How to Grow Nasturtiums UK
On this page
- Nasturtium (Tropaeolum majus)
- When to Plant Nasturtiums in the UK
- Quick Facts
- At a Glance
- Soil & Growing Conditions
- Growth Stages
- Harvest & Storage
- Diseases
- Pests
- Nasturtium, an Edible Flower with a Peppery Bite
- Plan your Nasturtiums planting
- Growing Nasturtium in another region
- References
- Frequently Asked Questions
In the UK, nasturtiums go in the ground early March to late May.
Timing is the decision that matters most in the UK: sowing early March, and that same window applies across all 4 regions covered here.
The short answer
- Plant
- Early March to late May
- Site
- 6+ hours of sun, soil pH 6–7
- Biggest risk
- Southern bacterial wilt
Core growing advice on this page is checked against named horticultural sources — see References.
Nasturtium (Tropaeolum majus)
8 sources cited · Verified
When to Plant Nasturtiums in the UK
When to plant nasturtiums in the UK: in Southern England, sow early March to late May. Find your area in the table below.
Quick Facts
At a Glance
Soil & Growing Conditions
Growth Stages
Harvest & Storage
Diseases
Pests
Nasturtium, an Edible Flower with a Peppery Bite
Plan your Nasturtiums planting
When to sow and plant Nasturtiums depends on your own frost dates. Check the UK vegetable planting calendar. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.
Growing Nasturtium in another region
Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.
References
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Seeds have a hard outer coating; soaking 8-24 hours before sowing speeds germination. Sow indoors in early spring, or outdoors March to June, ideally after last frost once soil has warmed, seeds about 1.5cm/half-inch deep. Space 15-30cm apart depending on variety, thinning to final spacing once large enough to handle.
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RHS explicitly does not recommend pesticide use against aphids; recommends tolerance, manual squashing, and encouraging/purchasing natural predators (ladybirds, hoverflies, lacewings, parasitoid wasps, earwigs) as biological control, especially under glass.
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RHS factsheet on glasshouse red spider mite (two-spotted spider mite), naming tomato and strawberry among the host plants affected under glass or in a polytunnel.
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RHS explicitly distinguishes yellow sticky traps as a monitoring tool rather than a standalone control method, and notes traps also catch non-target parasitoid wasps -- a genuine trade-off between two control methods, preserved rather than simplified. No specific pesticide/insecticidal soap product is named on this page (RHS links out to a general pesticides statement instead), so none is recorded here.
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RHS explicitly advises against slug pellets (even organic) due to wildlife harm, and cites RHS's own controlled trial finding no damage reduction from physical barriers (copper tape, bark mulch, eggshell, grit, wool) -- while also noting some other studies have shown copper barriers to repel slugs, a preserved disagreement rather than a silently resolved one. Details Nemaslug (Phasmarhabditis hermaphrodita) biological control including application temperature range and its lack of effect on snails specifically.
8 independent sources are cited for this crop. Where they disagree - soil pH is the clearest case - every figure is preserved rather than averaged into false precision.
Frequently Asked Questions
When should I sow nasturtiums in the UK?
In Southern England, from early March. In Scotland, wait until early March. Treat these as a guide rather than a fixed date — the governing rule is to sow only once frost risk has passed and temperatures are reliably warm enough.
When do I sow nasturtiums?
Sow early March to late May.
What soil pH do nasturtiums need?
A pH of about 6–7. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.
What problems affect nasturtiums?
Our data links 2 diseases and 7 pests to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
Most of the advice on this page comes down to timing and spacing — sowing at the right moment, rotating beds, and giving plants enough airflow. The UK Garden Planner lays your plot out month by month so those decisions are already made before the season starts.
Get the UK Garden Planner →Instant PDF download · Written for UK growing conditions
How this guide is put together
The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against RHS and Met Office guidance. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.
Related Problem Guides
Last verified 2026-08-30
Plan Nasturtiums by month
The months this guide gives for sowing or planting, each with the full list of jobs for that month in the UK:
More from the same group (herbs & aromatics):
Growing advice for your part of the UK
Timing and conditions change a lot inside one country. These guides cover frost dates and growing seasons region by region.
Where To Go From Here
Take this crop from reading into a written plan for your own beds.
Keep going
Plan the next step
Use the printable SoilCommander planner for your region to turn this guide into sowing dates, bed layouts and weekly garden tasks.