day (salads, cabbages)
May 14: root day (carrots, radishes)

Waning Moon phase (fruit and flower days)

May 15: fruit day (tomatoes, squash, melons)
May 16: flower day (rose bushes, flowering plants)
May 17: leaf day (lettuces, spinach)
May 18: root day (potatoes, beets)
May 19: fruit day (beans, peas)
May 20: flower day (ornamental plants)
May 21: leaf day (chard, Swiss chard)
May 22: root day (carrots, radishes)
May 23: fruit day (eggplants, peppers)
May 24: flower day (rose bushes, flowering plants)
May 25: leaf day (salads, cabbages)
May 26: root day (turnips, parsnips)
May 27: fruit day (cucumbers, zucchini)
May 28: flower day (ornamental plants)
May 29: leaf day (spinach, chard)
May 30: root day (potatoes)
May 31: fruit day (beans, peas)

These indications should be adapted according to your region and weather conditions. The lunar calendar is a complementary tool, not an absolute rule.

🛒 Where to buy plants, seeds and tools in May?

In May, garden centers and nurseries are overflowing with plants, seeds and tools. Here is where to find the best materials for your garden.

Organic seeds and plants

Kokopelli (organic and reproducible seeds)
La Bonne Graine (heirloom and organic seeds)
Biau Germe (organic and reproducible seeds)
Ferme de Sainte-Marthe (organic seeds)
Semaille (organic and reproducible seeds)
Online garden centers: Truffaut, Jardiland, Botanic

Plants and young plants

Local nurseries (for plants adapted to your region)
Garden centers: Truffaut, Jardiland, Botanic, Gamm Vert
Plant markets (organized by municipalities)
Producer groups (AMAP, short supply chains)
Online nurseries: Promesse de Fleurs, Bakker, Bakker France

Tools and equipment

Hand tools: trowels, rakes, hoes, pruning shears
Watering: watering cans, hoses, watering timers
Mulching: straw, ramial chipped wood, wood chips, mulch fabric
Protection: frost fleeces, tunnels, cloches
Stakes and supports: bamboo stakes, trellises, netting
Compost and fertilizers: mature compost, organic fertilizers, plant teas
Propagation materials: seed trays, cutting compost, hormones

For tools, prioritize quality and durability. Stainless steel or untreated wood tools should be preferred.

Rare and specific plants

Mediterranean plants: lavender, rosemary, rockroses (specialized nurseries)
Exotic plants: banana trees, cannas (tropical nurseries)
Rare climbing plants: clematis, trumpet vines, passion flowers (specialized nurseries)
Heirloom fruit trees: apple, pear, plum (fruit tree nurseries)
Rare perennials: hostas, heucheras, ferns (specialized nurseries)

For rare plants, consult specialized online nurseries or participate in plant swaps.

📅 Monthly checklist: summary of tasks to do in May

Here is a quick checklist so you don't forget anything in May. Print it out or save it to your phone!

Direct sowing: beans, zucchini, cucumbers, melons, sunflowers, nasturtiums, cosmos
Sowing under cover: tomatoes, eggplants, peppers, basil
Planting: tomatoes, zucchini, eggplants, peppers, basil, dahlias, tuberous begonias
Maintenance: mulching, watering, hoeing, weeding, removing suckers (tomatoes)
Protection: frost fleeces in case of frost, preventive treatments against diseases
Harvest: radishes, early carrots, turnips, spinach, salads, aromatic herbs
Propagation: herbaceous cuttings, perennial division, layering
Orchard: pruning after flowering, disease treatment, planting fruit trees
Ornamental garden: planting annuals, bed maintenance, perennial division
Balconies and terraces: planting flowering plants, arranging spaces
Watering: installing drip irrigation systems, mulching crops
Order: seeds for autumn and next spring

Adapt this list according to your region, your climate and the current weather. May is a variable month, be flexible!

💡 Expert tips for a successful garden in May

Here is advice from experienced gardeners to get the most out of your garden in May:

Optimize space

Use companion planting techniques: plant aromatic herbs between vegetables to repel pests
Set up vertical growing: pole beans, peas, cucurbits on trellises
Sow green manures in empty spaces to enrich the soil
Use pots and containers to grow on balconies, terraces and even in pathways
Prefer dwarf or compact varieties for small spaces

Manage water intelligently

Install rainwater collectors for watering
Use drip irrigation systems for demanding crops
Thick mulch (10 cm) to retain moisture and limit weeds
Water early morning or late evening to avoid evaporation
Avoid standing water which promotes root diseases
Check soil moisture with the finger test: soil should be cool deep down

Prevent rather than cure

Crop rotation: don't plant the same family in the same spot two years in a row
Choose resistant varieties: prefer tomatoes resistant to downy mildew, squash resistant to powdery mildew
Companion planting: basil with tomatoes, nasturtiums with squash, French marigolds with carrots
Plant teas and decoctions: nettle tea (fertilizer), horsetail tea (strengthens plants), tansy decoction (anti-downy mildew)
Regular monitoring: inspect your plants every 2-3 days to detect problems early

Prepare for summer

Prepare your crops for summer: mulch abundantly, install light shade for salads
Plant drought-resistant plants: lavender, rosemary, agaves, sedums
Set up water points for pollinators: small ponds, water dishes
Plan shelters for sensitive plants in case of heatwave: shade cloths, shaded tunnels
Plan your harvests: stagger sowings to have harvests spread out over time

In summary: May, the month of action in the garden!

May is a pivotal month when the gardener moves from preparation to action. It's time to sow, plant, maintain and protect your crops for abundant harvests and a flowering garden all summer long.

By following this complete guide, you will optimize your time, avoid common mistakes and fully enjoy the season. Don't forget: a successful garden starts right now!

Warning: in May, late frosts are still possible in some regions. Monitor weather forecasts and protect your sensitive plants if needed.

Official ecological gardening website
Gardening resources and advice
Online garden centers