Garden Guide

Garden Guide for Helsinki, Southern Finland

Helsinki is located in Hardiness Zone 6b and benefits from its proximity to the Baltic Sea, which leads to milder winters and cooler summers. The last frost typically occurs in late April, and the first in late October. Soils can vary but are often loamy-sandy and benefit from the addition of humus.

In Helsinki (Hardiness Zone 6b), you can start sowing after the last frost in late April. Cold-hardy plants like radishes (sow April to September) and lettuce (sow April to September) thrive here. Heat-loving crops such as tomatoes (start indoors April to May) and pumpkins (start indoors May to July) require starting indoors and protection from late frosts.

Zone 6b Last frost: Late April First frost: Late October Humid continental

Also applies to: Espoo, Vantaa, Porvoo, Hyvinkää, Lohja, Kotka

Plan your Helsinki garden in the Fryd app

Planting Calendar

When to start indoors, sow outdoors, and harvest in Helsinki.

Light Water Nutrients

Start indoors Sowing Harvest

Planting calendar for Helsinki, Zone 6b
Crop	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Carrots ●●● ●●○ ●○○
Lettuce (Lettuce) ●●○ ●●○ ●●○
Cucumber / Gherkin ●●● ●●○ ●●●
Courgette / Zucchini ●●● ●●● ●●●
Pepper / Paprika ●●● ●●○ ●●●
Potato ●●● ●●○ ●●●
Radishes ●●● ●●○ ●○○
Tomato (Bush tomato) ●●● ●●○ ●●●
Tomato (Cocktail bush tomato) ●●● ●●○ ●●●
Onion ●●● ●●○ ●●○
Bean (Dwarf bean) ●●● ●●○ ●○○
Pea ●●● ●●○ ●○○
Basil ●●● ●●○ ●●●
Beetroot ●●● ●●○ ●●○
Strawberry ●●● ●●○ ●●●
Kohlrabi / German turnip / Turnip cabbage ●●● ●●○ ●●○
Garlic ●●● ●●○ ●○○
Pumpkin / Squash ●●● ●●● ●●●
Broccoli ●●● ●●● ●●●
Chard ●●○ ●●○ ●●○

Carrots ●●● ●●○ ●○○

Lettuce (Lettuce) ●●○ ●●○ ●●○

Cucumber / Gherkin ●●● ●●○ ●●●

Courgette / Zucchini ●●● ●●● ●●●

Pepper / Paprika ●●● ●●○ ●●●

Potato ●●● ●●○ ●●●

Radishes ●●● ●●○ ●○○

Tomato (Bush tomato) ●●● ●●○ ●●●

Tomato (Cocktail bush tomato) ●●● ●●○ ●●●

Onion ●●● ●●○ ●●○

Bean (Dwarf bean) ●●● ●●○ ●○○

Pea ●●● ●●○ ●○○

Basil ●●● ●●○ ●●●

Beetroot ●●● ●●○ ●●○

Strawberry ●●● ●●○ ●●●

Kohlrabi / German turnip / Turnip cabbage ●●● ●●○ ●●○

Garlic ●●● ●●○ ●○○

Pumpkin / Squash ●●● ●●● ●●●

Broccoli ●●● ●●● ●●●

Chard ●●○ ●●○ ●●○

Planting Calendar Helsinki

Carrots: Sowing Apr - Jun, Harvest Aug - Oct (Light: high, Water: medium, Nutrients: low)
Lettuce (Lettuce): Start indoors Mar - Oct, Sowing Apr - Sep, Harvest May - Oct (Light: medium, Water: medium, Nutrients: medium)
Cucumber / Gherkin: Start indoors May - Jul, Sowing Jun - Jul, Harvest Jul - Sep (Light: high, Water: medium, Nutrients: high)
Courgette / Zucchini: Start indoors May - Jul, Sowing Jun - Jul, Harvest Aug - Oct (Light: high, Water: high, Nutrients: high)
Pepper / Paprika: Start indoors Feb - Mar, Sowing May - Jun, Harvest Jul - Oct (Light: high, Water: medium, Nutrients: high)
Potato: Start indoors Mar, Sowing Mar - Jun, Harvest Jun - Oct (Light: high, Water: medium, Nutrients: high)
Radishes: Sowing Apr - Sep, Harvest Jun - Oct (Light: high, Water: medium, Nutrients: low)
Tomato (Bush tomato): Start indoors Apr - May, Sowing Jun - Jul, Harvest Aug - Oct (Light: high, Water: medium, Nutrients: high)
Tomato (Cocktail bush tomato): Start indoors Apr - May, Sowing Jun - Jul, Harvest Aug - Oct (Light: high, Water: medium, Nutrients: high)
Onion: Start indoors Feb - Apr, Sowing Apr - May, Harvest Aug - Sep (Light: high, Water: medium, Nutrients: medium)
Bean (Dwarf bean): Start indoors May - Jun, Sowing Jun - Aug, Harvest Aug - Sep (Light: high, Water: medium, Nutrients: low)
Pea: Sowing Apr - Jul, Harvest Jun - Oct (Light: high, Water: medium, Nutrients: low)
Basil: Start indoors Apr - Aug, Sowing Jun - Aug, Harvest Jun - Oct (Light: high, Water: medium, Nutrients: high)
Beetroot: Start indoors Mar - Apr, Sowing Apr - Jul, Harvest Jul - Oct (Light: high, Water: medium, Nutrients: medium)
Strawberry: Start indoors Mar - Jun, Sowing Apr - Jul, Harvest Jun - Sep (Light: high, Water: medium, Nutrients: high)
Kohlrabi / German turnip / Turnip cabbage: Start indoors Apr - Jun, Sowing May - Jul, Harvest Jul - Oct (Light: high, Water: medium, Nutrients: medium)
Garlic: Sowing Sep - Nov, Harvest Jun - Aug (Light: high, Water: medium, Nutrients: low)
Pumpkin / Squash: Start indoors May - Jul, Sowing Jun - Jul, Harvest Sep - Oct (Light: high, Water: high, Nutrients: high)
Broccoli: Start indoors Mar - May, Sowing Jun - Jul, Harvest Aug - Oct (Light: high, Water: high, Nutrients: high)
Chard: Start indoors Mar - May, Sowing May - Jul, Harvest Jun - Oct (Light: medium, Water: medium, Nutrients: medium)

Based on Fryd planting data for Zone 6b, 2026.

Companion Planting for Helsinki

Plants that thrive together in Southern Finland.

Lettuce (Lettuce) + Carrots

Chard + Carrots

Lettuce (Lettuce) + Radishes

Onion + Cucumber / Gherkin

Garlic + Cucumber / Gherkin

Plan companions visually

Drag and drop crops in the Fryd bed planner to see companion matches.

Try Fryd →

Growing Tips for Helsinki

Get a Head Start by Starting Seeds Indoors

Many crops like lettuce (start indoors March to October), Swiss chard (start indoors March to May), and tomatoes (start indoors April to May) benefit from an early start indoors. This extends the growing season and protects young plants from Helsinki's cool spring temperatures.

Pay Attention to Your Soil

Most vegetables, such as carrots and onions, prefer loose, humus-rich, and well-draining soil. Regularly improve your garden soil with compost to optimize its structure and nutrient supply and prevent waterlogging.

Consistent Moisture is Key

Plants like radishes and broccoli need a consistent water supply to grow optimally and develop good quality. Avoid both drought and waterlogging to prevent woody texture or diseases.

Choose the Right Location

Most vegetables, especially heat-loving ones like tomatoes and peppers, need a sunny and sheltered spot. Make sure your plants receive at least 6 hours of direct sunlight per day to achieve abundant harvests.

Common Pests & Diseases

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Tackling Slugs

Slugs are often a problem in humid climates like Helsinki, especially for young lettuce and cabbage plants. Regularly hand-pick them, install slug fences, or use organic slug pellets to protect your plants.

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Keeping Aphids in Check

Aphids can infest many plants, including beans and Swiss chard. Spray affected plants with a soapy solution or introduce beneficial insects like ladybug larvae. A healthy plant is more resistant to pest infestations.

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Preventing Powdery Mildew

Powdery mildew can appear on cucumbers and pumpkins, especially in high humidity. Ensure good air circulation between plants and always water the root area, not the leaves. If infected, milk-water mixtures can help.

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Deterring Carrot Rust Fly

The carrot rust fly can damage carrots. Protect your carrot beds with a fine insect netting installed immediately after sowing. Companion planting with onions can also help, as their scent confuses the flies.

Frequently Asked Questions

When can I plant tomatoes in Helsinki?

You should start tomato seeds indoors in Helsinki from April to May. Transplant young plants outdoors only after the risk of frost has passed, typically late May to early June. Protect them from cool nights initially.

What Hardiness Zone is Helsinki, and what does that mean for my garden?

Helsinki is in Hardiness Zone 6b. This means you can grow a good variety of cold-hardy vegetables and fruits. However, heat-loving plants will require starting indoors and possibly protection from late frosts to be successful.

Which vegetables grow best in Helsinki?

Cold-hardy crops like lettuce, radishes, Swiss chard, carrots, peas, and various cabbage varieties such as kohlrabi and broccoli thrive particularly well in Helsinki. Potatoes and onions are also great choices for your garden.

When is the last frost in Helsinki?

The last frost in Helsinki is typically expected in late April. It's advisable to plant frost-sensitive plants outdoors only after this date to avoid damage and ensure safe growth.